mlxsw: pci: Wait after reset before accessing HW

After performing reset driver polls on HW indication until learning that the reset is done, but immediately after reset the device becomes unresponsive which might lead to completion timeout on the first read. Wait for 100ms before starting the polling. Fixes: 233fa44 ("mlxsw: pci: Implement reset done check") Signed-off-by: Yuval Mintz <[email protected]> Reviewed-by: Ido Schimmel <[email protected]> Signed-off-by: Jiri Pirko <[email protected]> Signed-off-by: David S. Miller <[email protected]>
modi0012 · Jan 10, 2018 · 8e033a9 · 8e033a9
1 parent fc23365
commit 8e033a9
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Showing 2 changed files with 7 additions and 1 deletion.
diff --git a/drivers/net/ethernet/mellanox/mlxsw/pci.c b/drivers/net/ethernet/mellanox/mlxsw/pci.c
@@ -1643,7 +1643,12 @@ static int mlxsw_pci_sw_reset(struct mlxsw_pci *mlxsw_pci,
 		return 0;
 	}
 
-	wmb(); /* reset needs to be written before we read control register */
+	/* Reset needs to be written before we read control register, and
+	 * we must wait for the HW to become responsive once again
+	 */
+	wmb();
+	msleep(MLXSW_PCI_SW_RESET_WAIT_MSECS);
+
 	end = jiffies + msecs_to_jiffies(MLXSW_PCI_SW_RESET_TIMEOUT_MSECS);
 	do {
 		u32 val = mlxsw_pci_read32(mlxsw_pci, FW_READY);

diff --git a/drivers/net/ethernet/mellanox/mlxsw/pci_hw.h b/drivers/net/ethernet/mellanox/mlxsw/pci_hw.h
@@ -59,6 +59,7 @@
 #define MLXSW_PCI_SW_RESET			0xF0010
 #define MLXSW_PCI_SW_RESET_RST_BIT		BIT(0)
 #define MLXSW_PCI_SW_RESET_TIMEOUT_MSECS	5000
+#define MLXSW_PCI_SW_RESET_WAIT_MSECS		100
 #define MLXSW_PCI_FW_READY			0xA1844
 #define MLXSW_PCI_FW_READY_MASK			0xFFFF
 #define MLXSW_PCI_FW_READY_MAGIC		0x5E