Re: [PATCH v2 3/6] staging: vc04_services: Drop global members for tracking connections

[Kieran Bingham <kieran.bingham@ideasonboard.com>]

Quoting Umang Jain (2024-03-14 10:06:04)
> Introduce a new struct vchiq_connected, responsible to track
> the connections to the vchiq platform driver. The struct is added
> as part of vchiq platform driver data (struct vchiq_drvdata).
> 
> Drop global members for tracking vchiq driver connections in
> vchiq_connected.[ch] and use the struct vchiq_connected present
> in struct vchiq_drvdata.
> 
> Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
> ---
>  .../interface/vchiq_arm/vchiq_arm.c           |  2 +-
>  .../interface/vchiq_arm/vchiq_arm.h           |  3 ++
>  .../interface/vchiq_arm/vchiq_connected.c     | 33 +++++++++----------
>  .../interface/vchiq_arm/vchiq_connected.h     | 15 +++++++--
>  4 files changed, 33 insertions(+), 20 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 52569517ba4e..8c7520dee5f4 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> @@ -550,7 +550,7 @@ 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(&drvdata->drv_connected);
>  
>         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 7fef05e7389c..f2fd572df2b3 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
> @@ -16,6 +16,7 @@
>  
>  #include "vchiq_core.h"
>  #include "vchiq_debugfs.h"
> +#include "vchiq_connected.h"
>  
>  /* Some per-instance constants */
>  #define MAX_COMPLETIONS 128
> @@ -31,6 +32,8 @@ enum USE_TYPE_E {
>  struct vchiq_drvdata {
>         const unsigned int cache_line_size;
>         struct rpi_firmware *fw;
> +
> +       struct vchiq_connected drv_connected;
>  };
>  
>  struct user_service {
> 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..bc21910fe823 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.c
> @@ -6,11 +6,6 @@
>  #include <linux/module.h>
>  #include <linux/mutex.h>
>  
> -#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);
>  
>  /*
> @@ -19,23 +14,27 @@ static   DEFINE_MUTEX(g_connected_mutex);
>   * be made immediately, otherwise it will be deferred until
>   * vchiq_call_connected_callbacks is called.
>   */
> -void vchiq_add_connected_callback(struct vchiq_device *device, void (*callback)(void))
> +void vchiq_add_connected_callback(struct vchiq_device *device,
> +                                 void (*callback)(void),
> +                                 struct vchiq_connected *drv_connected)

I think I would have called this 'struct vchiq_connection *connection'
but it doesn't really matter, so don't rework unless there's a 'need'
for another iteration.



Aha though I see vchiq_connected matches the name of this c module, so
maybe that's just as/more suitable.


Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

>  {
> +       unsigned int index;
> +
>         if (mutex_lock_killable(&g_connected_mutex))
>                 return;
>  
> -       if (g_connected) {
> +       if (drv_connected->connected) {
>                 /* We're already connected. Call the callback immediately. */
>                 callback();
>         } else {
> -               if (g_num_deferred_callbacks >= MAX_CALLBACKS) {
> +               if (drv_connected->num_deferred_callbacks >= VCHIQ_DRV_MAX_CALLBACKS) {
>                         dev_err(&device->dev,
>                                 "core: There already %d callback registered - please increase MAX_CALLBACKS\n",
> -                               g_num_deferred_callbacks);
> +                               drv_connected->num_deferred_callbacks);
>                 } else {
> -                       g_deferred_callback[g_num_deferred_callbacks] =
> -                               callback;
> -                       g_num_deferred_callbacks++;
> +                       index = drv_connected->num_deferred_callbacks;
> +                       drv_connected->deferred_callback[index] = callback;
> +                       drv_connected->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_connected *drv_connected)
>  {
>         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_connected->num_deferred_callbacks; i++)
> +               drv_connected->deferred_callback[i]();
>  
> -       g_num_deferred_callbacks = 0;
> -       g_connected = 1;
> +       drv_connected->num_deferred_callbacks = 0;
> +       drv_connected->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..66e56b5af46e 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.h
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.h
> @@ -6,7 +6,18 @@
>  #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);
> +#define  VCHIQ_DRV_MAX_CALLBACKS  10
> +
> +struct vchiq_connected {
> +       bool connected;
> +       int num_deferred_callbacks;
> +
> +       void (*deferred_callback[VCHIQ_DRV_MAX_CALLBACKS])(void);
> +};
> +
> +void vchiq_add_connected_callback(struct vchiq_device *device, void (*callback)(void),
> +                                 struct vchiq_connected *drv_connected);
> +void vchiq_call_connected_callbacks(struct vchiq_connected *drv_connected);
> +
>  
>  #endif /* VCHIQ_CONNECTED_H */
> -- 
> 2.43.0
>