mmc: propagate error codes back from bus drivers' suspend/resume methods

Especially for SDIO drivers which may have special conditions/errors to
report, it is a good thing to relay the returned error code back to upper
layers.

This also allows for the rationalization of the resume path where code to
"remove" a no-longer-existing or replaced card was duplicated into the
MMC, SD and SDIO bus drivers.

In the SDIO case, if a function suspend method returns an error, then all
previously suspended functions are resumed and the error returned.  An
exception is made for -ENOSYS which the core interprets as "we don't
support suspend so just kick the card out for suspend and return success".

When resuming SDIO cards, the core code only validates the manufacturer
and product IDs to make sure the same kind of card is still present before
invoking functions resume methods.  It's the function driver's
responsibility to perform further tests to confirm that the actual same
card is present (same MAC address, etc.) and return an error otherwise.

Signed-off-by: Nicolas Pitre <nico@marvell.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, 29 insertions, 25 deletions

diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index f4c8637fd072..cdb845b68ab5 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -302,6 +302,7 @@ static int mmc_sdio_init_card(struct mmc_host *host, u32 ocr,
 			goto err;
 		}
 		card = oldcard;
+		return 0;
 	}
 
 	/*
@@ -399,62 +400,65 @@ static void mmc_sdio_detect(struct mmc_host *host)
  * Therefore all registered functions must have drivers with suspend
  * and resume methods.  Failing that we simply remove the whole card.
  */
-static void mmc_sdio_suspend(struct mmc_host *host)
+static int mmc_sdio_suspend(struct mmc_host *host)
 {
-	int i;
+	int i, err = 0;
 
-	/* make sure all registered functions can suspend/resume */
 	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;
 			if (!pmops || !pmops->suspend || !pmops->resume) {
-				/* just remove the entire card in that case */
-				mmc_sdio_remove(host);
-				mmc_claim_host(host);
-				mmc_detach_bus(host);
-				mmc_release_host(host);
-				return;
-			}
+				/* force removal of entire card in that case */
+				err = -ENOSYS;
+			} else
+				err = pmops->suspend(&func->dev);
+			if (err)
+				break;
 		}
 	}
-
-	/* now suspend them */
-	for (i = 0; i < host->card->sdio_funcs; i++) {
+	while (err && --i >= 0) {
 		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;
-			pmops->suspend(&func->dev);
+			pmops->resume(&func->dev);
 		}
 	}
+
+	return err;
 }
 
-static void mmc_sdio_resume(struct mmc_host *host)
+static int mmc_sdio_resume(struct mmc_host *host)
 {
 	int i, err;
 
 	BUG_ON(!host);
 	BUG_ON(!host->card);
 
+	/* Basic card reinitialization. */
 	mmc_claim_host(host);
 	err = mmc_sdio_init_card(host, host->ocr, host->card);
 	mmc_release_host(host);
-	if (err) {
-		mmc_sdio_remove(host);
-		mmc_claim_host(host);
-		mmc_detach_bus(host);
-		mmc_release_host(host);
-		return;
-	}
 
-	/* resume all functions */
-	for (i = 0; i < host->card->sdio_funcs; i++) {
+	/*
+	 * If the card looked to be the same as before suspending, then
+	 * we proceed to resume all card functions.  If one of them returns
+	 * an error then we simply return that error to the core and the
+	 * card will be redetected as new.  It is the responsibility of
+	 * the function driver to perform further tests with the extra
+	 * knowledge it has of the card to confirm the card is indeed the
+	 * same as before suspending (same MAC address for network cards,
+	 * etc.) and return an error otherwise.
+	 */
+	for (i = 0; !err && 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;
-			pmops->resume(&func->dev);
+			err = pmops->resume(&func->dev);
 		}
 	}
+
+	return err;
 }
 
 static const struct mmc_bus_ops mmc_sdio_ops = {