sfc: support variable number of MAC stats

Medford2 NICs support more than MC_CMD_MAC_NSTATS stats, and report the new
 count in a field of MC_CMD_GET_CAPABILITIES_V4.  This also means that the
 end generation count moves (it is, as before, the last 64 bits of the DMA
 buffer, but that is no longer MC_CMD_MAC_GENERATION_END).
So read num_mac_stats from the GET_CAPABILITIES response, if present;
 otherwise assume MC_CMD_MAC_NSTATS; and always use num_mac_stats - 1 rather
 than MC_CMD_MAC_GENERATION_END.

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

drivers/net/ethernet/sfc/ef10.c

@@ -233,7 +233,7 @@ static int efx_ef10_get_vf_index(struct efx_nic *efx)
 
 static int efx_ef10_init_datapath_caps(struct efx_nic *efx)
 {
-	MCDI_DECLARE_BUF(outbuf, MC_CMD_GET_CAPABILITIES_V3_OUT_LEN);
+	MCDI_DECLARE_BUF(outbuf, MC_CMD_GET_CAPABILITIES_V4_OUT_LEN);
 	struct efx_ef10_nic_data *nic_data = efx->nic_data;
 	size_t outlen;
 	int rc;
@@ -306,6 +306,19 @@ static int efx_ef10_init_datapath_caps(struct efx_nic *efx)
 			  efx->vi_stride);
 	}
 
+	if (outlen >= MC_CMD_GET_CAPABILITIES_V4_OUT_LEN) {
+		efx->num_mac_stats = MCDI_WORD(outbuf,
+				GET_CAPABILITIES_V4_OUT_MAC_STATS_NUM_STATS);
+		netif_dbg(efx, probe, efx->net_dev,
+			  "firmware reports num_mac_stats = %u\n",
+			  efx->num_mac_stats);
+	} else {
+		/* leave num_mac_stats as the default value, MC_CMD_MAC_NSTATS */
+		netif_dbg(efx, probe, efx->net_dev,
+			  "firmware did not report num_mac_stats, assuming %u\n",
+			  efx->num_mac_stats);
+	}
+
 	return 0;
 }
 
@@ -1850,7 +1863,7 @@ static int efx_ef10_try_update_nic_stats_pf(struct efx_nic *efx)
 
 	dma_stats = efx->stats_buffer.addr;
 
-	generation_end = dma_stats[MC_CMD_MAC_GENERATION_END];
+	generation_end = dma_stats[efx->num_mac_stats - 1];
 	if (generation_end == EFX_MC_STATS_GENERATION_INVALID)
 		return 0;
 	rmb();
@@ -1898,7 +1911,7 @@ static int efx_ef10_try_update_nic_stats_vf(struct efx_nic *efx)
 	DECLARE_BITMAP(mask, EF10_STAT_COUNT);
 	__le64 generation_start, generation_end;
 	u64 *stats = nic_data->stats;
-	u32 dma_len = MC_CMD_MAC_NSTATS * sizeof(u64);
+	u32 dma_len = efx->num_mac_stats * sizeof(u64);
 	struct efx_buffer stats_buf;
 	__le64 *dma_stats;
 	int rc;
@@ -1923,7 +1936,7 @@ static int efx_ef10_try_update_nic_stats_vf(struct efx_nic *efx)
 	}
 
 	dma_stats = stats_buf.addr;
-	dma_stats[MC_CMD_MAC_GENERATION_END] = EFX_MC_STATS_GENERATION_INVALID;
+	dma_stats[efx->num_mac_stats - 1] = EFX_MC_STATS_GENERATION_INVALID;
 
 	MCDI_SET_QWORD(inbuf, MAC_STATS_IN_DMA_ADDR, stats_buf.dma_addr);
 	MCDI_POPULATE_DWORD_1(inbuf, MAC_STATS_IN_CMD,
@@ -1942,7 +1955,7 @@ static int efx_ef10_try_update_nic_stats_vf(struct efx_nic *efx)
 		goto out;
 	}
 
-	generation_end = dma_stats[MC_CMD_MAC_GENERATION_END];
+	generation_end = dma_stats[efx->num_mac_stats - 1];
 	if (generation_end == EFX_MC_STATS_GENERATION_INVALID) {
 		WARN_ON_ONCE(1);
 		goto out;

drivers/net/ethernet/sfc/efx.c

@@ -2983,6 +2983,8 @@ static int efx_init_struct(struct efx_nic *efx,
 		efx->type->rx_ts_offset - efx->type->rx_prefix_size;
 	spin_lock_init(&efx->stats_lock);
 	efx->vi_stride = EFX_DEFAULT_VI_STRIDE;
+	efx->num_mac_stats = MC_CMD_MAC_NSTATS;
+	BUILD_BUG_ON(MC_CMD_MAC_NSTATS - 1 != MC_CMD_MAC_GENERATION_END);
 	mutex_init(&efx->mac_lock);
 	efx->phy_op = &efx_dummy_phy_operations;
 	efx->mdio.dev = net_dev;

drivers/net/ethernet/sfc/mcdi_port.c

@@ -1087,7 +1087,7 @@ static int efx_mcdi_mac_stats(struct efx_nic *efx,
 	int period = action == EFX_STATS_ENABLE ? 1000 : 0;
 	dma_addr_t dma_addr = efx->stats_buffer.dma_addr;
 	u32 dma_len = action != EFX_STATS_DISABLE ?
-		MC_CMD_MAC_NSTATS * sizeof(u64) : 0;
+		efx->num_mac_stats * sizeof(u64) : 0;
 
 	BUILD_BUG_ON(MC_CMD_MAC_STATS_OUT_DMA_LEN != 0);
 
@@ -1121,7 +1121,7 @@ void efx_mcdi_mac_start_stats(struct efx_nic *efx)
 {
 	__le64 *dma_stats = efx->stats_buffer.addr;
 
-	dma_stats[MC_CMD_MAC_GENERATION_END] = EFX_MC_STATS_GENERATION_INVALID;
+	dma_stats[efx->num_mac_stats - 1] = EFX_MC_STATS_GENERATION_INVALID;
 
 	efx_mcdi_mac_stats(efx, EFX_STATS_ENABLE, 0);
 }
@@ -1139,10 +1139,10 @@ void efx_mcdi_mac_pull_stats(struct efx_nic *efx)
 	__le64 *dma_stats = efx->stats_buffer.addr;
 	int attempts = EFX_MAC_STATS_WAIT_ATTEMPTS;
 
-	dma_stats[MC_CMD_MAC_GENERATION_END] = EFX_MC_STATS_GENERATION_INVALID;
+	dma_stats[efx->num_mac_stats - 1] = EFX_MC_STATS_GENERATION_INVALID;
 	efx_mcdi_mac_stats(efx, EFX_STATS_PULL, 0);
 
-	while (dma_stats[MC_CMD_MAC_GENERATION_END] ==
+	while (dma_stats[efx->num_mac_stats - 1] ==
 				EFX_MC_STATS_GENERATION_INVALID &&
 			attempts-- != 0)
 		udelay(EFX_MAC_STATS_WAIT_US);
@@ -1167,7 +1167,7 @@ int efx_mcdi_port_probe(struct efx_nic *efx)
 
 	/* Allocate buffer for stats */
 	rc = efx_nic_alloc_buffer(efx, &efx->stats_buffer,
-				  MC_CMD_MAC_NSTATS * sizeof(u64), GFP_KERNEL);
+				  efx->num_mac_stats * sizeof(u64), GFP_KERNEL);
 	if (rc)
 		return rc;
 	netif_dbg(efx, probe, efx->net_dev,

drivers/net/ethernet/sfc/net_driver.h

@@ -774,6 +774,8 @@ struct vfdi_status;
  * @port_initialized: Port initialized?
  * @net_dev: Operating system network device. Consider holding the rtnl lock
  * @fixed_features: Features which cannot be turned off
+ * @num_mac_stats: Number of MAC stats reported by firmware (MAC_STATS_NUM_STATS
+ *	field of %MC_CMD_GET_CAPABILITIES_V4 response, or %MC_CMD_MAC_NSTATS)
  * @stats_buffer: DMA buffer for statistics
  * @phy_type: PHY type
  * @phy_op: PHY interface
@@ -922,6 +924,7 @@ struct efx_nic {
 
 	netdev_features_t fixed_features;
 
+	u16 num_mac_stats;
 	struct efx_buffer stats_buffer;
 	u64 rx_nodesc_drops_total;
 	u64 rx_nodesc_drops_while_down;

drivers/net/ethernet/sfc/siena.c

@@ -555,7 +555,7 @@ static int siena_try_update_nic_stats(struct efx_nic *efx)
 
 	dma_stats = efx->stats_buffer.addr;
 
-	generation_end = dma_stats[MC_CMD_MAC_GENERATION_END];
+	generation_end = dma_stats[efx->num_mac_stats - 1];
 	if (generation_end == EFX_MC_STATS_GENERATION_INVALID)
 		return 0;
 	rmb();