sfc: Split MAC stats DMA initiation and completion
From: Steve Hodgson <shodgson@solarflare.com>
Currently we initiate MAC stats DMA and busy-wait for completion when
stats are requested. We can improve on this with a periodic timer to
initiate and poll for stats, and opportunistically poll when stats are
requested.
Since efx_nic::stats_disable_count and efx_stats_{disable,enable}()
are Falcon-specific, rename them and move them accordingly.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/sfc/falcon.c b/drivers/net/sfc/falcon.c
index 9eec885..3ab2daf 100644
--- a/drivers/net/sfc/falcon.c
+++ b/drivers/net/sfc/falcon.c
@@ -36,8 +36,6 @@
**************************************************************************
*/
-static int disable_dma_stats;
-
/* This is set to 16 for a good reason. In summary, if larger than
* 16, the descriptor cache holds more than a default socket
* buffer's worth of packets (for UDP we can only have at most one
@@ -1890,7 +1888,7 @@
/* MAC stats will fail whilst the TX fifo is draining. Serialise
* the drain sequence with the statistics fetch */
- efx_stats_disable(efx);
+ falcon_stop_nic_stats(efx);
efx_reado(efx, ®, FR_AB_MAC_CTRL);
EFX_SET_OWORD_FIELD(reg, FRF_BB_TXFIFO_DRAIN_EN, 1);
@@ -1920,13 +1918,13 @@
udelay(10);
}
- efx_stats_enable(efx);
-
/* If we've reset the EM block and the link is up, then
* we'll have to kick the XAUI link so the PHY can recover */
if (efx->link_state.up && EFX_IS10G(efx) && EFX_WORKAROUND_5147(efx))
falcon_reset_xaui(efx);
+ falcon_start_nic_stats(efx);
+
return 0;
}
@@ -2010,25 +2008,19 @@
efx_writeo(efx, ®, FR_AZ_RX_CFG);
}
-int falcon_dma_stats(struct efx_nic *efx, unsigned int done_offset)
+static void falcon_stats_request(struct efx_nic *efx)
{
+ struct falcon_nic_data *nic_data = efx->nic_data;
efx_oword_t reg;
- u32 *dma_done;
- int i;
- if (disable_dma_stats)
- return 0;
+ WARN_ON(nic_data->stats_pending);
+ WARN_ON(nic_data->stats_disable_count);
- /* Statistics fetch will fail if the MAC is in TX drain */
- if (falcon_rev(efx) >= FALCON_REV_B0) {
- efx_oword_t temp;
- efx_reado(efx, &temp, FR_AB_MAC_CTRL);
- if (EFX_OWORD_FIELD(temp, FRF_BB_TXFIFO_DRAIN_EN))
- return 0;
- }
+ if (nic_data->stats_dma_done == NULL)
+ return; /* no mac selected */
- dma_done = (efx->stats_buffer.addr + done_offset);
- *dma_done = FALCON_STATS_NOT_DONE;
+ *nic_data->stats_dma_done = FALCON_STATS_NOT_DONE;
+ nic_data->stats_pending = true;
wmb(); /* ensure done flag is clear */
/* Initiate DMA transfer of stats */
@@ -2038,17 +2030,37 @@
efx->stats_buffer.dma_addr);
efx_writeo(efx, ®, FR_AB_MAC_STAT_DMA);
- /* Wait for transfer to complete */
- for (i = 0; i < 400; i++) {
- if (*(volatile u32 *)dma_done == FALCON_STATS_DONE) {
- rmb(); /* Ensure the stats are valid. */
- return 0;
- }
- udelay(10);
- }
+ mod_timer(&nic_data->stats_timer, round_jiffies_up(jiffies + HZ / 2));
+}
- EFX_ERR(efx, "timed out waiting for statistics\n");
- return -ETIMEDOUT;
+static void falcon_stats_complete(struct efx_nic *efx)
+{
+ struct falcon_nic_data *nic_data = efx->nic_data;
+
+ if (!nic_data->stats_pending)
+ return;
+
+ nic_data->stats_pending = 0;
+ if (*nic_data->stats_dma_done == FALCON_STATS_DONE) {
+ rmb(); /* read the done flag before the stats */
+ efx->mac_op->update_stats(efx);
+ } else {
+ EFX_ERR(efx, "timed out waiting for statistics\n");
+ }
+}
+
+static void falcon_stats_timer_func(unsigned long context)
+{
+ struct efx_nic *efx = (struct efx_nic *)context;
+ struct falcon_nic_data *nic_data = efx->nic_data;
+
+ spin_lock(&efx->stats_lock);
+
+ falcon_stats_complete(efx);
+ if (nic_data->stats_disable_count == 0)
+ falcon_stats_request(efx);
+
+ spin_unlock(&efx->stats_lock);
}
/**************************************************************************
@@ -2206,10 +2218,12 @@
int falcon_switch_mac(struct efx_nic *efx)
{
struct efx_mac_operations *old_mac_op = efx->mac_op;
+ struct falcon_nic_data *nic_data = efx->nic_data;
+ unsigned int stats_done_offset;
int rc = 0;
/* Don't try to fetch MAC stats while we're switching MACs */
- efx_stats_disable(efx);
+ falcon_stop_nic_stats(efx);
/* Internal loopbacks override the phy speed setting */
if (efx->loopback_mode == LOOPBACK_GMAC) {
@@ -2224,6 +2238,12 @@
efx->mac_op = (EFX_IS10G(efx) ?
&falcon_xmac_operations : &falcon_gmac_operations);
+ if (EFX_IS10G(efx))
+ stats_done_offset = XgDmaDone_offset;
+ else
+ stats_done_offset = GDmaDone_offset;
+ nic_data->stats_dma_done = efx->stats_buffer.addr + stats_done_offset;
+
if (old_mac_op == efx->mac_op)
goto out;
@@ -2235,7 +2255,7 @@
rc = falcon_reset_macs(efx);
out:
- efx_stats_enable(efx);
+ falcon_start_nic_stats(efx);
return rc;
}
@@ -2900,6 +2920,10 @@
goto fail6;
}
+ nic_data->stats_disable_count = 1;
+ setup_timer(&nic_data->stats_timer, &falcon_stats_timer_func,
+ (unsigned long)efx);
+
return 0;
fail6:
@@ -3125,11 +3149,58 @@
void falcon_update_nic_stats(struct efx_nic *efx)
{
+ struct falcon_nic_data *nic_data = efx->nic_data;
efx_oword_t cnt;
+ if (nic_data->stats_disable_count)
+ return;
+
efx_reado(efx, &cnt, FR_AZ_RX_NODESC_DROP);
efx->n_rx_nodesc_drop_cnt +=
EFX_OWORD_FIELD(cnt, FRF_AB_RX_NODESC_DROP_CNT);
+
+ if (nic_data->stats_pending &&
+ *nic_data->stats_dma_done == FALCON_STATS_DONE) {
+ nic_data->stats_pending = false;
+ rmb(); /* read the done flag before the stats */
+ efx->mac_op->update_stats(efx);
+ }
+}
+
+void falcon_start_nic_stats(struct efx_nic *efx)
+{
+ struct falcon_nic_data *nic_data = efx->nic_data;
+
+ spin_lock_bh(&efx->stats_lock);
+ if (--nic_data->stats_disable_count == 0)
+ falcon_stats_request(efx);
+ spin_unlock_bh(&efx->stats_lock);
+}
+
+void falcon_stop_nic_stats(struct efx_nic *efx)
+{
+ struct falcon_nic_data *nic_data = efx->nic_data;
+ int i;
+
+ might_sleep();
+
+ spin_lock_bh(&efx->stats_lock);
+ ++nic_data->stats_disable_count;
+ spin_unlock_bh(&efx->stats_lock);
+
+ del_timer_sync(&nic_data->stats_timer);
+
+ /* Wait enough time for the most recent transfer to
+ * complete. */
+ for (i = 0; i < 4 && nic_data->stats_pending; i++) {
+ if (*nic_data->stats_dma_done == FALCON_STATS_DONE)
+ break;
+ msleep(1);
+ }
+
+ spin_lock_bh(&efx->stats_lock);
+ falcon_stats_complete(efx);
+ spin_unlock_bh(&efx->stats_lock);
}
/**************************************************************************