Re: [PATCH] remoteproc: qcom: Use of_reserved_mem_lookup()

[Bjorn Andersson]

On Wed, May 31, 2023 at 11:34:54AM +0200, Stephan Gerhold wrote:
> Reserved memory can be either looked up using the generic function
> of_address_to_resource() or using the special of_reserved_mem_lookup().
> The latter has the advantage that it ensures that the referenced memory
> region was really reserved and is not e.g. status = "disabled".
> 
> of_reserved_mem also supports allocating reserved memory dynamically at
> boot time. This works only when using of_reserved_mem_lookup() since
> there won't be a fixed address in the device tree.
> 
> Switch the code to use of_reserved_mem_lookup(), similar to
> qcom_q6v5_wcss.c which is using it already. There is no functional
> difference for static reserved memory allocations.
> 
> While at it this also adds two missing of_node_put() calls in
> qcom_q6v5_pas.c.
> 
> Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx>
> ---
> See e.g. [1] for an example of dynamically allocated reserved memory.
> (This patch does *not* depend on [1] and is useful without as well...)
> 
> NOTE: Changes in qcom_q6v5_adsp.c and qcom_q6v5_pas.c are untested,
> I only checked qcom_q6v5_mss.c and qcom_wcnss.c on MSM8916/DB410c.
> The code changes are pretty similar for all of those though.
> 
> [1]: https://lore.kernel.org/linux-arm-msm/20230510-dt-resv-bottom-up-v1-5-3bf68873dbed@xxxxxxxxxxx/
> ---
>  drivers/remoteproc/qcom_q6v5_adsp.c | 22 ++++++++--------
>  drivers/remoteproc/qcom_q6v5_mss.c  | 35 +++++++++++++++----------
>  drivers/remoteproc/qcom_q6v5_pas.c  | 51 ++++++++++++++++++++-----------------
>  drivers/remoteproc/qcom_wcnss.c     | 24 ++++++++---------
>  4 files changed, 69 insertions(+), 63 deletions(-)
> 
> diff --git a/drivers/remoteproc/qcom_q6v5_adsp.c b/drivers/remoteproc/qcom_q6v5_adsp.c
> index 6777a3bd6226..948b3d00a564 100644
> --- a/drivers/remoteproc/qcom_q6v5_adsp.c
> +++ b/drivers/remoteproc/qcom_q6v5_adsp.c
> @@ -14,8 +14,8 @@
>  #include <linux/kernel.h>
>  #include <linux/mfd/syscon.h>
>  #include <linux/module.h>
> -#include <linux/of_address.h>
>  #include <linux/of_device.h>
> +#include <linux/of_reserved_mem.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_domain.h>
>  #include <linux/pm_runtime.h>
> @@ -637,28 +637,26 @@ static int adsp_init_mmio(struct qcom_adsp *adsp,
>  
>  static int adsp_alloc_memory_region(struct qcom_adsp *adsp)
>  {
> +	struct reserved_mem *rmem = NULL;
>  	struct device_node *node;
> -	struct resource r;
> -	int ret;
>  
>  	node = of_parse_phandle(adsp->dev->of_node, "memory-region", 0);
> +	if (node)
> +		rmem = of_reserved_mem_lookup(node);
> +	of_node_put(node);
> +
>  	if (!node) {
> -		dev_err(adsp->dev, "no memory-region specified\n");
> +		dev_err(adsp->dev, "unable to resolve memory-region\n");
>  		return -EINVAL;
>  	}
>  
> -	ret = of_address_to_resource(node, 0, &r);
> -	of_node_put(node);
> -	if (ret)
> -		return ret;
> -
> -	adsp->mem_phys = adsp->mem_reloc = r.start;
> -	adsp->mem_size = resource_size(&r);

Aren't you missing a check for !rmem here? (The others has it)

Regards,
Bjorn