linux-kernel - Re: [PATCH v5] remoteproc: Make rproc_get_by

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Date: Wed, 7 Feb 2024 16:18:50 -0600
From: Tanmay Shah <tanmay.shah@....com>
To: andersson@...nel.org, mathieu.poirier@...aro.org
Cc: linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
 Ben Levinsky <ben.levinsky@...inx.com>, Tarak Reddy <tarak.reddy@....com>
Subject: Re: [PATCH v5] remoteproc: Make rproc_get_by_phandle() work for
 clusters

Rejected-by: Tanmay Shah <tanmay.shah@....com>

I will send new v5 with change long included.

On 1/30/24 9:48 AM, Tanmay Shah wrote:
> From: Mathieu Poirier <mathieu.poirier@...aro.org>
>
> Multi-cluster remoteproc designs typically have the following DT
> declaration:
>
>         remoteproc-cluster {
>                 compatible = "soc,remoteproc-cluster";
>
>                 core0: core0 {
>                         compatible = "soc,remoteproc-core"
>                         memory-region;
>                         sram;
>                 };
>
>                 core1: core1 {
>                         compatible = "soc,remoteproc-core"
>                         memory-region;
>                         sram;
>                 }
>         };
>
> A driver exists for the cluster rather than the individual cores
> themselves so that operation mode and HW specific configurations
> applicable to the cluster can be made.
>
> Because the driver exists at the cluster level and not the individual
> core level, function rproc_get_by_phandle() fails to return the
> remoteproc associated with the phandled it is called for.
>
> This patch enhances rproc_get_by_phandle() by looking for the cluster's
> driver when the driver for the immediate remoteproc's parent is not
> found.
>
> Reported-by: Ben Levinsky <ben.levinsky@...inx.com>
> Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> Co-developed-by: Tarak Reddy <tarak.reddy@....com>
> Signed-off-by: Tarak Reddy <tarak.reddy@....com>
> Co-developed-by: Tanmay Shah <tanmay.shah@....com>
> Signed-off-by: Tanmay Shah <tanmay.shah@....com>
> ---
>  drivers/remoteproc/remoteproc_core.c | 29 ++++++++++++++++++++++++++--
>  1 file changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 695cce218e8c..f276956f2c5c 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -33,6 +33,7 @@
>  #include <linux/idr.h>
>  #include <linux/elf.h>
>  #include <linux/crc32.h>
> +#include <linux/of_platform.h>
>  #include <linux/of_reserved_mem.h>
>  #include <linux/virtio_ids.h>
>  #include <linux/virtio_ring.h>
> @@ -2112,6 +2113,7 @@ EXPORT_SYMBOL(rproc_detach);
>  struct rproc *rproc_get_by_phandle(phandle phandle)
>  {
>  	struct rproc *rproc = NULL, *r;
> +	struct device_driver *driver;
>  	struct device_node *np;
>  
>  	np = of_find_node_by_phandle(phandle);
> @@ -2122,7 +2124,26 @@ struct rproc *rproc_get_by_phandle(phandle phandle)
>  	list_for_each_entry_rcu(r, &rproc_list, node) {
>  		if (r->dev.parent && device_match_of_node(r->dev.parent, np)) {
>  			/* prevent underlying implementation from being removed */
> -			if (!try_module_get(r->dev.parent->driver->owner)) {
> +
> +			/*
> +			 * If the remoteproc's parent has a driver, the
> +			 * remoteproc is not part of a cluster and we can use
> +			 * that driver.
> +			 */
> +			driver = r->dev.parent->driver;
> +
> +			/*
> +			 * If the remoteproc's parent does not have a driver,
> +			 * look for the driver associated with the cluster.
> +			 */
> +			if (!driver) {
> +				if (r->dev.parent->parent)
> +					driver = r->dev.parent->parent->driver;
> +				if (!driver)
> +					break;
> +			}
> +
> +			if (!try_module_get(driver->owner)) {
>  				dev_err(&r->dev, "can't get owner\n");
>  				break;
>  			}
> @@ -2533,7 +2554,11 @@ EXPORT_SYMBOL(rproc_free);
>   */
>  void rproc_put(struct rproc *rproc)
>  {
> -	module_put(rproc->dev.parent->driver->owner);
> +	if (rproc->dev.parent->driver)
> +		module_put(rproc->dev.parent->driver->owner);
> +	else
> +		module_put(rproc->dev.parent->parent->driver->owner);
> +
>  	put_device(&rproc->dev);
>  }
>  EXPORT_SYMBOL(rproc_put);
>
> base-commit: 99f59b148871dadb9104366e3d25b120a97f897b