From: Pierre Ossman Infrastructure for 4-bit bus transfers with SD cards. Signed-off-by: Pierre Ossman Cc: Russell King Cc: David Brownell Signed-off-by: Andrew Morton --- drivers/mmc/mmc.c | 36 ++++++++++++++++++++++++++++++++++++ include/linux/mmc/host.h | 9 +++++++++ include/linux/mmc/protocol.h | 7 +++++++ 3 files changed, 52 insertions(+) diff -puN drivers/mmc/mmc.c~sd-4-bit-bus drivers/mmc/mmc.c --- devel/drivers/mmc/mmc.c~sd-4-bit-bus 2005-07-30 00:17:00.000000000 -0700 +++ devel-akpm/drivers/mmc/mmc.c 2005-07-30 00:17:00.000000000 -0700 @@ -335,6 +335,40 @@ static int mmc_select_card(struct mmc_ho if (err != MMC_ERR_NONE) return err; + /* + * Default bus width is 1 bit. + */ + host->ios.bus_width = MMC_BUS_WIDTH_1; + + /* + * We can only change the bus width of the selected + * card so therefore we have to put the handling + * here. + */ + if (host->caps & MMC_CAP_4_BIT_DATA) { + /* + * The card is in 1 bit mode by default so + * we only need to change if it supports the + * wider version. + */ + if (mmc_card_sd(card) && + (card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) { + struct mmc_command cmd; + cmd.opcode = SD_APP_SET_BUS_WIDTH; + cmd.arg = SD_BUS_WIDTH_4; + cmd.flags = MMC_RSP_R1; + + err = mmc_wait_for_app_cmd(host, card->rca, &cmd, + CMD_RETRIES); + if (err != MMC_ERR_NONE) + return err; + + host->ios.bus_width = MMC_BUS_WIDTH_4; + } + } + + host->ops->set_ios(host, &host->ios); + return MMC_ERR_NONE; } @@ -644,6 +678,7 @@ static void mmc_power_up(struct mmc_host host->ios.vdd = bit; host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN; host->ios.power_mode = MMC_POWER_UP; + host->ios.bus_width = MMC_BUS_WIDTH_1; host->ops->set_ios(host, &host->ios); mmc_delay(1); @@ -661,6 +696,7 @@ static void mmc_power_off(struct mmc_hos host->ios.vdd = 0; host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN; host->ios.power_mode = MMC_POWER_OFF; + host->ios.bus_width = MMC_BUS_WIDTH_1; host->ops->set_ios(host, &host->ios); } diff -puN include/linux/mmc/host.h~sd-4-bit-bus include/linux/mmc/host.h --- devel/include/linux/mmc/host.h~sd-4-bit-bus 2005-07-30 00:17:00.000000000 -0700 +++ devel-akpm/include/linux/mmc/host.h 2005-07-30 00:17:00.000000000 -0700 @@ -51,6 +51,11 @@ struct mmc_ios { #define MMC_POWER_OFF 0 #define MMC_POWER_UP 1 #define MMC_POWER_ON 2 + + unsigned char bus_width; /* data bus width */ + +#define MMC_BUS_WIDTH_1 0 +#define MMC_BUS_WIDTH_4 2 }; struct mmc_host_ops { @@ -70,6 +75,10 @@ struct mmc_host { u32 ocr_avail; char host_name[8]; + unsigned long caps; /* Host capabilities */ + +#define MMC_CAP_4_BIT_DATA (1 << 0) /* Can the host do 4 bit transfers */ + /* host specific block data */ unsigned int max_seg_size; /* see blk_queue_max_segment_size */ unsigned short max_hw_segs; /* see blk_queue_max_hw_segments */ diff -puN include/linux/mmc/protocol.h~sd-4-bit-bus include/linux/mmc/protocol.h --- devel/include/linux/mmc/protocol.h~sd-4-bit-bus 2005-07-30 00:17:00.000000000 -0700 +++ devel-akpm/include/linux/mmc/protocol.h 2005-07-30 00:17:00.000000000 -0700 @@ -236,5 +236,12 @@ struct _mmc_csd { #define CSD_SPEC_VER_2 2 /* Implements system specification 2.0 - 2.2 */ #define CSD_SPEC_VER_3 3 /* Implements system specification 3.1 */ + +/* + * SD bus widths + */ +#define SD_BUS_WIDTH_1 0 +#define SD_BUS_WIDTH_4 2 + #endif /* MMC_MMC_PROTOCOL_H */ _