mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
synced 2024-11-14 07:11:52 +02:00
fc54b9bf15
(stable-branch of Openmoko) git-svn-id: svn://svn.openwrt.org/openwrt/trunk@13613 3c298f89-4303-0410-b956-a3cf2f4a3e73
110 lines
3.4 KiB
Diff
110 lines
3.4 KiB
Diff
From ef2376d29e996d9d21a9e5798cb88aa73f734c83 Mon Sep 17 00:00:00 2001
|
|
From: Andy Green <andy@openmoko.com>
|
|
Date: Thu, 17 Jul 2008 10:02:35 +0100
|
|
Subject: [PATCH] add-limit-sdcard-clk-cmdline.patch
|
|
|
|
This patch allows you to control the maximum clock rate that will
|
|
be selected for SD Card access, from the kernel commandline using
|
|
|
|
glamo_mci.sd_max_clk=10000000
|
|
|
|
and also from
|
|
|
|
echo 10000000 > /sys/module/glamo_mci/parameters/sd_max_clk
|
|
|
|
although you have to suspend and resume to make the limit operational
|
|
on the actual SD_CLK line.
|
|
|
|
Clocks that are possible are divided down from ~50MHz, so 25000000,
|
|
16666666, 12500000, 10000000, etc. With Freerunner A5 revision that
|
|
has 100R series resistors in SD Card signals, I didn't get reliable
|
|
operation above 16MHz. With A6 revision the series resistors went
|
|
down to 75R, maybe it can work at 25MHz.
|
|
|
|
Reducing the clock rate is something to try if you find that your
|
|
SD Card is not communicating properly with the default speed.
|
|
|
|
Signed-off-by: Andy Green <andy@openmoko.com>
|
|
---
|
|
drivers/mfd/glamo/glamo-mci.c | 38 +++++++++++++++++++++++++++++---------
|
|
1 files changed, 29 insertions(+), 9 deletions(-)
|
|
|
|
diff --git a/drivers/mfd/glamo/glamo-mci.c b/drivers/mfd/glamo/glamo-mci.c
|
|
index 350b47d..6729244 100644
|
|
--- a/drivers/mfd/glamo/glamo-mci.c
|
|
+++ b/drivers/mfd/glamo/glamo-mci.c
|
|
@@ -40,6 +40,24 @@ static spinlock_t clock_lock;
|
|
|
|
static void glamo_mci_send_request(struct mmc_host *mmc);
|
|
|
|
+/*
|
|
+ * Max SD clock rate
|
|
+ *
|
|
+ * held at /(3 + 1) due to concerns of 100R recommended series resistor
|
|
+ * allows 16MHz @ 4-bit --> 8MBytes/sec raw
|
|
+ *
|
|
+ * you can override this on kernel commandline using
|
|
+ *
|
|
+ * glamo_mci.sd_max_clk=10000000
|
|
+ *
|
|
+ * for example
|
|
+ */
|
|
+
|
|
+static int sd_max_clk = 50000000 / 3;
|
|
+module_param(sd_max_clk, int, 0644);
|
|
+
|
|
+
|
|
+
|
|
unsigned char CRC7(u8 * pu8, int cnt)
|
|
{
|
|
u8 crc = 0;
|
|
@@ -676,9 +694,9 @@ static void glamo_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
|
|
(ios->power_mode == MMC_POWER_UP)) {
|
|
dev_info(&host->pdev->dev,
|
|
"powered (vdd = %d) clk: %lukHz div=%d (req: %ukHz). "
|
|
- "Bus width=%d\n",ios->vdd,
|
|
- host->real_rate / 1000, host->real_rate,
|
|
- ios->clock / 1000, ios->bus_width);
|
|
+ "Bus width=%d\n",(int)ios->vdd,
|
|
+ host->real_rate / 1000, (int)host->clk_div,
|
|
+ ios->clock / 1000, (int)ios->bus_width);
|
|
} else
|
|
dev_info(&host->pdev->dev, "glamo_mci_set_ios: power down.\n");
|
|
|
|
@@ -800,11 +818,7 @@ static int glamo_mci_probe(struct platform_device *pdev)
|
|
MMC_CAP_MMC_HIGHSPEED |
|
|
MMC_CAP_SD_HIGHSPEED;
|
|
mmc->f_min = host->clk_rate / 256;
|
|
- /*
|
|
- * held at /4 due to concerns of 100R recommended series resistor
|
|
- * allows 16MHz @ 4-bit --> 8MBytes/sec raw
|
|
- */
|
|
- mmc->f_max = host->clk_rate / 3;
|
|
+ mmc->f_max = sd_max_clk;
|
|
|
|
mmc->max_blk_count = (1 << 16) - 1; /* GLAMO_REG_MMC_RB_BLKCNT */
|
|
mmc->max_blk_size = (1 << 12) - 1; /* GLAMO_REG_MMC_RB_BLKLEN */
|
|
@@ -866,12 +880,18 @@ static int glamo_mci_suspend(struct platform_device *dev, pm_message_t state)
|
|
{
|
|
struct mmc_host *mmc = platform_get_drvdata(dev);
|
|
struct glamo_mci_host *host = mmc_priv(mmc);
|
|
+ int ret;
|
|
|
|
host->suspending++;
|
|
if (host->pdata->mci_all_dependencies_resumed)
|
|
(host->pdata->mci_suspending)(dev);
|
|
|
|
- return mmc_suspend_host(mmc, state);
|
|
+ ret = mmc_suspend_host(mmc, state);
|
|
+
|
|
+ /* so that when we resume, we use any modified max rate */
|
|
+ mmc->f_max = sd_max_clk;
|
|
+
|
|
+ return ret;
|
|
}
|
|
|
|
int glamo_mci_resume(struct platform_device *dev)
|
|
--
|
|
1.5.6.5
|
|
|