mmc: core: Add deferred bus resume policy.

A card driver can now specify that the underlying bus should *not*
auto-resume with the rest of the system. This is useful for reducing resume
latency as well as saving power when the card driver is not using the
bus. In the future, we'll add support for manual suspend

Signed-off-by: San Mehat <san@google.com>
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 2929765..1e0cdf7 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -295,6 +295,10 @@
 	const struct mmc_bus_ops *bus_ops;	/* current bus driver */
 	unsigned int		bus_refs;	/* reference counter */
 
+	unsigned int		bus_resume_flags;
+#define MMC_BUSRESUME_MANUAL_RESUME	(1 << 0)
+#define MMC_BUSRESUME_NEEDS_RESUME	(1 << 1)
+
 	unsigned int		sdio_irqs;
 	struct task_struct	*sdio_irq_thread;
 	atomic_t		sdio_irq_thread_abort;
@@ -354,6 +358,17 @@
 #define mmc_dev(x)	((x)->parent)
 #define mmc_classdev(x)	(&(x)->class_dev)
 #define mmc_hostname(x)	(dev_name(&(x)->class_dev))
+#define mmc_bus_needs_resume(host) ((host)->bus_resume_flags & MMC_BUSRESUME_NEEDS_RESUME)
+
+static inline void mmc_set_bus_resume_policy(struct mmc_host *host, int manual)
+{
+	if (manual)
+		host->bus_resume_flags |= MMC_BUSRESUME_MANUAL_RESUME;
+	else
+		host->bus_resume_flags &= ~MMC_BUSRESUME_MANUAL_RESUME;
+}
+
+extern int mmc_resume_bus(struct mmc_host *host);
 
 extern int mmc_suspend_host(struct mmc_host *);
 extern int mmc_resume_host(struct mmc_host *);