Re: [PATCH v8 1/4] soc: ti: pruss: Add pruss_get()/put() API

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

On Wed, Apr 12, 2023 at 04:00:09PM +0530, MD Danish Anwar wrote:
> From: Tero Kristo <t-kristo@ti.com>
> 
> Add two new get and put API, pruss_get() and pruss_put() to the
> PRUSS platform driver to allow client drivers to request a handle
> to a PRUSS device. This handle will be used by client drivers to
> request various operations of the PRUSS platform driver through
> additional API that will be added in the following patches.
> 
> The pruss_get() function returns the pruss handle corresponding
> to a PRUSS device referenced by a PRU remoteproc instance. The
> pruss_put() is the complimentary function to pruss_get().
> 
> Co-developed-by: Suman Anna <s-anna@ti.com>
> Signed-off-by: Suman Anna <s-anna@ti.com>
> Signed-off-by: Tero Kristo <t-kristo@ti.com>
> Co-developed-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
> Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
> Signed-off-by: Puranjay Mohan <p-mohan@ti.com>
> Reviewed-by: Roger Quadros <rogerq@kernel.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       | 62 ++++++++++++++++++++++++++++++++++++
>  include/linux/pruss_driver.h | 18 +++++++++++
>  2 files changed, 80 insertions(+)
> 

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

> diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
> index 6882c86b3ce5..3fac92df8790 100644
> --- a/drivers/soc/ti/pruss.c
> +++ b/drivers/soc/ti/pruss.c
> @@ -6,6 +6,7 @@
>   * Author(s):
>   *	Suman Anna <s-anna@ti.com>
>   *	Andrew F. Davis <afd@ti.com>
> + *	Tero Kristo <t-kristo@ti.com>
>   */
>  
>  #include <linux/clk-provider.h>
> @@ -18,6 +19,7 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/pruss_driver.h>
>  #include <linux/regmap.h>
> +#include <linux/remoteproc.h>
>  #include <linux/slab.h>
>  
>  /**
> @@ -30,6 +32,66 @@ struct pruss_private_data {
>  	bool has_core_mux_clock;
>  };
>  
> +/**
> + * pruss_get() - get the pruss for a given PRU remoteproc
> + * @rproc: remoteproc handle of a PRU instance
> + *
> + * Finds the parent pruss device for a PRU given the @rproc handle of the
> + * PRU remote processor. This function increments the pruss device's refcount,
> + * so always use pruss_put() to decrement it back once pruss isn't needed
> + * anymore.
> + *
> + * This API doesn't check if @rproc is valid or not. It is expected the caller
> + * will have done a pru_rproc_get() on @rproc, before calling this API to make
> + * sure that @rproc is valid.
> + *
> + * Return: pruss handle on success, and an ERR_PTR on failure using one
> + * of the following error values
> + *    -EINVAL if invalid parameter
> + *    -ENODEV if PRU device or PRUSS device is not found
> + */
> +struct pruss *pruss_get(struct rproc *rproc)
> +{
> +	struct pruss *pruss;
> +	struct device *dev;
> +	struct platform_device *ppdev;
> +
> +	if (IS_ERR_OR_NULL(rproc))
> +		return ERR_PTR(-EINVAL);
> +
> +	dev = &rproc->dev;
> +
> +	/* make sure it is PRU rproc */
> +	if (!dev->parent || !is_pru_rproc(dev->parent))
> +		return ERR_PTR(-ENODEV);
> +
> +	ppdev = to_platform_device(dev->parent->parent);
> +	pruss = platform_get_drvdata(ppdev);
> +	if (!pruss)
> +		return ERR_PTR(-ENODEV);
> +
> +	get_device(pruss->dev);
> +
> +	return pruss;
> +}
> +EXPORT_SYMBOL_GPL(pruss_get);
> +
> +/**
> + * pruss_put() - decrement pruss device's usecount
> + * @pruss: pruss handle
> + *
> + * Complimentary function for pruss_get(). Needs to be called
> + * after the PRUSS is used, and only if the pruss_get() succeeds.
> + */
> +void pruss_put(struct pruss *pruss)
> +{
> +	if (IS_ERR_OR_NULL(pruss))
> +		return;
> +
> +	put_device(pruss->dev);
> +}
> +EXPORT_SYMBOL_GPL(pruss_put);
> +
>  static void pruss_of_free_clk_provider(void *data)
>  {
>  	struct device_node *clk_mux_np = data;
> diff --git a/include/linux/pruss_driver.h b/include/linux/pruss_driver.h
> index ecfded30ed05..cb40c2b31045 100644
> --- a/include/linux/pruss_driver.h
> +++ b/include/linux/pruss_driver.h
> @@ -9,7 +9,9 @@
>  #ifndef _PRUSS_DRIVER_H_
>  #define _PRUSS_DRIVER_H_
>  
> +#include <linux/remoteproc/pruss.h>
>  #include <linux/types.h>
> +#include <linux/err.h>
>  
>  /*
>   * enum pruss_mem - PRUSS memory range identifiers
> @@ -51,4 +53,20 @@ struct pruss {
>  	struct clk *iep_clk_mux;
>  };
>  
> +#if IS_ENABLED(CONFIG_TI_PRUSS)
> +
> +struct pruss *pruss_get(struct rproc *rproc);
> +void pruss_put(struct pruss *pruss);
> +
> +#else
> +
> +static inline struct pruss *pruss_get(struct rproc *rproc)
> +{
> +	return ERR_PTR(-EOPNOTSUPP);
> +}
> +
> +static inline void pruss_put(struct pruss *pruss) { }
> +
> +#endif /* CONFIG_TI_PRUSS */
> +
>  #endif	/* _PRUSS_DRIVER_H_ */
> -- 
> 2.34.1
>