linux-kernel - Re: [PATCH v4 06/11] remoteproc: stm32: Properly set co-processor state when attaching

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Date:   Mon, 22 Jun 2020 11:05:45 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>
Cc:     ohad@...ery.com, mcoquelin.stm32@...il.com,
        alexandre.torgue@...com, loic.pallardy@...com,
        arnaud.pouliquen@...com, linux-remoteproc@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 06/11] remoteproc: stm32: Properly set co-processor
 state when attaching

On Mon 01 Jun 10:55 PDT 2020, Mathieu Poirier wrote:

> Introduce the required mechanic to set the state of the M4 in order
> to properly deal with scenarios where the co-processor has been
> stated by another entity.
> 
> Mainly based on the work published by Arnaud Pouliquen [1].
> 
> [1]. https://patchwork.kernel.org/project/linux-remoteproc/list/?series=239877
> 
> Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>

Reviewed-by: Bjorn Andersson <bjorn.andersson@...aro.org>

> ---
>  drivers/remoteproc/stm32_rproc.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
> 
> diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
> index 80fd8fd831da..2154c8b90a2a 100644
> --- a/drivers/remoteproc/stm32_rproc.c
> +++ b/drivers/remoteproc/stm32_rproc.c
> @@ -38,6 +38,13 @@
>  #define STM32_MBX_VQ1_ID	1
>  #define STM32_MBX_SHUTDOWN	"shutdown"
>  
> +#define M4_STATE_OFF		0
> +#define M4_STATE_INI		1
> +#define M4_STATE_CRUN		2
> +#define M4_STATE_CSTOP		3
> +#define M4_STATE_STANDBY	4
> +#define M4_STATE_CRASH		5
> +
>  struct stm32_syscon {
>  	struct regmap *map;
>  	u32 reg;
> @@ -635,12 +642,30 @@ static int stm32_rproc_parse_dt(struct platform_device *pdev,
>  	return 0;
>  }
>  
> +static int stm32_rproc_get_m4_status(struct stm32_rproc *ddata,
> +				     unsigned int *state)
> +{
> +	/* See stm32_rproc_parse_dt() */
> +	if (!ddata->m4_state.map) {
> +		/*
> +		 * We couldn't get the coprocessor's state, assume
> +		 * it is not running.
> +		 */
> +		state = M4_STATE_OFF;
> +		return 0;
> +	}
> +
> +	return regmap_read(ddata->m4_state.map, ddata->m4_state.reg, state);
> +}
> +
> +
>  static int stm32_rproc_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct stm32_rproc *ddata;
>  	struct device_node *np = dev->of_node;
>  	struct rproc *rproc;
> +	unsigned int state;
>  	int ret;
>  
>  	ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
> @@ -663,6 +688,13 @@ static int stm32_rproc_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto free_rproc;
>  
> +	ret = stm32_rproc_get_m4_status(ddata, &state);
> +	if (ret)
> +		goto free_rproc;
> +
> +	if (state == M4_STATE_CRUN)

I presume this won't ever be e.g. M4_STATE_CRASH or M4_STATE_STANDBY?

Regards,
Bjorn

> +		rproc->state = RPROC_DETACHED;
> +
>  	rproc->has_iommu = false;
>  	ddata->workqueue = create_workqueue(dev_name(dev));
>  	if (!ddata->workqueue) {
> -- 
> 2.20.1
>