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Subject[PATCH AUTOSEL for 4.14 110/110] mlxsw: pci: Wait after reset before accessing HW
Date
From: Yuval Mintz <yuvalm@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 <yuvalm@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/net/ethernet/mellanox/mlxsw/pci.c | 7 ++++++-
drivers/net/ethernet/mellanox/mlxsw/pci_hw.h | 1 +
2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/pci.c b/drivers/net/ethernet/mellanox/mlxsw/pci.c
index 23f7d828cf67..6ef20e5cc77d 100644
--- 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
index a6441208e9d9..fb082ad21b00 100644
--- 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
--
2.11.0
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