Subject: Re: [PATCH v7 2/4] soc: ti: pruss: Add pruss_{request,release}_mem_region() API

From: Mathieu Poirier <[email-masked]>
Date: Tue, 11 Apr 2023 11:51:37 -0600

On Tue, Apr 04, 2023 at 05:23:34PM +0530, MD Danish Anwar wrote:
> From: "Andrew F. Davis" <[email-masked]>
> 
> Add two new API - pruss_request_mem_region() & pruss_release_mem_region(),
> to the PRUSS platform driver to allow client drivers to acquire and release
> the common memory resources present within a PRU-ICSS subsystem. This
> allows the client drivers to directly manipulate the respective memories,
> as per their design contract with the associated firmware.
> 
> Co-developed-by: Suman Anna <[email-masked]>
> Signed-off-by: Suman Anna <[email-masked]>
> Signed-off-by: Andrew F. Davis <[email-masked]>
> Co-developed-by: Grzegorz Jaszczyk <[email-masked]>
> Signed-off-by: Grzegorz Jaszczyk <[email-masked]>
> Reviewed-by: Roger Quadros <[email-masked]>
> Acked-by: Mathieu Poirier <[email-masked]>
> Reviewed-by: Tony Lindgren <[email-masked]>
> Signed-off-by: MD Danish Anwar <[email-masked]>
> ---
>  drivers/soc/ti/pruss.c           | 77 ++++++++++++++++++++++++++++++++
>  include/linux/pruss_internal.h   | 27 +++--------
>  include/linux/remoteproc/pruss.h | 39 ++++++++++++++++
>  3 files changed, 121 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
> index 28b77d715903..7aa0f7171af1 100644
> --- a/drivers/soc/ti/pruss.c
> +++ b/drivers/soc/ti/pruss.c
> @@ -92,6 +92,82 @@ void pruss_put(struct pruss *pruss)
>  }
>  EXPORT_SYMBOL_GPL(pruss_put);
>  
> +/**
> + * pruss_request_mem_region() - request a memory resource
> + * @pruss: the pruss instance
> + * @mem_id: the memory resource id
> + * @region: pointer to memory region structure to be filled in
> + *
> + * This function allows a client driver to request a memory resource,
> + * and if successful, will let the client driver own the particular
> + * memory region until released using the pruss_release_mem_region()
> + * API.
> + *
> + * Return: 0 if requested memory region is available (in such case pointer to
> + * memory region is returned via @region), an error otherwise
> + */
> +int pruss_request_mem_region(struct pruss *pruss, enum pruss_mem mem_id,
> +			     struct pruss_mem_region *region)
> +{
> +	if (!pruss || !region || mem_id >= PRUSS_MEM_MAX)
> +		return -EINVAL;
> +
> +	mutex_lock(&pruss->lock);
> +
> +	if (pruss->mem_in_use[mem_id]) {
> +		mutex_unlock(&pruss->lock);
> +		return -EBUSY;
> +	}
> +
> +	*region = pruss->mem_regions[mem_id];
> +	pruss->mem_in_use[mem_id] = region;
> +
> +	mutex_unlock(&pruss->lock);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(pruss_request_mem_region);
> +
> +/**
> + * pruss_release_mem_region() - release a memory resource
> + * @pruss: the pruss instance
> + * @region: the memory region to release
> + *
> + * This function is the complimentary function to
> + * pruss_request_mem_region(), and allows the client drivers to
> + * release back a memory resource.
> + *
> + * Return: 0 on success, an error code otherwise
> + */
> +int pruss_release_mem_region(struct pruss *pruss,
> +			     struct pruss_mem_region *region)
> +{
> +	int id;
> +
> +	if (!pruss || !region)
> +		return -EINVAL;
> +
> +	mutex_lock(&pruss->lock);
> +
> +	/* find out the memory region being released */
> +	for (id = 0; id < PRUSS_MEM_MAX; id++) {
> +		if (pruss->mem_in_use[id] == region)
> +			break;
> +	}
> +
> +	if (id == PRUSS_MEM_MAX) {
> +		mutex_unlock(&pruss->lock);
> +		return -EINVAL;
> +	}
> +
> +	pruss->mem_in_use[id] = NULL;
> +
> +	mutex_unlock(&pruss->lock);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(pruss_release_mem_region);
> +

These stay here.

>  static void pruss_of_free_clk_provider(void *data)
>  {
>  	struct device_node *clk_mux_np = data;
> @@ -294,6 +370,7 @@ static int pruss_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  
>  	pruss->dev = dev;
> +	mutex_init(&pruss->lock);
>  
>  	child = of_get_child_by_name(np, "memories");
>  	if (!child) {
> diff --git a/include/linux/pruss_internal.h b/include/linux/pruss_internal.h
> index 8f91cb164054..cf5287fa01df 100644
> --- a/include/linux/pruss_internal.h
> +++ b/include/linux/pruss_internal.h
> @@ -9,37 +9,18 @@
>  #ifndef _PRUSS_INTERNAL_H_
>  #define _PRUSS_INTERNAL_H_
>  
> +#include <linux/mutex.h>
>  #include <linux/remoteproc/pruss.h>
>  #include <linux/types.h>
>  
> -/*
> - * enum pruss_mem - PRUSS memory range identifiers
> - */
> -enum pruss_mem {
> -	PRUSS_MEM_DRAM0 = 0,
> -	PRUSS_MEM_DRAM1,
> -	PRUSS_MEM_SHRD_RAM2,
> -	PRUSS_MEM_MAX,
> -};
> -
> -/**
> - * struct pruss_mem_region - PRUSS memory region structure
> - * @va: kernel virtual address of the PRUSS memory region
> - * @pa: physical (bus) address of the PRUSS memory region
> - * @size: size of the PRUSS memory region
> - */
> -struct pruss_mem_region {
> -	void __iomem *va;
> -	phys_addr_t pa;
> -	size_t size;
> -};
> -

These stay here.

>  /**
>   * struct pruss - PRUSS parent structure
>   * @dev: pruss device pointer
>   * @cfg_base: base iomap for CFG region
>   * @cfg_regmap: regmap for config region
>   * @mem_regions: data for each of the PRUSS memory regions
> + * @mem_in_use: to indicate if memory resource is in use
> + * @lock: mutex to serialize access to resources
>   * @core_clk_mux: clk handle for PRUSS CORE_CLK_MUX
>   * @iep_clk_mux: clk handle for PRUSS IEP_CLK_MUX
>   */
> @@ -48,6 +29,8 @@ struct pruss {
>  	void __iomem *cfg_base;
>  	struct regmap *cfg_regmap;
>  	struct pruss_mem_region mem_regions[PRUSS_MEM_MAX];
> +	struct pruss_mem_region *mem_in_use[PRUSS_MEM_MAX];
> +	struct mutex lock; /* PRU resource lock */
>  	struct clk *core_clk_mux;
>  	struct clk *iep_clk_mux;
>  };
> diff --git a/include/linux/remoteproc/pruss.h b/include/linux/remoteproc/pruss.h
> index 93a98cac7829..33f930e0a0ce 100644
> --- a/include/linux/remoteproc/pruss.h
> +++ b/include/linux/remoteproc/pruss.h
> @@ -44,6 +44,28 @@ enum pru_ctable_idx {
>  	PRU_C31,
>  };
>  
> +/*
> + * enum pruss_mem - PRUSS memory range identifiers
> + */
> +enum pruss_mem {
> +	PRUSS_MEM_DRAM0 = 0,
> +	PRUSS_MEM_DRAM1,
> +	PRUSS_MEM_SHRD_RAM2,
> +	PRUSS_MEM_MAX,
> +};
> +
> +/**
> + * struct pruss_mem_region - PRUSS memory region structure
> + * @va: kernel virtual address of the PRUSS memory region
> + * @pa: physical (bus) address of the PRUSS memory region
> + * @size: size of the PRUSS memory region
> + */
> +struct pruss_mem_region {
> +	void __iomem *va;
> +	phys_addr_t pa;
> +	size_t size;
> +};
> +
>  struct device_node;
>  struct rproc;
>  struct pruss;
> @@ -52,6 +74,10 @@ struct pruss;
>  
>  struct pruss *pruss_get(struct rproc *rproc);
>  void pruss_put(struct pruss *pruss);
> +int pruss_request_mem_region(struct pruss *pruss, enum pruss_mem mem_id,
> +			     struct pruss_mem_region *region);
> +int pruss_release_mem_region(struct pruss *pruss,
> +			     struct pruss_mem_region *region);
>  
>  #else
>  
> @@ -62,6 +88,19 @@ static inline struct pruss *pruss_get(struct rproc *rproc)
>  
>  static inline void pruss_put(struct pruss *pruss) { }
>  
> +static inline int pruss_request_mem_region(struct pruss *pruss,
> +					   enum pruss_mem mem_id,
> +					   struct pruss_mem_region *region)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
> +static inline int pruss_release_mem_region(struct pruss *pruss,
> +					   struct pruss_mem_region *region)
> +{
> +	return -EOPNOTSUPP;
> +}
> +

These go in pruss_driver.h

>  #endif /* CONFIG_TI_PRUSS */
>  
>  #if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
> -- 
> 2.25.1
>