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mmc: sd: query function modes for uhs cards

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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 <arindam.nath@amd.com>
Reviewed-by: Philip Rakity <prakity@marvell.com>
Tested-by: Philip Rakity <prakity@marvell.com>
Acked-by: Zhangfei Gao <zhangfei.gao@marvell.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Arindam Nath 2011-05-05 12:18:58 +05:30 committed by Chris Ball
parent f2119df6b7
commit 013909c4ff
2 changed files with 62 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

68
drivers/mmc/core/sd.c
View File

@ -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);

4
include/linux/mmc/card.h
View File

@ -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 {