Re: [PATCH v2 1/9] firmware: qcom: pas: add qcom_pas_context_init() for pre-allocated context

[Alex Elder <elder@ieee.org>]

On 11/13/26 12:50 PM, Mukesh Ojha wrote:
> devm_qcom_pas_context_alloc() allocates and initializes a struct
> qcom_pas_context using devres.  Several callers, however, either live
> entirely on the stack (short-lived helper functions) or embed the
> context in a larger structure that is already managed by other means.
> Forcing those callers through the devm allocation path is wasteful and,
> in the case of functions called on every power cycle, causes a devres
> entry to accumulate on every invocation.
> 
> Add qcom_pas_context_init() that initializes a caller-supplied struct
> qcom_pas_context in place using memset + field assignment, with no
> allocation at all.  Rework devm_qcom_pas_context_alloc() to delegate
> to qcom_pas_context_init() after the kzalloc, so both helpers share
> the same initialization logic.
> 
> Update the kernel-doc for qcom_mdt_pas_load() to reflect that the PAS
> context may now be initialized by either qcom_pas_context_init() or
> devm_qcom_pas_context_alloc().
> 
> Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>

This looks good to me.  Thank you for implementing it.

Signed-off-by: Alex Elder <elder@riscstar.com>

> ---
>   drivers/firmware/qcom/qcom_pas.c       | 26 ++++++++++++++++++++++----
>   drivers/soc/qcom/mdt_loader.c          |  4 ++--
>   include/linux/firmware/qcom/qcom_pas.h |  2 ++
>   3 files changed, 26 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/firmware/qcom/qcom_pas.c b/drivers/firmware/qcom/qcom_pas.c
> index d74dd7b4f332..fdf62003fbf1 100644
> --- a/drivers/firmware/qcom/qcom_pas.c
> +++ b/drivers/firmware/qcom/qcom_pas.c
> @@ -14,6 +14,27 @@
>   
>   static struct qcom_pas_ops *ops_ptr;
>   
> +/**
> + * qcom_pas_context_init() - Initialize a peripheral authentication service
> + *			     context for a given peripheral
> + *
> + * @ctx:	  Caller-provided PAS context to initialize
> + * @dev:	  PAS firmware device
> + * @pas_id:	  peripheral authentication service id
> + * @mem_phys:	  Subsystem reserve memory start address
> + * @mem_size:	  Subsystem reserve memory size
> + */
> +void qcom_pas_context_init(struct qcom_pas_context *ctx, struct device *dev,
> +			   u32 pas_id, phys_addr_t mem_phys, size_t mem_size)
> +{
> +	memset(ctx, 0, sizeof(*ctx));
> +	ctx->dev = dev;
> +	ctx->pas_id = pas_id;
> +	ctx->mem_phys = mem_phys;
> +	ctx->mem_size = mem_size;
> +}
> +EXPORT_SYMBOL_GPL(qcom_pas_context_init);
> +
>   /**
>    * devm_qcom_pas_context_alloc() - Allocate peripheral authentication service
>    *				   context for a given peripheral
> @@ -39,10 +60,7 @@ struct qcom_pas_context *devm_qcom_pas_context_alloc(struct device *dev,
>   	if (!ctx)
>   		return ERR_PTR(-ENOMEM);
>   
> -	ctx->dev = dev;
> -	ctx->pas_id = pas_id;
> -	ctx->mem_phys = mem_phys;
> -	ctx->mem_size = mem_size;
> +	qcom_pas_context_init(ctx, dev, pas_id, mem_phys, mem_size);
>   
>   	return ctx;
>   }
> diff --git a/drivers/soc/qcom/mdt_loader.c b/drivers/soc/qcom/mdt_loader.c
> index 0d55e9e0af3f..c6ec67e1da09 100644
> --- a/drivers/soc/qcom/mdt_loader.c
> +++ b/drivers/soc/qcom/mdt_loader.c
> @@ -476,8 +476,8 @@ EXPORT_SYMBOL_GPL(qcom_mdt_load);
>    * firmware segments (e.g., .bXX files). Authentication of the segments done
>    * by a separate call.
>    *
> - * The PAS context must be initialized using devm_qcom_pas_context_alloc()
> - * prior to invoking this function.
> + * The PAS context must be initialized using qcom_pas_context_init() or
> + * devm_qcom_pas_context_alloc() prior to invoking this function.
>    *
>    * @ctx:        Pointer to the PAS (Peripheral Authentication Service) context
>    * @fw:         Firmware object representing the .mdt file
> diff --git a/include/linux/firmware/qcom/qcom_pas.h b/include/linux/firmware/qcom/qcom_pas.h
> index 1d132e89536e..458075868bf5 100644
> --- a/include/linux/firmware/qcom/qcom_pas.h
> +++ b/include/linux/firmware/qcom/qcom_pas.h
> @@ -36,6 +36,8 @@ static inline void __iomem *qcom_pas_ctx_map(struct qcom_pas_context *ctx)
>   }
>   
>   bool qcom_pas_is_available(void);
> +void qcom_pas_context_init(struct qcom_pas_context *ctx, struct device *dev,
> +			   u32 pas_id, phys_addr_t mem_phys, size_t mem_size);
>   struct qcom_pas_context *devm_qcom_pas_context_alloc(struct device *dev,
>   						     u32 pas_id,
>   						     phys_addr_t mem_phys,