This is a note to let you know that I've just added the patch titled
w1: mxc_w1: Fix timeout resolution problem leading to bus error
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the char-misc-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From e1a26e13baf690444a254c4c4f088e1d059a942a Mon Sep 17 00:00:00 2001
From: Martin Fuzzey <martin.fuzzey@flowbird.group>
Date: Wed, 30 Sep 2020 10:36:46 +0200
Subject: w1: mxc_w1: Fix timeout resolution problem leading to bus error
On my platform (i.MX53) bus access sometimes fails with
w1_search: max_slave_count 64 reached, will continue next search.
The reason is the use of jiffies to implement a 200us timeout in
mxc_w1_ds2_touch_bit().
On some platforms the jiffies timer resolution is insufficient for this.
Fix by replacing jiffies by ktime_get().
For consistency apply the same change to the other use of jiffies in
mxc_w1_ds2_reset_bus().
Fixes: f80b2581a706 ("w1: mxc_w1: Optimize mxc_w1_ds2_touch_bit()")
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Martin Fuzzey <martin.fuzzey@flowbird.group>
Link: https://lore.kernel.org/r/1601455030-6607-1-git-send-email-martin.fuzzey@flowbird.group
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/w1/masters/mxc_w1.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/w1/masters/mxc_w1.c b/drivers/w1/masters/mxc_w1.c
index 1ca880e01476..090cbbf9e1e2 100644
--- a/drivers/w1/masters/mxc_w1.c
+++ b/drivers/w1/masters/mxc_w1.c
@@ -7,7 +7,7 @@
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
-#include <linux/jiffies.h>
+#include <linux/ktime.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
@@ -40,12 +40,12 @@ struct mxc_w1_device {
static u8 mxc_w1_ds2_reset_bus(void *data)
{
struct mxc_w1_device *dev = data;
- unsigned long timeout;
+ ktime_t timeout;
writeb(MXC_W1_CONTROL_RPP, dev->regs + MXC_W1_CONTROL);
/* Wait for reset sequence 511+512us, use 1500us for sure */
- timeout = jiffies + usecs_to_jiffies(1500);
+ timeout = ktime_add_us(ktime_get(), 1500);
udelay(511 + 512);
@@ -55,7 +55,7 @@ static u8 mxc_w1_ds2_reset_bus(void *data)
/* PST bit is valid after the RPP bit is self-cleared */
if (!(ctrl & MXC_W1_CONTROL_RPP))
return !(ctrl & MXC_W1_CONTROL_PST);
- } while (time_is_after_jiffies(timeout));
+ } while (ktime_before(ktime_get(), timeout));
return 1;
}
@@ -68,12 +68,12 @@ static u8 mxc_w1_ds2_reset_bus(void *data)
static u8 mxc_w1_ds2_touch_bit(void *data, u8 bit)
{
struct mxc_w1_device *dev = data;
- unsigned long timeout;
+ ktime_t timeout;
writeb(MXC_W1_CONTROL_WR(bit), dev->regs + MXC_W1_CONTROL);
/* Wait for read/write bit (60us, Max 120us), use 200us for sure */
- timeout = jiffies + usecs_to_jiffies(200);
+ timeout = ktime_add_us(ktime_get(), 200);
udelay(60);
@@ -83,7 +83,7 @@ static u8 mxc_w1_ds2_touch_bit(void *data, u8 bit)
/* RDST bit is valid after the WR1/RD bit is self-cleared */
if (!(ctrl & MXC_W1_CONTROL_WR(bit)))
return !!(ctrl & MXC_W1_CONTROL_RDST);
- } while (time_is_after_jiffies(timeout));
+ } while (ktime_before(ktime_get(), timeout));
return 0;
}
--
2.28.0
