diff options
| author | Ulf Hansson <ulf.hansson@linaro.org> | 2020-10-29 09:57:16 +0800 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2020-11-16 11:59:28 +0100 |
| commit | ead49373d2916080509f51fc6a4ee8f9bc021b9b (patch) | |
| tree | a3cf2dc4cbd8a310aebc4d7c996e65641e7a7613 /include/linux/mmc | |
| parent | 9baf7c5e3ab364c038070a3b396de3b8a10016cd (diff) | |
mmc: core: Initial support for SD express card/host
In the SD specification v7.10 the SD express card has been added. This new
type of removable SD card, can be managed via a PCIe/NVMe based interface,
while also allowing backwards compatibility towards the legacy SD
interface.
To keep the backwards compatibility, it's required to start the
initialization through the legacy SD interface. If it turns out that the
mmc host and the SD card, both supports the PCIe/NVMe interface, then a
switch should be allowed.
Therefore, let's introduce some basic support for this type of SD cards to
the mmc core. The mmc host, should set MMC_CAP2_SD_EXP if it supports this
interface and MMC_CAP2_SD_EXP_1_2V, if also 1.2V is supported, as to inform
the core about it.
To deal with the switch to the PCIe/NVMe interface, the mmc host is
required to implement a new host ops, ->init_sd_express(). Based on the
initial communication between the host and the card, host->ios.timing is
set to either MMC_TIMING_SD_EXP or MMC_TIMING_SD_EXP_1_2V, depending on if
1.2V is supported or not. In this way, the mmc host can check these values
in its ->init_sd_express() ops, to know how to proceed with the handover.
Note that, to manage card insert/removal, the mmc core sticks with using
the ->get_cd() callback, which means it's the host's responsibility to make
sure it provides valid data, even if the card may be managed by PCIe/NVMe
at the moment. As long as the card seems to be present, the mmc core keeps
the card powered on.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Rui Feng <rui_feng@realsil.com.cn>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/1603936636-3126-1-git-send-email-rui_feng@realsil.com.cn
Diffstat (limited to 'include/linux/mmc')
| -rw-r--r-- | include/linux/mmc/host.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index c079b932330f..01bba36545c5 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -60,6 +60,8 @@ struct mmc_ios { #define MMC_TIMING_MMC_DDR52 8 #define MMC_TIMING_MMC_HS200 9 #define MMC_TIMING_MMC_HS400 10 +#define MMC_TIMING_SD_EXP 11 +#define MMC_TIMING_SD_EXP_1_2V 12 unsigned char signal_voltage; /* signalling voltage (1.8V or 3.3V) */ @@ -173,6 +175,9 @@ struct mmc_host_ops { */ int (*multi_io_quirk)(struct mmc_card *card, unsigned int direction, int blk_size); + + /* Initialize an SD express card, mandatory for MMC_CAP2_SD_EXP. */ + int (*init_sd_express)(struct mmc_host *host, struct mmc_ios *ios); }; struct mmc_cqe_ops { @@ -358,6 +363,8 @@ struct mmc_host { #define MMC_CAP2_HS200_1_2V_SDR (1 << 6) /* can support */ #define MMC_CAP2_HS200 (MMC_CAP2_HS200_1_8V_SDR | \ MMC_CAP2_HS200_1_2V_SDR) +#define MMC_CAP2_SD_EXP (1 << 7) /* SD express via PCIe */ +#define MMC_CAP2_SD_EXP_1_2V (1 << 8) /* SD express 1.2V */ #define MMC_CAP2_CD_ACTIVE_HIGH (1 << 10) /* Card-detect signal active high */ #define MMC_CAP2_RO_ACTIVE_HIGH (1 << 11) /* Write-protect signal active high */ #define MMC_CAP2_NO_PRESCAN_POWERUP (1 << 14) /* Don't power up before scan */ |