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

Umang Jain <umang.jain@xxxxxxxxxxxxxxxx> · Fri, 22 Mar 2024 10:25:49 +0530

Hi Laurent,

On 22/03/24 12:42 am, Laurent Pinchart wrote:
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@xxxxxxxxxxxxxxxx>
---
  .../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 ?

yes, I looked into this - and it turned out the DEFINE_MUTEX 
implementation differs based on whether CONFIG_PREEMPT_RT is enabled or 
not, and I am not very sure if replacing it with struct mutex would have 
repercussions. I don't understand these bits very well yet and it seems 
(from a cursory look that DEFINE_MUTEX seems to be statically declared...)



  
  /*
@@ -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 */








