From 013909c4ffd16ded4895528b856fd8782df04dc6 Mon Sep 17 00:00:00 2001 From: Arindam Nath Date: Thu, 5 May 2011 12:18:58 +0530 Subject: [PATCH] mmc: sd: query function modes for uhs cards SD cards which conform to Physical Layer Spec v3.01 can support additional Bus Speed Modes, Driver Strength, and Current Limit other than the default values. We use CMD6 mode 0 to read these additional card functions. The values read here will be used during UHS-I initialization steps. Tested by Zhangfei Gao with a Toshiba uhs card and general hs card, on mmp2 in SDMA mode. Signed-off-by: Arindam Nath Reviewed-by: Philip Rakity Tested-by: Philip Rakity Acked-by: Zhangfei Gao Signed-off-by: Chris Ball --- drivers/mmc/core/sd.c | 68 ++++++++++++++++++++++++++++++++++------ include/linux/mmc/card.h | 4 +++ 2 files changed, 62 insertions(+), 10 deletions(-) diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c index b0cd285d272a..8285842f19e9 100644 --- a/drivers/mmc/core/sd.c +++ b/drivers/mmc/core/sd.c @@ -189,6 +189,9 @@ static int mmc_decode_scr(struct mmc_card *card) scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4); scr->bus_widths = UNSTUFF_BITS(resp, 48, 4); + if (scr->sda_vsn == SCR_SPEC_VER_2) + /* Check if Physical Layer Spec v3.0 is supported */ + scr->sda_spec3 = UNSTUFF_BITS(resp, 47, 1); if (UNSTUFF_BITS(resp, 55, 1)) card->erased_byte = 0xFF; @@ -274,29 +277,74 @@ static int mmc_read_switch(struct mmc_card *card) status = kmalloc(64, GFP_KERNEL); if (!status) { printk(KERN_ERR "%s: could not allocate a buffer for " - "switch capabilities.\n", mmc_hostname(card->host)); + "switch capabilities.\n", + mmc_hostname(card->host)); return -ENOMEM; } + /* Find out the supported Bus Speed Modes. */ err = mmc_sd_switch(card, 0, 0, 1, status); if (err) { - /* If the host or the card can't do the switch, - * fail more gracefully. */ - if ((err != -EINVAL) - && (err != -ENOSYS) - && (err != -EFAULT)) + /* + * If the host or the card can't do the switch, + * fail more gracefully. + */ + if (err != -EINVAL && err != -ENOSYS && err != -EFAULT) goto out; - printk(KERN_WARNING "%s: problem reading switch " - "capabilities, performance might suffer.\n", + printk(KERN_WARNING "%s: problem reading Bus Speed modes.\n", mmc_hostname(card->host)); err = 0; goto out; } - if (status[13] & 0x02) - card->sw_caps.hs_max_dtr = 50000000; + if (card->scr.sda_spec3) { + card->sw_caps.sd3_bus_mode = status[13]; + + /* Find out Driver Strengths supported by the card */ + err = mmc_sd_switch(card, 0, 2, 1, status); + if (err) { + /* + * If the host or the card can't do the switch, + * fail more gracefully. + */ + if (err != -EINVAL && err != -ENOSYS && err != -EFAULT) + goto out; + + printk(KERN_WARNING "%s: problem reading " + "Driver Strength.\n", + mmc_hostname(card->host)); + err = 0; + + goto out; + } + + card->sw_caps.sd3_drv_type = status[9]; + + /* Find out Current Limits supported by the card */ + err = mmc_sd_switch(card, 0, 3, 1, status); + if (err) { + /* + * If the host or the card can't do the switch, + * fail more gracefully. + */ + if (err != -EINVAL && err != -ENOSYS && err != -EFAULT) + goto out; + + printk(KERN_WARNING "%s: problem reading " + "Current Limit.\n", + mmc_hostname(card->host)); + err = 0; + + goto out; + } + + card->sw_caps.sd3_curr_limit = status[7]; + } else { + if (status[13] & 0x02) + card->sw_caps.hs_max_dtr = 50000000; + } out: kfree(status); diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h index 72a98681ef47..56f4d9234a66 100644 --- a/include/linux/mmc/card.h +++ b/include/linux/mmc/card.h @@ -67,6 +67,7 @@ struct mmc_ext_csd { struct sd_scr { unsigned char sda_vsn; + unsigned char sda_spec3; unsigned char bus_widths; #define SD_SCR_BUS_WIDTH_1 (1<<0) #define SD_SCR_BUS_WIDTH_4 (1<<2) @@ -80,6 +81,9 @@ struct sd_ssr { struct sd_switch_caps { unsigned int hs_max_dtr; + unsigned int sd3_bus_mode; + unsigned int sd3_drv_type; + unsigned int sd3_curr_limit; }; struct sdio_cccr {