2020-02-02 15:02:08

by Jonas Danielsson

Subject: [PATCH] mmc: atmel-mci: Add error injection via debugfs

From: Jonas Danielsson <[email protected]>

This functionality was useful for us while debugging issues with
a vendor wifi-driver that misbehaved on the SDIO bus.

This will allow you to check how SDIO clients handle mmc
command and data errors.

Signed-off-by: Jonas Danielsson <[email protected]>
---
drivers/mmc/host/atmel-mci.c | 24 ++++++++++++++++++++++--
1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index a9dad641c..11289c8e5 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -328,6 +328,8 @@ struct atmel_mci {
u32 data_status;
u32 stop_cmdr;

+ bool force_cmd_error;
+ bool force_data_error;
struct tasklet_struct tasklet;
unsigned long pending_events;
unsigned long completed_events;
@@ -618,6 +620,14 @@ static void atmci_init_debugfs(struct atmel_mci_slot *slot)
if (!node)
goto err;

+ node = debugfs_create_bool("force_cmd_error", 644, root, &host->force_cmd_error);
+ if (!node)
+ goto err;
+
+ node = debugfs_create_bool("force_data_error", 644, root, &host->force_data_error);
+ if (!node)
+ goto err;
+
node = debugfs_create_u32("state", S_IRUSR, root, (u32 *)&host->state);
if (!node)
goto err;
@@ -1807,7 +1817,12 @@ static void atmci_tasklet_func(unsigned long priv)
* If there is a command error don't start
* data transfer.
*/
- if (mrq->cmd->error) {
+ if (mrq->cmd->error || host->force_cmd_error) {
+ if (host->force_cmd_error) {
+ dev_info(&host->pdev->dev, "FSM: forced cmd error!\n");
+ host->force_cmd_error = false;
+ mrq->cmd->error = -EINVAL;
+ }
host->stop_transfer(host);
host->data = NULL;
atmci_writel(host, ATMCI_IDR,
@@ -1939,7 +1954,11 @@ static void atmci_tasklet_func(unsigned long priv)
atmci_writel(host, ATMCI_IDR, ATMCI_TXRDY | ATMCI_RXRDY
| ATMCI_DATA_ERROR_FLAGS);
status = host->data_status;
- if (unlikely(status)) {
+ if (unlikely(status) || host->force_data_error) {
+ if (data && host->force_data_error) {
+ dev_info(&host->pdev->dev, "FSM: forced data error!\n");
+ host->force_data_error = false;
+ }
host->stop_transfer(host);
host->data = NULL;
if (data) {
@@ -2519,6 +2538,7 @@ static int atmci_probe(struct platform_device *pdev)
return -ENOMEM;

host->pdev = pdev;
+ host->force_data_error = host->force_cmd_error = false;
spin_lock_init(&host->lock);
INIT_LIST_HEAD(&host->queue);

--
2.23.0

2020-02-02 22:14:02

by Jonas Danielsson

Subject: Re: [PATCH] mmc: atmel-mci: Add error injection via debugfs

On Sun, Feb 2, 2020 at 4:01 PM Jonas Danielsson
<[email protected]> wrote:
>
> From: Jonas Danielsson <[email protected]>
>
> This functionality was useful for us while debugging issues with
> a vendor wifi-driver that misbehaved on the SDIO bus.
>
> This will allow you to check how SDIO clients handle mmc
> command and data errors.
>
> Signed-off-by: Jonas Danielsson <[email protected]>
> ---
> drivers/mmc/host/atmel-mci.c | 24 ++++++++++++++++++++++--
> 1 file changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
> index a9dad641c..11289c8e5 100644
> --- a/drivers/mmc/host/atmel-mci.c
> +++ b/drivers/mmc/host/atmel-mci.c
> @@ -328,6 +328,8 @@ struct atmel_mci {
> u32 data_status;
> u32 stop_cmdr;
>
> + bool force_cmd_error;
> + bool force_data_error;
> struct tasklet_struct tasklet;
> unsigned long pending_events;
> unsigned long completed_events;
> @@ -618,6 +620,14 @@ static void atmci_init_debugfs(struct atmel_mci_slot *slot)
> if (!node)
> goto err;
>
> + node = debugfs_create_bool("force_cmd_error", 644, root, &host->force_cmd_error);
> + if (!node)
> + goto err;
> +
> + node = debugfs_create_bool("force_data_error", 644, root, &host->force_data_error);
> + if (!node)
> + goto err;
> +
> node = debugfs_create_u32("state", S_IRUSR, root, (u32 *)&host->state);
> if (!node)
> goto err;
> @@ -1807,7 +1817,12 @@ static void atmci_tasklet_func(unsigned long priv)
> * If there is a command error don't start
> * data transfer.
> */
> - if (mrq->cmd->error) {
> + if (mrq->cmd->error || host->force_cmd_error) {
> + if (host->force_cmd_error) {
> + dev_info(&host->pdev->dev, "FSM: forced cmd error!\n");
> + host->force_cmd_error = false;
> + mrq->cmd->error = -EINVAL;
> + }
> host->stop_transfer(host);
> host->data = NULL;
> atmci_writel(host, ATMCI_IDR,
> @@ -1939,7 +1954,11 @@ static void atmci_tasklet_func(unsigned long priv)
> atmci_writel(host, ATMCI_IDR, ATMCI_TXRDY | ATMCI_RXRDY
> | ATMCI_DATA_ERROR_FLAGS);
> status = host->data_status;
> - if (unlikely(status)) {
> + if (unlikely(status) || host->force_data_error) {
> + if (data && host->force_data_error) {
> + dev_info(&host->pdev->dev, "FSM: forced data error!\n");
> + host->force_data_error = false;
> + }
> host->stop_transfer(host);
> host->data = NULL;
> if (data) {
> @@ -2519,6 +2538,7 @@ static int atmci_probe(struct platform_device *pdev)
> return -ENOMEM;
>
> host->pdev = pdev;
> + host->force_data_error = host->force_cmd_error = false;
> spin_lock_init(&host->lock);
> INIT_LIST_HEAD(&host->queue);
>
> --
> 2.23.0
>

Haha, I just noticed that this is available from the general fault
injection framework. So sorry for the noise!