Re: [PATCH 06/13] coresight: etb10: Handle errors enabling the device

Mathieu Poirier
2018-08-14T17:57:58Z

Hi Suzuki,

On Mon, Aug 06, 2018 at 02:41:48PM +0100, Suzuki K Poulose wrote:
> Prepare the etb10 driver to return errors in enabling
> the device.
>
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> drivers/hwtracing/coresight/coresight-etb10.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
> index 9fd77fd..37d2c88 100644
> --- a/drivers/hwtracing/coresight/coresight-etb10.c
> +++ b/drivers/hwtracing/coresight/coresight-etb10.c
> @@ -107,7 +107,7 @@ static unsigned int etb_get_buffer_depth(struct etb_drvdata *drvdata)
> return depth;
> }
>
> -static void etb_enable_hw(struct etb_drvdata *drvdata)
> +static void __etb_enable_hw(struct etb_drvdata *drvdata)
> {
> int i;
> u32 depth;
> @@ -135,6 +135,12 @@ static void etb_enable_hw(struct etb_drvdata *drvdata)
> CS_LOCK(drvdata->base);
> }
>
> +static int etb_enable_hw(struct etb_drvdata *drvdata)
> +{
> + __etb_enable_hw(drvdata);
> + return 0;
> +}
> +
> static int etb_enable(struct coresight_device *csdev, u32 mode, void *data)
> {
> int ret = 0;
> @@ -150,7 +156,7 @@ static int etb_enable(struct coresight_device *csdev, u32 mode, void *data)
> if (mode == CS_MODE_PERF) {
> ret = etb_set_buffer(csdev, (struct perf_output_handle *)data);
> if (ret)
> - goto out;
> + return ret;
> }
>
> val = local_cmpxchg(&drvdata->mode,
> @@ -172,12 +178,14 @@ static int etb_enable(struct coresight_device *csdev, u32 mode, void *data)
> goto out;
>
> spin_lock_irqsave(&drvdata->spinlock, flags);
> - etb_enable_hw(drvdata);
> + ret = etb_enable_hw(drvdata);
> spin_unlock_irqrestore(&drvdata->spinlock, flags);
>
> -out:
> - if (!ret)
> + if (ret)
> + local_cmpxchg(&drvdata->mode, mode, CS_MODE_DISABLED);
> + else

I also have to do hackish things with my work on
CPU-wide trace scenarios because drvdata->mode is of type local_t. Instead of
living with it I'll send out a patch later today that moves it to a u32 like ETF
and ETR.

Please look at it and if you're happy, add it to this patchset and do your
modifications on top of it.

Thanks,
Mathieu

> dev_dbg(drvdata->dev, "ETB enabled\n");
> +
> return ret;
> }
>
> --
> 2.7.4
>