On 2017/12/19 18:43, Fabien DESSENNE wrote:
Hi,
On 16/12/17 12:54, Jia-Ju Bai wrote:
The driver may sleep under a spinlock.
The function call path is:
bdisp_device_run (acquire the spinlock)
bdisp_hw_reset
msleep --> may sleep
To fix it, readl_poll_timeout_atomic is used to replace msleep.
This bug is found by my static analysis tool(DSAC) and
checked by my code review.
Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
---
drivers/media/platform/sti/bdisp/bdisp-hw.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/media/platform/sti/bdisp/bdisp-hw.c b/drivers/media/platform/sti/bdisp/bdisp-hw.c
index b7892f3..e94a371 100644
--- a/drivers/media/platform/sti/bdisp/bdisp-hw.c
+++ b/drivers/media/platform/sti/bdisp/bdisp-hw.c
@@ -5,6 +5,7 @@
*/
#include <linux/delay.h>
This delay.h include is no more needed, remove it.
+#include <linux/iopoll.h>
#include "bdisp.h"
#include "bdisp-filter.h"
@@ -366,7 +367,7 @@ struct bdisp_filter_addr {
*/
int bdisp_hw_reset(struct bdisp_dev *bdisp)
{
- unsigned int i;
+ u32 tmp;
dev_dbg(bdisp->dev, "%s\n", __func__);
@@ -379,15 +380,14 @@ int bdisp_hw_reset(struct bdisp_dev *bdisp)
writel(0, bdisp->regs + BLT_CTL);
/* Wait for reset done */
- for (i = 0; i < POLL_RST_MAX; i++) {
- if (readl(bdisp->regs + BLT_STA1) & BLT_STA1_IDLE)
- break;
- msleep(POLL_RST_DELAY_MS);
- }
- if (i == POLL_RST_MAX)
As recommended by Mauro, please add this comment:
Despite the large timeout, most of the time the reset happens without
needing any delays
+ if (readl_poll_timeout_atomic(bdisp->regs + BLT_STA1, tmp,
+ (tmp & BLT_STA1_IDLE), POLL_RST_DELAY_MS,
+ POLL_RST_DELAY_MS * POLL_RST_MAX)) {
read_poll_timeout expects US timings, not MS.
dev_err(bdisp->dev, "Reset timeout\n");
+ return -EAGAIN;
+ }
- return (i == POLL_RST_MAX) ? -EAGAIN : 0;
+ return 0;
}
/**
Hi,
Okay, I have submitted a new patch according to your advice :)
Thanks,
Jia-Ju Bai
