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Subject[PATCH 18/32] omap_hsmmc: support for deeper power saving states
From a86c083ca740b4311daf3dc8e219506b63756896 Mon Sep 17 00:00:00 2001
From: Denis Karpov <ext-denis.2.karpov@nokia.com>
Date: Mon, 11 May 2009 14:41:30 +0300
Subject: [PATCH] omap_hsmmc: support for deeper power saving states

Support for multi-level dynamic power saving states in omap_hsmmc
(ENABLED->DISABLED->OFF).
In the "deepest" state (OFF) we switch off the voltage regulators.

Signed-off-by: Denis Karpov <ext-denis.2.karpov@nokia.com>
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
---
arch/arm/mach-omap2/mmc-twl4030.c | 3 +
arch/arm/mach-omap2/mmc-twl4030.h | 1 +
arch/arm/plat-omap/include/mach/mmc.h | 3 +
drivers/mmc/host/omap_hsmmc.c | 245 +++++++++++++++++++++++++++++----
4 files changed, 222 insertions(+), 30 deletions(-)

diff --git a/arch/arm/mach-omap2/mmc-twl4030.c b/arch/arm/mach-omap2/mmc-twl4030.c
index 67c22c6..3678f0e 100644
--- a/arch/arm/mach-omap2/mmc-twl4030.c
+++ b/arch/arm/mach-omap2/mmc-twl4030.c
@@ -412,6 +412,9 @@ void __init twl4030_mmc_init(struct twl4030_hsmmc_info *controllers)
if (c->nonremovable)
mmc->slots[0].nonremovable = 1;

+ if (c->power_saving)
+ mmc->slots[0].power_saving = 1;
+
/* NOTE: MMC slots should have a Vcc regulator set up.
* This may be from a TWL4030-family chip, another
* controllable regulator, or a fixed supply.
diff --git a/arch/arm/mach-omap2/mmc-twl4030.h b/arch/arm/mach-omap2/mmc-twl4030.h
index 75b0c64..a47e685 100644
--- a/arch/arm/mach-omap2/mmc-twl4030.h
+++ b/arch/arm/mach-omap2/mmc-twl4030.h
@@ -13,6 +13,7 @@ struct twl4030_hsmmc_info {
bool ext_clock; /* use external pin for input clock */
bool cover_only; /* No card detect - just cover switch */
bool nonremovable; /* Nonremovable e.g. eMMC */
+ bool power_saving; /* Try to sleep or power off when possible */
int gpio_cd; /* or -EINVAL */
int gpio_wp; /* or -EINVAL */
char *name; /* or NULL for default */
diff --git a/arch/arm/plat-omap/include/mach/mmc.h b/arch/arm/plat-omap/include/mach/mmc.h
index bab486c..82f1e29 100644
--- a/arch/arm/plat-omap/include/mach/mmc.h
+++ b/arch/arm/plat-omap/include/mach/mmc.h
@@ -86,6 +86,9 @@ struct omap_mmc_platform_data {
/* nonremovable e.g. eMMC */
unsigned nonremovable:1;

+ /* Try to sleep or power off when possible */
+ unsigned power_saving:1;
+
int switch_pin; /* gpio (card detect) */
int gpio_wp; /* gpio (write protect) */

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 7b56988..c69ab89 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -111,6 +111,10 @@
#define OMAP_MMC_MASTER_CLOCK 96000000
#define DRIVER_NAME "mmci-omap-hs"

+/* Timeouts for entering power saving states on inactivity, msec */
+#define OMAP_MMC_DISABLED_TIMEOUT 100
+#define OMAP_MMC_OFF_TIMEOUT 1000
+
/*
* One controller can have multiple slots, like on some omap boards using
* omap.c controller driver. Luckily this is not currently done on any known
@@ -155,6 +159,7 @@ struct mmc_omap_host {
int dbclk_enabled;
int response_busy;
int context_loss;
+ int dpm_state;

struct omap_mmc_platform_data *pdata;
};
@@ -985,29 +990,6 @@ mmc_omap_prepare_data(struct mmc_omap_host *host, struct mmc_request *req)
return 0;
}

-static int omap_mmc_enable(struct mmc_host *mmc)
-{
- struct mmc_omap_host *host = mmc_priv(mmc);
- int err;
-
- err = clk_enable(host->fclk);
- if (err)
- return err;
- dev_dbg(mmc_dev(host->mmc), "mmc_fclk: enabled\n");
- omap_mmc_restore_ctx(host);
- return 0;
-}
-
-static int omap_mmc_disable(struct mmc_host *mmc, int lazy)
-{
- struct mmc_omap_host *host = mmc_priv(mmc);
-
- omap_mmc_save_ctx(host);
- clk_disable(host->fclk);
- dev_dbg(mmc_dev(host->mmc), "mmc_fclk: disabled\n");
- return 0;
-}
-
/*
* Request function. for read/write operation
*/
@@ -1061,6 +1043,8 @@ static void omap_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
host->power_mode = ios->power_mode;
}

+ /* FIXME: set registers based only on changes to ios */
+
con = OMAP_HSMMC_READ(host->base, CON);
switch (mmc->ios.bus_width) {
case MMC_BUS_WIDTH_8:
@@ -1133,7 +1117,10 @@ static void omap_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
else
OMAP_HSMMC_WRITE(host->base, CON, con & ~OD);

- mmc_host_lazy_disable(host->mmc);
+ if (host->power_mode == MMC_POWER_OFF)
+ mmc_host_disable(host->mmc);
+ else
+ mmc_host_lazy_disable(host->mmc);
}

static int omap_hsmmc_get_cd(struct mmc_host *mmc)
@@ -1183,7 +1170,191 @@ static void omap_hsmmc_init(struct mmc_omap_host *host)
set_sd_bus_power(host);
}

-static struct mmc_host_ops mmc_omap_ops = {
+/*
+ * Dynamic power saving handling, FSM:
+ * ENABLED -> DISABLED -> OFF
+ * ^___________| |
+ * |______________________|
+ *
+ * ENABLED: mmc host is fully functional
+ * DISABLED: fclk is off
+ * OFF: fclk is off,voltage regulator is off
+ *
+ * Transition handlers return the timeout for the next state transition
+ * or negative error.
+ */
+
+enum {ENABLED = 0, DISABLED, OFF};
+
+/* Handler for [ENABLED -> DISABLED] transition */
+static int omap_mmc_enabled_to_disabled(struct mmc_omap_host *host)
+{
+ omap_mmc_save_ctx(host);
+ clk_disable(host->fclk);
+ host->dpm_state = DISABLED;
+
+ dev_dbg(mmc_dev(host->mmc), "ENABLED -> DISABLED\n");
+
+ if (host->power_mode == MMC_POWER_OFF)
+ return 0;
+
+ return msecs_to_jiffies(OMAP_MMC_OFF_TIMEOUT);
+}
+
+/* Handler for [DISABLED -> OFF] transition */
+static int omap_mmc_disabled_to_off(struct mmc_omap_host *host)
+{
+ int new_state;
+
+ dev_dbg(mmc_dev(host->mmc), "DISABLED -> OFF\n");
+
+ if (!mmc_try_claim_host(host->mmc))
+ return 0;
+
+ clk_enable(host->fclk);
+
+ omap_mmc_restore_ctx(host);
+
+ if ((host->mmc->caps & MMC_CAP_NONREMOVABLE) ||
+ mmc_slot(host).card_detect ||
+ (mmc_slot(host).get_cover_state &&
+ mmc_slot(host).get_cover_state(host->dev, host->slot_id))) {
+ mmc_power_save_host(host->mmc);
+ new_state = OFF;
+ } else
+ new_state = DISABLED;
+
+ OMAP_HSMMC_WRITE(host->base, ISE, 0);
+ OMAP_HSMMC_WRITE(host->base, IE, 0);
+ OMAP_HSMMC_WRITE(host->base, HCTL,
+ OMAP_HSMMC_READ(host->base, HCTL) & ~SDBP);
+
+ clk_disable(host->fclk);
+ clk_disable(host->iclk);
+ clk_disable(host->dbclk);
+
+ host->dpm_state = new_state;
+
+ mmc_release_host(host->mmc);
+
+ return 0;
+}
+
+/* Handler for [DISABLED -> ENABLED] transition */
+static int omap_mmc_disabled_to_enabled(struct mmc_omap_host *host)
+{
+ int err;
+
+ err = clk_enable(host->fclk);
+ if (err < 0)
+ return err;
+
+ omap_mmc_restore_ctx(host);
+
+ host->dpm_state = ENABLED;
+
+ dev_dbg(mmc_dev(host->mmc), "DISABLED -> ENABLED\n");
+
+ return 0;
+}
+
+/* Handler for [OFF -> ENABLED] transition */
+static int omap_mmc_off_to_enabled(struct mmc_omap_host *host)
+{
+ clk_enable(host->fclk);
+ clk_enable(host->iclk);
+
+ if (clk_enable(host->dbclk))
+ dev_dbg(mmc_dev(host->mmc),
+ "Enabling debounce clk failed\n");
+
+ omap_mmc_restore_ctx(host);
+ omap_hsmmc_init(host);
+ mmc_power_restore_host(host->mmc);
+
+ host->dpm_state = ENABLED;
+
+ dev_dbg(mmc_dev(host->mmc), "OFF -> ENABLED\n");
+
+ return 0;
+}
+
+/*
+ * Bring MMC host to ENABLED from any other PM state.
+ */
+static int omap_mmc_enable(struct mmc_host *mmc)
+{
+ struct mmc_omap_host *host = mmc_priv(mmc);
+
+ switch (host->dpm_state) {
+ case DISABLED:
+ return omap_mmc_disabled_to_enabled(host);
+ case OFF:
+ return omap_mmc_off_to_enabled(host);
+ default:
+ dev_dbg(mmc_dev(host->mmc), "UNKNOWN state\n");
+ return -EINVAL;
+ }
+}
+
+/*
+ * Bring MMC host in PM state (one level deeper).
+ */
+static int omap_mmc_disable(struct mmc_host *mmc, int lazy)
+{
+ struct mmc_omap_host *host = mmc_priv(mmc);
+
+ switch (host->dpm_state) {
+ case ENABLED: {
+ int delay;
+
+ delay = omap_mmc_enabled_to_disabled(host);
+ if (lazy || delay < 0)
+ return delay;
+ return 0;
+ }
+ case DISABLED:
+ return omap_mmc_disabled_to_off(host);
+ default:
+ dev_dbg(mmc_dev(host->mmc), "UNKNOWN state\n");
+ return -EINVAL;
+ }
+}
+
+static int omap_mmc_enable_fclk(struct mmc_host *mmc)
+{
+ struct mmc_omap_host *host = mmc_priv(mmc);
+ int err;
+
+ err = clk_enable(host->fclk);
+ if (err)
+ return err;
+ dev_dbg(mmc_dev(host->mmc), "mmc_fclk: enabled\n");
+ omap_mmc_restore_ctx(host);
+ return 0;
+}
+
+static int omap_mmc_disable_fclk(struct mmc_host *mmc, int lazy)
+{
+ struct mmc_omap_host *host = mmc_priv(mmc);
+
+ omap_mmc_save_ctx(host);
+ clk_disable(host->fclk);
+ dev_dbg(mmc_dev(host->mmc), "mmc_fclk: disabled\n");
+ return 0;
+}
+
+static const struct mmc_host_ops mmc_omap_ops = {
+ .enable = omap_mmc_enable_fclk,
+ .disable = omap_mmc_disable_fclk,
+ .request = omap_mmc_request,
+ .set_ios = omap_mmc_set_ios,
+ .get_cd = omap_hsmmc_get_cd,
+ .get_ro = omap_hsmmc_get_ro,
+ /* NYET -- enable_sdio_irq */
+};
+
+static const struct mmc_host_ops mmc_omap_ps_ops = {
.enable = omap_mmc_enable,
.disable = omap_mmc_disable,
.request = omap_mmc_request,
@@ -1207,15 +1378,22 @@ static int mmc_regs_show(struct seq_file *s, void *data)

seq_printf(s, "mmc%d:\n"
" enabled:\t%d\n"
+ " dpm_state:\t%d\n"
" nesting_cnt:\t%d\n"
" ctx_loss:\t%d:%d\n"
"\nregs:\n",
- mmc->index, mmc->enabled ? 1 : 0, mmc->nesting_cnt,
+ mmc->index, mmc->enabled ? 1 : 0,
+ host->dpm_state, mmc->nesting_cnt,
host->context_loss, context_loss);

+ if (host->suspended || host->dpm_state == OFF) {
+ seq_printf(s, "host suspended, can't read registers\n");
+ return 0;
+ }
+
if (clk_enable(host->fclk) != 0) {
seq_printf(s, "can't read the regs\n");
- goto err;
+ return 0;
}

seq_printf(s, "SYSCONFIG:\t0x%08x\n",
@@ -1234,7 +1412,7 @@ static int mmc_regs_show(struct seq_file *s, void *data)
OMAP_HSMMC_READ(host->base, CAPA));

clk_disable(host->fclk);
-err:
+
return 0;
}

@@ -1316,7 +1494,11 @@ static int __init omap_mmc_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, host);
INIT_WORK(&host->mmc_carddetect_work, mmc_omap_detect);

- mmc->ops = &mmc_omap_ops;
+ if (pdata->slots[host->slot_id].power_saving)
+ mmc->ops = &mmc_omap_ps_ops;
+ else
+ mmc->ops = &mmc_omap_ops;
+
mmc->f_min = 400000;
mmc->f_max = 52000000;

@@ -1339,7 +1521,10 @@ static int __init omap_mmc_probe(struct platform_device *pdev)
omap_mmc_save_ctx(host);

mmc->caps |= MMC_CAP_DISABLE;
- mmc_set_disable_delay(mmc, msecs_to_jiffies(100));
+ mmc_set_disable_delay(mmc, msecs_to_jiffies(OMAP_MMC_DISABLED_TIMEOUT));
+ /* we start off in DISABLED state */
+ host->dpm_state = DISABLED;
+
if (mmc_host_enable(host->mmc) != 0) {
clk_put(host->iclk);
clk_put(host->fclk);
--
1.5.6.3


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