diff options
| author | Hans de Goede <hdegoede@redhat.com> | 2015-04-01 17:26:23 +0200 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2015-04-02 10:59:10 +0200 |
| commit | 81f8a7be6642b4c26ab681b2e0f4c4120a6de1b0 (patch) | |
| tree | 24868729a06b2b5fe678e7c9649c7e5a90cff9dc | |
| parent | 2391b340ca5b7dd041a2bf86afe12bc004acb583 (diff) | |
mmc: Add support for marking hpi as broken through devicetree
The eMMC on a tablet I've will stop working / communicating as soon as
the kernel executes:
mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_HPI_MGMT, 1,
card->ext_csd.generic_cmd6_time);
There seems to be no way to reliable identify eMMC-s which have a broken
hpi implementation, but at least for eMMC's which are soldered onto a board
we can work around this by specifying that hpi is broken in devicetree.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
| -rw-r--r-- | Documentation/devicetree/bindings/mmc/mmc-card.txt | 31 | ||||
| -rw-r--r-- | drivers/mmc/core/mmc.c | 10 |
2 files changed, 40 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/mmc/mmc-card.txt b/Documentation/devicetree/bindings/mmc/mmc-card.txt new file mode 100644 index 000000000000..a70fcd65b9ea --- /dev/null +++ b/Documentation/devicetree/bindings/mmc/mmc-card.txt @@ -0,0 +1,31 @@ +mmc-card / eMMC bindings +------------------------ + +This documents describes the devicetree bindings for a mmc-host controller +child node describing a mmc-card / an eMMC, see "Use of Function subnodes" +in mmc.txt + +Required properties: +-compatible : Must be "mmc-card" +-reg : Must be <0> + +Optional properties: +-broken-hpi : Use this to indicate that the mmc-card has a broken hpi + implementation, and that hpi should not be used + +Example: + +&mmc2 { + pinctrl-names = "default"; + pinctrl-0 = <&mmc2_pins_a>; + vmmc-supply = <®_vcc3v3>; + bus-width = <8>; + non-removable; + status = "okay"; + + mmccard: mmccard@0 { + reg = <0>; + compatible = "mmc-card"; + broken-hpi; + }; +}; diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index 1d41e8541f38..c84131e28625 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -11,6 +11,7 @@ */ #include <linux/err.h> +#include <linux/of.h> #include <linux/slab.h> #include <linux/stat.h> #include <linux/pm_runtime.h> @@ -336,6 +337,8 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd) { int err = 0, idx; unsigned int part_size; + struct device_node *np; + bool broken_hpi = false; /* Version is coded in the CSD_STRUCTURE byte in the EXT_CSD register */ card->ext_csd.raw_ext_csd_structure = ext_csd[EXT_CSD_STRUCTURE]; @@ -349,6 +352,11 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd) } } + np = mmc_of_find_child_device(card->host, 0); + if (np && of_device_is_compatible(np, "mmc-card")) + broken_hpi = of_property_read_bool(np, "broken-hpi"); + of_node_put(np); + /* * The EXT_CSD format is meant to be forward compatible. As long * as CSD_STRUCTURE does not change, all values for EXT_CSD_REV @@ -494,7 +502,7 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd) } /* check whether the eMMC card supports HPI */ - if (ext_csd[EXT_CSD_HPI_FEATURES] & 0x1) { + if (!broken_hpi && (ext_csd[EXT_CSD_HPI_FEATURES] & 0x1)) { card->ext_csd.hpi = 1; if (ext_csd[EXT_CSD_HPI_FEATURES] & 0x2) card->ext_csd.hpi_cmd = MMC_STOP_TRANSMISSION; |