From 9b258baec1e2f8f196d4b42857044887fba3a86b Mon Sep 17 00:00:00 2001
From: Stepan Blyschak <stepanb@nvidia.com>
Date: Mon, 20 Jun 2022 15:02:27 +0300
Subject: [PATCH] [patch] mlxsw: i2c: Prevent transaction execution for special
chip states
Do not run transaction in cases chip is in reset or in-filed update states.
This patch fixes an issue encountered during SONiC warm-reboot: during
ISSU start the kernel reports that CPU stall is detected:
```
INFO: rcu_sched detected stalls on CPUs/tasks
```
This patch won't be upstreamed due to the upstream driver not supporting
ISSU.
Signed-off-by: Stepan Blyschak <stepanb@nvidia.com>
---
...2c-Prevent-transaction-execution-for.patch | 126 ++++++++++++++++++
patch/series | 1 +
2 files changed, 127 insertions(+)
create mode 100644 patch/0065-TMP-mlxsw-i2c-Prevent-transaction-execution-for.patch
diff --git a/patch/0065-TMP-mlxsw-i2c-Prevent-transaction-execution-for.patch b/patch/0065-TMP-mlxsw-i2c-Prevent-transaction-execution-for.patch
new file mode 100644
index 000000000..16b1eab20
--- /dev/null
+++ b/patch/0065-TMP-mlxsw-i2c-Prevent-transaction-execution-for.patch
@@ -0,0 +1,126 @@
+From d3e0bf403d527f717a62ea328781256f999d4f95 Mon Sep 17 00:00:00 2001
+From: Stepan Blyschak <stepanb@nvidia.com>
+Date: Mon, 20 Jun 2022 19:28:04 +0300
+Subject: [PATCH] TMP: mlxsw: i2c: Prevent transaction execution for special
+ chip states
+
+Do not run transaction in cases chip is in reset or in-service update
+states. In such case firmware is not accessible and will reject transaction
+with the relevant status "RUNNING_RESET" or "FW_ISSU_ONGOING".
+In case transaction is failed do to one of these reasons, stop sending
+transactions. In such case driver is about to be removed since it
+cannot continue running after reset or in-service update. And
+re-probed again after reset or in-service update is completed.
+
+Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
+Signed-off-by: Stepan Blyschak <stepanb@nvidia.com>
+---
+ drivers/net/ethernet/mellanox/mlxsw/cmd.h | 4 ++++
+ drivers/net/ethernet/mellanox/mlxsw/i2c.c | 29 ++++++++++++++++++++---
+ 2 files changed, 30 insertions(+), 3 deletions(-)
+
+diff --git a/drivers/net/ethernet/mellanox/mlxsw/cmd.h b/drivers/net/ethernet/mellanox/mlxsw/cmd.h
+index 91f68fb0b..d8ecb8c8a 100644
+--- a/drivers/net/ethernet/mellanox/mlxsw/cmd.h
++++ b/drivers/net/ethernet/mellanox/mlxsw/cmd.h
+@@ -149,6 +149,8 @@ enum mlxsw_cmd_status {
+ MLXSW_CMD_STATUS_BAD_NVMEM = 0x0B,
+ /* Device is currently running reset */
+ MLXSW_CMD_STATUS_RUNNING_RESET = 0x26,
++ /* FW ISSU ongoing. */
++ MLXSW_CMD_STATUS_FW_ISSU = 0x27,
+ /* Bad management packet (silently discarded). */
+ MLXSW_CMD_STATUS_BAD_PKT = 0x30,
+ };
+@@ -180,6 +182,8 @@ static inline const char *mlxsw_cmd_status_str(u8 status)
+ return "BAD_NVMEM";
+ case MLXSW_CMD_STATUS_RUNNING_RESET:
+ return "RUNNING_RESET";
++ case MLXSW_CMD_STATUS_FW_ISSU:
++ return "FW_ISSU_ONGOING";
+ case MLXSW_CMD_STATUS_BAD_PKT:
+ return "BAD_PKT";
+ default:
+diff --git a/drivers/net/ethernet/mellanox/mlxsw/i2c.c b/drivers/net/ethernet/mellanox/mlxsw/i2c.c
+index 939b692ff..3c9d2c7a0 100644
+--- a/drivers/net/ethernet/mellanox/mlxsw/i2c.c
++++ b/drivers/net/ethernet/mellanox/mlxsw/i2c.c
+@@ -63,6 +63,7 @@
+ * @core: switch core pointer;
+ * @bus_info: bus info block;
+ * @block_size: maximum block size allowed to pass to under layer;
++ * @status: status to indicate chip reset or in-service update;
+ */
+ struct mlxsw_i2c {
+ struct {
+@@ -76,6 +77,7 @@ struct mlxsw_i2c {
+ struct mlxsw_core *core;
+ struct mlxsw_bus_info bus_info;
+ u16 block_size;
++ u8 status;
+ };
+
+ #define MLXSW_I2C_READ_MSG(_client, _addr_buf, _buf, _len) { \
+@@ -222,6 +224,19 @@ static int mlxsw_i2c_write_cmd(struct i2c_client *client,
+ return 0;
+ }
+
++static bool
++mlxsw_i2c_cmd_status_verify(struct device *dev, struct mlxsw_i2c *mlxsw_i2c,
++ u8 status)
++{
++ if (status == MLXSW_CMD_STATUS_FW_ISSU ||
++ status == MLXSW_CMD_STATUS_RUNNING_RESET) {
++ mlxsw_i2c->status = status;
++ dev_info(dev, "FW status=%x(%s)): Access to device is not allowed in this state\n", status, mlxsw_cmd_status_str(status));
++ return true;
++ }
++ return false;
++}
++
+ /* Routine posts initialization command to ASIC through mail box. */
+ static int
+ mlxsw_i2c_write_init_cmd(struct i2c_client *client,
+@@ -405,6 +420,10 @@ mlxsw_i2c_cmd(struct device *dev, u16 opcode, u32 in_mod, size_t in_mbox_size,
+
+ WARN_ON(in_mbox_size % sizeof(u32) || out_mbox_size % sizeof(u32));
+
++ /* Do not run transaction if chip is in reset or in-service update state. */
++ if (mlxsw_i2c->status)
++ return 0;
++
+ if (in_mbox) {
+ reg_size = mlxsw_i2c_get_reg_size(in_mbox);
+ num = reg_size / mlxsw_i2c->block_size;
+@@ -479,6 +498,8 @@ mlxsw_i2c_cmd(struct device *dev, u16 opcode, u32 in_mod, size_t in_mbox_size,
+
+ cmd_fail:
+ mutex_unlock(&mlxsw_i2c->cmd.lock);
++ if (mlxsw_i2c_cmd_status_verify(&client->dev, mlxsw_i2c, *status))
++ err = 0;
+ return err;
+ }
+
+@@ -608,14 +629,16 @@ static int mlxsw_i2c_probe(struct i2c_client *client,
+ /* Wait until go bit is cleared. */
+ err = mlxsw_i2c_wait_go_bit(client, mlxsw_i2c, &status);
+ if (err) {
+- dev_err(&client->dev, "HW semaphore is not released");
++ if (!mlxsw_i2c_cmd_status_verify(&client->dev, mlxsw_i2c, status))
++ dev_err(&client->dev, "HW semaphore is not released");
+ goto errout;
+ }
+
+ /* Validate transaction completion status. */
+ if (status) {
+- dev_err(&client->dev, "Bad transaction completion status %x\n",
+- status);
++ if (!mlxsw_i2c_cmd_status_verify(&client->dev, mlxsw_i2c, status))
++ dev_err(&client->dev, "Bad transaction completion status %x\n",
++ status);
+ err = -EIO;
+ goto errout;
+ }
+--
+2.17.1
+
diff --git a/patch/series b/patch/series
index a7b25f41e..a3b2c7c34 100755
--- a/patch/series
+++ b/patch/series
@@ -84,6 +84,7 @@ net-sch_generic-fix-the-missing-new-qdisc-assignment.patch
0031-backport-nvme-Add-hardware-monitoring-support.patch
0032-platform-mellanox-mlxreg-hotplug-Use-capability-regi.patch
0064-platform-mellanox-mlxreg-io-Fix-read-access-of-n-byt.patch
+0065-TMP-mlxsw-i2c-Prevent-transaction-execution-for.patch
0144-platform-x86-mlx-platform-Fix-cpld-_pn-register-seco.patch
# Cisco patches for 4.19 kernel