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From: Siddharth Gupta <sidgup@codeaurora.org>
To: bjorn.andersson@linaro.org, ohad@wizery.com,
	linux-remoteproc@vger.kernel.org
Cc: Siddharth Gupta <sidgup@codeaurora.org>,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, psodagud@codeaurora.org,
	stable@vger.kernel.org
Subject: [PATCH 1/3] remoteproc: core: Move cdev add before device add
Date: Mon, 17 May 2021 13:45:47 -0700
Message-ID: <1621284349-22752-2-git-send-email-sidgup@codeaurora.org> (raw)
In-Reply-To: <1621284349-22752-1-git-send-email-sidgup@codeaurora.org>

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
   devtmpfs.
 - 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 <sidgup@codeaurora.org>
---
 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 626a6b90f..562355a 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -2316,6 +2316,11 @@ 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;
@@ -2329,11 +2334,6 @@ int rproc_add(struct rproc *rproc)
 	/* create debugfs entries */
 	rproc_create_debug_dir(rproc);
 
-	/* 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 index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-17 20:45 [PATCH 0/3] remoteproc: core: Fixes for rproc cdev and add Siddharth Gupta
2021-05-17 20:45 ` Siddharth Gupta [this message]
2021-05-28  3:43   ` [PATCH 1/3] remoteproc: core: Move cdev add before device add Bjorn Andersson
2021-05-17 20:45 ` [PATCH 2/3] remoteproc: core: Move validate " Siddharth Gupta
2021-05-28  3:44   ` Bjorn Andersson
2021-05-17 20:45 ` [PATCH 3/3] remoteproc: core: Cleanup device in case of failure Siddharth Gupta
2021-05-28  3:50   ` Bjorn Andersson

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