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Subject[PATCH 2/3] mmc: core: rocr verification
Date
From: yong mao <yong.mao@mediatek.com>

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@mediatek.com>
---
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
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