kernel/drivers/mmc/core/sd.c, branch linux-5.1.y

mmc: core: Verify SD bus width

2019-05-31T13:43:14Z

[ Upstream commit 9e4be8d03f50d1b25c38e2b59e73b194c130df7d ] The SD Physical Layer Spec says the following: Since the SD Memory Card shall support at least the two bus modes 1-bit or 4-bit width, then any SD Card shall set at least bits 0 and 2 (SD_BUS_WIDTH="0101"). This change verifies the card has specified a bus width. AMD SDHC Device 7806 can get into a bad state after a card disconnect where anything transferred via the DATA lines will always result in a zero filled buffer. Currently the driver will continue without error if the HC is in this condition. A block device will be created, but reading from it will result in a zero buffer. This makes it seem like the SD device has been erased, when in actuality the data is never getting copied from the DATA lines to the data buffer. SCR is the first command in the SD initialization sequence that uses the DATA lines. By checking that the response was invalid, we can abort mounting the card. Reviewed-by: Avri Altman Signed-off-by: Raul E Rangel Signed-off-by: Ulf Hansson Signed-off-by: Sasha Levin

mmc: core: Add a debug print when the card may have been replaced

2019-02-28T08:28:27Z

If the card was removed in suspended state and a new one was inserted, print a debug log when the check detects that it's not the old card. Signed-off-by: hongjiefang Signed-off-by: Ulf Hansson

mmc: core: Add discard support to sd

2019-02-28T08:16:12Z

SD spec v5.1 adds discard support. The flows and commands are similar to mmc, so just set the discard arg in CMD38. A host which supports DISCARD shall check if the DISCARD_SUPPORT (b313) is set in the SD_STATUS register. If the card does not support discard, the host shall not issue DISCARD command, but ERASE command instead. Post the DISCARD operation, the card may de-allocate the discarded blocks partially or completely. So the host mustn't make any assumptions concerning the content of the discarded region. This is unlike ERASE command, in which the region is guaranteed to contain either '0's or '1's, depends on the content of DATA_STAT_AFTER_ERASE (b55) in the scr register. One more important difference compared to ERASE is the busy timeout which we will address on the next patch. Signed-off-by: Avri Altman Signed-off-by: Ulf Hansson

mmc: core: Indicate SD specs higher than 4.0

2019-02-25T07:40:58Z

SD specs version 4.x and 5.x have a dedicated slices in the SCR register. Higher versions will rely on a combination of the existing fields. Signed-off-by: Avri Altman Signed-off-by: Ulf Hansson

mmc: core: Calculate the discard arg only once

2019-02-25T07:40:58Z

In MMC, the discard arg is a read-only ext_csd parameter - set it once on card init. To be consistent, do that for SD as well even though its discard arg is always 0x0. Signed-off-by: Avri Altman Signed-off-by: Ulf Hansson

mmc: core: Rename ->reset() bus ops to ->hw_reset()

2018-05-08T07:33:29Z

The bus ops ->reset() executes a full HW reset of the card, as the calling function mmc_hw_reset() also indicates by its name. Let's convert to follow the similar names, for both the bus ops callback and for the corresponding bus ops functions, as to clarify the purpose of code. Signed-off-by: Ulf Hansson Tested-by: Quentin Schulz Reviewed-by: Shawn Lin

mmc: core: Add capability to avoid 3.3V signaling

2018-05-02T13:08:44Z

Some SD host controllers cannot handle extended use of 3.3V signaling. To accommodate these controllers, add a capability that requires us to negotiate the voltage down from 3.3V during card initialization. Signed-off-by: Kyle Roeschley Signed-off-by: Jennifer Dahm Signed-off-by: Ulf Hansson

mmc: core: Export card RCA register via sysfs

2018-03-15T13:43:05Z

This patch exports RCA register to sysfs which will help in reading the disk identification information. Reviewed-by: Shawn Lin Signed-off-by: Harish Jenny K N Signed-off-by: Ulf Hansson

mmc: sd: Remove redundant err assignment from mmc_read_switch

2018-03-15T08:32:30Z

Variable err would be firstly initialized by the return value of mmc_sd_switch(). Signed-off-by: Shawn Lin Signed-off-by: Ulf Hansson

mmc: core: Don't try UHS-I mode if 4-bit mode isn't supported

2018-03-15T08:30:39Z

Per SD specification physical layer v4.0, section 3.9.4, it says "UHS-I supports only 4-bit mode. Host shall select 4-bit mode by ACMD6. However mmc_sd_init_uhs_card() still go ahead to initialize the cards anyway, whether card or host won't support 4-bit mode. This breaks the platforms which could support UHS-I mode but on some certain boards only support 1-bit mode with a UHS-I card inserted, as all the tuning process is broken due to this. Alternatively, we should check the return value from mmc_set_bus_width() to see if host could finish the request to switch the bus width on its side. But that needs more thing to do than this patch that just bails out early to try high speed mode if 4-bit mode isn't available for whatever reason. And this patch could also fix the same problem for sdio since R4_18V_PRESENT won't be set for ocr when mmc_sdio_init_card() finds mmc_host_uhs() is false. Note that this patch doesn't keep the checking of card->scr.sda_spec3 and comparing card->scr.bus_widths with SD_SCR_BUS_WIDTH_4 within mmc_sd_init_uhs_card() since if the sd cards response with SD_ROCR_S18A, it definitely supports UHS-I mode, which implicitly means these checkings are always true. Signed-off-by: Shawn Lin Signed-off-by: Ulf Hansson