[PATCH 2/3] mmc: core: rocr verification

[Yong Mao]

From: yong mao <yong.mao@xxxxxxxxxxxx>

Some UHS SDIO devices can't enter to stable state after changing the
voltage from 1.8v to 3.3v even after a power cycle.
Verifying the rocr and the result of mmc_set_signal_voltage, if it
is not expected, power cycle SDIO device and re-initialize it again.
Thus will re-initialize the SDIO device successfully.

Signed-off-by: Yong Mao <yong.mao@xxxxxxxxxxxx>
---
 drivers/mmc/core/sdio.c  | 14 +++++++++++++-
 include/linux/mmc/sdio.h |  2 ++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index ada0a80..f173cad 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -553,6 +553,12 @@ static void mmc_sdio_resend_if_cond(struct mmc_host *host,
 	mmc_remove_card(card);
 }
 
+static bool mmc_sdio_valid_rocr(u32 rocr)
+{
+	return (rocr & MMC_CARD_BUSY) && R4_OCR(rocr) &&
+		R4_FUNCTION_NUMBER(rocr);
+}
+
 /*
  * Handle the detection and initialisation of a card.
  *
@@ -605,6 +611,12 @@ static int mmc_sdio_init_card(struct mmc_host *host, u32 ocr,
 		goto err;
 	}
 
+	if (!mmc_sdio_valid_rocr(rocr)) {
+		mmc_sdio_resend_if_cond(host, card);
+		retries--;
+		goto try_again;
+	}
+
 	if ((rocr & R4_MEMORY_PRESENT) &&
 	    mmc_sd_get_cid(host, ocr & rocr, card->raw_cid, NULL) == 0) {
 		card->type = MMC_TYPE_SD_COMBO;
@@ -646,7 +658,7 @@ static int mmc_sdio_init_card(struct mmc_host *host, u32 ocr,
 	 */
 	if (rocr & ocr & R4_18V_PRESENT) {
 		err = mmc_set_uhs_voltage(host, ocr_card);
-		if (err == -EAGAIN) {
+		if (err == -EAGAIN || err == -EILSEQ) {
 			mmc_sdio_resend_if_cond(host, card);
 			retries--;
 			goto try_again;
diff --git a/include/linux/mmc/sdio.h b/include/linux/mmc/sdio.h
index e287699..03e23ec 100644
--- a/include/linux/mmc/sdio.h
+++ b/include/linux/mmc/sdio.h
@@ -36,6 +36,8 @@
 
 #define R4_18V_PRESENT (1<<24)
 #define R4_MEMORY_PRESENT (1 << 27)
+#define R4_OCR(x)		((x) & 0xFFFFFF)
+#define R4_FUNCTION_NUMBER(x)	(((x) & 0x70000000) >> 28)
 
 /*
   SDIO status in R5
-- 
1.9.1