diff options
| author | Pierre Ossman <drzeus-list@drzeus.cx> | 2005-09-06 15:18:55 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-07 16:57:51 -0700 |
| commit | f218278a456b3c272b480443c89004c3d2a49f18 (patch) | |
| tree | 8d9558816488311e06a7ad2434e342418f2c79d5 | |
| parent | a9c4342beb4cd28b3a05c3401195e2536c37c150 (diff) | |
[PATCH] sd: SD 4-bit bus
Infrastructure for 4-bit bus transfers with SD cards.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | drivers/mmc/mmc.c | 36 | ||||
| -rw-r--r-- | include/linux/mmc/host.h | 9 | ||||
| -rw-r--r-- | include/linux/mmc/protocol.h | 7 |
3 files changed, 52 insertions, 0 deletions
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index 21d4fb3314f..6414f071a2a 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -335,6 +335,40 @@ static int mmc_select_card(struct mmc_host *host, struct mmc_card *card) 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; } @@ -653,6 +687,7 @@ static void mmc_power_up(struct mmc_host *host) host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN; host->ios.chip_select = MMC_CS_DONTCARE; 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); @@ -671,6 +706,7 @@ static void mmc_power_off(struct mmc_host *host) host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN; host->ios.chip_select = MMC_CS_DONTCARE; host->ios.power_mode = MMC_POWER_OFF; + host->ios.bus_width = MMC_BUS_WIDTH_1; host->ops->set_ios(host, &host->ios); } diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 8c5f71376e4..6014160d9c0 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -57,6 +57,11 @@ 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 { @@ -77,6 +82,10 @@ struct mmc_host { unsigned int f_max; u32 ocr_avail; + 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 --git a/include/linux/mmc/protocol.h b/include/linux/mmc/protocol.h index 896342817b9..f819cae9226 100644 --- a/include/linux/mmc/protocol.h +++ b/include/linux/mmc/protocol.h @@ -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 */ |