1 files changed, 47 insertions, 0 deletions

diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 3e7615e9087e..338a9b3d51e4 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -51,6 +51,35 @@ struct mmc_ios {
 };
 
 struct mmc_host_ops {
+        /*
+         * Hosts that support power saving can use the 'enable' and 'disable'
+         * methods to exit and enter power saving states. 'enable' is called
+         * when the host is claimed and 'disable' is called (or scheduled with
+         * a delay) when the host is released. The 'disable' is scheduled if
+         * the disable delay set by 'mmc_set_disable_delay()' is non-zero,
+         * otherwise 'disable' is called immediately. 'disable' may be
+         * scheduled repeatedly, to permit ever greater power saving at the
+         * expense of ever greater latency to re-enable. Rescheduling is
+         * determined by the return value of the 'disable' method. A positive
+         * value gives the delay in milliseconds.
+         *
+         * In the case where a host function (like set_ios) may be called
+         * with or without the host claimed, enabling and disabling can be
+         * done directly and will nest correctly. Call 'mmc_host_enable()' and
+         * 'mmc_host_lazy_disable()' for this purpose, but note that these
+         * functions must be paired.
+         *
+         * Alternatively, 'mmc_host_enable()' may be paired with
+         * 'mmc_host_disable()' which calls 'disable' immediately.  In this
+         * case the 'disable' method will be called with 'lazy' set to 0.
+         * This is mainly useful for error paths.
+         *
+         * Because lazy disable may be called from a work queue, the 'disable'
+         * method must claim the host when 'lazy' != 0, which will work
+         * correctly because recursion is detected and handled.
+         */
+        int (*enable)(struct mmc_host *host);
+        int (*disable)(struct mmc_host *host, int lazy);
         void    (*request)(struct mmc_host *host, struct mmc_request *req);
         /*
          * Avoid calling these three functions too often or in a "fast path",
@@ -118,6 +147,7 @@ struct mmc_host {
 #define MMC_CAP_SPI             (1 << 4)        /* Talks only SPI protocols */
 #define MMC_CAP_NEEDS_POLL      (1 << 5)        /* Needs polling for card-detection */
 #define MMC_CAP_8_BIT_DATA      (1 << 6)        /* Can the host do 8 bit transfers */
+#define MMC_CAP_DISABLE         (1 << 7)        /* Can the host be disabled */
 
         /* host specific block data */
         unsigned int            max_seg_size;   /* see blk_queue_max_segment_size */
@@ -142,6 +172,13 @@ struct mmc_host {
         unsigned int            removed:1;      /* host is being removed */
 #endif
 
+        /* Only used with MMC_CAP_DISABLE */
+        int                     enabled;        /* host is enabled */
+        int                     nesting_cnt;    /* "enable" nesting count */
+        int                     en_dis_recurs;  /* detect recursion */
+        unsigned int            disable_delay;  /* disable delay in msecs */
+        struct delayed_work     disable;        /* disabling work */
+
         struct mmc_card         *card;          /* device attached to this host */
 
         wait_queue_head_t       wq;
@@ -197,5 +234,15 @@ struct regulator;
 int mmc_regulator_get_ocrmask(struct regulator *supply);
 int mmc_regulator_set_ocr(struct regulator *supply, unsigned short vdd_bit);
 
+int mmc_host_enable(struct mmc_host *host);
+int mmc_host_disable(struct mmc_host *host);
+int mmc_host_lazy_disable(struct mmc_host *host);
+
+static inline void mmc_set_disable_delay(struct mmc_host *host,
+                                         unsigned int disable_delay)
+{
+        host->disable_delay = disable_delay;
+}
+
 #endif