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authorDaniel Drake <dsd@laptop.org>2012-11-25 18:01:19 +0000
committerMarcel Ziswiler <marcel.ziswiler@toradex.com>2013-04-18 14:01:32 +0200
commite892379bb58aed6db12e45d033f99f532055a1b4 (patch)
tree5ef1c19b61d899e5fa063d3d6e8a5264a718a1ff
parent5aca4fabc06a93cfd0c99025fb38e3594a5d048c (diff)
mmc: sdhci: add quirk for lack of 1.8v support
The OLPC XO-1.75 laptop includes a SDHCI controller which is 1.8v capable, and it truthfully reports so in its capabilities. This alternate voltage is used for driving new "UHS-I" SD cards at their full speed. However, what the controller doesn't know is that the motherboard physically doesn't have a 1.8v supply available. Add a quirk so that systems such as this one can override disable 1.8v support, adding support for UHS-I cards (by running them at 3.3v). This avoids a problem where the system would first try to run the card at 1.8v, fail, and then not be able to fully reset the card to retry at the normal 3.3v voltage. This is more appropriate than using the MISSING_CAPS quirk, which is intended for cases where the SDHCI controller is actually lying about its capabilities, and would force us to somehow override both caps words from another source. Signed-off-by: Daniel Drake <dsd@laptop.org> Reviewed-by: Philip Rakity <prakity@nvidia.com> Signed-off-by: Chris Ball <cjb@laptop.org>
-rw-r--r--drivers/mmc/host/sdhci.c10
-rw-r--r--include/linux/mmc/sdhci.h2
2 files changed, 9 insertions, 3 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index aa03ca7d5226..da1547ffc9da 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2661,9 +2661,13 @@ int sdhci_add_host(struct sdhci_host *host)
mmc_card_is_removable(mmc) && !(host->ops->get_cd))
mmc->caps |= MMC_CAP_NEEDS_POLL;
- /* UHS-I mode(s) supported by the host controller. */
- if (host->version >= SDHCI_SPEC_300)
- mmc->caps |= MMC_CAP_UHS_SDR12 | MMC_CAP_UHS_SDR25;
+ if (host->quirks & SDHCI_QUIRK2_NO_1_8_V)
+ caps[1] &= ~(SDHCI_SUPPORT_SDR104 | SDHCI_SUPPORT_SDR50 |
+ SDHCI_SUPPORT_DDR50);
+ else
+ /* UHS-I mode(s) supported by the host controller. */
+ if (host->version >= SDHCI_SPEC_300)
+ mmc->caps |= MMC_CAP_UHS_SDR12 | MMC_CAP_UHS_SDR25;
/* SDR104 supports also implies SDR50 support */
if (caps[1] & SDHCI_SUPPORT_SDR104)
diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index 5ee48390decc..db86304e1c28 100644
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h
@@ -93,6 +93,8 @@ struct sdhci_host {
#define SDHCI_QUIRK_NON_STANDARD_TUNING (1ULL<<33)
/* Controller doesn't calculate max_discard_to */
#define SDHCI_QUIRK_NO_CALC_MAX_DISCARD_TO (1ULL<<34)
+/* The system physically doesn't support 1.8v, even if the host does */
+#define SDHCI_QUIRK2_NO_1_8_V (1ULL<<35)
int irq; /* Device IRQ */
void __iomem *ioaddr; /* Mapped address */