[PATCH 18/18] MMC: OMAP: Do not busy wait for end of command for ever

[PATCH 18/18] MMC: OMAP: Do not busy wait for end of command for ever

[Carlos Aguiar]

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 cb7cb34..0f18b3b 100644
--- a/drivers/mmc/host/omap.c
+++ b/drivers/mmc/host/omap.c
@@ -1276,11 +1276,17 @@ 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

[PATCH 00/18] MMC: OMAP: Sync MMC OMAP driver with mainline tree

[Carlos Aguiar]

Hi Pierre, Tony and folks,

The new version of the patch series that follows is a synchronization
of MMC OMAP driver from Linux-OMAP tree into mainline tree.

Improvements and corrections are based on comments from Pierre Ossman and 
Roel Kluin, from LKML.

Just to remind you, basically it brings MMC multislot support for OMAP boards 
with one slot (like H2 1611, H3 1710) or two slots (like H4 2420 and N800).
Others boards supported by such feature are: N770, Siemens SX1 and Apollon.

BR,

Carlos.

-- 
Carlos Eduardo Aguiar
Nokia Institute of Technology - INdT
Open Source Mobile Research Center - OSMRC - Manaus
Core Team
Phone: +55 92 2126-1079
Mobile: +55 92 8127-1797
E-mail: carlos.aguiar@indt.org.br

Re: [PATCH 00/18] MMC: OMAP: Sync MMC OMAP driver with mainline tree

[Pierre Ossman]

On Fri, 14 Mar 2008 15:35:56 -0400
Carlos Aguiar <carlos.aguiar@indt.org.br> wrote:

Except for the issue with the device attributes, the patch set looks fine. Send me a fix for that patch (and affected subsequent) and I'll queue it up.

-- 
     -- Pierre Ossman

  Linux kernel, MMC maintainer        http://www.kernel.org
  PulseAudio, core developer          http://pulseaudio.org
  rdesktop, core developer          http://www.rdesktop.org

[PATCH 18/18] MMC: OMAP: Do not busy wait for end of command for ever

[Carlos Aguiar]

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 b28ae3b..2468e2f 100644
--- a/drivers/mmc/host/omap.c
+++ b/drivers/mmc/host/omap.c
@@ -1276,11 +1276,17 @@ 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

[PATCH 18/18] MMC: OMAP: Do not busy wait for end of command for ever

[Carlos Aguiar]

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