bkinnightskytw
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ethercat
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Switched to tx socket buffer ring to avoid race conditions when multiple 

instances call ec_device_send() in short intervals.
This commit is contained in:
Florian Pose 2007-08-09 15:45:56 +00:00
parent 68e6dfc108
commit 0d16910def
2 changed files with 56 additions and 28 deletions
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78
master/device.c
View File

@ -69,6 +69,8 @@ int ec_device_init(ec_device_t *device, /**< EtherCAT device */
ec_master_t *master /**< master owning the device */
)
{
unsigned int i;
struct ethhdr *eth;
#ifdef EC_DEBUG_IF
char ifname[10];
char mb = 'x';
@ -79,6 +81,7 @@ int ec_device_init(ec_device_t *device, /**< EtherCAT device */
#endif
device->master = master;
device->tx_ring_index = 0;
#ifdef EC_DEBUG_IF
if (device == &master->main_device)
@ -94,29 +97,33 @@ int ec_device_init(ec_device_t *device, /**< EtherCAT device */
}
#endif
if (!(device->tx_skb = dev_alloc_skb(ETH_FRAME_LEN))) {
EC_ERR("Error allocating device socket buffer!\n");
#ifdef EC_DEBUG_IF
goto out_debug;
#else
goto out_return;
#endif
}
for (i = 0; i < EC_TX_RING_SIZE; i++)
device->tx_skb[i] = NULL;
// add Ethernet-II-header
skb_reserve(device->tx_skb, ETH_HLEN);
device->eth = (struct ethhdr *) skb_push(device->tx_skb, ETH_HLEN);
device->eth->h_proto = htons(0x88A4);
memset(device->eth->h_dest, 0xFF, ETH_ALEN);
for (i = 0; i < EC_TX_RING_SIZE; i++) {
if (!(device->tx_skb[i] = dev_alloc_skb(ETH_FRAME_LEN))) {
EC_ERR("Error allocating device socket buffer!\n");
goto out_tx_ring;
}
// add Ethernet-II-header
skb_reserve(device->tx_skb[i], ETH_HLEN);
eth = (struct ethhdr *) skb_push(device->tx_skb[i], ETH_HLEN);
eth->h_proto = htons(0x88A4);
memset(eth->h_dest, 0xFF, ETH_ALEN);
}
ec_device_detach(device); // resets remaining fields
return 0;
out_tx_ring:
for (i = 0; i < EC_TX_RING_SIZE; i++)
if (device->tx_skb[i])
dev_kfree_skb(device->tx_skb[i]);
#ifdef EC_DEBUG_IF
out_debug:
ec_debug_clear(&device->dbg);
out_return:
#endif
out_return:
return -1;
}
@ -128,8 +135,11 @@ int ec_device_init(ec_device_t *device, /**< EtherCAT device */
void ec_device_clear(ec_device_t *device /**< EtherCAT device */)
{
unsigned int i;
if (device->open) ec_device_close(device);
dev_kfree_skb(device->tx_skb);
for (i = 0; i < EC_TX_RING_SIZE; i++)
dev_kfree_skb(device->tx_skb[i]);
#ifdef EC_DEBUG_IF
ec_debug_clear(&device->dbg);
#endif
@ -147,14 +157,20 @@ void ec_device_attach(ec_device_t *device, /**< EtherCAT device */
struct module *module /**< the device's module */
)
{
unsigned int i;
struct ethhdr *eth;
ec_device_detach(device); // resets fields
device->dev = net_dev;
device->poll = poll;
device->module = module;
device->tx_skb->dev = net_dev;
memcpy(device->eth->h_source, net_dev->dev_addr, ETH_ALEN);
for (i = 0; i < EC_TX_RING_SIZE; i++) {
device->tx_skb[i]->dev = net_dev;
eth = (struct ethhdr *) (device->tx_skb[i]->data + ETH_HLEN);
memcpy(eth->h_source, net_dev->dev_addr, ETH_ALEN);
}
}
/*****************************************************************************/
@ -165,6 +181,8 @@ void ec_device_attach(ec_device_t *device, /**< EtherCAT device */
void ec_device_detach(ec_device_t *device /**< EtherCAT device */)
{
unsigned int i;
device->dev = NULL;
device->poll = NULL;
device->module = NULL;
@ -172,7 +190,8 @@ void ec_device_detach(ec_device_t *device /**< EtherCAT device */)
device->link_state = 0; // down
device->tx_count = 0;
device->rx_count = 0;
device->tx_skb->dev = NULL;
for (i = 0; i < EC_TX_RING_SIZE; i++)
device->tx_skb[i]->dev = NULL;
}
/*****************************************************************************/
@ -236,7 +255,12 @@ int ec_device_close(ec_device_t *device /**< EtherCAT device */)
uint8_t *ec_device_tx_data(ec_device_t *device /**< EtherCAT device */)
{
return device->tx_skb->data + ETH_HLEN;
/* cycle through socket buffers, because otherwise there is a race
* condition, if multiple frames are sent and the DMA is not scheduled in
* between. */
device->tx_ring_index++;
device->tx_ring_index %= EC_TX_RING_SIZE;
return device->tx_skb[device->tx_ring_index]->data + ETH_HLEN;
}
/*****************************************************************************/
@ -251,27 +275,29 @@ void ec_device_send(ec_device_t *device, /**< EtherCAT device */
size_t size /**< number of bytes to send */
)
{
struct sk_buff *skb = device->tx_skb[device->tx_ring_index];
if (unlikely(!device->link_state)) // Link down
return;
// set the right length for the data
device->tx_skb->len = ETH_HLEN + size;
skb->len = ETH_HLEN + size;
if (unlikely(device->master->debug_level > 1)) {
EC_DBG("sending frame:\n");
ec_print_data(device->tx_skb->data + ETH_HLEN, size);
ec_print_data(skb->data + ETH_HLEN, size);
}
#ifdef EC_DEBUG_IF
ec_debug_send(&device->dbg, device->tx_skb->data, ETH_HLEN + size);
ec_debug_send(&device->dbg, skb->data, ETH_HLEN + size);
#endif
#ifdef EC_DEBUG_RING
ec_device_debug_ring_append(
device, TX, device->tx_skb->data + ETH_HLEN, size);
device, TX, skb->data + ETH_HLEN, size);
#endif
// start sending
device->dev->hard_start_xmit(device->tx_skb, device->dev);
device->dev->hard_start_xmit(skb, device->dev);
device->tx_count++;
}
@ -389,7 +415,7 @@ void ecdev_receive(ec_device_t *device, /**< EtherCAT device */
if (unlikely(device->master->debug_level > 1)) {
EC_DBG("Received frame:\n");
ec_print_data_diff(device->tx_skb->data + ETH_HLEN, ec_data, ec_size);
ec_print_data(ec_data, ec_size);
}
#ifdef EC_DEBUG_IF

6
master/device.h
View File

@ -47,6 +47,8 @@
#include "../devices/ecdev.h"
#include "globals.h"
#define EC_TX_RING_SIZE 2
#ifdef EC_DEBUG_IF
#include "debug.h"
#endif
@ -84,8 +86,8 @@ struct ec_device
struct module *module; /**< pointer to the device's owning module */
uint8_t open; /**< true, if the net_device has been opened */
uint8_t link_state; /**< device link state */
struct sk_buff *tx_skb; /**< transmit socket buffer */
struct ethhdr *eth; /**< pointer to ethernet header in socket buffer */
struct sk_buff *tx_skb[EC_TX_RING_SIZE]; /**< transmit skb ring */
unsigned int tx_ring_index;
cycles_t cycles_poll; /**< cycles of last poll */
#ifdef EC_DEBUG_RING
struct timeval timeval_poll;