linux-kernel - [PATCH v3 01/12] misc: fastrpc: separate fastrpc device from channel context

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Date:   Wed, 26 Jan 2022 13:52:53 +0000
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     robh+dt@...nel.org, gregkh@...uxfoundation.org
Cc:     devicetree@...r.kernel.org, ekangupt@....qualcomm.com,
        bkumar@....qualcomm.com, linux-kernel@...r.kernel.org,
        srini@...nel.org, bjorn.andersson@...aro.org,
        linux-arm-msm@...r.kernel.org,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: [PATCH v3 01/12] misc: fastrpc: separate fastrpc device from channel context

Currently fastrpc misc device instance is within channel context struct
with a kref. So we have 2 structs with refcount, both of them managing the
same channel context structure.

Separate fastrpc device from channel context and by adding a dedicated
fastrpc_device structure, this should clean the structures a bit and also help
when adding secure device node support.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
---
 drivers/misc/fastrpc.c | 48 ++++++++++++++++++++++++++++++++++--------
 1 file changed, 39 insertions(+), 9 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 4ccbf43e6bfa..00cf0dbb6084 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -78,7 +78,7 @@
 #define USER_PD		(1)
 #define SENSORS_PD	(2)
 
-#define miscdev_to_cctx(d) container_of(d, struct fastrpc_channel_ctx, miscdev)
+#define miscdev_to_fdevice(d) container_of(d, struct fastrpc_device, miscdev)
 
 static const char *domains[FASTRPC_DEV_MAX] = { "adsp", "mdsp",
 						"sdsp", "cdsp"};
@@ -212,8 +212,13 @@ struct fastrpc_channel_ctx {
 	spinlock_t lock;
 	struct idr ctx_idr;
 	struct list_head users;
-	struct miscdevice miscdev;
 	struct kref refcount;
+	struct fastrpc_device *fdevice;
+};
+
+struct fastrpc_device {
+	struct fastrpc_channel_ctx *cctx;
+	struct miscdevice miscdev;
 };
 
 struct fastrpc_user {
@@ -1220,10 +1225,14 @@ static int fastrpc_device_release(struct inode *inode, struct file *file)
 
 static int fastrpc_device_open(struct inode *inode, struct file *filp)
 {
-	struct fastrpc_channel_ctx *cctx = miscdev_to_cctx(filp->private_data);
+	struct fastrpc_channel_ctx *cctx = NULL;
+	struct fastrpc_device *fdevice = NULL;
 	struct fastrpc_user *fl = NULL;
 	unsigned long flags;
 
+	fdevice = miscdev_to_fdevice(filp->private_data);
+	cctx = fdevice->cctx;
+
 	fl = kzalloc(sizeof(*fl), GFP_KERNEL);
 	if (!fl)
 		return -ENOMEM;
@@ -1608,6 +1617,29 @@ static struct platform_driver fastrpc_cb_driver = {
 	},
 };
 
+static int fastrpc_device_register(struct device *dev, struct fastrpc_channel_ctx *cctx,
+				   const char *domain)
+{
+	struct fastrpc_device *fdev;
+	int err;
+
+	fdev = devm_kzalloc(dev, sizeof(*fdev), GFP_KERNEL);
+	if (!fdev)
+		return -ENOMEM;
+
+	fdev->cctx = cctx;
+	fdev->miscdev.minor = MISC_DYNAMIC_MINOR;
+	fdev->miscdev.fops = &fastrpc_fops;
+	fdev->miscdev.name = devm_kasprintf(dev, GFP_KERNEL, "fastrpc-%s", domain);
+	err = misc_register(&fdev->miscdev);
+	if (err)
+		kfree(fdev);
+	else
+		cctx->fdevice = fdev;
+
+	return err;
+}
+
 static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
 {
 	struct device *rdev = &rpdev->dev;
@@ -1637,11 +1669,7 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
 	if (!data)
 		return -ENOMEM;
 
-	data->miscdev.minor = MISC_DYNAMIC_MINOR;
-	data->miscdev.name = devm_kasprintf(rdev, GFP_KERNEL, "fastrpc-%s",
-					    domains[domain_id]);
-	data->miscdev.fops = &fastrpc_fops;
-	err = misc_register(&data->miscdev);
+	err = fastrpc_device_register(rdev, data, domains[domain_id]);
 	if (err) {
 		kfree(data);
 		return err;
@@ -1681,7 +1709,9 @@ static void fastrpc_rpmsg_remove(struct rpmsg_device *rpdev)
 		fastrpc_notify_users(user);
 	spin_unlock_irqrestore(&cctx->lock, flags);
 
-	misc_deregister(&cctx->miscdev);
+	if (cctx->fdevice)
+		misc_deregister(&cctx->fdevice->miscdev);
+
 	of_platform_depopulate(&rpdev->dev);
 
 	cctx->rpdev = NULL;
-- 
2.21.0