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SubjectRe: [PATCH] mmc: core: Fix mmc_select_hs200() regression in v4.7-rc.
On Tue, 07 Jun 2016, Peter Griffin wrote:

> mmc_select_bus_width() returns bus width (4 or 8) on success or
> zero if unsupported. If bus width is set successfully we then wish
> to switch to HS200 mode.
>
> This avoids the following error message in v4.70-rc2
>
> [ 2.523674] mmc0: mmc_select_hs200 failed, error 3
> [ 2.528516] mmc0: error 3 whilst initialising MMC card
>
> With this patch card is enumerated correctly
>
> [ 2.468065] mmc0: new HS200 MMC card at address 0001
> [ 2.468335] mmcblk0: mmc0:0001 P1XXXX 7.20 GiB
> [ 2.468441] mmcblk0boot0: mmc0:0001 P1XXXX partition 1 2.00 MiB
> [ 2.468552] mmcblk0boot1: mmc0:0001 P1XXXX partition 2 2.00 MiB
> [ 2.468651] mmcblk0rpmb: mmc0:0001 P1XXXX partition 3 128 KiB
> [ 2.469269] mmcblk0: p1
>
> Fixes: 287980e (remove lots of IS_ERR_VALUE abuses)
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/mmc/core/mmc.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index c984321..aafb73d 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1276,7 +1276,7 @@ static int mmc_select_hs200(struct mmc_card *card)
> * switch to HS200 mode if bus width is set successfully.
> */
> err = mmc_select_bus_width(card);
> - if (!err) {
> + if (err > 0) {
> val = EXT_CSD_TIMING_HS200 |
> card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
> err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> @@ -1583,7 +1583,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
> } else if (mmc_card_hs(card)) {
> /* Select the desired bus width optionally */
> err = mmc_select_bus_width(card);
> - if (!err) {
> + if (err > 0) {
> err = mmc_select_hs_ddr(card);
> if (err)
> goto free_card;

Looks like this has already been 'fixed' in -rc2.

Although, this patch does not work for me.

commit f741494363c6c90e6744117d2771bbdf0fb3c455
Author: Chen-Yu Tsai <wens@csie.org>
Date: Sun May 29 15:04:42 2016 +0800

mmc: fix mmc mode selection for HS-DDR and higher

When IS_ERR_VALUE was removed from the mmc core code, it was replaced
with a simple not-zero check. This does not work, as the value checked
is the return value for mmc_select_bus_width, which returns the set
bit width on success. This made eMMC modes higher than HS-DDR unusable.

Fix this by checking for a positive return value instead.

Fixes: 287980e49ffc ("remove lots of IS_ERR_VALUE abuses")
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index c984321..5d438ad 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1276,7 +1276,7 @@ static int mmc_select_hs200(struct mmc_card *card)
* switch to HS200 mode if bus width is set successfully.
*/
err = mmc_select_bus_width(card);
- if (!err) {
+ if (err >= 0) {
val = EXT_CSD_TIMING_HS200 |
card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
@@ -1583,7 +1583,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
} else if (mmc_card_hs(card)) {
/* Select the desired bus width optionally */
err = mmc_select_bus_width(card);
- if (!err) {
+ if (err >= 0) {
err = mmc_select_hs_ddr(card);
if (err)
goto free_card;
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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