--- a/master/device.c Thu Aug 09 15:01:14 2007 +0000
+++ b/master/device.c Thu Aug 09 15:45:56 2007 +0000
@@ -69,6 +69,8 @@
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 @@
#endif
device->master = master;
+ device->tx_ring_index = 0;
#ifdef EC_DEBUG_IF
if (device == &master->main_device)
@@ -94,29 +97,33 @@
}
#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
- }
-
- // 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++)
+ device->tx_skb[i] = NULL;
+
+ 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;
-#ifdef EC_DEBUG_IF
- out_debug:
+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
ec_debug_clear(&device->dbg);
-#endif
- out_return:
+out_return:
+#endif
return -1;
}
@@ -128,8 +135,11 @@
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 @@
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_detach(ec_device_t *device /**< EtherCAT device */)
{
+ unsigned int i;
+
device->dev = NULL;
device->poll = NULL;
device->module = NULL;
@@ -172,7 +190,8 @@
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 @@
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 @@
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);
- }
-
-#ifdef EC_DEBUG_IF
- ec_debug_send(&device->dbg, device->tx_skb->data, ETH_HLEN + size);
+ ec_print_data(skb->data + ETH_HLEN, size);
+ }
+
+#ifdef EC_DEBUG_IF
+ 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 @@
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
--- a/master/device.h Thu Aug 09 15:01:14 2007 +0000
+++ b/master/device.h Thu Aug 09 15:45:56 2007 +0000
@@ -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 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;