lkml.org 
[lkml]   [2008]   [Jan]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 18/18] MMC: OMAP: Do not busy wait for end of command for ever
From: Jarkko Lavinen <jarkko.lavinen@nokia.com>

The limit was a fixed 100k limit in the busy loop, which is not
accurate. It would better to have time limit for the worst case
which occurs when sending 80 cycles at 400 kHz and takes about
200 microseconds, so limit the max time spend in the busy loop
for some 250 microseconds.

Signed-off-by: Jarkko Lavinen <jarkko.lavinen@nokia.com>
---
drivers/mmc/host/omap.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c
index 5349f9f..c52815b 100644
--- a/drivers/mmc/host/omap.c
+++ b/drivers/mmc/host/omap.c
@@ -1294,11 +1294,17 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
OMAP_MMC_WRITE(host, CON, dsor);
slot->saved_con = dsor;
if (ios->power_mode == MMC_POWER_ON) {
+ /* worst case at 400kHz, 80 cycles makes 200 microsecs */
+ int usecs = 250;
+
/* Send clock cycles, poll completion */
OMAP_MMC_WRITE(host, IE, 0);
OMAP_MMC_WRITE(host, STAT, 0xffff);
OMAP_MMC_WRITE(host, CMD, 1 << 7);
- while ((OMAP_MMC_READ(host, STAT) & 1) == 0);
+ while (usecs > 0 && (OMAP_MMC_READ(host, STAT) & 1) == 0) {
+ udelay(1);
+ usecs--;
+ }
OMAP_MMC_WRITE(host, STAT, 1);
}

-- 1.5.3.GIT


\
 
 \ /
  Last update: 2008-01-28 20:19    [W:0.021 / U:0.456 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site