Re: [PATCH v3 4/6] staging: vc04_services: Drop global members for tracking connections

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Umang,

Thank you for the patch.

On Thu, Mar 21, 2024 at 04:07:38PM +0530, Umang Jain wrote:
> Drop global members for tracking vchiq driver connections in
> vchiq_connected.[ch] and use the struct vchiq_drv_mgmt to
> track the connections.

I'd write "Move global connection tracking to vchiq_drv_mgmt" in the
subject line, as you're not just dropping them completely. Same in the
commit message.

> Also, store a vchiq_drv_mgmt pointer to struct vchiq_device to
> have easy access to struct vchiq_drv_mgmt across vchiq devices.
> 
> Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
> ---
>  .../interface/vchiq_arm/vchiq_arm.c           |  2 +-
>  .../interface/vchiq_arm/vchiq_arm.h           |  6 +++++
>  .../interface/vchiq_arm/vchiq_bus.c           |  4 +++
>  .../interface/vchiq_arm/vchiq_bus.h           |  3 +++
>  .../interface/vchiq_arm/vchiq_connected.c     | 25 +++++++++----------
>  .../interface/vchiq_arm/vchiq_connected.h     |  3 ++-
>  6 files changed, 28 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> index 01b4e4b010c6..ba096bcb32c8 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> @@ -559,7 +559,7 @@ static int vchiq_platform_init(struct platform_device *pdev, struct vchiq_state
>  	dev_dbg(&pdev->dev, "arm: vchiq_init - done (slots %pK, phys %pad)\n",
>  		vchiq_slot_zero, &slot_phys);
>  
> -	vchiq_call_connected_callbacks();
> +	vchiq_call_connected_callbacks(drv_mgmt);
>  
>  	return 0;
>  }
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
> index fc4122c27e94..1190fab2efc4 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
> @@ -23,6 +23,8 @@
>  #define MAX_ELEMENTS 8
>  #define MSG_QUEUE_SIZE 128
>  
> +#define VCHIQ_DRV_MAX_CALLBACKS 10

It would be nice to remove this, but I think we can live with it for
now.

> +
>  enum USE_TYPE_E {
>  	USE_TYPE_SERVICE,
>  	USE_TYPE_VCHIQ
> @@ -35,6 +37,10 @@ struct vchiq_platform_info {
>  struct vchiq_drv_mgmt {
>  	struct rpi_firmware *fw;
>  	const struct vchiq_platform_info *pinfo;
> +
> +	bool connected;
> +	int num_deferred_callbacks;
> +	void (*deferred_callback[VCHIQ_DRV_MAX_CALLBACKS])(void);
>  };
>  
>  struct user_service {
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.c
> index 68f830d75531..fb837e64838b 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.c
> @@ -54,6 +54,7 @@ static void vchiq_device_release(struct device *dev)
>  struct vchiq_device *
>  vchiq_device_register(struct device *parent, const char *name)
>  {
> +	struct platform_device *pdev;
>  	struct vchiq_device *device;
>  	int ret;
>  
> @@ -67,6 +68,9 @@ vchiq_device_register(struct device *parent, const char *name)
>  	device->dev.dma_mask = &device->dev.coherent_dma_mask;
>  	device->dev.release = vchiq_device_release;
>  
> +	pdev = to_platform_device(parent);
> +	device->drv_mgmt = platform_get_drvdata(pdev);

	device->drv_mgmt = dev_get_drvdata(parent);

> +
>  	of_dma_configure(&device->dev, parent->of_node, true);
>  
>  	ret = device_register(&device->dev);
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.h
> index 4db86e76edbd..b0e85ca2365e 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.h
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.h
> @@ -9,8 +9,11 @@
>  #include <linux/device.h>
>  #include <linux/mod_devicetable.h>
>  
> +#include "vchiq_arm.h"
> +

Use a declaration instead.

struct vchiq_drv_mgmt;

>  struct vchiq_device {
>  	struct device dev;
> +	struct vchiq_drv_mgmt *drv_mgmt;
>  };
>  
>  struct vchiq_driver {
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.c
> index 4604a2f4d2de..ec5e9107868e 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.c
> @@ -8,9 +8,6 @@
>  
>  #define  MAX_CALLBACKS  10
>  
> -static   int                        g_connected;
> -static   int                        g_num_deferred_callbacks;
> -static   void (*g_deferred_callback[MAX_CALLBACKS])(void);
>  static   DEFINE_MUTEX(g_connected_mutex);

Any reason not to move this to vchiq_drv_mgmt ?

>  
>  /*
> @@ -21,21 +18,23 @@ static   DEFINE_MUTEX(g_connected_mutex);
>   */
>  void vchiq_add_connected_callback(struct vchiq_device *device, void (*callback)(void))
>  {
> +	struct vchiq_drv_mgmt *drv_mgmt = device->drv_mgmt;
> +
>  	if (mutex_lock_killable(&g_connected_mutex))
>  		return;
>  
> -	if (g_connected) {
> +	if (drv_mgmt->connected) {
>  		/* We're already connected. Call the callback immediately. */
>  		callback();
>  	} else {
> -		if (g_num_deferred_callbacks >= MAX_CALLBACKS) {
> +		if (drv_mgmt->num_deferred_callbacks >= MAX_CALLBACKS) {
>  			dev_err(&device->dev,
>  				"core: There already %d callback registered - please increase MAX_CALLBACKS\n",
> -				g_num_deferred_callbacks);
> +				drv_mgmt->num_deferred_callbacks);
>  		} else {
> -			g_deferred_callback[g_num_deferred_callbacks] =
> +			drv_mgmt->deferred_callback[drv_mgmt->num_deferred_callbacks] =
>  				callback;
> -			g_num_deferred_callbacks++;
> +			drv_mgmt->num_deferred_callbacks++;
>  		}
>  	}
>  	mutex_unlock(&g_connected_mutex);
> @@ -46,17 +45,17 @@ EXPORT_SYMBOL(vchiq_add_connected_callback);
>   * This function is called by the vchiq stack once it has been connected to
>   * the videocore and clients can start to use the stack.
>   */
> -void vchiq_call_connected_callbacks(void)
> +void vchiq_call_connected_callbacks(struct vchiq_drv_mgmt *drv_mgmt)
>  {
>  	int i;
>  
>  	if (mutex_lock_killable(&g_connected_mutex))
>  		return;
>  
> -	for (i = 0; i <  g_num_deferred_callbacks; i++)
> -		g_deferred_callback[i]();
> +	for (i = 0; i <  drv_mgmt->num_deferred_callbacks; i++)
> +		drv_mgmt->deferred_callback[i]();
>  
> -	g_num_deferred_callbacks = 0;
> -	g_connected = 1;
> +	drv_mgmt->num_deferred_callbacks = 0;
> +	drv_mgmt->connected = true;
>  	mutex_unlock(&g_connected_mutex);
>  }
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.h
> index e4ed56446f8a..0a3adefc69e0 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.h
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.h
> @@ -1,12 +1,13 @@
>  /* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
>  /* Copyright (c) 2010-2012 Broadcom. All rights reserved. */
>  
> +#include "vchiq_arm.h"

Structure declaration too.

>  #include "vchiq_bus.h"
>  
>  #ifndef VCHIQ_CONNECTED_H
>  #define VCHIQ_CONNECTED_H
>  
>  void vchiq_add_connected_callback(struct vchiq_device *device, void (*callback)(void));
> -void vchiq_call_connected_callbacks(void);
> +void vchiq_call_connected_callbacks(struct vchiq_drv_mgmt *mgmt);
>  
>  #endif /* VCHIQ_CONNECTED_H */

-- 
Regards,

Laurent Pinchart