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linux/drivers/net/tile/tilepro.c
Chris Metcalf d91c641233 tile on-chip network driver: sync up with latest fixes 
Combine the "command" and "completion" locks into a single lock,
on each egress queue, to improve efficiency.

Support the use of 4KB pages in the "egress queue".

Delete the unused "duplicate ACK compression" code.

Filter "bad" (i.e. truncated) packets.

Avoid corrupting "dev->napi_list", by sequentializing modifications.

Deregister for incoming packets during stop, to reduce unexpected
interrupts.  Also, encourage active NAPI loops to complete before
we disable NAPI, which would otherwise crash.

Free any pending completions after shutting down LEPP.

Use a single, permanently registered, IRQ handler, to avoid situations
in which the IRQ handler was firing after being freed, and ignore any
"unexpected" interrupts.

Drop egress packets, instead of spinning, if the hardware cannot keep
up, or is disconnected.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-10 13:18:12 -05:00

2467 lines
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/*
* Copyright 2011 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/kernel.h> /* printk() */
#include <linux/slab.h> /* kmalloc() */
#include <linux/errno.h> /* error codes */
#include <linux/types.h> /* size_t */
#include <linux/interrupt.h>
#include <linux/in.h>
#include <linux/netdevice.h> /* struct device, and other headers */
#include <linux/etherdevice.h> /* eth_type_trans */
#include <linux/skbuff.h>
#include <linux/ioctl.h>
#include <linux/cdev.h>
#include <linux/hugetlb.h>
#include <linux/in6.h>
#include <linux/timer.h>
#include <linux/io.h>
#include <asm/checksum.h>
#include <asm/homecache.h>
#include <hv/drv_xgbe_intf.h>
#include <hv/drv_xgbe_impl.h>
#include <hv/hypervisor.h>
#include <hv/netio_intf.h>
/* For TSO */
#include <linux/ip.h>
#include <linux/tcp.h>
/*
* First, "tile_net_init_module()" initializes all four "devices" which
* can be used by linux.
*
* Then, "ifconfig DEVICE up" calls "tile_net_open()", which analyzes
* the network cpus, then uses "tile_net_open_aux()" to initialize
* LIPP/LEPP, and then uses "tile_net_open_inner()" to register all
* the tiles, provide buffers to LIPP, allow ingress to start, and
* turn on hypervisor interrupt handling (and NAPI) on all tiles.
*
* If registration fails due to the link being down, then "retry_work"
* is used to keep calling "tile_net_open_inner()" until it succeeds.
*
* If "ifconfig DEVICE down" is called, it uses "tile_net_stop()" to
* stop egress, drain the LIPP buffers, unregister all the tiles, stop
* LIPP/LEPP, and wipe the LEPP queue.
*
* We start out with the ingress interrupt enabled on each CPU. When
* this interrupt fires, we disable it, and call "napi_schedule()".
* This will cause "tile_net_poll()" to be called, which will pull
* packets from the netio queue, filtering them out, or passing them
* to "netif_receive_skb()". If our budget is exhausted, we will
* return, knowing we will be called again later. Otherwise, we
* reenable the ingress interrupt, and call "napi_complete()".
*
* HACK: Since disabling the ingress interrupt is not reliable, we
* ignore the interrupt if the global "active" flag is false.
*
*
* NOTE: The use of "native_driver" ensures that EPP exists, and that
* we are using "LIPP" and "LEPP".
*
* NOTE: Failing to free completions for an arbitrarily long time
* (which is defined to be illegal) does in fact cause bizarre
* problems. The "egress_timer" helps prevent this from happening.
*/
/* HACK: Allow use of "jumbo" packets. */
/* This should be 1500 if "jumbo" is not set in LIPP. */
/* This should be at most 10226 (10240 - 14) if "jumbo" is set in LIPP. */
/* ISSUE: This has not been thoroughly tested (except at 1500). */
#define TILE_NET_MTU 1500
/* HACK: Define to support GSO. */
/* ISSUE: This may actually hurt performance of the TCP blaster. */
/* #define TILE_NET_GSO */
/* Define this to collapse "duplicate" acks. */
/* #define IGNORE_DUP_ACKS */
/* HACK: Define this to verify incoming packets. */
/* #define TILE_NET_VERIFY_INGRESS */
/* Use 3000 to enable the Linux Traffic Control (QoS) layer, else 0. */
#define TILE_NET_TX_QUEUE_LEN 0
/* Define to dump packets (prints out the whole packet on tx and rx). */
/* #define TILE_NET_DUMP_PACKETS */
/* Define to enable debug spew (all PDEBUG's are enabled). */
/* #define TILE_NET_DEBUG */
/* Define to activate paranoia checks. */
/* #define TILE_NET_PARANOIA */
/* Default transmit lockup timeout period, in jiffies. */
#define TILE_NET_TIMEOUT (5 * HZ)
/* Default retry interval for bringing up the NetIO interface, in jiffies. */
#define TILE_NET_RETRY_INTERVAL (5 * HZ)
/* Number of ports (xgbe0, xgbe1, gbe0, gbe1). */
#define TILE_NET_DEVS 4
/* Paranoia. */
#if NET_IP_ALIGN != LIPP_PACKET_PADDING
#error "NET_IP_ALIGN must match LIPP_PACKET_PADDING."
#endif
/* Debug print. */
#ifdef TILE_NET_DEBUG
#define PDEBUG(fmt, args...) net_printk(fmt, ## args)
#else
#define PDEBUG(fmt, args...)
#endif
MODULE_AUTHOR("Tilera");
MODULE_LICENSE("GPL");
/*
* Queue of incoming packets for a specific cpu and device.
*
* Includes a pointer to the "system" data, and the actual "user" data.
*/
struct tile_netio_queue {
netio_queue_impl_t *__system_part;
netio_queue_user_impl_t __user_part;
};
/*
* Statistics counters for a specific cpu and device.
*/
struct tile_net_stats_t {
u32 rx_packets;
u32 rx_bytes;
u32 tx_packets;
u32 tx_bytes;
};
/*
* Info for a specific cpu and device.
*
* ISSUE: There is a "dev" pointer in "napi" as well.
*/
struct tile_net_cpu {
/* The NAPI struct. */
struct napi_struct napi;
/* Packet queue. */
struct tile_netio_queue queue;
/* Statistics. */
struct tile_net_stats_t stats;
/* True iff NAPI is enabled. */
bool napi_enabled;
/* True if this tile has succcessfully registered with the IPP. */
bool registered;
/* True if the link was down last time we tried to register. */
bool link_down;
/* True if "egress_timer" is scheduled. */
bool egress_timer_scheduled;
/* Number of small sk_buffs which must still be provided. */
unsigned int num_needed_small_buffers;
/* Number of large sk_buffs which must still be provided. */
unsigned int num_needed_large_buffers;
/* A timer for handling egress completions. */
struct timer_list egress_timer;
};
/*
* Info for a specific device.
*/
struct tile_net_priv {
/* Our network device. */
struct net_device *dev;
/* Pages making up the egress queue. */
struct page *eq_pages;
/* Address of the actual egress queue. */
lepp_queue_t *eq;
/* Protects "eq". */
spinlock_t eq_lock;
/* The hypervisor handle for this interface. */
int hv_devhdl;
/* The intr bit mask that IDs this device. */
u32 intr_id;
/* True iff "tile_net_open_aux()" has succeeded. */
bool partly_opened;
/* True iff the device is "active". */
bool active;
/* Effective network cpus. */
struct cpumask network_cpus_map;
/* Number of network cpus. */
int network_cpus_count;
/* Credits per network cpu. */
int network_cpus_credits;
/* Network stats. */
struct net_device_stats stats;
/* For NetIO bringup retries. */
struct delayed_work retry_work;
/* Quick access to per cpu data. */
struct tile_net_cpu *cpu[NR_CPUS];
};
/* Log2 of the number of small pages needed for the egress queue. */
#define EQ_ORDER get_order(sizeof(lepp_queue_t))
/* Size of the egress queue's pages. */
#define EQ_SIZE (1 << (PAGE_SHIFT + EQ_ORDER))
/*
* The actual devices (xgbe0, xgbe1, gbe0, gbe1).
*/
static struct net_device *tile_net_devs[TILE_NET_DEVS];
/*
* The "tile_net_cpu" structures for each device.
*/
static DEFINE_PER_CPU(struct tile_net_cpu, hv_xgbe0);
static DEFINE_PER_CPU(struct tile_net_cpu, hv_xgbe1);
static DEFINE_PER_CPU(struct tile_net_cpu, hv_gbe0);
static DEFINE_PER_CPU(struct tile_net_cpu, hv_gbe1);
/*
* True if "network_cpus" was specified.
*/
static bool network_cpus_used;
/*
* The actual cpus in "network_cpus".
*/
static struct cpumask network_cpus_map;
#ifdef TILE_NET_DEBUG
/*
* printk with extra stuff.
*
* We print the CPU we're running in brackets.
*/
static void net_printk(char *fmt, ...)
{
int i;
int len;
va_list args;
static char buf[256];
len = sprintf(buf, "tile_net[%2.2d]: ", smp_processor_id());
va_start(args, fmt);
i = vscnprintf(buf + len, sizeof(buf) - len - 1, fmt, args);
va_end(args);
buf[255] = '\0';
pr_notice(buf);
}
#endif
#ifdef TILE_NET_DUMP_PACKETS
/*
* Dump a packet.
*/
static void dump_packet(unsigned char *data, unsigned long length, char *s)
{
int my_cpu = smp_processor_id();
unsigned long i;
char buf[128];
static unsigned int count;
pr_info("dump_packet(data %p, length 0x%lx s %s count 0x%x)\n",
data, length, s, count++);
pr_info("\n");
for (i = 0; i < length; i++) {
if ((i & 0xf) == 0)
sprintf(buf, "[%02d] %8.8lx:", my_cpu, i);
sprintf(buf + strlen(buf), " %2.2x", data[i]);
if ((i & 0xf) == 0xf || i == length - 1) {
strcat(buf, "\n");
pr_info("%s", buf);
}
}
}
#endif
/*
* Provide support for the __netio_fastio1() swint
* (see <hv/drv_xgbe_intf.h> for how it is used).
*
* The fastio swint2 call may clobber all the caller-saved registers.
* It rarely clobbers memory, but we allow for the possibility in
* the signature just to be on the safe side.
*
* Also, gcc doesn't seem to allow an input operand to be
* clobbered, so we fake it with dummy outputs.
*
* This function can't be static because of the way it is declared
* in the netio header.
*/
inline int __netio_fastio1(u32 fastio_index, u32 arg0)
{
long result, clobber_r1, clobber_r10;
asm volatile("swint2"
: "=R00" (result),
"=R01" (clobber_r1), "=R10" (clobber_r10)
: "R10" (fastio_index), "R01" (arg0)
: "memory", "r2", "r3", "r4",
"r5", "r6", "r7", "r8", "r9",
"r11", "r12", "r13", "r14",
"r15", "r16", "r17", "r18", "r19",
"r20", "r21", "r22", "r23", "r24",
"r25", "r26", "r27", "r28", "r29");
return result;
}
/*
* Provide a linux buffer to LIPP.
*/
static void tile_net_provide_linux_buffer(struct tile_net_cpu *info,
void *va, bool small)
{
struct tile_netio_queue *queue = &info->queue;
/* Convert "va" and "small" to "linux_buffer_t". */
unsigned int buffer = ((unsigned int)(__pa(va) >> 7) << 1) + small;
__netio_fastio_free_buffer(queue->__user_part.__fastio_index, buffer);
}
/*
* Provide a linux buffer for LIPP.
*
* Note that the ACTUAL allocation for each buffer is a "struct sk_buff",
* plus a chunk of memory that includes not only the requested bytes, but
* also NET_SKB_PAD bytes of initial padding, and a "struct skb_shared_info".
*
* Note that "struct skb_shared_info" is 88 bytes with 64K pages and
* 268 bytes with 4K pages (since the frags[] array needs 18 entries).
*
* Without jumbo packets, the maximum packet size will be 1536 bytes,
* and we use 2 bytes (NET_IP_ALIGN) of padding. ISSUE: If we told
* the hardware to clip at 1518 bytes instead of 1536 bytes, then we
* could save an entire cache line, but in practice, we don't need it.
*
* Since CPAs are 38 bits, and we can only encode the high 31 bits in
* a "linux_buffer_t", the low 7 bits must be zero, and thus, we must
* align the actual "va" mod 128.
*
* We assume that the underlying "head" will be aligned mod 64. Note
* that in practice, we have seen "head" NOT aligned mod 128 even when
* using 2048 byte allocations, which is surprising.
*
* If "head" WAS always aligned mod 128, we could change LIPP to
* assume that the low SIX bits are zero, and the 7th bit is one, that
* is, align the actual "va" mod 128 plus 64, which would be "free".
*
* For now, the actual "head" pointer points at NET_SKB_PAD bytes of
* padding, plus 28 or 92 bytes of extra padding, plus the sk_buff
* pointer, plus the NET_IP_ALIGN padding, plus 126 or 1536 bytes for
* the actual packet, plus 62 bytes of empty padding, plus some
* padding and the "struct skb_shared_info".
*
* With 64K pages, a large buffer thus needs 32+92+4+2+1536+62+88
* bytes, or 1816 bytes, which fits comfortably into 2048 bytes.
*
* With 64K pages, a small buffer thus needs 32+92+4+2+126+88
* bytes, or 344 bytes, which means we are wasting 64+ bytes, and
* could presumably increase the size of small buffers.
*
* With 4K pages, a large buffer thus needs 32+92+4+2+1536+62+268
* bytes, or 1996 bytes, which fits comfortably into 2048 bytes.
*
* With 4K pages, a small buffer thus needs 32+92+4+2+126+268
* bytes, or 524 bytes, which is annoyingly wasteful.
*
* Maybe we should increase LIPP_SMALL_PACKET_SIZE to 192?
*
* ISSUE: Maybe we should increase "NET_SKB_PAD" to 64?
*/
static bool tile_net_provide_needed_buffer(struct tile_net_cpu *info,
bool small)
{
#if TILE_NET_MTU <= 1536
/* Without "jumbo", 2 + 1536 should be sufficient. */
unsigned int large_size = NET_IP_ALIGN + 1536;
#else
/* ISSUE: This has not been tested. */
unsigned int large_size = NET_IP_ALIGN + TILE_NET_MTU + 100;
#endif
/* Avoid "false sharing" with last cache line. */
/* ISSUE: This is already done by "dev_alloc_skb()". */
unsigned int len =
(((small ? LIPP_SMALL_PACKET_SIZE : large_size) +
CHIP_L2_LINE_SIZE() - 1) & -CHIP_L2_LINE_SIZE());
unsigned int padding = 128 - NET_SKB_PAD;
unsigned int align;
struct sk_buff *skb;
void *va;
struct sk_buff **skb_ptr;
/* Request 96 extra bytes for alignment purposes. */
skb = dev_alloc_skb(len + padding);
if (skb == NULL)
return false;
/* Skip 32 or 96 bytes to align "data" mod 128. */
align = -(long)skb->data & (128 - 1);
BUG_ON(align > padding);
skb_reserve(skb, align);
/* This address is given to IPP. */
va = skb->data;
/* Buffers must not span a huge page. */
BUG_ON(((((long)va & ~HPAGE_MASK) + len) & HPAGE_MASK) != 0);
#ifdef TILE_NET_PARANOIA
#if CHIP_HAS_CBOX_HOME_MAP()
if (hash_default) {
HV_PTE pte = *virt_to_pte(current->mm, (unsigned long)va);
if (hv_pte_get_mode(pte) != HV_PTE_MODE_CACHE_HASH_L3)
panic("Non-HFH ingress buffer! VA=%p Mode=%d PTE=%llx",
va, hv_pte_get_mode(pte), hv_pte_val(pte));
}
#endif
#endif
/* Invalidate the packet buffer. */
if (!hash_default)
__inv_buffer(va, len);
/* Skip two bytes to satisfy LIPP assumptions. */
/* Note that this aligns IP on a 16 byte boundary. */
/* ISSUE: Do this when the packet arrives? */
skb_reserve(skb, NET_IP_ALIGN);
/* Save a back-pointer to 'skb'. */
skb_ptr = va - sizeof(*skb_ptr);
*skb_ptr = skb;
/* Make sure "skb_ptr" has been flushed. */
__insn_mf();
/* Provide the new buffer. */
tile_net_provide_linux_buffer(info, va, small);
return true;
}
/*
* Provide linux buffers for LIPP.
*/
static void tile_net_provide_needed_buffers(struct tile_net_cpu *info)
{
while (info->num_needed_small_buffers != 0) {
if (!tile_net_provide_needed_buffer(info, true))
goto oops;
info->num_needed_small_buffers--;
}
while (info->num_needed_large_buffers != 0) {
if (!tile_net_provide_needed_buffer(info, false))
goto oops;
info->num_needed_large_buffers--;
}
return;
oops:
/* Add a description to the page allocation failure dump. */
pr_notice("Could not provide a linux buffer to LIPP.\n");
}
/*
* Grab some LEPP completions, and store them in "comps", of size
* "comps_size", and return the number of completions which were
* stored, so the caller can free them.
*/
static unsigned int tile_net_lepp_grab_comps(lepp_queue_t *eq,
struct sk_buff *comps[],
unsigned int comps_size,
unsigned int min_size)
{
unsigned int n = 0;
unsigned int comp_head = eq->comp_head;
unsigned int comp_busy = eq->comp_busy;
while (comp_head != comp_busy && n < comps_size) {
comps[n++] = eq->comps[comp_head];
LEPP_QINC(comp_head);
}
if (n < min_size)
return 0;
eq->comp_head = comp_head;
return n;
}
/*
* Free some comps, and return true iff there are still some pending.
*/
static bool tile_net_lepp_free_comps(struct net_device *dev, bool all)
{
struct tile_net_priv *priv = netdev_priv(dev);
lepp_queue_t *eq = priv->eq;
struct sk_buff *olds[64];
unsigned int wanted = 64;
unsigned int i, n;
bool pending;
spin_lock(&priv->eq_lock);
if (all)
eq->comp_busy = eq->comp_tail;
n = tile_net_lepp_grab_comps(eq, olds, wanted, 0);
pending = (eq->comp_head != eq->comp_tail);
spin_unlock(&priv->eq_lock);
for (i = 0; i < n; i++)
kfree_skb(olds[i]);
return pending;
}
/*
* Make sure the egress timer is scheduled.
*
* Note that we use "schedule if not scheduled" logic instead of the more
* obvious "reschedule" logic, because "reschedule" is fairly expensive.
*/
static void tile_net_schedule_egress_timer(struct tile_net_cpu *info)
{
if (!info->egress_timer_scheduled) {
mod_timer_pinned(&info->egress_timer, jiffies + 1);
info->egress_timer_scheduled = true;
}
}
/*
* The "function" for "info->egress_timer".
*
* This timer will reschedule itself as long as there are any pending
* completions expected (on behalf of any tile).
*
* ISSUE: Realistically, will the timer ever stop scheduling itself?
*
* ISSUE: This timer is almost never actually needed, so just use a global
* timer that can run on any tile.
*
* ISSUE: Maybe instead track number of expected completions, and free
* only that many, resetting to zero if "pending" is ever false.
*/
static void tile_net_handle_egress_timer(unsigned long arg)
{
struct tile_net_cpu *info = (struct tile_net_cpu *)arg;
struct net_device *dev = info->napi.dev;
/* The timer is no longer scheduled. */
info->egress_timer_scheduled = false;
/* Free comps, and reschedule timer if more are pending. */
if (tile_net_lepp_free_comps(dev, false))
tile_net_schedule_egress_timer(info);
}
#ifdef IGNORE_DUP_ACKS
/*
* Help detect "duplicate" ACKs. These are sequential packets (for a
* given flow) which are exactly 66 bytes long, sharing everything but
* ID=2@0x12, Hsum=2@0x18, Ack=4@0x2a, WinSize=2@0x30, Csum=2@0x32,
* Tstamps=10@0x38. The ID's are +1, the Hsum's are -1, the Ack's are
* +N, and the Tstamps are usually identical.
*
* NOTE: Apparently truly duplicate acks (with identical "ack" values),
* should not be collapsed, as they are used for some kind of flow control.
*/
static bool is_dup_ack(char *s1, char *s2, unsigned int len)
{
int i;
unsigned long long ignorable = 0;
/* Identification. */
ignorable |= (1ULL << 0x12);
ignorable |= (1ULL << 0x13);
/* Header checksum. */
ignorable |= (1ULL << 0x18);
ignorable |= (1ULL << 0x19);
/* ACK. */
ignorable |= (1ULL << 0x2a);
ignorable |= (1ULL << 0x2b);
ignorable |= (1ULL << 0x2c);
ignorable |= (1ULL << 0x2d);
/* WinSize. */
ignorable |= (1ULL << 0x30);
ignorable |= (1ULL << 0x31);
/* Checksum. */
ignorable |= (1ULL << 0x32);
ignorable |= (1ULL << 0x33);
for (i = 0; i < len; i++, ignorable >>= 1) {
if ((ignorable & 1) || (s1[i] == s2[i]))
continue;
#ifdef TILE_NET_DEBUG
/* HACK: Mention non-timestamp diffs. */
if (i < 0x38 && i != 0x2f &&
net_ratelimit())
pr_info("Diff at 0x%x\n", i);
#endif
return false;
}
#ifdef TILE_NET_NO_SUPPRESS_DUP_ACKS
/* HACK: Do not suppress truly duplicate ACKs. */
/* ISSUE: Is this actually necessary or helpful? */
if (s1[0x2a] == s2[0x2a] &&
s1[0x2b] == s2[0x2b] &&
s1[0x2c] == s2[0x2c] &&
s1[0x2d] == s2[0x2d]) {
return false;
}
#endif
return true;
}
#endif
static void tile_net_discard_aux(struct tile_net_cpu *info, int index)
{
struct tile_netio_queue *queue = &info->queue;
netio_queue_impl_t *qsp = queue->__system_part;
netio_queue_user_impl_t *qup = &queue->__user_part;
int index2_aux = index + sizeof(netio_pkt_t);
int index2 =
((index2_aux ==
qsp->__packet_receive_queue.__last_packet_plus_one) ?
0 : index2_aux);
netio_pkt_t *pkt = (netio_pkt_t *)((unsigned long) &qsp[1] + index);
/* Extract the "linux_buffer_t". */
unsigned int buffer = pkt->__packet.word;
/* Convert "linux_buffer_t" to "va". */
void *va = __va((phys_addr_t)(buffer >> 1) << 7);
/* Acquire the associated "skb". */
struct sk_buff **skb_ptr = va - sizeof(*skb_ptr);
struct sk_buff *skb = *skb_ptr;
kfree_skb(skb);
/* Consume this packet. */
qup->__packet_receive_read = index2;
}
/*
* Like "tile_net_poll()", but just discard packets.
*/
static void tile_net_discard_packets(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
struct tile_netio_queue *queue = &info->queue;
netio_queue_impl_t *qsp = queue->__system_part;
netio_queue_user_impl_t *qup = &queue->__user_part;
while (qup->__packet_receive_read !=
qsp->__packet_receive_queue.__packet_write) {
int index = qup->__packet_receive_read;
tile_net_discard_aux(info, index);
}
}
/*
* Handle the next packet. Return true if "processed", false if "filtered".
*/
static bool tile_net_poll_aux(struct tile_net_cpu *info, int index)
{
struct net_device *dev = info->napi.dev;
struct tile_netio_queue *queue = &info->queue;
netio_queue_impl_t *qsp = queue->__system_part;
netio_queue_user_impl_t *qup = &queue->__user_part;
struct tile_net_stats_t *stats = &info->stats;
int filter;
int index2_aux = index + sizeof(netio_pkt_t);
int index2 =
((index2_aux ==
qsp->__packet_receive_queue.__last_packet_plus_one) ?
0 : index2_aux);
netio_pkt_t *pkt = (netio_pkt_t *)((unsigned long) &qsp[1] + index);
netio_pkt_metadata_t *metadata = NETIO_PKT_METADATA(pkt);
/* Extract the packet size. FIXME: Shouldn't the second line */
/* get subtracted? Mostly moot, since it should be "zero". */
unsigned long len =
(NETIO_PKT_CUSTOM_LENGTH(pkt) +
NET_IP_ALIGN - NETIO_PACKET_PADDING);
/* Extract the "linux_buffer_t". */
unsigned int buffer = pkt->__packet.word;
/* Extract "small" (vs "large"). */
bool small = ((buffer & 1) != 0);
/* Convert "linux_buffer_t" to "va". */
void *va = __va((phys_addr_t)(buffer >> 1) << 7);
/* Extract the packet data pointer. */
/* Compare to "NETIO_PKT_CUSTOM_DATA(pkt)". */
unsigned char *buf = va + NET_IP_ALIGN;
/* Invalidate the packet buffer. */
if (!hash_default)
__inv_buffer(buf, len);
/* ISSUE: Is this needed? */
dev->last_rx = jiffies;
#ifdef TILE_NET_DUMP_PACKETS
dump_packet(buf, len, "rx");
#endif /* TILE_NET_DUMP_PACKETS */
#ifdef TILE_NET_VERIFY_INGRESS
if (!NETIO_PKT_L4_CSUM_CORRECT_M(metadata, pkt) &&
NETIO_PKT_L4_CSUM_CALCULATED_M(metadata, pkt)) {
/* Bug 6624: Includes UDP packets with a "zero" checksum. */
pr_warning("Bad L4 checksum on %d byte packet.\n", len);
}
if (!NETIO_PKT_L3_CSUM_CORRECT_M(metadata, pkt) &&
NETIO_PKT_L3_CSUM_CALCULATED_M(metadata, pkt)) {
dump_packet(buf, len, "rx");
panic("Bad L3 checksum.");
}
switch (NETIO_PKT_STATUS_M(metadata, pkt)) {
case NETIO_PKT_STATUS_OVERSIZE:
if (len >= 64) {
dump_packet(buf, len, "rx");
panic("Unexpected OVERSIZE.");
}
break;
case NETIO_PKT_STATUS_BAD:
pr_warning("Unexpected BAD %ld byte packet.\n", len);
}
#endif
filter = 0;
/* ISSUE: Filter TCP packets with "bad" checksums? */
if (!(dev->flags & IFF_UP)) {
/* Filter packets received before we're up. */
filter = 1;
} else if (NETIO_PKT_STATUS_M(metadata, pkt) == NETIO_PKT_STATUS_BAD) {
/* Filter "truncated" packets. */
filter = 1;
} else if (!(dev->flags & IFF_PROMISC)) {
/* FIXME: Implement HW multicast filter. */
if (!is_multicast_ether_addr(buf)) {
/* Filter packets not for our address. */
const u8 *mine = dev->dev_addr;
filter = compare_ether_addr(mine, buf);
}
}
if (filter) {
/* ISSUE: Update "drop" statistics? */
tile_net_provide_linux_buffer(info, va, small);
} else {
/* Acquire the associated "skb". */
struct sk_buff **skb_ptr = va - sizeof(*skb_ptr);
struct sk_buff *skb = *skb_ptr;
/* Paranoia. */
if (skb->data != buf)
panic("Corrupt linux buffer from LIPP! "
"VA=%p, skb=%p, skb->data=%p\n",
va, skb, skb->data);
/* Encode the actual packet length. */
skb_put(skb, len);
/* NOTE: This call also sets "skb->dev = dev". */
skb->protocol = eth_type_trans(skb, dev);
/* Avoid recomputing "good" TCP/UDP checksums. */
if (NETIO_PKT_L4_CSUM_CORRECT_M(metadata, pkt))
skb->ip_summed = CHECKSUM_UNNECESSARY;
netif_receive_skb(skb);
stats->rx_packets++;
stats->rx_bytes += len;
if (small)
info->num_needed_small_buffers++;
else
info->num_needed_large_buffers++;
}
/* Return four credits after every fourth packet. */
if (--qup->__receive_credit_remaining == 0) {
u32 interval = qup->__receive_credit_interval;
qup->__receive_credit_remaining = interval;
__netio_fastio_return_credits(qup->__fastio_index, interval);
}
/* Consume this packet. */
qup->__packet_receive_read = index2;
return !filter;
}
/*
* Handle some packets for the given device on the current CPU.
*
* If "tile_net_stop()" is called on some other tile while this
* function is running, we will return, hopefully before that
* other tile asks us to call "napi_disable()".
*
* The "rotting packet" race condition occurs if a packet arrives
* during the extremely narrow window between the queue appearing to
* be empty, and the ingress interrupt being re-enabled. This happens
* a LOT under heavy network load.
*/
static int tile_net_poll(struct napi_struct *napi, int budget)
{
struct net_device *dev = napi->dev;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
struct tile_netio_queue *queue = &info->queue;
netio_queue_impl_t *qsp = queue->__system_part;
netio_queue_user_impl_t *qup = &queue->__user_part;
unsigned int work = 0;
while (priv->active) {
int index = qup->__packet_receive_read;
if (index == qsp->__packet_receive_queue.__packet_write)
break;
if (tile_net_poll_aux(info, index)) {
if (++work >= budget)
goto done;
}
}
napi_complete(&info->napi);
if (!priv->active)
goto done;
/* Re-enable the ingress interrupt. */
enable_percpu_irq(priv->intr_id);
/* HACK: Avoid the "rotting packet" problem (see above). */
if (qup->__packet_receive_read !=
qsp->__packet_receive_queue.__packet_write) {
/* ISSUE: Sometimes this returns zero, presumably */
/* because an interrupt was handled for this tile. */
(void)napi_reschedule(&info->napi);
}
done:
if (priv->active)
tile_net_provide_needed_buffers(info);
return work;
}
/*
* Handle an ingress interrupt for the given device on the current cpu.
*
* ISSUE: Sometimes this gets called after "disable_percpu_irq()" has
* been called! This is probably due to "pending hypervisor downcalls".
*
* ISSUE: Is there any race condition between the "napi_schedule()" here
* and the "napi_complete()" call above?
*/
static irqreturn_t tile_net_handle_ingress_interrupt(int irq, void *dev_ptr)
{
struct net_device *dev = (struct net_device *)dev_ptr;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
/* Disable the ingress interrupt. */
disable_percpu_irq(priv->intr_id);
/* Ignore unwanted interrupts. */
if (!priv->active)
return IRQ_HANDLED;
/* ISSUE: Sometimes "info->napi_enabled" is false here. */
napi_schedule(&info->napi);
return IRQ_HANDLED;
}
/*
* One time initialization per interface.
*/
static int tile_net_open_aux(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
int ret;
int dummy;
unsigned int epp_lotar;
/*
* Find out where EPP memory should be homed.
*/
ret = hv_dev_pread(priv->hv_devhdl, 0,
(HV_VirtAddr)&epp_lotar, sizeof(epp_lotar),
NETIO_EPP_SHM_OFF);
if (ret < 0) {
pr_err("could not read epp_shm_queue lotar.\n");
return -EIO;
}
/*
* Home the page on the EPP.
*/
{
int epp_home = hv_lotar_to_cpu(epp_lotar);
homecache_change_page_home(priv->eq_pages, EQ_ORDER, epp_home);
}
/*
* Register the EPP shared memory queue.
*/
{
netio_ipp_address_t ea = {
.va = 0,
.pa = __pa(priv->eq),
.pte = hv_pte(0),
.size = EQ_SIZE,
};
ea.pte = hv_pte_set_lotar(ea.pte, epp_lotar);
ea.pte = hv_pte_set_mode(ea.pte, HV_PTE_MODE_CACHE_TILE_L3);
ret = hv_dev_pwrite(priv->hv_devhdl, 0,
(HV_VirtAddr)&ea,
sizeof(ea),
NETIO_EPP_SHM_OFF);
if (ret < 0)
return -EIO;
}
/*
* Start LIPP/LEPP.
*/
if (hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&dummy,
sizeof(dummy), NETIO_IPP_START_SHIM_OFF) < 0) {
pr_warning("Failed to start LIPP/LEPP.\n");
return -EIO;
}
return 0;
}
/*
* Register with hypervisor on the current CPU.
*
* Strangely, this function does important things even if it "fails",
* which is especially common if the link is not up yet. Hopefully
* these things are all "harmless" if done twice!
*/
static void tile_net_register(void *dev_ptr)
{
struct net_device *dev = (struct net_device *)dev_ptr;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info;
struct tile_netio_queue *queue;
/* Only network cpus can receive packets. */
int queue_id =
cpumask_test_cpu(my_cpu, &priv->network_cpus_map) ? 0 : 255;
netio_input_config_t config = {
.flags = 0,
.num_receive_packets = priv->network_cpus_credits,
.queue_id = queue_id
};
int ret = 0;
netio_queue_impl_t *queuep;
PDEBUG("tile_net_register(queue_id %d)\n", queue_id);
if (!strcmp(dev->name, "xgbe0"))
info = &__get_cpu_var(hv_xgbe0);
else if (!strcmp(dev->name, "xgbe1"))
info = &__get_cpu_var(hv_xgbe1);
else if (!strcmp(dev->name, "gbe0"))
info = &__get_cpu_var(hv_gbe0);
else if (!strcmp(dev->name, "gbe1"))
info = &__get_cpu_var(hv_gbe1);
else
BUG();
/* Initialize the egress timer. */
init_timer(&info->egress_timer);
info->egress_timer.data = (long)info;
info->egress_timer.function = tile_net_handle_egress_timer;
priv->cpu[my_cpu] = info;
/*
* Register ourselves with LIPP. This does a lot of stuff,
* including invoking the LIPP registration code.
*/
ret = hv_dev_pwrite(priv->hv_devhdl, 0,
(HV_VirtAddr)&config,
sizeof(netio_input_config_t),
NETIO_IPP_INPUT_REGISTER_OFF);
PDEBUG("hv_dev_pwrite(NETIO_IPP_INPUT_REGISTER_OFF) returned %d\n",
ret);
if (ret < 0) {
if (ret != NETIO_LINK_DOWN) {
printk(KERN_DEBUG "hv_dev_pwrite "
"NETIO_IPP_INPUT_REGISTER_OFF failure %d\n",
ret);
}
info->link_down = (ret == NETIO_LINK_DOWN);
return;
}
/*
* Get the pointer to our queue's system part.
*/
ret = hv_dev_pread(priv->hv_devhdl, 0,
(HV_VirtAddr)&queuep,
sizeof(netio_queue_impl_t *),
NETIO_IPP_INPUT_REGISTER_OFF);
PDEBUG("hv_dev_pread(NETIO_IPP_INPUT_REGISTER_OFF) returned %d\n",
ret);
PDEBUG("queuep %p\n", queuep);
if (ret <= 0) {
/* ISSUE: Shouldn't this be a fatal error? */
pr_err("hv_dev_pread NETIO_IPP_INPUT_REGISTER_OFF failure\n");
return;
}
queue = &info->queue;
queue->__system_part = queuep;
memset(&queue->__user_part, 0, sizeof(netio_queue_user_impl_t));
/* This is traditionally "config.num_receive_packets / 2". */
queue->__user_part.__receive_credit_interval = 4;
queue->__user_part.__receive_credit_remaining =
queue->__user_part.__receive_credit_interval;
/*
* Get a fastio index from the hypervisor.
* ISSUE: Shouldn't this check the result?
*/
ret = hv_dev_pread(priv->hv_devhdl, 0,
(HV_VirtAddr)&queue->__user_part.__fastio_index,
sizeof(queue->__user_part.__fastio_index),
NETIO_IPP_GET_FASTIO_OFF);
PDEBUG("hv_dev_pread(NETIO_IPP_GET_FASTIO_OFF) returned %d\n", ret);
/* Now we are registered. */
info->registered = true;
}
/*
* Deregister with hypervisor on the current CPU.
*
* This simply discards all our credits, so no more packets will be
* delivered to this tile. There may still be packets in our queue.
*
* Also, disable the ingress interrupt.
*/
static void tile_net_deregister(void *dev_ptr)
{
struct net_device *dev = (struct net_device *)dev_ptr;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
/* Disable the ingress interrupt. */
disable_percpu_irq(priv->intr_id);
/* Do nothing else if not registered. */
if (info == NULL || !info->registered)
return;
{
struct tile_netio_queue *queue = &info->queue;
netio_queue_user_impl_t *qup = &queue->__user_part;
/* Discard all our credits. */
__netio_fastio_return_credits(qup->__fastio_index, -1);
}
}
/*
* Unregister with hypervisor on the current CPU.
*
* Also, disable the ingress interrupt.
*/
static void tile_net_unregister(void *dev_ptr)
{
struct net_device *dev = (struct net_device *)dev_ptr;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
int ret;
int dummy = 0;
/* Disable the ingress interrupt. */
disable_percpu_irq(priv->intr_id);
/* Do nothing else if not registered. */
if (info == NULL || !info->registered)
return;
/* Unregister ourselves with LIPP/LEPP. */
ret = hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&dummy,
sizeof(dummy), NETIO_IPP_INPUT_UNREGISTER_OFF);
if (ret < 0)
panic("Failed to unregister with LIPP/LEPP!\n");
/* Discard all packets still in our NetIO queue. */
tile_net_discard_packets(dev);
/* Reset state. */
info->num_needed_small_buffers = 0;
info->num_needed_large_buffers = 0;
/* Cancel egress timer. */
del_timer(&info->egress_timer);
info->egress_timer_scheduled = false;
}
/*
* Helper function for "tile_net_stop()".
*
* Also used to handle registration failure in "tile_net_open_inner()",
* when the various extra steps in "tile_net_stop()" are not necessary.
*/
static void tile_net_stop_aux(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
int i;
int dummy = 0;
/*
* Unregister all tiles, so LIPP will stop delivering packets.
* Also, delete all the "napi" objects (sequentially, to protect
* "dev->napi_list").
*/
on_each_cpu(tile_net_unregister, (void *)dev, 1);
for_each_online_cpu(i) {
struct tile_net_cpu *info = priv->cpu[i];
if (info != NULL && info->registered) {
netif_napi_del(&info->napi);
info->registered = false;
}
}
/* Stop LIPP/LEPP. */
if (hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&dummy,
sizeof(dummy), NETIO_IPP_STOP_SHIM_OFF) < 0)
panic("Failed to stop LIPP/LEPP!\n");
priv->partly_opened = 0;
}
/*
* Disable NAPI for the given device on the current cpu.
*/
static void tile_net_stop_disable(void *dev_ptr)
{
struct net_device *dev = (struct net_device *)dev_ptr;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
/* Disable NAPI if needed. */
if (info != NULL && info->napi_enabled) {
napi_disable(&info->napi);
info->napi_enabled = false;
}
}
/*
* Enable NAPI and the ingress interrupt for the given device
* on the current cpu.
*
* ISSUE: Only do this for "network cpus"?
*/
static void tile_net_open_enable(void *dev_ptr)
{
struct net_device *dev = (struct net_device *)dev_ptr;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
/* Enable NAPI. */
napi_enable(&info->napi);
info->napi_enabled = true;
/* Enable the ingress interrupt. */
enable_percpu_irq(priv->intr_id);
}
/*
* tile_net_open_inner does most of the work of bringing up the interface.
* It's called from tile_net_open(), and also from tile_net_retry_open().
* The return value is 0 if the interface was brought up, < 0 if
* tile_net_open() should return the return value as an error, and > 0 if
* tile_net_open() should return success and schedule a work item to
* periodically retry the bringup.
*/
static int tile_net_open_inner(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info;
struct tile_netio_queue *queue;
int result = 0;
int i;
int dummy = 0;
/*
* First try to register just on the local CPU, and handle any
* semi-expected "link down" failure specially. Note that we
* do NOT call "tile_net_stop_aux()", unlike below.
*/
tile_net_register(dev);
info = priv->cpu[my_cpu];
if (!info->registered) {
if (info->link_down)
return 1;
return -EAGAIN;
}
/*
* Now register everywhere else. If any registration fails,
* even for "link down" (which might not be possible), we
* clean up using "tile_net_stop_aux()". Also, add all the
* "napi" objects (sequentially, to protect "dev->napi_list").
* ISSUE: Only use "netif_napi_add()" for "network cpus"?
*/
smp_call_function(tile_net_register, (void *)dev, 1);
for_each_online_cpu(i) {
struct tile_net_cpu *info = priv->cpu[i];
if (info->registered)
netif_napi_add(dev, &info->napi, tile_net_poll, 64);
else
result = -EAGAIN;
}
if (result != 0) {
tile_net_stop_aux(dev);
return result;
}
queue = &info->queue;
if (priv->intr_id == 0) {
unsigned int irq;
/*
* Acquire the irq allocated by the hypervisor. Every
* queue gets the same irq. The "__intr_id" field is
* "1 << irq", so we use "__ffs()" to extract "irq".
*/
priv->intr_id = queue->__system_part->__intr_id;
BUG_ON(priv->intr_id == 0);
irq = __ffs(priv->intr_id);
/*
* Register the ingress interrupt handler for this
* device, permanently.
*
* We used to call "free_irq()" in "tile_net_stop()",
* and then re-register the handler here every time,
* but that caused DNP errors in "handle_IRQ_event()"
* because "desc->action" was NULL. See bug 9143.
*/
tile_irq_activate(irq, TILE_IRQ_PERCPU);
BUG_ON(request_irq(irq, tile_net_handle_ingress_interrupt,
0, dev->name, (void *)dev) != 0);
}
{
/* Allocate initial buffers. */
int max_buffers =
priv->network_cpus_count * priv->network_cpus_credits;
info->num_needed_small_buffers =
min(LIPP_SMALL_BUFFERS, max_buffers);
info->num_needed_large_buffers =
min(LIPP_LARGE_BUFFERS, max_buffers);
tile_net_provide_needed_buffers(info);
if (info->num_needed_small_buffers != 0 ||
info->num_needed_large_buffers != 0)
panic("Insufficient memory for buffer stack!");
}
/* We are about to be active. */
priv->active = true;
/* Make sure "active" is visible to all tiles. */
mb();
/* On each tile, enable NAPI and the ingress interrupt. */
on_each_cpu(tile_net_open_enable, (void *)dev, 1);
/* Start LIPP/LEPP and activate "ingress" at the shim. */
if (hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&dummy,
sizeof(dummy), NETIO_IPP_INPUT_INIT_OFF) < 0)
panic("Failed to activate the LIPP Shim!\n");
/* Start our transmit queue. */
netif_start_queue(dev);
return 0;
}
/*
* Called periodically to retry bringing up the NetIO interface,
* if it doesn't come up cleanly during tile_net_open().
*/
static void tile_net_open_retry(struct work_struct *w)
{
struct delayed_work *dw =
container_of(w, struct delayed_work, work);
struct tile_net_priv *priv =
container_of(dw, struct tile_net_priv, retry_work);
/*
* Try to bring the NetIO interface up. If it fails, reschedule
* ourselves to try again later; otherwise, tell Linux we now have
* a working link. ISSUE: What if the return value is negative?
*/
if (tile_net_open_inner(priv->dev) != 0)
schedule_delayed_work(&priv->retry_work,
TILE_NET_RETRY_INTERVAL);
else
netif_carrier_on(priv->dev);
}
/*
* Called when a network interface is made active.
*
* Returns 0 on success, negative value on failure.
*
* The open entry point is called when a network interface is made
* active by the system (IFF_UP). At this point all resources needed
* for transmit and receive operations are allocated, the interrupt
* handler is registered with the OS (if needed), the watchdog timer
* is started, and the stack is notified that the interface is ready.
*
* If the actual link is not available yet, then we tell Linux that
* we have no carrier, and we keep checking until the link comes up.
*/
static int tile_net_open(struct net_device *dev)
{
int ret = 0;
struct tile_net_priv *priv = netdev_priv(dev);
/*
* We rely on priv->partly_opened to tell us if this is the
* first time this interface is being brought up. If it is
* set, the IPP was already initialized and should not be
* initialized again.
*/
if (!priv->partly_opened) {
int count;
int credits;
/* Initialize LIPP/LEPP, and start the Shim. */
ret = tile_net_open_aux(dev);
if (ret < 0) {
pr_err("tile_net_open_aux failed: %d\n", ret);
return ret;
}
/* Analyze the network cpus. */
if (network_cpus_used)
cpumask_copy(&priv->network_cpus_map,
&network_cpus_map);
else
cpumask_copy(&priv->network_cpus_map, cpu_online_mask);
count = cpumask_weight(&priv->network_cpus_map);
/* Limit credits to available buffers, and apply min. */
credits = max(16, (LIPP_LARGE_BUFFERS / count) & ~1);
/* Apply "GBE" max limit. */
/* ISSUE: Use higher limit for XGBE? */
credits = min(NETIO_MAX_RECEIVE_PKTS, credits);
priv->network_cpus_count = count;
priv->network_cpus_credits = credits;
#ifdef TILE_NET_DEBUG
pr_info("Using %d network cpus, with %d credits each\n",
priv->network_cpus_count, priv->network_cpus_credits);
#endif
priv->partly_opened = 1;
} else {
/* FIXME: Is this possible? */
/* printk("Already partly opened.\n"); */
}
/*
* Attempt to bring up the link.
*/
ret = tile_net_open_inner(dev);
if (ret <= 0) {
if (ret == 0)
netif_carrier_on(dev);
return ret;
}
/*
* We were unable to bring up the NetIO interface, but we want to
* try again in a little bit. Tell Linux that we have no carrier
* so it doesn't try to use the interface before the link comes up
* and then remember to try again later.
*/
netif_carrier_off(dev);
schedule_delayed_work(&priv->retry_work, TILE_NET_RETRY_INTERVAL);
return 0;
}
static int tile_net_drain_lipp_buffers(struct tile_net_priv *priv)
{
int n = 0;
/* Drain all the LIPP buffers. */
while (true) {
int buffer;
/* NOTE: This should never fail. */
if (hv_dev_pread(priv->hv_devhdl, 0, (HV_VirtAddr)&buffer,
sizeof(buffer), NETIO_IPP_DRAIN_OFF) < 0)
break;
/* Stop when done. */
if (buffer == 0)
break;
{
/* Convert "linux_buffer_t" to "va". */
void *va = __va((phys_addr_t)(buffer >> 1) << 7);
/* Acquire the associated "skb". */
struct sk_buff **skb_ptr = va - sizeof(*skb_ptr);
struct sk_buff *skb = *skb_ptr;
kfree_skb(skb);
}
n++;
}
return n;
}
/*
* Disables a network interface.
*
* Returns 0, this is not allowed to fail.
*
* The close entry point is called when an interface is de-activated
* by the OS. The hardware is still under the drivers control, but
* needs to be disabled. A global MAC reset is issued to stop the
* hardware, and all transmit and receive resources are freed.
*
* ISSUE: How closely does "netif_running(dev)" mirror "priv->active"?
*
* Before we are called by "__dev_close()", "netif_running()" will
* have been cleared, so no NEW calls to "tile_net_poll()" will be
* made by "netpoll_poll_dev()".
*
* Often, this can cause some tiles to still have packets in their
* queues, so we must call "tile_net_discard_packets()" later.
*
* Note that some other tile may still be INSIDE "tile_net_poll()",
* and in fact, many will be, if there is heavy network load.
*
* Calling "on_each_cpu(tile_net_stop_disable, (void *)dev, 1)" when
* any tile is still "napi_schedule()"'d will induce a horrible crash
* when "msleep()" is called. This includes tiles which are inside
* "tile_net_poll()" which have not yet called "napi_complete()".
*
* So, we must first try to wait long enough for other tiles to finish
* with any current "tile_net_poll()" call, and, hopefully, to clear
* the "scheduled" flag. ISSUE: It is unclear what happens to tiles
* which have called "napi_schedule()" but which had not yet tried to
* call "tile_net_poll()", or which exhausted their budget inside
* "tile_net_poll()" just before this function was called.
*/
static int tile_net_stop(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
PDEBUG("tile_net_stop()\n");
/* Start discarding packets. */
priv->active = false;
/* Make sure "active" is visible to all tiles. */
mb();
/*
* On each tile, make sure no NEW packets get delivered, and
* disable the ingress interrupt.
*
* Note that the ingress interrupt can fire AFTER this,
* presumably due to packets which were recently delivered,
* but it will have no effect.
*/
on_each_cpu(tile_net_deregister, (void *)dev, 1);
/* Optimistically drain LIPP buffers. */
(void)tile_net_drain_lipp_buffers(priv);
/* ISSUE: Only needed if not yet fully open. */
cancel_delayed_work_sync(&priv->retry_work);
/* Can't transmit any more. */
netif_stop_queue(dev);
/* Disable NAPI on each tile. */
on_each_cpu(tile_net_stop_disable, (void *)dev, 1);
/*
* Drain any remaining LIPP buffers. NOTE: This "printk()"
* has never been observed, but in theory it could happen.
*/
if (tile_net_drain_lipp_buffers(priv) != 0)
printk("Had to drain some extra LIPP buffers!\n");
/* Stop LIPP/LEPP. */
tile_net_stop_aux(dev);
/*
* ISSUE: It appears that, in practice anyway, by the time we
* get here, there are no pending completions, but just in case,
* we free (all of) them anyway.
*/
while (tile_net_lepp_free_comps(dev, true))
/* loop */;
/* Wipe the EPP queue. */
memset(priv->eq, 0, sizeof(lepp_queue_t));
/* Evict the EPP queue. */
finv_buffer(priv->eq, EQ_SIZE);
return 0;
}
/*
* Prepare the "frags" info for the resulting LEPP command.
*
* If needed, flush the memory used by the frags.
*/
static unsigned int tile_net_tx_frags(lepp_frag_t *frags,
struct sk_buff *skb,
void *b_data, unsigned int b_len)
{
unsigned int i, n = 0;
struct skb_shared_info *sh = skb_shinfo(skb);
phys_addr_t cpa;
if (b_len != 0) {
if (!hash_default)
finv_buffer_remote(b_data, b_len, 0);
cpa = __pa(b_data);
frags[n].cpa_lo = cpa;
frags[n].cpa_hi = cpa >> 32;
frags[n].length = b_len;
frags[n].hash_for_home = hash_default;
n++;
}
for (i = 0; i < sh->nr_frags; i++) {
skb_frag_t *f = &sh->frags[i];
unsigned long pfn = page_to_pfn(f->page);
/* FIXME: Compute "hash_for_home" properly. */
/* ISSUE: The hypervisor checks CHIP_HAS_REV1_DMA_PACKETS(). */
int hash_for_home = hash_default;
/* FIXME: Hmmm. */
if (!hash_default) {
void *va = pfn_to_kaddr(pfn) + f->page_offset;
BUG_ON(PageHighMem(f->page));
finv_buffer_remote(va, f->size, 0);
}
cpa = ((phys_addr_t)pfn << PAGE_SHIFT) + f->page_offset;
frags[n].cpa_lo = cpa;
frags[n].cpa_hi = cpa >> 32;
frags[n].length = f->size;
frags[n].hash_for_home = hash_for_home;
n++;
}
return n;
}
/*
* This function takes "skb", consisting of a header template and a
* payload, and hands it to LEPP, to emit as one or more segments,
* each consisting of a possibly modified header, plus a piece of the
* payload, via a process known as "tcp segmentation offload".
*
* Usually, "data" will contain the header template, of size "sh_len",
* and "sh->frags" will contain "skb->data_len" bytes of payload, and
* there will be "sh->gso_segs" segments.
*
* Sometimes, if "sendfile()" requires copying, we will be called with
* "data" containing the header and payload, with "frags" being empty.
*
* In theory, "sh->nr_frags" could be 3, but in practice, it seems
* that this will never actually happen.
*
* See "emulate_large_send_offload()" for some reference code, which
* does not handle checksumming.
*
* ISSUE: How do we make sure that high memory DMA does not migrate?
*/
static int tile_net_tx_tso(struct sk_buff *skb, struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
struct tile_net_stats_t *stats = &info->stats;
struct skb_shared_info *sh = skb_shinfo(skb);
unsigned char *data = skb->data;
/* The ip header follows the ethernet header. */
struct iphdr *ih = ip_hdr(skb);
unsigned int ih_len = ih->ihl * 4;
/* Note that "nh == ih", by definition. */
unsigned char *nh = skb_network_header(skb);
unsigned int eh_len = nh - data;
/* The tcp header follows the ip header. */
struct tcphdr *th = (struct tcphdr *)(nh + ih_len);
unsigned int th_len = th->doff * 4;
/* The total number of header bytes. */
/* NOTE: This may be less than skb_headlen(skb). */
unsigned int sh_len = eh_len + ih_len + th_len;
/* The number of payload bytes at "skb->data + sh_len". */
/* This is non-zero for sendfile() without HIGHDMA. */
unsigned int b_len = skb_headlen(skb) - sh_len;
/* The total number of payload bytes. */
unsigned int d_len = b_len + skb->data_len;
/* The maximum payload size. */
unsigned int p_len = sh->gso_size;
/* The total number of segments. */
unsigned int num_segs = sh->gso_segs;
/* The temporary copy of the command. */
u32 cmd_body[(LEPP_MAX_CMD_SIZE + 3) / 4];
lepp_tso_cmd_t *cmd = (lepp_tso_cmd_t *)cmd_body;
/* Analyze the "frags". */
unsigned int num_frags =
tile_net_tx_frags(cmd->frags, skb, data + sh_len, b_len);
/* The size of the command, including frags and header. */
size_t cmd_size = LEPP_TSO_CMD_SIZE(num_frags, sh_len);
/* The command header. */
lepp_tso_cmd_t cmd_init = {
.tso = true,
.header_size = sh_len,
.ip_offset = eh_len,
.tcp_offset = eh_len + ih_len,
.payload_size = p_len,
.num_frags = num_frags,
};
unsigned long irqflags;
lepp_queue_t *eq = priv->eq;
struct sk_buff *olds[8];
unsigned int wanted = 8;
unsigned int i, nolds = 0;
unsigned int cmd_head, cmd_tail, cmd_next;
unsigned int comp_tail;
/* Paranoia. */
BUG_ON(skb->protocol != htons(ETH_P_IP));
BUG_ON(ih->protocol != IPPROTO_TCP);
BUG_ON(skb->ip_summed != CHECKSUM_PARTIAL);
BUG_ON(num_frags > LEPP_MAX_FRAGS);
/*--BUG_ON(num_segs != (d_len + (p_len - 1)) / p_len); */
BUG_ON(num_segs <= 1);
/* Finish preparing the command. */
/* Copy the command header. */
*cmd = cmd_init;
/* Copy the "header". */
memcpy(&cmd->frags[num_frags], data, sh_len);
/* Prefetch and wait, to minimize time spent holding the spinlock. */
prefetch_L1(&eq->comp_tail);
prefetch_L1(&eq->cmd_tail);
mb();
/* Enqueue the command. */
spin_lock_irqsave(&priv->eq_lock, irqflags);
/*
* Handle completions if needed to make room.
* HACK: Spin until there is sufficient room.
*/
if (lepp_num_free_comp_slots(eq) == 0) {
nolds = tile_net_lepp_grab_comps(eq, olds, wanted, 0);
if (nolds == 0) {
busy:
spin_unlock_irqrestore(&priv->eq_lock, irqflags);
return NETDEV_TX_BUSY;
}
}
cmd_head = eq->cmd_head;
cmd_tail = eq->cmd_tail;
/* Prepare to advance, detecting full queue. */
cmd_next = cmd_tail + cmd_size;
if (cmd_tail < cmd_head && cmd_next >= cmd_head)
goto busy;
if (cmd_next > LEPP_CMD_LIMIT) {
cmd_next = 0;
if (cmd_next == cmd_head)
goto busy;
}
/* Copy the command. */
memcpy(&eq->cmds[cmd_tail], cmd, cmd_size);
/* Advance. */
cmd_tail = cmd_next;
/* Record "skb" for eventual freeing. */
comp_tail = eq->comp_tail;
eq->comps[comp_tail] = skb;
LEPP_QINC(comp_tail);
eq->comp_tail = comp_tail;
/* Flush before allowing LEPP to handle the command. */
/* ISSUE: Is this the optimal location for the flush? */
__insn_mf();
eq->cmd_tail = cmd_tail;
/* NOTE: Using "4" here is more efficient than "0" or "2", */
/* and, strangely, more efficient than pre-checking the number */
/* of available completions, and comparing it to 4. */
if (nolds == 0)
nolds = tile_net_lepp_grab_comps(eq, olds, wanted, 4);
spin_unlock_irqrestore(&priv->eq_lock, irqflags);
/* Handle completions. */
for (i = 0; i < nolds; i++)
kfree_skb(olds[i]);
/* Update stats. */
stats->tx_packets += num_segs;
stats->tx_bytes += (num_segs * sh_len) + d_len;
/* Make sure the egress timer is scheduled. */
tile_net_schedule_egress_timer(info);
return NETDEV_TX_OK;
}
/*
* Transmit a packet (called by the kernel via "hard_start_xmit" hook).
*/
static int tile_net_tx(struct sk_buff *skb, struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
struct tile_net_stats_t *stats = &info->stats;
unsigned long irqflags;
struct skb_shared_info *sh = skb_shinfo(skb);
unsigned int len = skb->len;
unsigned char *data = skb->data;
unsigned int csum_start = skb->csum_start - skb_headroom(skb);
lepp_frag_t frags[LEPP_MAX_FRAGS];
unsigned int num_frags;
lepp_queue_t *eq = priv->eq;
struct sk_buff *olds[8];
unsigned int wanted = 8;
unsigned int i, nolds = 0;
unsigned int cmd_size = sizeof(lepp_cmd_t);
unsigned int cmd_head, cmd_tail, cmd_next;
unsigned int comp_tail;
lepp_cmd_t cmds[LEPP_MAX_FRAGS];
/*
* This is paranoia, since we think that if the link doesn't come
* up, telling Linux we have no carrier will keep it from trying
* to transmit. If it does, though, we can't execute this routine,
* since data structures we depend on aren't set up yet.
*/
if (!info->registered)
return NETDEV_TX_BUSY;
/* Save the timestamp. */
dev->trans_start = jiffies;
#ifdef TILE_NET_PARANOIA
#if CHIP_HAS_CBOX_HOME_MAP()
if (hash_default) {
HV_PTE pte = *virt_to_pte(current->mm, (unsigned long)data);
if (hv_pte_get_mode(pte) != HV_PTE_MODE_CACHE_HASH_L3)
panic("Non-HFH egress buffer! VA=%p Mode=%d PTE=%llx",
data, hv_pte_get_mode(pte), hv_pte_val(pte));
}
#endif
#endif
#ifdef TILE_NET_DUMP_PACKETS
/* ISSUE: Does not dump the "frags". */
dump_packet(data, skb_headlen(skb), "tx");
#endif /* TILE_NET_DUMP_PACKETS */
if (sh->gso_size != 0)
return tile_net_tx_tso(skb, dev);
/* Prepare the commands. */
num_frags = tile_net_tx_frags(frags, skb, data, skb_headlen(skb));
for (i = 0; i < num_frags; i++) {
bool final = (i == num_frags - 1);
lepp_cmd_t cmd = {
.cpa_lo = frags[i].cpa_lo,
.cpa_hi = frags[i].cpa_hi,
.length = frags[i].length,
.hash_for_home = frags[i].hash_for_home,
.send_completion = final,
.end_of_packet = final
};
if (i == 0 && skb->ip_summed == CHECKSUM_PARTIAL) {
cmd.compute_checksum = 1;
cmd.checksum_data.bits.start_byte = csum_start;
cmd.checksum_data.bits.count = len - csum_start;
cmd.checksum_data.bits.destination_byte =
csum_start + skb->csum_offset;
}
cmds[i] = cmd;
}
/* Prefetch and wait, to minimize time spent holding the spinlock. */
prefetch_L1(&eq->comp_tail);
prefetch_L1(&eq->cmd_tail);
mb();
/* Enqueue the commands. */
spin_lock_irqsave(&priv->eq_lock, irqflags);
/*
* Handle completions if needed to make room.
* HACK: Spin until there is sufficient room.
*/
if (lepp_num_free_comp_slots(eq) == 0) {
nolds = tile_net_lepp_grab_comps(eq, olds, wanted, 0);
if (nolds == 0) {
busy:
spin_unlock_irqrestore(&priv->eq_lock, irqflags);
return NETDEV_TX_BUSY;
}
}
cmd_head = eq->cmd_head;
cmd_tail = eq->cmd_tail;
/* Copy the commands, or fail. */
for (i = 0; i < num_frags; i++) {
/* Prepare to advance, detecting full queue. */
cmd_next = cmd_tail + cmd_size;
if (cmd_tail < cmd_head && cmd_next >= cmd_head)
goto busy;
if (cmd_next > LEPP_CMD_LIMIT) {
cmd_next = 0;
if (cmd_next == cmd_head)
goto busy;
}
/* Copy the command. */
*(lepp_cmd_t *)&eq->cmds[cmd_tail] = cmds[i];
/* Advance. */
cmd_tail = cmd_next;
}
/* Record "skb" for eventual freeing. */
comp_tail = eq->comp_tail;
eq->comps[comp_tail] = skb;
LEPP_QINC(comp_tail);
eq->comp_tail = comp_tail;
/* Flush before allowing LEPP to handle the command. */
/* ISSUE: Is this the optimal location for the flush? */
__insn_mf();
eq->cmd_tail = cmd_tail;
/* NOTE: Using "4" here is more efficient than "0" or "2", */
/* and, strangely, more efficient than pre-checking the number */
/* of available completions, and comparing it to 4. */
if (nolds == 0)
nolds = tile_net_lepp_grab_comps(eq, olds, wanted, 4);
spin_unlock_irqrestore(&priv->eq_lock, irqflags);
/* Handle completions. */
for (i = 0; i < nolds; i++)
kfree_skb(olds[i]);
/* HACK: Track "expanded" size for short packets (e.g. 42 < 60). */
stats->tx_packets++;
stats->tx_bytes += ((len >= ETH_ZLEN) ? len : ETH_ZLEN);
/* Make sure the egress timer is scheduled. */
tile_net_schedule_egress_timer(info);
return NETDEV_TX_OK;
}
/*
* Deal with a transmit timeout.
*/
static void tile_net_tx_timeout(struct net_device *dev)
{
PDEBUG("tile_net_tx_timeout()\n");
PDEBUG("Transmit timeout at %ld, latency %ld\n", jiffies,
jiffies - dev->trans_start);
/* XXX: ISSUE: This doesn't seem useful for us. */
netif_wake_queue(dev);
}
/*
* Ioctl commands.
*/
static int tile_net_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
return -EOPNOTSUPP;
}
/*
* Get System Network Statistics.
*
* Returns the address of the device statistics structure.
*/
static struct net_device_stats *tile_net_get_stats(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
u32 rx_packets = 0;
u32 tx_packets = 0;
u32 rx_bytes = 0;
u32 tx_bytes = 0;
int i;
for_each_online_cpu(i) {
if (priv->cpu[i]) {
rx_packets += priv->cpu[i]->stats.rx_packets;
rx_bytes += priv->cpu[i]->stats.rx_bytes;
tx_packets += priv->cpu[i]->stats.tx_packets;
tx_bytes += priv->cpu[i]->stats.tx_bytes;
}
}
priv->stats.rx_packets = rx_packets;
priv->stats.rx_bytes = rx_bytes;
priv->stats.tx_packets = tx_packets;
priv->stats.tx_bytes = tx_bytes;
return &priv->stats;
}
/*
* Change the "mtu".
*
* The "change_mtu" method is usually not needed.
* If you need it, it must be like this.
*/
static int tile_net_change_mtu(struct net_device *dev, int new_mtu)
{
PDEBUG("tile_net_change_mtu()\n");
/* Check ranges. */
if ((new_mtu < 68) || (new_mtu > 1500))
return -EINVAL;
/* Accept the value. */
dev->mtu = new_mtu;
return 0;
}
/*
* Change the Ethernet Address of the NIC.
*
* The hypervisor driver does not support changing MAC address. However,
* the IPP does not do anything with the MAC address, so the address which
* gets used on outgoing packets, and which is accepted on incoming packets,
* is completely up to the NetIO program or kernel driver which is actually
* handling them.
*
* Returns 0 on success, negative on failure.
*/
static int tile_net_set_mac_address(struct net_device *dev, void *p)
{
struct sockaddr *addr = p;
if (!is_valid_ether_addr(addr->sa_data))
return -EINVAL;
/* ISSUE: Note that "dev_addr" is now a pointer. */
memcpy(dev->dev_addr, addr->sa_data, dev->addr_len);
return 0;
}
/*
* Obtain the MAC address from the hypervisor.
* This must be done before opening the device.
*/
static int tile_net_get_mac(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
char hv_dev_name[32];
int len;
__netio_getset_offset_t offset = { .word = NETIO_IPP_PARAM_OFF };
int ret;
/* For example, "xgbe0". */
strcpy(hv_dev_name, dev->name);
len = strlen(hv_dev_name);
/* For example, "xgbe/0". */
hv_dev_name[len] = hv_dev_name[len - 1];
hv_dev_name[len - 1] = '/';
len++;
/* For example, "xgbe/0/native_hash". */
strcpy(hv_dev_name + len, hash_default ? "/native_hash" : "/native");
/* Get the hypervisor handle for this device. */
priv->hv_devhdl = hv_dev_open((HV_VirtAddr)hv_dev_name, 0);
PDEBUG("hv_dev_open(%s) returned %d %p\n",
hv_dev_name, priv->hv_devhdl, &priv->hv_devhdl);
if (priv->hv_devhdl < 0) {
if (priv->hv_devhdl == HV_ENODEV)
printk(KERN_DEBUG "Ignoring unconfigured device %s\n",
hv_dev_name);
else
printk(KERN_DEBUG "hv_dev_open(%s) returned %d\n",
hv_dev_name, priv->hv_devhdl);
return -1;
}
/*
* Read the hardware address from the hypervisor.
* ISSUE: Note that "dev_addr" is now a pointer.
*/
offset.bits.class = NETIO_PARAM;
offset.bits.addr = NETIO_PARAM_MAC;
ret = hv_dev_pread(priv->hv_devhdl, 0,
(HV_VirtAddr)dev->dev_addr, dev->addr_len,
offset.word);
PDEBUG("hv_dev_pread(NETIO_PARAM_MAC) returned %d\n", ret);
if (ret <= 0) {
printk(KERN_DEBUG "hv_dev_pread(NETIO_PARAM_MAC) %s failed\n",
dev->name);
/*
* Since the device is configured by the hypervisor but we
* can't get its MAC address, we are most likely running
* the simulator, so let's generate a random MAC address.
*/
random_ether_addr(dev->dev_addr);
}
return 0;
}
static struct net_device_ops tile_net_ops = {
.ndo_open = tile_net_open,
.ndo_stop = tile_net_stop,
.ndo_start_xmit = tile_net_tx,
.ndo_do_ioctl = tile_net_ioctl,
.ndo_get_stats = tile_net_get_stats,
.ndo_change_mtu = tile_net_change_mtu,
.ndo_tx_timeout = tile_net_tx_timeout,
.ndo_set_mac_address = tile_net_set_mac_address
};
/*
* The setup function.
*
* This uses ether_setup() to assign various fields in dev, including
* setting IFF_BROADCAST and IFF_MULTICAST, then sets some extra fields.
*/
static void tile_net_setup(struct net_device *dev)
{
PDEBUG("tile_net_setup()\n");
ether_setup(dev);
dev->netdev_ops = &tile_net_ops;
dev->watchdog_timeo = TILE_NET_TIMEOUT;
/* We want lockless xmit. */
dev->features |= NETIF_F_LLTX;
/* We support hardware tx checksums. */
dev->features |= NETIF_F_HW_CSUM;
/* We support scatter/gather. */
dev->features |= NETIF_F_SG;
/* We support TSO. */
dev->features |= NETIF_F_TSO;
#ifdef TILE_NET_GSO
/* We support GSO. */
dev->features |= NETIF_F_GSO;
#endif
if (hash_default)
dev->features |= NETIF_F_HIGHDMA;
/* ISSUE: We should support NETIF_F_UFO. */
dev->tx_queue_len = TILE_NET_TX_QUEUE_LEN;
dev->mtu = TILE_NET_MTU;
}
/*
* Allocate the device structure, register the device, and obtain the
* MAC address from the hypervisor.
*/
static struct net_device *tile_net_dev_init(const char *name)
{
int ret;
struct net_device *dev;
struct tile_net_priv *priv;
/*
* Allocate the device structure. This allocates "priv", calls
* tile_net_setup(), and saves "name". Normally, "name" is a
* template, instantiated by register_netdev(), but not for us.
*/
dev = alloc_netdev(sizeof(*priv), name, tile_net_setup);
if (!dev) {
pr_err("alloc_netdev(%s) failed\n", name);
return NULL;
}
priv = netdev_priv(dev);
/* Initialize "priv". */
memset(priv, 0, sizeof(*priv));
/* Save "dev" for "tile_net_open_retry()". */
priv->dev = dev;
INIT_DELAYED_WORK(&priv->retry_work, tile_net_open_retry);
spin_lock_init(&priv->eq_lock);
/* Allocate "eq". */
priv->eq_pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, EQ_ORDER);
if (!priv->eq_pages) {
free_netdev(dev);
return NULL;
}
priv->eq = page_address(priv->eq_pages);
/* Register the network device. */
ret = register_netdev(dev);
if (ret) {
pr_err("register_netdev %s failed %d\n", dev->name, ret);
__free_pages(priv->eq_pages, EQ_ORDER);
free_netdev(dev);
return NULL;
}
/* Get the MAC address. */
ret = tile_net_get_mac(dev);
if (ret < 0) {
unregister_netdev(dev);
__free_pages(priv->eq_pages, EQ_ORDER);
free_netdev(dev);
return NULL;
}
return dev;
}
/*
* Module cleanup.
*
* FIXME: If compiled as a module, this module cannot be "unloaded",
* because the "ingress interrupt handler" is registered permanently.
*/
static void tile_net_cleanup(void)
{
int i;
for (i = 0; i < TILE_NET_DEVS; i++) {
if (tile_net_devs[i]) {
struct net_device *dev = tile_net_devs[i];
struct tile_net_priv *priv = netdev_priv(dev);
unregister_netdev(dev);
finv_buffer(priv->eq, EQ_SIZE);
__free_pages(priv->eq_pages, EQ_ORDER);
free_netdev(dev);
}
}
}
/*
* Module initialization.
*/
static int tile_net_init_module(void)
{
pr_info("Tilera IPP Net Driver\n");
tile_net_devs[0] = tile_net_dev_init("xgbe0");
tile_net_devs[1] = tile_net_dev_init("xgbe1");
tile_net_devs[2] = tile_net_dev_init("gbe0");
tile_net_devs[3] = tile_net_dev_init("gbe1");
return 0;
}
module_init(tile_net_init_module);
module_exit(tile_net_cleanup);
#ifndef MODULE
/*
* The "network_cpus" boot argument specifies the cpus that are dedicated
* to handle ingress packets.
*
* The parameter should be in the form "network_cpus=m-n[,x-y]", where
* m, n, x, y are integer numbers that represent the cpus that can be
* neither a dedicated cpu nor a dataplane cpu.
*/
static int __init network_cpus_setup(char *str)
{
int rc = cpulist_parse_crop(str, &network_cpus_map);
if (rc != 0) {
pr_warning("network_cpus=%s: malformed cpu list\n",
str);
} else {
/* Remove dedicated cpus. */
cpumask_and(&network_cpus_map, &network_cpus_map,
cpu_possible_mask);
if (cpumask_empty(&network_cpus_map)) {
pr_warning("Ignoring network_cpus='%s'.\n",
str);
} else {
char buf[1024];
cpulist_scnprintf(buf, sizeof(buf), &network_cpus_map);
pr_info("Linux network CPUs: %s\n", buf);
network_cpus_used = true;
}
}
return 0;
}
__setup("network_cpus=", network_cpus_setup);
#endif
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