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>
Acked-by: Matt Fleming <matt@console-pimps.org>
Cc: Ian Molton <ian@mnementh.co.uk>
Cc: "Roberto A. Foglietta" <roberto.foglietta@gmail.com>
Cc: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Cc: Denis Karpov <ext-denis.2.karpov@nokia.com>
Cc: Pierre Ossman <pierre@ossman.eu>
Cc: Philip Langdale <philipl@overt.org>
Cc: "Madhusudhan" <madhu.cr@ti.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 215 insertions, 30 deletions

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index a20c38385d2..016914c2c4e 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -113,6 +113,10 @@
 #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
@@ -157,6 +161,7 @@ struct mmc_omap_host {
         int                     dbclk_enabled;
         int                     response_busy;
         int                     context_loss;
+        int                     dpm_state;
 
         struct  omap_mmc_platform_data  *pdata;
 };
@@ -992,29 +997,6 @@ 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
  */
@@ -1068,6 +1050,8 @@ 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:
@@ -1140,7 +1124,10 @@ 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)
@@ -1190,7 +1177,191 @@ 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,
@@ -1214,15 +1385,22 @@ 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",
@@ -1241,7 +1419,7 @@ static int mmc_regs_show(struct seq_file *s, void *data)
                         OMAP_HSMMC_READ(host->base, CAPA));
 
         clk_disable(host->fclk);
-err:
+
         return 0;
 }
 
@@ -1323,7 +1501,11 @@ 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;
 
@@ -1346,7 +1528,10 @@ 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, 100);
+        mmc_set_disable_delay(mmc, 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);