mmc: core: Validate suspend prerequisites for SDIO at SUSPEND_PREPARE

This patch moves the validation for all the suspend prerequisites to be
done at SUSPEND_PREPARE notification. Previously in the SDIO case parts
of the validation was done from mmc_suspend_host.

This patch invents a new pre_suspend bus_ops callback and implements it
for SDIO. Returning an error code from it, will mean at SUSPEND_PREPARE
notification, the card will be removed before proceeding with the
suspend sequence.

Signed-off-by: Ulf Hansson <[e-mail]>
Tested-by: Jaehoon Chung <[e-mail]>
Signed-off-by: Chris Ball <[e-mail]>

drivers/mmc/core/core.c

···
 	if (host->bus_ops && !host->bus_dead) {
 		if (host->bus_ops->suspend)
 			err = host->bus_ops->suspend(host);
-
-		if (err == -ENOSYS || !host->bus_ops->resume) {
-			/*
-			 * We simply "remove" the card in this case.
-			 * It will be redetected on resume.  (Calling
-			 * bus_ops->remove() with a claimed host can
-			 * deadlock.)
-			 */
-			host->bus_ops->remove(host);
-			mmc_claim_host(host);
-			mmc_detach_bus(host);
-			mmc_power_off(host);
-			mmc_release_host(host);
-			host->pm_flags = 0;
-			err = 0;
-		}
 	}
 	mmc_bus_put(host);
 
···
 	struct mmc_host *host = container_of(
 		notify_block, struct mmc_host, pm_notify);
 	unsigned long flags;
+	int err = 0;
 
 	switch (mode) {
 	case PM_HIBERNATION_PREPARE:
···
 		spin_unlock_irqrestore(&host->lock, flags);
 		cancel_delayed_work_sync(&host->detect);
 
-		if (!host->bus_ops || host->bus_ops->suspend)
+		if (!host->bus_ops)
+			break;
+
+		/* Validate prerequisites for suspend */
+		if (host->bus_ops->pre_suspend)
+			err = host->bus_ops->pre_suspend(host);
+		if (!err && host->bus_ops->suspend)
 			break;
 
 		/* Calling bus_ops->remove() with a claimed host can deadlock */

drivers/mmc/core/core.h

···
 struct mmc_bus_ops {
 	void (*remove)(struct mmc_host *);
 	void (*detect)(struct mmc_host *);
+	int (*pre_suspend)(struct mmc_host *);
 	int (*suspend)(struct mmc_host *);
 	int (*resume)(struct mmc_host *);
 	int (*runtime_suspend)(struct mmc_host *);

drivers/mmc/core/sdio.c

···
 }
 
 /*
- * SDIO suspend.  We need to suspend all functions separately.
+ * SDIO pre_suspend.  We need to suspend all functions separately.
  * Therefore all registered functions must have drivers with suspend
  * and resume methods.  Failing that we simply remove the whole card.
  */
-static int mmc_sdio_suspend(struct mmc_host *host)
+static int mmc_sdio_pre_suspend(struct mmc_host *host)
 {
 	int i, err = 0;
 
···
 			if (!pmops || !pmops->suspend || !pmops->resume) {
 				/* force removal of entire card in that case */
 				err = -ENOSYS;
-			} else
-				err = pmops->suspend(&func->dev);
+				break;
+			}
+		}
+	}
+
+	return err;
+}
+
+/*
+ * SDIO suspend.  Suspend all functions separately.
+ */
+static int mmc_sdio_suspend(struct mmc_host *host)
+{
+	int i, err = 0;
+
+	for (i = 0; i < host->card->sdio_funcs; i++) {
+		struct sdio_func *func = host->card->sdio_func[i];
+		if (func && sdio_func_present(func) && func->dev.driver) {
+			const struct dev_pm_ops *pmops = func->dev.driver->pm;
+			err = pmops->suspend(&func->dev);
 			if (err)
 				break;
 		}
···
 static const struct mmc_bus_ops mmc_sdio_ops = {
 	.remove = mmc_sdio_remove,
 	.detect = mmc_sdio_detect,
+	.pre_suspend = mmc_sdio_pre_suspend,
 	.suspend = mmc_sdio_suspend,
 	.resume = mmc_sdio_resume,
 	.runtime_suspend = mmc_sdio_runtime_suspend,