Re: [PATCH v8 2/4] soc: ti: pruss: Add pruss_{request,release}_mem_region() API

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Wed, Apr 12, 2023 at 04:00:10PM +0530, MD Danish Anwar wrote:
> From: "Andrew F. Davis" <afd@ti.com>
> 
> 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 <s-anna@ti.com>
> Signed-off-by: Suman Anna <s-anna@ti.com>
> Signed-off-by: Andrew F. Davis <afd@ti.com>
> Co-developed-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
> Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
> Reviewed-by: Roger Quadros <rogerq@kernel.org>
> Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> Reviewed-by: Tony Lindgren <tony@atomide.com>
> Reviewed-by: Simon Horman <simon.horman@corigine.com>
> Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
> ---
>  drivers/soc/ti/pruss.c       | 77 ++++++++++++++++++++++++++++++++++++
>  include/linux/pruss_driver.h | 22 +++++++++++
>  2 files changed, 99 insertions(+)
>

Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>

> diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
> index 3fac92df8790..8ada3758b31a 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);
> +
>  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_driver.h b/include/linux/pruss_driver.h
> index cb40c2b31045..c8f2e53b911b 100644
> --- a/include/linux/pruss_driver.h
> +++ b/include/linux/pruss_driver.h
> @@ -9,6 +9,7 @@
>  #ifndef _PRUSS_DRIVER_H_
>  #define _PRUSS_DRIVER_H_
>  
> +#include <linux/mutex.h>
>  #include <linux/remoteproc/pruss.h>
>  #include <linux/types.h>
>  #include <linux/err.h>
> @@ -41,6 +42,8 @@ struct pruss_mem_region {
>   * @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
>   */
> @@ -49,6 +52,8 @@ 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;
>  };
> @@ -57,6 +62,10 @@ 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
>  
> @@ -67,6 +76,19 @@ 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;
> +}
> +
>  #endif /* CONFIG_TI_PRUSS */
>  
>  #endif	/* _PRUSS_DRIVER_H_ */
> -- 
> 2.34.1
>