Re: [patch 1/1]sdhci: sdhc spec 3.0 add some modification

[zhangfei gao]

On Wed, Aug 11, 2010 at 12:32 AM, Matt Fleming <m...@console-pimps.org> wrote:
> On Mon, Aug 09, 2010 at 08:33:16PM +0800, zhangfei gao wrote:
>>
>> Thanks for your careful review, in our platform, we use max/min for
>> the max_div, so miss this modification :(
>> Update the patch, help review again.
>
> What do you mean? Where does max/min come from? It would definitely
> be best if everybody uses the same code to calculate max_div. Have
> you tested the max_div changes? Are you now using this patch on
> your platform or are you still maintaining a patch to do it a
> different way?
>
> If you've got a separate patch and it does this things better
> than the way we currently do them, get it upstream! :-)
>

Hi, Matt

Thanks for your reminder, totally agree with you.
We also use this patch in our platform, and find another issue, div
should +=2 instead of *=2.
-       for (div = 1;div < 256;div *= 2) {
+       for (div = 1;div < max_div;div += 2) {

Update patch, help review.

>From 517077ffae66dd12c409b7c6b41a7014db66a3cc Mon Sep 17 00:00:00 2001
From: Zhangfei Gao <zg...@marvell.com>
Date: Fri, 6 Aug 2010 07:10:01 +0800
Subject: [PATCH] sdhc: support 10-bit divided clock Mode

Signed-off-by: Zhangfei Gao <zg...@marvell.com>
Reviewed-by: Matt Fleming <m...@console-pimps.org>
---
 drivers/mmc/host/sdhci.c |   14 ++++++++++----
 drivers/mmc/host/sdhci.h |    4 ++++
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index c6d1bd8..b2d5e5e 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -978,7 +978,7 @@ static void sdhci_finish_command(struct sdhci_host *host)

 static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
 {
-       int div;
+       int div, max_div;
        u16 clk;
        unsigned long timeout;

@@ -996,13 +996,19 @@ static void sdhci_set_clock(struct sdhci_host
*host, unsigned int clock)
        if (clock == 0)
                goto out;

-       for (div = 1;div < 256;div *= 2) {
+       if (host->version >= SDHCI_SPEC_300)
+               max_div = 2046;
+       else
+               max_div = 256;
+
+       for (div = 1;div < max_div;div += 2) {
                if ((host->max_clk / div) <= clock)
                        break;
        }
        div >>= 1;

-       clk = div << SDHCI_DIVIDER_SHIFT;
+       clk = (div & SDHCI_DIV_MASK) << SDHCI_DIVIDER_SHIFT;
+       clk |= ((div & SDHCI_DIV_HI_MASK) >> SDHCI_DIVIDER_SHIFT) <<
SDHCI_DIVIDER_SHIFT_HI;
        clk |= SDHCI_CLOCK_INT_EN;
        sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);

@@ -1681,7 +1687,7 @@ int sdhci_add_host(struct sdhci_host *host)
        host->version = sdhci_readw(host, SDHCI_HOST_VERSION);
        host->version = (host->version & SDHCI_SPEC_VER_MASK)
                                >> SDHCI_SPEC_VER_SHIFT;
-       if (host->version > SDHCI_SPEC_200) {
+       if (host->version > SDHCI_SPEC_300) {
                printk(KERN_ERR "%s: Unknown controller version (%d). "
                        "You may experience problems.\n", mmc_hostname(mmc),
                        host->version);
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index c846813..7c09b4f 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -85,6 +85,9 @@

 #define SDHCI_CLOCK_CONTROL    0x2C
 #define  SDHCI_DIVIDER_SHIFT   8
+#define  SDHCI_DIVIDER_SHIFT_HI        6
+#define  SDHCI_DIV_MASK        0xFF
+#define  SDHCI_DIV_HI_MASK     0x300
 #define  SDHCI_CLOCK_CARD_EN   0x0004
 #define  SDHCI_CLOCK_INT_STABLE        0x0002
 #define  SDHCI_CLOCK_INT_EN    0x0001
@@ -177,6 +180,7 @@
 #define  SDHCI_SPEC_VER_SHIFT  0
 #define   SDHCI_SPEC_100       0
 #define   SDHCI_SPEC_200       1
+#define   SDHCI_SPEC_300       2

 struct sdhci_ops;

-- 
1.6.0.4

0001-sdhc-support-10-bit-divided-clock-Mode.patch
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