staging: vc04_services: Move variables for tracking connections

Connections to the vchiq driver are tracked using global variables.
Drop those and introduce them as members of struct vchiq_drv_mgmt.
Hence, struct vchiq_drv_mgmt will be used to track the connections.

Also, store a vchiq_drv_mgmt pointer to struct vchiq_device to
have easy access to struct vchiq_drv_mgmt across vchiq devices.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Link: https://lore.kernel.org/r/20240412075743.60712-5-umang.jain@ideasonboard.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Umang Jain

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c

@@ -545,7 +545,8 @@ 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();
+	mutex_init(&drv_mgmt->connected_mutex);
+	vchiq_call_connected_callbacks(drv_mgmt);
 
 	return 0;
 }

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h

@@ -20,6 +20,8 @@
 #define MAX_ELEMENTS 8
 #define MSG_QUEUE_SIZE 128
 
+#define VCHIQ_DRV_MAX_CALLBACKS 10
+
 struct rpi_firmware;
 
 enum USE_TYPE_E {
@@ -34,6 +36,13 @@ struct vchiq_platform_info {
 struct vchiq_drv_mgmt {
 	struct rpi_firmware *fw;
 	const struct vchiq_platform_info *info;
+
+	bool connected;
+	int num_deferred_callbacks;
+	/* Protects connected and num_deferred_callbacks */
+	struct mutex connected_mutex;
+
+	void (*deferred_callback[VCHIQ_DRV_MAX_CALLBACKS])(void);
 };
 
 struct user_service {

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.c

@@ -11,6 +11,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 
+#include "vchiq_arm.h"
 #include "vchiq_bus.h"
 
 static int vchiq_bus_type_match(struct device *dev, struct device_driver *drv)
@@ -77,6 +78,8 @@ vchiq_device_register(struct device *parent, const char *name)
 	device->dev.dma_mask = &device->dev.coherent_dma_mask;
 	device->dev.release = vchiq_device_release;
 
+	device->drv_mgmt = dev_get_drvdata(parent);
+
 	of_dma_configure(&device->dev, parent->of_node, true);
 
 	ret = device_register(&device->dev);

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_bus.h

@@ -9,8 +9,11 @@
 #include <linux/device.h>
 #include <linux/mod_devicetable.h>
 
+struct vchiq_drv_mgmt;
+
 struct vchiq_device {
 	struct device dev;
+	struct vchiq_drv_mgmt *drv_mgmt;
 };
 
 struct vchiq_driver {

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.c

@@ -1,18 +1,14 @@
 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /* Copyright (c) 2010-2012 Broadcom. All rights reserved. */
 
+#include "vchiq_arm.h"
 #include "vchiq_connected.h"
 #include "vchiq_core.h"
 #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);
-
 /*
  * This function is used to defer initialization until the vchiq stack is
  * initialized. If the stack is already initialized, then the callback will
@@ -21,42 +17,44 @@ static   DEFINE_MUTEX(g_connected_mutex);
  */
 void vchiq_add_connected_callback(struct vchiq_device *device, void (*callback)(void))
 {
-	if (mutex_lock_killable(&g_connected_mutex))
+	struct vchiq_drv_mgmt *drv_mgmt = device->drv_mgmt;
+
+	if (mutex_lock_killable(&drv_mgmt->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);
+	mutex_unlock(&drv_mgmt->connected_mutex);
 }
 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))
+	if (mutex_lock_killable(&drv_mgmt->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;
-	mutex_unlock(&g_connected_mutex);
+	drv_mgmt->num_deferred_callbacks = 0;
+	drv_mgmt->connected = true;
+	mutex_unlock(&drv_mgmt->connected_mutex);
 }

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.h

@@ -6,7 +6,9 @@
 #ifndef VCHIQ_CONNECTED_H
 #define VCHIQ_CONNECTED_H
 
+struct vchiq_drv_mgmt;
+
 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 */