linux/drivers/net/caif/caif_shmcore.c

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/*
* Copyright (C) ST-Ericsson AB 2010
* Contact: Sjur Brendeland / sjur.brandeland@stericsson.com
* Authors: Amarnath Revanna / amarnath.bangalore.revanna@stericsson.com,
* Daniel Martensson / daniel.martensson@stericsson.com
* License terms: GNU General Public License (GPL) version 2
*/
#define pr_fmt(fmt) KBUILD_MODNAME ":" __func__ "():" fmt
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <net/caif/caif_device.h>
#include <net/caif/caif_shm.h>
#define NR_TX_BUF 6
#define NR_RX_BUF 6
#define TX_BUF_SZ 0x2000
#define RX_BUF_SZ 0x2000
#define CAIF_NEEDED_HEADROOM 32
#define CAIF_FLOW_ON 1
#define CAIF_FLOW_OFF 0
#define LOW_WATERMARK 3
#define HIGH_WATERMARK 4
/* Maximum number of CAIF buffers per shared memory buffer. */
#define SHM_MAX_FRMS_PER_BUF 10
/*
* Size in bytes of the descriptor area
* (With end of descriptor signalling)
*/
#define SHM_CAIF_DESC_SIZE ((SHM_MAX_FRMS_PER_BUF + 1) * \
sizeof(struct shm_pck_desc))
/*
* Offset to the first CAIF frame within a shared memory buffer.
* Aligned on 32 bytes.
*/
#define SHM_CAIF_FRM_OFS (SHM_CAIF_DESC_SIZE + (SHM_CAIF_DESC_SIZE % 32))
/* Number of bytes for CAIF shared memory header. */
#define SHM_HDR_LEN 1
/* Number of padding bytes for the complete CAIF frame. */
#define SHM_FRM_PAD_LEN 4
#define CAIF_MAX_MTU 4096
#define SHM_SET_FULL(x) (((x+1) & 0x0F) << 0)
#define SHM_GET_FULL(x) (((x >> 0) & 0x0F) - 1)
#define SHM_SET_EMPTY(x) (((x+1) & 0x0F) << 4)
#define SHM_GET_EMPTY(x) (((x >> 4) & 0x0F) - 1)
#define SHM_FULL_MASK (0x0F << 0)
#define SHM_EMPTY_MASK (0x0F << 4)
struct shm_pck_desc {
/*
* Offset from start of shared memory area to start of
* shared memory CAIF frame.
*/
u32 frm_ofs;
u32 frm_len;
};
struct buf_list {
unsigned char *desc_vptr;
u32 phy_addr;
u32 index;
u32 len;
u32 frames;
u32 frm_ofs;
struct list_head list;
};
struct shm_caif_frm {
/* Number of bytes of padding before the CAIF frame. */
u8 hdr_ofs;
};
struct shmdrv_layer {
/* caif_dev_common must always be first in the structure*/
struct caif_dev_common cfdev;
u32 shm_tx_addr;
u32 shm_rx_addr;
u32 shm_base_addr;
u32 tx_empty_available;
spinlock_t lock;
struct list_head tx_empty_list;
struct list_head tx_pend_list;
struct list_head tx_full_list;
struct list_head rx_empty_list;
struct list_head rx_pend_list;
struct list_head rx_full_list;
struct workqueue_struct *pshm_tx_workqueue;
struct workqueue_struct *pshm_rx_workqueue;
struct work_struct shm_tx_work;
struct work_struct shm_rx_work;
struct sk_buff_head sk_qhead;
struct shmdev_layer *pshm_dev;
};
static int shm_netdev_open(struct net_device *shm_netdev)
{
netif_wake_queue(shm_netdev);
return 0;
}
static int shm_netdev_close(struct net_device *shm_netdev)
{
netif_stop_queue(shm_netdev);
return 0;
}
int caif_shmdrv_rx_cb(u32 mbx_msg, void *priv)
{
struct buf_list *pbuf;
struct shmdrv_layer *pshm_drv;
struct list_head *pos;
u32 avail_emptybuff = 0;
unsigned long flags = 0;
pshm_drv = (struct shmdrv_layer *)priv;
/* Check for received buffers. */
if (mbx_msg & SHM_FULL_MASK) {
int idx;
spin_lock_irqsave(&pshm_drv->lock, flags);
/* Check whether we have any outstanding buffers. */
if (list_empty(&pshm_drv->rx_empty_list)) {
/* Release spin lock. */
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* We print even in IRQ context... */
pr_warn("No empty Rx buffers to fill: "
"mbx_msg:%x\n", mbx_msg);
/* Bail out. */
goto err_sync;
}
pbuf =
list_entry(pshm_drv->rx_empty_list.next,
struct buf_list, list);
idx = pbuf->index;
/* Check buffer synchronization. */
if (idx != SHM_GET_FULL(mbx_msg)) {
/* We print even in IRQ context... */
pr_warn(
"phyif_shm_mbx_msg_cb: RX full out of sync:"
" idx:%d, msg:%x SHM_GET_FULL(mbx_msg):%x\n",
idx, mbx_msg, SHM_GET_FULL(mbx_msg));
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* Bail out. */
goto err_sync;
}
list_del_init(&pbuf->list);
list_add_tail(&pbuf->list, &pshm_drv->rx_full_list);
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* Schedule RX work queue. */
if (!work_pending(&pshm_drv->shm_rx_work))
queue_work(pshm_drv->pshm_rx_workqueue,
&pshm_drv->shm_rx_work);
}
/* Check for emptied buffers. */
if (mbx_msg & SHM_EMPTY_MASK) {
int idx;
spin_lock_irqsave(&pshm_drv->lock, flags);
/* Check whether we have any outstanding buffers. */
if (list_empty(&pshm_drv->tx_full_list)) {
/* We print even in IRQ context... */
pr_warn("No TX to empty: msg:%x\n", mbx_msg);
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* Bail out. */
goto err_sync;
}
pbuf =
list_entry(pshm_drv->tx_full_list.next,
struct buf_list, list);
idx = pbuf->index;
/* Check buffer synchronization. */
if (idx != SHM_GET_EMPTY(mbx_msg)) {
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* We print even in IRQ context... */
pr_warn("TX empty "
"out of sync:idx:%d, msg:%x\n", idx, mbx_msg);
/* Bail out. */
goto err_sync;
}
list_del_init(&pbuf->list);
/* Reset buffer parameters. */
pbuf->frames = 0;
pbuf->frm_ofs = SHM_CAIF_FRM_OFS;
list_add_tail(&pbuf->list, &pshm_drv->tx_empty_list);
/* Check the available no. of buffers in the empty list */
list_for_each(pos, &pshm_drv->tx_empty_list)
avail_emptybuff++;
/* Check whether we have to wake up the transmitter. */
if ((avail_emptybuff > HIGH_WATERMARK) &&
(!pshm_drv->tx_empty_available)) {
pshm_drv->tx_empty_available = 1;
pshm_drv->cfdev.flowctrl
(pshm_drv->pshm_dev->pshm_netdev,
CAIF_FLOW_ON);
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* Schedule the work queue. if required */
if (!work_pending(&pshm_drv->shm_tx_work))
queue_work(pshm_drv->pshm_tx_workqueue,
&pshm_drv->shm_tx_work);
} else
spin_unlock_irqrestore(&pshm_drv->lock, flags);
}
return 0;
err_sync:
return -EIO;
}
static void shm_rx_work_func(struct work_struct *rx_work)
{
struct shmdrv_layer *pshm_drv;
struct buf_list *pbuf;
unsigned long flags = 0;
struct sk_buff *skb;
char *p;
int ret;
pshm_drv = container_of(rx_work, struct shmdrv_layer, shm_rx_work);
while (1) {
struct shm_pck_desc *pck_desc;
spin_lock_irqsave(&pshm_drv->lock, flags);
/* Check for received buffers. */
if (list_empty(&pshm_drv->rx_full_list)) {
spin_unlock_irqrestore(&pshm_drv->lock, flags);
break;
}
pbuf =
list_entry(pshm_drv->rx_full_list.next, struct buf_list,
list);
list_del_init(&pbuf->list);
/* Retrieve pointer to start of the packet descriptor area. */
pck_desc = (struct shm_pck_desc *) pbuf->desc_vptr;
/*
* Check whether descriptor contains a CAIF shared memory
* frame.
*/
while (pck_desc->frm_ofs) {
unsigned int frm_buf_ofs;
unsigned int frm_pck_ofs;
unsigned int frm_pck_len;
/*
* Check whether offset is within buffer limits
* (lower).
*/
if (pck_desc->frm_ofs <
(pbuf->phy_addr - pshm_drv->shm_base_addr))
break;
/*
* Check whether offset is within buffer limits
* (higher).
*/
if (pck_desc->frm_ofs >
((pbuf->phy_addr - pshm_drv->shm_base_addr) +
pbuf->len))
break;
/* Calculate offset from start of buffer. */
frm_buf_ofs =
pck_desc->frm_ofs - (pbuf->phy_addr -
pshm_drv->shm_base_addr);
/*
* Calculate offset and length of CAIF packet while
* taking care of the shared memory header.
*/
frm_pck_ofs =
frm_buf_ofs + SHM_HDR_LEN +
(*(pbuf->desc_vptr + frm_buf_ofs));
frm_pck_len =
(pck_desc->frm_len - SHM_HDR_LEN -
(*(pbuf->desc_vptr + frm_buf_ofs)));
/* Check whether CAIF packet is within buffer limits */
if ((frm_pck_ofs + pck_desc->frm_len) > pbuf->len)
break;
/* Get a suitable CAIF packet and copy in data. */
skb = netdev_alloc_skb(pshm_drv->pshm_dev->pshm_netdev,
frm_pck_len + 1);
BUG_ON(skb == NULL);
p = skb_put(skb, frm_pck_len);
memcpy(p, pbuf->desc_vptr + frm_pck_ofs, frm_pck_len);
skb->protocol = htons(ETH_P_CAIF);
skb_reset_mac_header(skb);
skb->dev = pshm_drv->pshm_dev->pshm_netdev;
/* Push received packet up the stack. */
ret = netif_rx_ni(skb);
if (!ret) {
pshm_drv->pshm_dev->pshm_netdev->stats.
rx_packets++;
pshm_drv->pshm_dev->pshm_netdev->stats.
rx_bytes += pck_desc->frm_len;
} else
++pshm_drv->pshm_dev->pshm_netdev->stats.
rx_dropped;
/* Move to next packet descriptor. */
pck_desc++;
}
list_add_tail(&pbuf->list, &pshm_drv->rx_pend_list);
spin_unlock_irqrestore(&pshm_drv->lock, flags);
}
/* Schedule the work queue. if required */
if (!work_pending(&pshm_drv->shm_tx_work))
queue_work(pshm_drv->pshm_tx_workqueue, &pshm_drv->shm_tx_work);
}
static void shm_tx_work_func(struct work_struct *tx_work)
{
u32 mbox_msg;
unsigned int frmlen, avail_emptybuff, append = 0;
unsigned long flags = 0;
struct buf_list *pbuf = NULL;
struct shmdrv_layer *pshm_drv;
struct shm_caif_frm *frm;
struct sk_buff *skb;
struct shm_pck_desc *pck_desc;
struct list_head *pos;
pshm_drv = container_of(tx_work, struct shmdrv_layer, shm_tx_work);
do {
/* Initialize mailbox message. */
mbox_msg = 0x00;
avail_emptybuff = 0;
spin_lock_irqsave(&pshm_drv->lock, flags);
/* Check for pending receive buffers. */
if (!list_empty(&pshm_drv->rx_pend_list)) {
pbuf = list_entry(pshm_drv->rx_pend_list.next,
struct buf_list, list);
list_del_init(&pbuf->list);
list_add_tail(&pbuf->list, &pshm_drv->rx_empty_list);
/*
* Value index is never changed,
* so read access should be safe.
*/
mbox_msg |= SHM_SET_EMPTY(pbuf->index);
}
skb = skb_peek(&pshm_drv->sk_qhead);
if (skb == NULL)
goto send_msg;
/* Check the available no. of buffers in the empty list */
list_for_each(pos, &pshm_drv->tx_empty_list)
avail_emptybuff++;
if ((avail_emptybuff < LOW_WATERMARK) &&
pshm_drv->tx_empty_available) {
/* Update blocking condition. */
pshm_drv->tx_empty_available = 0;
pshm_drv->cfdev.flowctrl
(pshm_drv->pshm_dev->pshm_netdev,
CAIF_FLOW_OFF);
}
/*
* We simply return back to the caller if we do not have space
* either in Tx pending list or Tx empty list. In this case,
* we hold the received skb in the skb list, waiting to
* be transmitted once Tx buffers become available
*/
if (list_empty(&pshm_drv->tx_empty_list))
goto send_msg;
/* Get the first free Tx buffer. */
pbuf = list_entry(pshm_drv->tx_empty_list.next,
struct buf_list, list);
do {
if (append) {
skb = skb_peek(&pshm_drv->sk_qhead);
if (skb == NULL)
break;
}
frm = (struct shm_caif_frm *)
(pbuf->desc_vptr + pbuf->frm_ofs);
frm->hdr_ofs = 0;
frmlen = 0;
frmlen += SHM_HDR_LEN + frm->hdr_ofs + skb->len;
/* Add tail padding if needed. */
if (frmlen % SHM_FRM_PAD_LEN)
frmlen += SHM_FRM_PAD_LEN -
(frmlen % SHM_FRM_PAD_LEN);
/*
* Verify that packet, header and additional padding
* can fit within the buffer frame area.
*/
if (frmlen >= (pbuf->len - pbuf->frm_ofs))
break;
if (!append) {
list_del_init(&pbuf->list);
append = 1;
}
skb = skb_dequeue(&pshm_drv->sk_qhead);
/* Copy in CAIF frame. */
skb_copy_bits(skb, 0, pbuf->desc_vptr +
pbuf->frm_ofs + SHM_HDR_LEN +
frm->hdr_ofs, skb->len);
pshm_drv->pshm_dev->pshm_netdev->stats.tx_packets++;
pshm_drv->pshm_dev->pshm_netdev->stats.tx_bytes +=
frmlen;
dev_kfree_skb(skb);
/* Fill in the shared memory packet descriptor area. */
pck_desc = (struct shm_pck_desc *) (pbuf->desc_vptr);
/* Forward to current frame. */
pck_desc += pbuf->frames;
pck_desc->frm_ofs = (pbuf->phy_addr -
pshm_drv->shm_base_addr) +
pbuf->frm_ofs;
pck_desc->frm_len = frmlen;
/* Terminate packet descriptor area. */
pck_desc++;
pck_desc->frm_ofs = 0;
/* Update buffer parameters. */
pbuf->frames++;
pbuf->frm_ofs += frmlen + (frmlen % 32);
} while (pbuf->frames < SHM_MAX_FRMS_PER_BUF);
/* Assign buffer as full. */
list_add_tail(&pbuf->list, &pshm_drv->tx_full_list);
append = 0;
mbox_msg |= SHM_SET_FULL(pbuf->index);
send_msg:
spin_unlock_irqrestore(&pshm_drv->lock, flags);
if (mbox_msg)
pshm_drv->pshm_dev->pshmdev_mbxsend
(pshm_drv->pshm_dev->shm_id, mbox_msg);
} while (mbox_msg);
}
static int shm_netdev_tx(struct sk_buff *skb, struct net_device *shm_netdev)
{
struct shmdrv_layer *pshm_drv;
unsigned long flags = 0;
pshm_drv = netdev_priv(shm_netdev);
spin_lock_irqsave(&pshm_drv->lock, flags);
skb_queue_tail(&pshm_drv->sk_qhead, skb);
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* Schedule Tx work queue. for deferred processing of skbs*/
if (!work_pending(&pshm_drv->shm_tx_work))
queue_work(pshm_drv->pshm_tx_workqueue, &pshm_drv->shm_tx_work);
return 0;
}
static const struct net_device_ops netdev_ops = {
.ndo_open = shm_netdev_open,
.ndo_stop = shm_netdev_close,
.ndo_start_xmit = shm_netdev_tx,
};
static void shm_netdev_setup(struct net_device *pshm_netdev)
{
struct shmdrv_layer *pshm_drv;
pshm_netdev->netdev_ops = &netdev_ops;
pshm_netdev->mtu = CAIF_MAX_MTU;
pshm_netdev->type = ARPHRD_CAIF;
pshm_netdev->hard_header_len = CAIF_NEEDED_HEADROOM;
pshm_netdev->tx_queue_len = 0;
pshm_netdev->destructor = free_netdev;
pshm_drv = netdev_priv(pshm_netdev);
/* Initialize structures in a clean state. */
memset(pshm_drv, 0, sizeof(struct shmdrv_layer));
pshm_drv->cfdev.link_select = CAIF_LINK_LOW_LATENCY;
}
int caif_shmcore_probe(struct shmdev_layer *pshm_dev)
{
int result, j;
struct shmdrv_layer *pshm_drv = NULL;
pshm_dev->pshm_netdev = alloc_netdev(sizeof(struct shmdrv_layer),
"cfshm%d", shm_netdev_setup);
if (!pshm_dev->pshm_netdev)
return -ENOMEM;
pshm_drv = netdev_priv(pshm_dev->pshm_netdev);
pshm_drv->pshm_dev = pshm_dev;
/*
* Initialization starts with the verification of the
* availability of MBX driver by calling its setup function.
* MBX driver must be available by this time for proper
* functioning of SHM driver.
*/
if ((pshm_dev->pshmdev_mbxsetup
(caif_shmdrv_rx_cb, pshm_dev, pshm_drv)) != 0) {
pr_warn("Could not config. SHM Mailbox,"
" Bailing out.....\n");
free_netdev(pshm_dev->pshm_netdev);
return -ENODEV;
}
skb_queue_head_init(&pshm_drv->sk_qhead);
pr_info("SHM DEVICE[%d] PROBED BY DRIVER, NEW SHM DRIVER"
" INSTANCE AT pshm_drv =0x%p\n",
pshm_drv->pshm_dev->shm_id, pshm_drv);
if (pshm_dev->shm_total_sz <
(NR_TX_BUF * TX_BUF_SZ + NR_RX_BUF * RX_BUF_SZ)) {
pr_warn("ERROR, Amount of available"
" Phys. SHM cannot accomodate current SHM "
"driver configuration, Bailing out ...\n");
free_netdev(pshm_dev->pshm_netdev);
return -ENOMEM;
}
pshm_drv->shm_base_addr = pshm_dev->shm_base_addr;
pshm_drv->shm_tx_addr = pshm_drv->shm_base_addr;
if (pshm_dev->shm_loopback)
pshm_drv->shm_rx_addr = pshm_drv->shm_tx_addr;
else
pshm_drv->shm_rx_addr = pshm_dev->shm_base_addr +
(NR_TX_BUF * TX_BUF_SZ);
INIT_LIST_HEAD(&pshm_drv->tx_empty_list);
INIT_LIST_HEAD(&pshm_drv->tx_pend_list);
INIT_LIST_HEAD(&pshm_drv->tx_full_list);
INIT_LIST_HEAD(&pshm_drv->rx_empty_list);
INIT_LIST_HEAD(&pshm_drv->rx_pend_list);
INIT_LIST_HEAD(&pshm_drv->rx_full_list);
INIT_WORK(&pshm_drv->shm_tx_work, shm_tx_work_func);
INIT_WORK(&pshm_drv->shm_rx_work, shm_rx_work_func);
pshm_drv->pshm_tx_workqueue =
create_singlethread_workqueue("shm_tx_work");
pshm_drv->pshm_rx_workqueue =
create_singlethread_workqueue("shm_rx_work");
for (j = 0; j < NR_TX_BUF; j++) {
struct buf_list *tx_buf =
kmalloc(sizeof(struct buf_list), GFP_KERNEL);
if (tx_buf == NULL) {
pr_warn("ERROR, Could not"
" allocate dynamic mem. for tx_buf,"
" Bailing out ...\n");
free_netdev(pshm_dev->pshm_netdev);
return -ENOMEM;
}
tx_buf->index = j;
tx_buf->phy_addr = pshm_drv->shm_tx_addr + (TX_BUF_SZ * j);
tx_buf->len = TX_BUF_SZ;
tx_buf->frames = 0;
tx_buf->frm_ofs = SHM_CAIF_FRM_OFS;
if (pshm_dev->shm_loopback)
tx_buf->desc_vptr = (char *)tx_buf->phy_addr;
else
tx_buf->desc_vptr =
ioremap(tx_buf->phy_addr, TX_BUF_SZ);
list_add_tail(&tx_buf->list, &pshm_drv->tx_empty_list);
}
for (j = 0; j < NR_RX_BUF; j++) {
struct buf_list *rx_buf =
kmalloc(sizeof(struct buf_list), GFP_KERNEL);
if (rx_buf == NULL) {
pr_warn("ERROR, Could not"
" allocate dynamic mem.for rx_buf,"
" Bailing out ...\n");
free_netdev(pshm_dev->pshm_netdev);
return -ENOMEM;
}
rx_buf->index = j;
rx_buf->phy_addr = pshm_drv->shm_rx_addr + (RX_BUF_SZ * j);
rx_buf->len = RX_BUF_SZ;
if (pshm_dev->shm_loopback)
rx_buf->desc_vptr = (char *)rx_buf->phy_addr;
else
rx_buf->desc_vptr =
ioremap(rx_buf->phy_addr, RX_BUF_SZ);
list_add_tail(&rx_buf->list, &pshm_drv->rx_empty_list);
}
pshm_drv->tx_empty_available = 1;
result = register_netdev(pshm_dev->pshm_netdev);
if (result)
pr_warn("ERROR[%d], SHM could not, "
"register with NW FRMWK Bailing out ...\n", result);
return result;
}
void caif_shmcore_remove(struct net_device *pshm_netdev)
{
struct buf_list *pbuf;
struct shmdrv_layer *pshm_drv = NULL;
pshm_drv = netdev_priv(pshm_netdev);
while (!(list_empty(&pshm_drv->tx_pend_list))) {
pbuf =
list_entry(pshm_drv->tx_pend_list.next,
struct buf_list, list);
list_del(&pbuf->list);
kfree(pbuf);
}
while (!(list_empty(&pshm_drv->tx_full_list))) {
pbuf =
list_entry(pshm_drv->tx_full_list.next,
struct buf_list, list);
list_del(&pbuf->list);
kfree(pbuf);
}
while (!(list_empty(&pshm_drv->tx_empty_list))) {
pbuf =
list_entry(pshm_drv->tx_empty_list.next,
struct buf_list, list);
list_del(&pbuf->list);
kfree(pbuf);
}
while (!(list_empty(&pshm_drv->rx_full_list))) {
pbuf =
list_entry(pshm_drv->tx_full_list.next,
struct buf_list, list);
list_del(&pbuf->list);
kfree(pbuf);
}
while (!(list_empty(&pshm_drv->rx_pend_list))) {
pbuf =
list_entry(pshm_drv->tx_pend_list.next,
struct buf_list, list);
list_del(&pbuf->list);
kfree(pbuf);
}
while (!(list_empty(&pshm_drv->rx_empty_list))) {
pbuf =
list_entry(pshm_drv->rx_empty_list.next,
struct buf_list, list);
list_del(&pbuf->list);
kfree(pbuf);
}
/* Destroy work queues. */
destroy_workqueue(pshm_drv->pshm_tx_workqueue);
destroy_workqueue(pshm_drv->pshm_rx_workqueue);
unregister_netdev(pshm_netdev);
}