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* [patch] sdhci: correct f_min in sd 3.0
@ 2010-09-20  7:32 zhangfei gao
  2010-09-24  2:06 ` Chris Ball
  2010-09-24  3:24 ` Chris Ball
  0 siblings, 2 replies; 7+ messages in thread
From: zhangfei gao @ 2010-09-20  7:32 UTC (permalink / raw)
  To: Chris Ball; +Cc: linux-mmc, Kyungmin Park

[-- Attachment #1: Type: text/plain, Size: 905 bytes --]

>From 83140093bbcd325605135c23740b30b6eeec778f Mon Sep 17 00:00:00 2001
From: Zhangfei Gao <zhangfei.gao@marvell.com>
Date: Mon, 20 Sep 2010 15:15:18 -0400
Subject: [PATCH 4/4] sdhci: correct f_min in sd 3.0

Change-Id: Ie8604dbb5296b15da67071164564f21c60652b60

Signed-off-by: Zhangfei Gao <zhangfei.gao@marvell.com>
---
 drivers/mmc/host/sdhci.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index f980fb7..5346803 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1835,6 +1835,8 @@ int sdhci_add_host(struct sdhci_host *host)
 	mmc->ops = &sdhci_ops;
 	if (host->ops->get_min_clock)
 		mmc->f_min = host->ops->get_min_clock(host);
+	else if (host->version >= SDHCI_SPEC_300)
+		mmc->f_min = host->max_clk / 2046;
 	else
 		mmc->f_min = host->max_clk / 256;
 	mmc->f_max = host->max_clk;
-- 
1.7.0.4

[-- Attachment #2: 0004-sdhci-correct-f_min-in-sd-3.0.patch --]
[-- Type: text/x-patch, Size: 905 bytes --]

From 83140093bbcd325605135c23740b30b6eeec778f Mon Sep 17 00:00:00 2001
From: Zhangfei Gao <zhangfei.gao@marvell.com>
Date: Mon, 20 Sep 2010 15:15:18 -0400
Subject: [PATCH 4/4] sdhci: correct f_min in sd 3.0

Change-Id: Ie8604dbb5296b15da67071164564f21c60652b60

Signed-off-by: Zhangfei Gao <zhangfei.gao@marvell.com>
---
 drivers/mmc/host/sdhci.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index f980fb7..5346803 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1835,6 +1835,8 @@ int sdhci_add_host(struct sdhci_host *host)
 	mmc->ops = &sdhci_ops;
 	if (host->ops->get_min_clock)
 		mmc->f_min = host->ops->get_min_clock(host);
+	else if (host->version >= SDHCI_SPEC_300)
+		mmc->f_min = host->max_clk / 2046;
 	else
 		mmc->f_min = host->max_clk / 256;
 	mmc->f_max = host->max_clk;
-- 
1.7.0.4


^ permalink raw reply related	[flat|nested] 7+ messages in thread
* Re: [patch] sdhci: correct f_min in sd 3.0
@ 2010-09-28  4:05 Philip Rakity
  2010-09-28  4:58 ` zhangfei gao
  0 siblings, 1 reply; 7+ messages in thread
From: Philip Rakity @ 2010-09-28  4:05 UTC (permalink / raw)
  To: linux-mmc@vger.kernel.org; +Cc: Zhangfei Gao


The code snippet
> +			for (div = 2; div < SDHCI_MAX_DIV_SPEC_300; div += 2) {
>  				if ((host->max_clk / div) <= clock)
>  					break;

is not correct.  In sdio 3.0 the value is not a power of 2 for the divider but the value to be divided down-- all the bits count
2) 10-bit Divided Clock
Host Controller Version 3.00 supports this mandatory mode instead of the
8-bit Divided Clock Mode.  The length of the divider is extended to 10 bits and all
divider values shall be supported.
3FFh    1/2046  Divided Clock

Philip

Hi Zhangfei,

On Sat, Sep 25, 2010 at 12:23:33AM -0400, zhangfei gao wrote:
> From: Zhangfei Gao <zhangfei.gao@marvell.com>
> Date: Mon, 20 Sep 2010 15:15:18 -0400
> Subject: [PATCH] sdhci: correct f_min in sd 3.0
> 
> Signed-off-by: Zhangfei Gao <zhangfei.gao@marvell.com>
> ---
>  drivers/mmc/host/sdhci.c |    8 +++++---
>  drivers/mmc/host/sdhci.h |    3 +++
>  2 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 5928b0a..829e78a 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1007,14 +1007,14 @@ static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
>  		if (host->max_clk <= clock)
>  			div = 1;
>  		else {
> -			for (div = 2; div < 2046; div += 2) {
> +			for (div = 2; div < SDHCI_MAX_DIV_SPEC_300; div += 2) {
>  				if ((host->max_clk / div) <= clock)
>  					break;
>  			}
>  		}
>  	} else {
>  		/* Version 2.00 divisors must be a power of 2. */
> -		for (div = 1; div < 256; div *= 2) {
> +		for (div = 1; div < SDHCI_MAX_DIV_SPEC_200; div *= 2) {
>  			if ((host->max_clk / div) <= clock)
>  				break;
>  		}
> @@ -1836,8 +1836,10 @@ int sdhci_add_host(struct sdhci_host *host)
>  	mmc->ops = &sdhci_ops;
>  	if (host->ops->get_min_clock)
>  		mmc->f_min = host->ops->get_min_clock(host);
> +	else if (host->version >= SDHCI_SPEC_300)
> +		mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300;
>  	else
> -		mmc->f_min = host->max_clk / 256;
> +		mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_200;
>  	mmc->f_max = host->max_clk;
>  	mmc->caps |= MMC_CAP_SDIO_IRQ;
>  
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index ae28a31..d35fb3d 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -185,6 +185,9 @@
>  #define   SDHCI_SPEC_200	1
>  #define   SDHCI_SPEC_300	2
>  
> +#define	SDHCI_MAX_DIV_SPEC_200	256
> +#define	SDHCI_MAX_DIV_SPEC_300	2046
> +
>  struct sdhci_ops;
>  
>  struct sdhci_host {

Thanks very much, I've applied this to mmc-next now.

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child
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^ permalink raw reply	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2010-09-28  4:58 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-09-20  7:32 [patch] sdhci: correct f_min in sd 3.0 zhangfei gao
2010-09-24  2:06 ` Chris Ball
2010-09-24  3:24 ` Chris Ball
2010-09-25  4:23   ` zhangfei gao
2010-09-28  3:13     ` Chris Ball
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2010-09-28  4:05 Philip Rakity
2010-09-28  4:58 ` zhangfei gao

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