mmc: core: proper ocr negotiation during resume

Prasanna NAVARATNA
2013-05-16T05:15:07Z

Hello,

There seems some problem with ocr negotiation during resume. While going for
suspend, in mmc_power_off function, it resets ocr mask to be the highest
possible voltage supported for this mmc host. This value will be used at
next power up without actually negotiating with card's ocr by querying, as
done during initialization. This results in higher voltage during resume
compared to voltage used during initialization.

To fix this issue, i propose the following patch. Please review :-

>From 305c151cb5b217ff7c622a769df120b14153c25a Mon Sep 17 00:00:00 2001
From: Prasanna NAVARATNA <prasanna.navaratna@broadcom.com>
Date: Thu, 4 Apr 2013 19:55:19 +0530
Subject: [PATCH] mmc: core: proper ocr negotiation during resume

Save the card ocr into struct mmc_card when read from card
during initialization of sd/mmc/sdio.
Druing mmc_resume_host, supply saved card's ocr to
mmc_select_voltage so as to negotiate voltage appropriately.
---
drivers/mmc/core/core.c | 1 +
drivers/mmc/core/mmc.c | 3 +++
drivers/mmc/core/sd.c | 3 +++
drivers/mmc/core/sdio.c | 3 +++
include/linux/mmc/card.h | 1 +
5 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index ad7decc..e61b5ab 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2680,6 +2680,7 @@ int mmc_resume_host(struct mmc_host *host)
if (host->bus_ops && !host->bus_dead) {
if (!mmc_card_keep_power(host)) {
mmc_power_up(host);
+ host->ocr = host->card ? host->card->ocr : host->ocr;
mmc_select_voltage(host, host->ocr);
/*
* Tell runtime PM core we just powered up the card,
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 0cbd1ef..9b4b3a5 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1566,6 +1566,9 @@ int mmc_attach_mmc(struct mmc_host *host)
ocr &= ~0x7F;
}

+ /* Save the card OCR */
+ host->card->ocr = ocr;
+
host->ocr = mmc_select_voltage(host, ocr);

/*
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 9e645e1..965504b 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1185,6 +1185,9 @@ int mmc_attach_sd(struct mmc_host *host)
ocr &= ~MMC_VDD_165_195;
}

+ /* Save the card OCR */
+ host->card->ocr = ocr;
+
host->ocr = mmc_select_voltage(host, ocr);

/*
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index aa0719a..3f9e08d 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -1090,6 +1090,9 @@ int mmc_attach_sdio(struct mmc_host *host)
ocr &= ~0x7F;
}

+ /* Save the card OCR */
+ host->card->ocr = ocr;
+
host->ocr = mmc_select_voltage(host, ocr);

/*
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index f31725b..1bbec2f 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -273,6 +273,7 @@ struct mmc_card {
u32 raw_cid[4]; /* raw card CID */
u32 raw_csd[4]; /* raw card CSD */
u32 raw_scr[2]; /* raw card SCR */
+ u32 ocr; /* card OCR */
struct mmc_cid cid; /* card identification */
struct mmc_csd csd; /* card specific */
struct mmc_ext_csd ext_csd; /* mmc v4 extended card specific */
--
1.7.6