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From 1e888ff376c880b2803aecea3f69d28dc2ae4349 Mon Sep 17 00:00:00 2001
From: Naushir Patuck <naush@raspberrypi.com>
Date: Wed, 2 Dec 2020 15:26:09 +0000
Subject: [PATCH] media: bcm2835-unicam: Return early from
stop_streaming() if stopped
clk_disable_unprepare() is called unconditionally in stop_streaming().
This is incorrect in the cases where start_streaming() fails, and
unprepares all clocks as part of the failure cleanup. To avoid this,
ensure that clk_disable_unprepare() is only called in stop_streaming()
if the clocks are in a prepared state.
Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
---
drivers/media/platform/bcm2835/bcm2835-unicam.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
--- a/drivers/media/platform/bcm2835/bcm2835-unicam.c
+++ b/drivers/media/platform/bcm2835/bcm2835-unicam.c
@@ -426,6 +426,8 @@ struct unicam_device {
struct clk *clock;
/* vpu clock handle */
struct clk *vpu_clock;
+ /* clock status for error handling */
+ bool clocks_enabled;
/* V4l2 device */
struct v4l2_device v4l2_dev;
struct media_device mdev;
@@ -1724,6 +1726,7 @@ static int unicam_start_streaming(struct
goto err_disable_unicam;
}
+ dev->clocks_enabled = true;
return 0;
err_disable_unicam:
@@ -1750,8 +1753,6 @@ static void unicam_stop_streaming(struct
node->streaming = false;
if (node->pad_id == IMAGE_PAD) {
- int ret;
-
/*
* Stop streaming the sensor and disable the peripheral.
* We cannot continue streaming embedded data with the
@@ -1762,12 +1763,13 @@ static void unicam_stop_streaming(struct
unicam_disable(dev);
- ret = clk_set_min_rate(dev->vpu_clock, 0);
- if (ret)
- unicam_err(dev, "failed to reset the min VPU clock\n");
+ if (dev->clocks_enabled) {
+ if (clk_set_min_rate(dev->vpu_clock, 0))
+ unicam_err(dev, "failed to reset the min VPU clock\n");
- clk_disable_unprepare(dev->vpu_clock);
- clk_disable_unprepare(dev->clock);
+ clk_disable_unprepare(dev->vpu_clock);
+ clk_disable_unprepare(dev->clock);
+ }
unicam_runtime_put(dev);
} else if (node->pad_id == METADATA_PAD) {
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