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linux/drivers/net/ixp2000/ixpdev.c
Stephen Hemminger bea3348eef [NET]: Make NAPI polling independent of struct net_device objects. 
Several devices have multiple independant RX queues per net
device, and some have a single interrupt doorbell for several
queues.

In either case, it's easier to support layouts like that if the
structure representing the poll is independant from the net
device itself.

The signature of the ->poll() call back goes from:

	int foo_poll(struct net_device *dev, int *budget)

to

	int foo_poll(struct napi_struct *napi, int budget)

The caller is returned the number of RX packets processed (or
the number of "NAPI credits" consumed if you want to get
abstract).  The callee no longer messes around bumping
dev->quota, *budget, etc. because that is all handled in the
caller upon return.

The napi_struct is to be embedded in the device driver private data
structures.

Furthermore, it is the driver's responsibility to disable all NAPI
instances in it's ->stop() device close handler.  Since the
napi_struct is privatized into the driver's private data structures,
only the driver knows how to get at all of the napi_struct instances
it may have per-device.

With lots of help and suggestions from Rusty Russell, Roland Dreier,
Michael Chan, Jeff Garzik, and Jamal Hadi Salim.

Bug fixes from Thomas Graf, Roland Dreier, Peter Zijlstra,
Joseph Fannin, Scott Wood, Hans J. Koch, and Michael Chan.

[ Ported to current tree and all drivers converted.  Integrated
  Stephen's follow-on kerneldoc additions, and restored poll_list
  handling to the old style to fix mutual exclusion issues.  -DaveM ]

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:47:45 -07:00

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/*
* IXP2000 MSF network device driver
* Copyright (C) 2004, 2005 Lennert Buytenhek <buytenh@wantstofly.org>
* Dedicated to Marija Kulikova.
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <asm/hardware/uengine.h>
#include <asm/mach-types.h>
#include <asm/io.h>
#include "ixp2400_rx.ucode"
#include "ixp2400_tx.ucode"
#include "ixpdev_priv.h"
#include "ixpdev.h"
#define DRV_MODULE_VERSION "0.2"
static int nds_count;
static struct net_device **nds;
static int nds_open;
static void (*set_port_admin_status)(int port, int up);
static struct ixpdev_rx_desc * const rx_desc =
(struct ixpdev_rx_desc *)(IXP2000_SRAM0_VIRT_BASE + RX_BUF_DESC_BASE);
static struct ixpdev_tx_desc * const tx_desc =
(struct ixpdev_tx_desc *)(IXP2000_SRAM0_VIRT_BASE + TX_BUF_DESC_BASE);
static int tx_pointer;
static int ixpdev_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ixpdev_priv *ip = netdev_priv(dev);
struct ixpdev_tx_desc *desc;
int entry;
if (unlikely(skb->len > PAGE_SIZE)) {
/* @@@ Count drops. */
dev_kfree_skb(skb);
return 0;
}
entry = tx_pointer;
tx_pointer = (tx_pointer + 1) % TX_BUF_COUNT;
desc = tx_desc + entry;
desc->pkt_length = skb->len;
desc->channel = ip->channel;
skb_copy_and_csum_dev(skb, phys_to_virt(desc->buf_addr));
dev_kfree_skb(skb);
ixp2000_reg_write(RING_TX_PENDING,
TX_BUF_DESC_BASE + (entry * sizeof(struct ixpdev_tx_desc)));
dev->trans_start = jiffies;
local_irq_disable();
ip->tx_queue_entries++;
if (ip->tx_queue_entries == TX_BUF_COUNT_PER_CHAN)
netif_stop_queue(dev);
local_irq_enable();
return 0;
}
static int ixpdev_rx(struct net_device *dev, int processed, int budget)
{
while (processed < budget) {
struct ixpdev_rx_desc *desc;
struct sk_buff *skb;
void *buf;
u32 _desc;
_desc = ixp2000_reg_read(RING_RX_DONE);
if (_desc == 0)
return 0;
desc = rx_desc +
((_desc - RX_BUF_DESC_BASE) / sizeof(struct ixpdev_rx_desc));
buf = phys_to_virt(desc->buf_addr);
if (desc->pkt_length < 4 || desc->pkt_length > PAGE_SIZE) {
printk(KERN_ERR "ixp2000: rx err, length %d\n",
desc->pkt_length);
goto err;
}
if (desc->channel < 0 || desc->channel >= nds_count) {
printk(KERN_ERR "ixp2000: rx err, channel %d\n",
desc->channel);
goto err;
}
/* @@@ Make FCS stripping configurable. */
desc->pkt_length -= 4;
if (unlikely(!netif_running(nds[desc->channel])))
goto err;
skb = dev_alloc_skb(desc->pkt_length + 2);
if (likely(skb != NULL)) {
skb_reserve(skb, 2);
skb_copy_to_linear_data(skb, buf, desc->pkt_length);
skb_put(skb, desc->pkt_length);
skb->protocol = eth_type_trans(skb, nds[desc->channel]);
skb->dev->last_rx = jiffies;
netif_receive_skb(skb);
}
err:
ixp2000_reg_write(RING_RX_PENDING, _desc);
processed++;
}
return processed;
}
/* dev always points to nds[0]. */
static int ixpdev_poll(struct napi_struct *napi, int budget)
{
struct ixpdev_priv *ip = container_of(napi, struct ixpdev_priv, napi);
struct net_device *dev = ip->dev;
int rx;
/* @@@ Have to stop polling when nds[0] is administratively
* downed while we are polling. */
rx = 0;
do {
ixp2000_reg_write(IXP2000_IRQ_THD_RAW_STATUS_A_0, 0x00ff);
rx = ixpdev_rx(dev, rx, budget);
if (rx >= budget)
break;
} while (ixp2000_reg_read(IXP2000_IRQ_THD_RAW_STATUS_A_0) & 0x00ff);
netif_rx_complete(dev, napi);
ixp2000_reg_write(IXP2000_IRQ_THD_ENABLE_SET_A_0, 0x00ff);
return rx;
}
static void ixpdev_tx_complete(void)
{
int channel;
u32 wake;
wake = 0;
while (1) {
struct ixpdev_priv *ip;
u32 desc;
int entry;
desc = ixp2000_reg_read(RING_TX_DONE);
if (desc == 0)
break;
/* @@@ Check whether entries come back in order. */
entry = (desc - TX_BUF_DESC_BASE) / sizeof(struct ixpdev_tx_desc);
channel = tx_desc[entry].channel;
if (channel < 0 || channel >= nds_count) {
printk(KERN_ERR "ixp2000: txcomp channel index "
"out of bounds (%d, %.8i, %d)\n",
channel, (unsigned int)desc, entry);
continue;
}
ip = netdev_priv(nds[channel]);
if (ip->tx_queue_entries == TX_BUF_COUNT_PER_CHAN)
wake |= 1 << channel;
ip->tx_queue_entries--;
}
for (channel = 0; wake != 0; channel++) {
if (wake & (1 << channel)) {
netif_wake_queue(nds[channel]);
wake &= ~(1 << channel);
}
}
}
static irqreturn_t ixpdev_interrupt(int irq, void *dev_id)
{
u32 status;
status = ixp2000_reg_read(IXP2000_IRQ_THD_STATUS_A_0);
if (status == 0)
return IRQ_NONE;
/*
* Any of the eight receive units signaled RX?
*/
if (status & 0x00ff) {
struct net_device *dev = nds[0];
struct ixpdev_priv *ip = netdev_priv(dev);
ixp2000_reg_wrb(IXP2000_IRQ_THD_ENABLE_CLEAR_A_0, 0x00ff);
if (likely(napi_schedule_prep(&ip->napi))) {
__netif_rx_schedule(dev, &ip->napi);
} else {
printk(KERN_CRIT "ixp2000: irq while polling!!\n");
}
}
/*
* Any of the eight transmit units signaled TXdone?
*/
if (status & 0xff00) {
ixp2000_reg_wrb(IXP2000_IRQ_THD_RAW_STATUS_A_0, 0xff00);
ixpdev_tx_complete();
}
return IRQ_HANDLED;
}
#ifdef CONFIG_NET_POLL_CONTROLLER
static void ixpdev_poll_controller(struct net_device *dev)
{
disable_irq(IRQ_IXP2000_THDA0);
ixpdev_interrupt(IRQ_IXP2000_THDA0, dev);
enable_irq(IRQ_IXP2000_THDA0);
}
#endif
static int ixpdev_open(struct net_device *dev)
{
struct ixpdev_priv *ip = netdev_priv(dev);
int err;
napi_enable(&ip->napi);
if (!nds_open++) {
err = request_irq(IRQ_IXP2000_THDA0, ixpdev_interrupt,
IRQF_SHARED, "ixp2000_eth", nds);
if (err) {
nds_open--;
napi_disable(&ip->napi);
return err;
}
ixp2000_reg_write(IXP2000_IRQ_THD_ENABLE_SET_A_0, 0xffff);
}
set_port_admin_status(ip->channel, 1);
netif_start_queue(dev);
return 0;
}
static int ixpdev_close(struct net_device *dev)
{
struct ixpdev_priv *ip = netdev_priv(dev);
netif_stop_queue(dev);
napi_disable(&ip->napi);
set_port_admin_status(ip->channel, 0);
if (!--nds_open) {
ixp2000_reg_write(IXP2000_IRQ_THD_ENABLE_CLEAR_A_0, 0xffff);
free_irq(IRQ_IXP2000_THDA0, nds);
}
return 0;
}
struct net_device *ixpdev_alloc(int channel, int sizeof_priv)
{
struct net_device *dev;
struct ixpdev_priv *ip;
dev = alloc_etherdev(sizeof_priv);
if (dev == NULL)
return NULL;
dev->hard_start_xmit = ixpdev_xmit;
dev->open = ixpdev_open;
dev->stop = ixpdev_close;
#ifdef CONFIG_NET_POLL_CONTROLLER
dev->poll_controller = ixpdev_poll_controller;
#endif
dev->features |= NETIF_F_SG | NETIF_F_HW_CSUM;
ip = netdev_priv(dev);
ip->dev = dev;
netif_napi_add(dev, &ip->napi, ixpdev_poll, 64);
ip->channel = channel;
ip->tx_queue_entries = 0;
return dev;
}
int ixpdev_init(int __nds_count, struct net_device **__nds,
void (*__set_port_admin_status)(int port, int up))
{
int i;
int err;
BUILD_BUG_ON(RX_BUF_COUNT > 192 || TX_BUF_COUNT > 192);
printk(KERN_INFO "IXP2000 MSF ethernet driver %s\n", DRV_MODULE_VERSION);
nds_count = __nds_count;
nds = __nds;
set_port_admin_status = __set_port_admin_status;
for (i = 0; i < RX_BUF_COUNT; i++) {
void *buf;
buf = (void *)get_zeroed_page(GFP_KERNEL);
if (buf == NULL) {
err = -ENOMEM;
while (--i >= 0)
free_page((unsigned long)phys_to_virt(rx_desc[i].buf_addr));
goto err_out;
}
rx_desc[i].buf_addr = virt_to_phys(buf);
rx_desc[i].buf_length = PAGE_SIZE;
}
/* @@@ Maybe we shouldn't be preallocating TX buffers. */
for (i = 0; i < TX_BUF_COUNT; i++) {
void *buf;
buf = (void *)get_zeroed_page(GFP_KERNEL);
if (buf == NULL) {
err = -ENOMEM;
while (--i >= 0)
free_page((unsigned long)phys_to_virt(tx_desc[i].buf_addr));
goto err_free_rx;
}
tx_desc[i].buf_addr = virt_to_phys(buf);
}
/* 256 entries, ring status set means 'empty', base address 0x0000. */
ixp2000_reg_write(RING_RX_PENDING_BASE, 0x44000000);
ixp2000_reg_write(RING_RX_PENDING_HEAD, 0x00000000);
ixp2000_reg_write(RING_RX_PENDING_TAIL, 0x00000000);
/* 256 entries, ring status set means 'full', base address 0x0400. */
ixp2000_reg_write(RING_RX_DONE_BASE, 0x40000400);
ixp2000_reg_write(RING_RX_DONE_HEAD, 0x00000000);
ixp2000_reg_write(RING_RX_DONE_TAIL, 0x00000000);
for (i = 0; i < RX_BUF_COUNT; i++) {
ixp2000_reg_write(RING_RX_PENDING,
RX_BUF_DESC_BASE + (i * sizeof(struct ixpdev_rx_desc)));
}
ixp2000_uengine_load(0, &ixp2400_rx);
ixp2000_uengine_start_contexts(0, 0xff);
/* 256 entries, ring status set means 'empty', base address 0x0800. */
ixp2000_reg_write(RING_TX_PENDING_BASE, 0x44000800);
ixp2000_reg_write(RING_TX_PENDING_HEAD, 0x00000000);
ixp2000_reg_write(RING_TX_PENDING_TAIL, 0x00000000);
/* 256 entries, ring status set means 'full', base address 0x0c00. */
ixp2000_reg_write(RING_TX_DONE_BASE, 0x40000c00);
ixp2000_reg_write(RING_TX_DONE_HEAD, 0x00000000);
ixp2000_reg_write(RING_TX_DONE_TAIL, 0x00000000);
ixp2000_uengine_load(1, &ixp2400_tx);
ixp2000_uengine_start_contexts(1, 0xff);
for (i = 0; i < nds_count; i++) {
err = register_netdev(nds[i]);
if (err) {
while (--i >= 0)
unregister_netdev(nds[i]);
goto err_free_tx;
}
}
for (i = 0; i < nds_count; i++) {
printk(KERN_INFO "%s: IXP2000 MSF ethernet (port %d), "
"%.2x:%.2x:%.2x:%.2x:%.2x:%.2x.\n", nds[i]->name, i,
nds[i]->dev_addr[0], nds[i]->dev_addr[1],
nds[i]->dev_addr[2], nds[i]->dev_addr[3],
nds[i]->dev_addr[4], nds[i]->dev_addr[5]);
}
return 0;
err_free_tx:
for (i = 0; i < TX_BUF_COUNT; i++)
free_page((unsigned long)phys_to_virt(tx_desc[i].buf_addr));
err_free_rx:
for (i = 0; i < RX_BUF_COUNT; i++)
free_page((unsigned long)phys_to_virt(rx_desc[i].buf_addr));
err_out:
return err;
}
void ixpdev_deinit(void)
{
int i;
/* @@@ Flush out pending packets. */
for (i = 0; i < nds_count; i++)
unregister_netdev(nds[i]);
ixp2000_uengine_stop_contexts(1, 0xff);
ixp2000_uengine_stop_contexts(0, 0xff);
ixp2000_uengine_reset(0x3);
for (i = 0; i < TX_BUF_COUNT; i++)
free_page((unsigned long)phys_to_virt(tx_desc[i].buf_addr));
for (i = 0; i < RX_BUF_COUNT; i++)
free_page((unsigned long)phys_to_virt(rx_desc[i].buf_addr));
}
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