[PATCH v3] remoteproc: stm32: fix probe error case

[PATCH v3] remoteproc: stm32: fix probe error case

[Fabien Dessenne]

If the rproc driver is probed before the mailbox driver and if the rproc
Device Tree node has some mailbox properties, the rproc driver probe
shall be deferred instead of being probed without mailbox support.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
---
Changes since v2: free other requested mailboxes after one request fails
Changes since v1: test IS_ERR() before checking PTR_ERR()
---
 drivers/remoteproc/stm32_rproc.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
index 2cf4b29..4b67480 100644
--- a/drivers/remoteproc/stm32_rproc.c
+++ b/drivers/remoteproc/stm32_rproc.c
@@ -310,7 +310,7 @@ static const struct stm32_mbox stm32_rproc_mbox[MBOX_NB_MBX] = {
 	}
 };
 
-static void stm32_rproc_request_mbox(struct rproc *rproc)
+static int stm32_rproc_request_mbox(struct rproc *rproc)
 {
 	struct stm32_rproc *ddata = rproc->priv;
 	struct device *dev = &rproc->dev;
@@ -329,10 +329,16 @@ static void stm32_rproc_request_mbox(struct rproc *rproc)
 
 		ddata->mb[i].chan = mbox_request_channel_byname(cl, name);
 		if (IS_ERR(ddata->mb[i].chan)) {
+			if (PTR_ERR(ddata->mb[i].chan) == -EPROBE_DEFER) {
+				ddata->mb[i].chan = NULL;
+				return -EPROBE_DEFER;
+			}
 			dev_warn(dev, "cannot get %s mbox\n", name);
 			ddata->mb[i].chan = NULL;
 		}
 	}
+
+	return 0;
 }
 
 static int stm32_rproc_set_hold_boot(struct rproc *rproc, bool hold)
@@ -596,7 +602,9 @@ static int stm32_rproc_probe(struct platform_device *pdev)
 	if (ret)
 		goto free_rproc;
 
-	stm32_rproc_request_mbox(rproc);
+	ret = stm32_rproc_request_mbox(rproc);
+	if (ret)
+		goto free_mb;
 
 	ret = rproc_add(rproc);
 	if (ret)
-- 
2.7.4

Re: [PATCH v3] remoteproc: stm32: fix probe error case

[Bjorn Andersson]

On Wed 13 Nov 00:52 PST 2019, Fabien Dessenne wrote:

> If the rproc driver is probed before the mailbox driver and if the rproc
> Device Tree node has some mailbox properties, the rproc driver probe
> shall be deferred instead of being probed without mailbox support.
> 
> Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
> ---
> Changes since v2: free other requested mailboxes after one request fails
> Changes since v1: test IS_ERR() before checking PTR_ERR()
> ---
>  drivers/remoteproc/stm32_rproc.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
> index 2cf4b29..4b67480 100644
> --- a/drivers/remoteproc/stm32_rproc.c
> +++ b/drivers/remoteproc/stm32_rproc.c
> @@ -310,7 +310,7 @@ static const struct stm32_mbox stm32_rproc_mbox[MBOX_NB_MBX] = {
>  	}
>  };
>  
> -static void stm32_rproc_request_mbox(struct rproc *rproc)
> +static int stm32_rproc_request_mbox(struct rproc *rproc)
>  {
>  	struct stm32_rproc *ddata = rproc->priv;
>  	struct device *dev = &rproc->dev;
> @@ -329,10 +329,16 @@ static void stm32_rproc_request_mbox(struct rproc *rproc)
>  
>  		ddata->mb[i].chan = mbox_request_channel_byname(cl, name);
>  		if (IS_ERR(ddata->mb[i].chan)) {
> +			if (PTR_ERR(ddata->mb[i].chan) == -EPROBE_DEFER) {
> +				ddata->mb[i].chan = NULL;

So this relies on the caller jumping to stm32_rproc_free_mbox() to
release a subset of ddata->mb[x].chan. While this works I find it error
prone and would prefer the idiomatic solution of cleaning things up, in
this function, before returning.

So, could you please goto a snippet that loops backwards from i-- to 0
calling mbox_free_channel() and then return -EPROBE_DEFER instead?

Thanks,
Bjorn

> +				return -EPROBE_DEFER;
> +			}
>  			dev_warn(dev, "cannot get %s mbox\n", name);
>  			ddata->mb[i].chan = NULL;
>  		}
>  	}
> +
> +	return 0;
>  }
>  
>  static int stm32_rproc_set_hold_boot(struct rproc *rproc, bool hold)
> @@ -596,7 +602,9 @@ static int stm32_rproc_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto free_rproc;
>  
> -	stm32_rproc_request_mbox(rproc);
> +	ret = stm32_rproc_request_mbox(rproc);
> +	if (ret)
> +		goto free_mb;
>  
>  	ret = rproc_add(rproc);
>  	if (ret)
> -- 
> 2.7.4
>