sdio: put active devices into 1-bit mode during suspend

And bring them back to 4-bit mode during resume.

Signed-off-by: Daniel Drake <dsd@laptop.org>
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>

diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 5840de1..2dd4cfe 100644 (file)
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -187,6 +187,40 @@ static int sdio_disable_cd(struct mmc_card *card)
        return mmc_io_rw_direct(card, 1, 0, SDIO_CCCR_IF, ctrl, NULL);
 }
 
+/*
+ * Devices that remain active during a system suspend are
+ * put back into 1-bit mode.
+ */
+static int sdio_disable_wide(struct mmc_card *card)
+{
+       int ret;
+       u8 ctrl;
+
+       if (!(card->host->caps & MMC_CAP_4_BIT_DATA))
+               return 0;
+
+       if (card->cccr.low_speed && !card->cccr.wide_bus)
+               return 0;
+
+       ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_IF, 0, &ctrl);
+       if (ret)
+               return ret;
+
+       if (!(ctrl & SDIO_BUS_WIDTH_4BIT))
+               return 0;
+
+       ctrl &= ~SDIO_BUS_WIDTH_4BIT;
+       ctrl |= SDIO_BUS_ASYNC_INT;
+
+       ret = mmc_io_rw_direct(card, 1, 0, SDIO_CCCR_IF, ctrl, NULL);
+       if (ret)
+               return ret;
+
+       mmc_set_bus_width(card->host, MMC_BUS_WIDTH_1);
+
+       return 0;
+}
+
 /*
  * Test if the card supports high-speed mode and, if so, switch to it.
  */
@@ -427,6 +461,12 @@ static int mmc_sdio_suspend(struct mmc_host *host)
                }
        }
 
+       if (!err && host->pm_flags & MMC_PM_KEEP_POWER) {
+               mmc_claim_host(host);
+               sdio_disable_wide(host->card);
+               mmc_release_host(host);
+       }
+
        return err;
 }
 
@@ -441,6 +481,9 @@ static int mmc_sdio_resume(struct mmc_host *host)
        mmc_claim_host(host);
        err = mmc_sdio_init_card(host, host->ocr, host->card,
                                 (host->pm_flags & MMC_PM_KEEP_POWER));
+       if (!err)
+               /* We may have switched to 1-bit mode during suspend. */
+               err = sdio_enable_wide(host->card);
        if (!err && host->sdio_irqs)
                mmc_signal_sdio_irq(host);
        mmc_release_host(host);

diff --git a/include/linux/mmc/sdio.h b/include/linux/mmc/sdio.h
index 47ba464..0ebaef5 100644 (file)
--- a/include/linux/mmc/sdio.h
+++ b/include/linux/mmc/sdio.h
@@ -95,6 +95,8 @@
 #define  SDIO_BUS_WIDTH_1BIT   0x00
 #define  SDIO_BUS_WIDTH_4BIT   0x02
 
+#define  SDIO_BUS_ASYNC_INT    0x20
+
 #define  SDIO_BUS_CD_DISABLE     0x80  /* disable pull-up on DAT3 (pin 1) */
 
 #define SDIO_CCCR_CAPS         0x08