From 3fc2cbba40693892d19ca8edba765a3d7bd9d3a3 Mon Sep 17 00:00:00 2001 From: Martin Fuzzey Date: Wed, 30 Sep 2020 10:36:46 +0200 Subject: [PATCH] w1: mxc_w1: Fix timeout resolution problem leading to bus error commit c9723750a699c3bd465493ac2be8992b72ccb105 upstream. 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 Signed-off-by: Martin Fuzzey Link: https://lore.kernel.org/r/1601455030-6607-1-git-send-email-martin.fuzzey@flowbird.group Signed-off-by: Greg Kroah-Hartman --- 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 #include #include -#include +#include #include #include #include @@ -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; }