sfc: refactor EF10 stats handling

Separate the generation-count handling from the format conversion, to
 make it easier to re-use both for EF100.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 34 insertions, 34 deletions

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index c99fedb315fe..49af06ba7a8e 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -1279,6 +1279,14 @@ static int efx_ef10_dimension_resources(struct efx_nic *efx)
 	return 0;
 }
 
+static void efx_ef10_fini_nic(struct efx_nic *efx)
+{
+	struct efx_ef10_nic_data *nic_data = efx->nic_data;
+
+	kfree(nic_data->mc_stats);
+	nic_data->mc_stats = NULL;
+}
+
 static int efx_ef10_init_nic(struct efx_nic *efx)
 {
 	struct efx_ef10_nic_data *nic_data = efx->nic_data;
@@ -1300,6 +1308,11 @@ static int efx_ef10_init_nic(struct efx_nic *efx)
 		efx->must_realloc_vis = false;
 	}
 
+	nic_data->mc_stats = kmalloc(efx->num_mac_stats * sizeof(__le64),
+				     GFP_KERNEL);
+	if (!nic_data->mc_stats)
+		return -ENOMEM;
+
 	if (nic_data->must_restore_piobufs && nic_data->n_piobufs) {
 		rc = efx_ef10_alloc_piobufs(efx, nic_data->n_piobufs);
 		if (rc == 0) {
@@ -1775,55 +1788,42 @@ static size_t efx_ef10_update_stats_common(struct efx_nic *efx, u64 *full_stats,
 	return stats_count;
 }
 
-static int efx_ef10_try_update_nic_stats_pf(struct efx_nic *efx)
+static size_t efx_ef10_update_stats_pf(struct efx_nic *efx, u64 *full_stats,
+				       struct rtnl_link_stats64 *core_stats)
 {
 	struct efx_ef10_nic_data *nic_data = efx->nic_data;
 	DECLARE_BITMAP(mask, EF10_STAT_COUNT);
-	__le64 generation_start, generation_end;
 	u64 *stats = nic_data->stats;
-	__le64 *dma_stats;
 
 	efx_ef10_get_stat_mask(efx, mask);
 
-	dma_stats = efx->stats_buffer.addr;
-
-	generation_end = dma_stats[efx->num_mac_stats - 1];
-	if (generation_end == EFX_MC_STATS_GENERATION_INVALID)
-		return 0;
-	rmb();
-	efx_nic_update_stats(efx_ef10_stat_desc, EF10_STAT_COUNT, mask,
-			     stats, efx->stats_buffer.addr, false);
-	rmb();
-	generation_start = dma_stats[MC_CMD_MAC_GENERATION_START];
-	if (generation_end != generation_start)
-		return -EAGAIN;
+	efx_nic_copy_stats(efx, nic_data->mc_stats);
+	efx_nic_update_stats(efx_ef10_stat_desc, EF10_STAT_COUNT,
+			     mask, stats, nic_data->mc_stats, false);
 
 	/* Update derived statistics */
 	efx_nic_fix_nodesc_drop_stat(efx,
 				     &stats[EF10_STAT_port_rx_nodesc_drops]);
+	/* MC Firmware reads RX_BYTES and RX_GOOD_BYTES from the MAC.
+	 * It then calculates RX_BAD_BYTES and DMAs it to us with RX_BYTES.
+	 * We report these as port_rx_ stats. We are not given RX_GOOD_BYTES.
+	 * Here we calculate port_rx_good_bytes.
+	 */
 	stats[EF10_STAT_port_rx_good_bytes] =
 		stats[EF10_STAT_port_rx_bytes] -
 		stats[EF10_STAT_port_rx_bytes_minus_good_bytes];
+
+	/* The asynchronous reads used to calculate RX_BAD_BYTES in
+	 * MC Firmware are done such that we should not see an increase in
+	 * RX_BAD_BYTES when a good packet has arrived. Unfortunately this
+	 * does mean that the stat can decrease at times. Here we do not
+	 * update the stat unless it has increased or has gone to zero
+	 * (In the case of the NIC rebooting).
+	 * Please see Bug 33781 for a discussion of why things work this way.
+	 */
 	efx_update_diff_stat(&stats[EF10_STAT_port_rx_bad_bytes],
 			     stats[EF10_STAT_port_rx_bytes_minus_good_bytes]);
 	efx_update_sw_stats(efx, stats);
-	return 0;
-}
-
-
-static size_t efx_ef10_update_stats_pf(struct efx_nic *efx, u64 *full_stats,
-				       struct rtnl_link_stats64 *core_stats)
-{
-	int retry;
-
-	/* If we're unlucky enough to read statistics during the DMA, wait
-	 * up to 10ms for it to finish (typically takes <500us)
-	 */
-	for (retry = 0; retry < 100; ++retry) {
-		if (efx_ef10_try_update_nic_stats_pf(efx) == 0)
-			break;
-		udelay(100);
-	}
 
 	return efx_ef10_update_stats_common(efx, full_stats, core_stats);
 }
@@ -4033,7 +4033,7 @@ const struct efx_nic_type efx_hunt_a0_vf_nic_type = {
 	.remove = efx_ef10_remove,
 	.dimension_resources = efx_ef10_dimension_resources,
 	.init = efx_ef10_init_nic,
-	.fini = efx_port_dummy_op_void,
+	.fini = efx_ef10_fini_nic,
 	.map_reset_reason = efx_ef10_map_reset_reason,
 	.map_reset_flags = efx_ef10_map_reset_flags,
 	.reset = efx_ef10_reset,
@@ -4142,7 +4142,7 @@ const struct efx_nic_type efx_hunt_a0_nic_type = {
 	.remove = efx_ef10_remove,
 	.dimension_resources = efx_ef10_dimension_resources,
 	.init = efx_ef10_init_nic,
-	.fini = efx_port_dummy_op_void,
+	.fini = efx_ef10_fini_nic,
 	.map_reset_reason = efx_ef10_map_reset_reason,
 	.map_reset_flags = efx_ef10_map_reset_flags,
 	.reset = efx_ef10_reset,