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From: Siddharth Gupta <>
Cc: Siddharth Gupta <>,,,,,
Subject: [PATCH v2 1/4] remoteproc: core: Move cdev add before device add
Date: Mon, 14 Jun 2021 13:40:41 -0700	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

When cdev_add is called after device_add has been called there is no
way for the userspace to know about the addition of a cdev as cdev_add
itself doesn't trigger a uevent notification, or for the kernel to
know about the change to devt. This results in two problems:
 - mknod is never called for the cdev and hence no cdev appears on
 - sysfs links to the new cdev are not established.

The cdev needs to be added and devt assigned before device_add() is
called in order for the relevant sysfs and devtmpfs entries to be
created and the uevent to be properly populated.

Signed-off-by: Siddharth Gupta <>
Reviewed-by: Bjorn Andersson <>
 drivers/remoteproc/remoteproc_core.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 6348aaa..9ad8c5f 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -2333,6 +2333,11 @@ int rproc_add(struct rproc *rproc)
 	struct device *dev = &rproc->dev;
 	int ret;
+	/* add char device for this remoteproc */
+	ret = rproc_char_device_add(rproc);
+	if (ret < 0)
+		return ret;
 	ret = device_add(dev);
 	if (ret < 0)
 		return ret;
@@ -2346,11 +2351,6 @@ int rproc_add(struct rproc *rproc)
 	/* create debugfs entries */
-	/* add char device for this remoteproc */
-	ret = rproc_char_device_add(rproc);
-	if (ret < 0)
-		return ret;
 	/* if rproc is marked always-on, request it to boot */
 	if (rproc->auto_boot) {
 		ret = rproc_trigger_auto_boot(rproc);
Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

  reply	other threads:[~2021-06-14 20:41 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-14 20:40 [PATCH v2 0/4] remoteproc: core: Fixes for rproc cdev and add Siddharth Gupta
2021-06-14 20:40 ` Siddharth Gupta [this message]
2021-06-14 20:40 ` [PATCH v2 2/4] remoteproc: core: Move validate before device add Siddharth Gupta
2021-06-14 20:40 ` [PATCH v2 3/4] remoteproc: core: Fix cdev remove and rproc del Siddharth Gupta
2021-06-14 20:40 ` [PATCH v2 4/4] remoteproc: core: Cleanup device in case of failure Siddharth Gupta
2021-06-14 20:59 ` [PATCH v2 0/4] remoteproc: core: Fixes for rproc cdev and add Bjorn Andersson

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