Patch "mlxsw: pci: Wait after reset before accessing HW" has been added to the 4.14-stable tree

Patch "mlxsw: pci: Wait after reset before accessing HW" has been added to the 4.14-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    mlxsw: pci: Wait after reset before accessing HW

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mlxsw-pci-wait-after-reset-before-accessing-hw.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Wed Feb 28 16:23:28 CET 2018
From: Yuval Mintz <yuvalm@mellanox.com>
Date: Wed, 10 Jan 2018 11:42:43 +0100
Subject: mlxsw: pci: Wait after reset before accessing HW

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@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@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


Patches currently in stable-queue which might be from yuvalm@mellanox.com are

queue-4.14/mlxsw-pci-wait-after-reset-before-accessing-hw.patch