linux-kernel - Re: [PATCH v3 08/13] remoteproc: add prepare and unprepare ops

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Date:   Wed, 9 May 2018 17:52:49 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Loic Pallardy <loic.pallardy@...com>
Cc:     ohad@...ery.com, linux-remoteproc@...r.kernel.org,
        linux-kernel@...r.kernel.org, arnaud.pouliquen@...com,
        benjamin.gaignard@...aro.org
Subject: Re: [PATCH v3 08/13] remoteproc: add prepare and unprepare ops

On Thu 01 Mar 08:23 PST 2018, Loic Pallardy wrote:

> On some SoC architecture, it is needed to enable HW like
> clock, bus, regulator, memory region... before loading
> co-processor firmware.
> 
> This patch introduces prepare and unprepare ops to execute
> platform specific function before firmware loading and after
> stop execution.
> 
> Signed-off-by: Loic Pallardy <loic.pallardy@...com>
> ---
>  drivers/remoteproc/remoteproc_core.c | 20 +++++++++++++++++++-
>  include/linux/remoteproc.h           |  4 ++++
>  2 files changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 7a500cb..0ebbc4f 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -1058,12 +1058,22 @@ static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
>  		return ret;
>  	}
>  
> +	/* Prepare rproc for firmware loading if needed */
> +	if (rproc->ops->prepare) {
> +		ret = rproc->ops->prepare(rproc);
> +		if (ret) {
> +			dev_err(dev, "can't prepare rproc %s: %d\n",
> +				rproc->name, ret);
> +			goto disable_iommu;
> +		}
> +	}

We do allow drivers to implement custom versions of parse_fw() - and
they can call the resource-table-parse-fw from the custom function.

So with the proposed refactoring in patch 9 I would like for parse_fw()
to call back into the core to fill out the resource lists and then
before jumping to rproc_start() we loop over the allocator functions.

> +
>  	rproc->bootaddr = rproc_get_boot_addr(rproc, fw);
>  
>  	/* load resource table */
>  	ret = rproc_load_rsc_table(rproc, fw);
>  	if (ret)
> -		goto disable_iommu;
> +		goto unprepare_rproc;
>  
>  	/* reset max_notifyid */
>  	rproc->max_notifyid = -1;
> @@ -1086,6 +1096,10 @@ static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
>  	kfree(rproc->cached_table);
>  	rproc->cached_table = NULL;
>  	rproc->table_ptr = NULL;
> +unprepare_rproc:
> +	/* release HW resources if needed */
> +	if (rproc->ops->unprepare)
> +		rproc->ops->unprepare(rproc);
>  disable_iommu:
>  	rproc_disable_iommu(rproc);
>  	return ret;
> @@ -1331,6 +1345,10 @@ void rproc_shutdown(struct rproc *rproc)
>  	/* clean up all acquired resources */
>  	rproc_resource_cleanup(rproc);
>  
> +	/* release HW resources if needed */
> +	if (rproc->ops->unprepare)
> +		rproc->ops->unprepare(rproc);

And this would then be handled by the rproc_resource_cleanup() function,
looping over all resources and calling release().

Regards,
Bjorn