From d944934bbddc281938fb1905a69e35c0581937c2 Mon Sep 17 00:00:00 2001
From: Mike Westerhof <mwester@dls.net>
Date: Thu, 13 Nov 2008 20:39:36 +0000
Subject: [PATCH] GTA01-use-slow-SD-clock-when-gps-on.patch
This patch implements Andy Green's SD clock slow-down code
for the GTA01 device.
Signed-off-by: Mike Westerhof <mwester@dls.net>
---
arch/arm/mach-s3c2410/mach-gta01.c | 8 ++++++
drivers/mmc/host/s3cmci.c | 43 ++++++++++++++++++++++++++++++++++-
drivers/mmc/host/s3cmci.h | 1 +
include/asm-arm/arch-s3c2410/mci.h | 1 +
4 files changed, 51 insertions(+), 2 deletions(-)
diff --git a/arch/arm/mach-s3c2410/mach-gta01.c b/arch/arm/mach-s3c2410/mach-gta01.c
index a364b76..c0817dc 100644
--- a/arch/arm/mach-s3c2410/mach-gta01.c
+++ b/arch/arm/mach-s3c2410/mach-gta01.c
@@ -75,6 +75,8 @@
#include <asm/plat-s3c24xx/neo1973.h>
#include <asm/arch-s3c2410/neo1973-pm-gsm.h>
+#include "../plat-s3c24xx/neo1973_pm_gps.h"
+
#include <linux/jbt6k74.h>
static struct map_desc gta01_iodesc[] __initdata = {
@@ -432,9 +434,15 @@ static void gta01_mmc_set_power(unsigned char power_mode, unsigned short vdd)
}
}
+static int gta01_mmc_use_slow(void)
+{
+ return neo1973_pm_gps_is_on();
+}
+
static struct s3c24xx_mci_pdata gta01_mmc_cfg = {
.gpio_detect = GTA01_GPIO_nSD_DETECT,
.set_power = >a01_mmc_set_power,
+ .use_slow = >a01_mmc_use_slow,
.ocr_avail = MMC_VDD_165_195|MMC_VDD_20_21|
MMC_VDD_21_22|MMC_VDD_22_23|MMC_VDD_23_24|
MMC_VDD_24_25|MMC_VDD_25_26|MMC_VDD_26_27|
diff --git a/drivers/mmc/host/s3cmci.c b/drivers/mmc/host/s3cmci.c
index 8f88721..87d24b2 100644
--- a/drivers/mmc/host/s3cmci.c
+++ b/drivers/mmc/host/s3cmci.c
@@ -59,6 +59,23 @@ module_param(sd_max_clk, int, 0644);
static int sd_idleclk; /* disallow idle clock by default */
module_param(sd_idleclk, int, 0644);
+/*
+ * Slow SD clock rate
+ *
+ * you can override this on kernel commandline using
+ *
+ * s3cmci.sd_slow_ratio=8
+ *
+ * for example.
+ *
+ * A platform callback is used to decide effective clock rate. If not
+ * defined, then the max is used, if defined and the callback returns
+ * nonzero, the rate is divided by this factor.
+ */
+
+static int sd_slow_ratio = 8;
+module_param(sd_slow_ratio, int, 0644);
+
/* used to stash real idleclk state in suspend: we force it to run in there */
static int suspend_sd_idleclk;
@@ -252,7 +269,7 @@ static inline void do_pio_read(struct s3cmci_host *host)
void __iomem *from_ptr;
/* write real prescaler to host, it might be set slow to fix */
- writel(host->prescaler, host->base + S3C2410_SDIPRE);
+ writel(host->sdipre, host->base + S3C2410_SDIPRE);
from_ptr = host->base + host->sdidata;
@@ -755,7 +772,7 @@ static void finalize_request(struct s3cmci_host *host)
cmd->resp[3] = readl(host->base + S3C2410_SDIRSP3);
/* reset clock speed, as it could still be set low for */
- writel(host->prescaler, host->base + S3C2410_SDIPRE);
+ writel(host->sdipre, host->base + S3C2410_SDIPRE);
if (cmd->error)
debug_as_failure = 1;
@@ -1032,6 +1049,7 @@ static void s3cmci_send_request(struct mmc_host *mmc)
struct s3cmci_host *host = mmc_priv(mmc);
struct mmc_request *mrq = host->mrq;
struct mmc_command *cmd = host->cmd_is_stop?mrq->stop:mrq->cmd;
+ int pre;
host->ccnt++;
#ifdef CONFIG_MMC_DEBUG
@@ -1073,6 +1091,26 @@ static void s3cmci_send_request(struct mmc_host *mmc)
}
+ /* establish the correct prescaler depending on the sd_slow_ratio */
+
+ if ((sd_slow_ratio > 1) &&
+ host->pdata->use_slow && (host->pdata->use_slow)()) {
+ /* compute the slower speed */
+ pre = host->prescaler * sd_slow_ratio;
+ if (pre > 255)
+ pre = 255;
+ } else {
+ /* use the normal speed */
+ pre = host->prescaler;
+ }
+
+ if (host->sdipre != pre) {
+ dbg(host, dbg_conf, "prescaler changed: %d -> %d\n",
+ (int)host->sdipre, pre);
+ host->sdipre = pre;
+ writel(host->sdipre, host->base + S3C2410_SDIPRE);
+ }
+
__s3cmci_enable_clock(host);
s3cmci_send_command(host, cmd);
enable_irq(host->irq);
@@ -1138,6 +1176,7 @@ static void s3cmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
if (mci_psc > 255)
mci_psc = 255;
host->prescaler = mci_psc;
+ host->sdipre = mci_psc;
writel(host->prescaler, host->base + S3C2410_SDIPRE);
diff --git a/drivers/mmc/host/s3cmci.h b/drivers/mmc/host/s3cmci.h
index 9644b45..11974ff 100644
--- a/drivers/mmc/host/s3cmci.h
+++ b/drivers/mmc/host/s3cmci.h
@@ -32,6 +32,7 @@ struct s3cmci_host {
unsigned long clk_div;
unsigned long real_rate;
u8 prescaler;
+ u8 sdipre;
int is2440;
unsigned sdiimsk;
diff --git a/include/asm-arm/arch-s3c2410/mci.h b/include/asm-arm/arch-s3c2410/mci.h
index 24e6cd1..f087229 100644
--- a/include/asm-arm/arch-s3c2410/mci.h
+++ b/include/asm-arm/arch-s3c2410/mci.h
@@ -8,6 +8,7 @@ struct s3c24xx_mci_pdata {
unsigned int do_dma;
void (*set_power)(unsigned char power_mode,
unsigned short vdd);
+ int (*use_slow)(void);
};
#endif /* _ARCH_NCI_H */
--
1.5.6.5