4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yuval Mintz <yuv...@mellanox.com>


[ Upstream commit 8e033a93b37f37aa9fca71a370a895155320af60 ]

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: 233fa44bd67a ("mlxsw: pci: Implement reset done check")
Signed-off-by: Yuval Mintz <yuv...@mellanox.com>
Reviewed-by: Ido Schimmel <ido...@mellanox.com>
Signed-off-by: Jiri Pirko <j...@mellanox.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlxsw/pci.c    |    7 ++++++-
 drivers/net/ethernet/mellanox/mlxsw/pci_hw.h |    1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

--- 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 mlx
                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);
--- 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


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