[PATCH v2] mmc: sdhci: add quirk for broken write protect detection
From: Eli Billauer <eli.billauer@gmail.com>
Date: 2014-03-02 11:36:18
Also in:
linux-mmc, lkml
Subsystem:
multimedia card (mmc), secure digital (sd) and sdio subsystem, open firmware and flattened device tree bindings, secure digital host controller interface (sdhci) driver, the rest · Maintainers:
Ulf Hansson, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Adrian Hunter, Linus Torvalds
The write protection signal is absent on a board based upon Xilinx' Zynq
processor ("ZyBo"). This leads the kernel to think that the MicroSD card is
write protected, and causes a kernel panic during boot, as root fails to
mount RW.
This patch adds a quirk and an optional OF property, sdhci,broken-wp to
work around this issue.
Signed-off-by: Eli Billauer <eli.billauer@gmail.com>
---
Documentation/devicetree/bindings/mmc/mmc.txt | 2 ++
drivers/mmc/host/sdhci-pltfm.c | 4 +++-
drivers/mmc/host/sdhci.c | 2 ++
include/linux/mmc/sdhci.h | 2 ++
4 files changed, 9 insertions(+), 1 deletions(-)
diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
index 458b57f..83a39c1 100644
--- a/Documentation/devicetree/bindings/mmc/mmc.txt
+++ b/Documentation/devicetree/bindings/mmc/mmc.txt@@ -21,6 +21,8 @@ Optional properties: below for the case, when a GPIO is used for the CD line - wp-inverted: when present, polarity on the WP line is inverted. See the note below for the case, when a GPIO is used for the WP line +- broken-wp: when present, no indication of write protection is available, + and write protection is assumed always off. - max-frequency: maximum operating clock frequency - no-1-8-v: when present, denotes that 1.8v card voltage is not supported on this system, even if the controller claims it is.
diff --git a/drivers/mmc/host/sdhci-pltfm.c b/drivers/mmc/host/sdhci-pltfm.c
index bef250e..dac20af 100644
--- a/drivers/mmc/host/sdhci-pltfm.c
+++ b/drivers/mmc/host/sdhci-pltfm.c@@ -80,7 +80,9 @@ void sdhci_get_of_property(struct platform_device *pdev) bus_width == 1)) host->quirks |= SDHCI_QUIRK_FORCE_1_BIT_DATA; - if (sdhci_of_wp_inverted(np)) + if (of_get_property(np, "sdhci,broken-wp", NULL)) + host->quirks2 |= SDHCI_QUIRK2_BROKEN_WRITE_PROTECT; + else if (sdhci_of_wp_inverted(np)) host->quirks |= SDHCI_QUIRK_INVERTED_WRITE_PROTECT; if (of_get_property(np, "broken-cd", NULL))
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 9ddef47..6c77f2e 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c@@ -1657,6 +1657,8 @@ static int sdhci_check_ro(struct sdhci_host *host) is_readonly = 0; else if (host->ops->get_ro) is_readonly = host->ops->get_ro(host); + else if (host->quirks2 & SDHCI_QUIRK2_BROKEN_WRITE_PROTECT) + is_readonly = 0; else is_readonly = !(sdhci_readl(host, SDHCI_PRESENT_STATE) & SDHCI_WRITE_PROTECT);
diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index 362927c4..0f6ef9d 100644
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h@@ -100,6 +100,8 @@ struct sdhci_host { #define SDHCI_QUIRK2_BROKEN_HOST_CONTROL (1<<5) /* Controller does not support HS200 */ #define SDHCI_QUIRK2_BROKEN_HS200 (1<<6) +/* There is no indication for write protection at all, assume RW */ +#define SDHCI_QUIRK2_BROKEN_WRITE_PROTECT (1<<7) int irq; /* Device IRQ */ void __iomem *ioaddr; /* Mapped address */
--
1.7.2.3