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mmc: core: add eMMC hardware reset support

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eMMC's may have a hardware reset line.  This patch provides a
host controller operation to implement hardware reset and
a function to reset and reinitialize the card.  Also, for MMC,
the reset is always performed before initialization.

The host must set the new host capability MMC_CAP_HW_RESET
to enable hardware reset.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Adrian Hunter
2011-08-29 16:42:11 +03:00
committed by Chris Ball
parent 8e3336b1e4
commit b2499518b5
6 changed files with 107 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

94
drivers/mmc/core/core.c
View File

@@ -1776,6 +1776,94 @@ int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen)
}
EXPORT_SYMBOL(mmc_set_blocklen);
static void mmc_hw_reset_for_init(struct mmc_host *host)
{
if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
return;
mmc_host_clk_hold(host);
host->ops->hw_reset(host);
mmc_host_clk_release(host);
}
int mmc_can_reset(struct mmc_card *card)
{
u8 rst_n_function;
if (!mmc_card_mmc(card))
return 0;
rst_n_function = card->ext_csd.rst_n_function;
if ((rst_n_function & EXT_CSD_RST_N_EN_MASK) != EXT_CSD_RST_N_ENABLED)
return 0;
return 1;
}
EXPORT_SYMBOL(mmc_can_reset);
static int mmc_do_hw_reset(struct mmc_host *host, int check)
{
struct mmc_card *card = host->card;
if (!host->bus_ops->power_restore)
return -EOPNOTSUPP;
if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
return -EOPNOTSUPP;
if (!card)
return -EINVAL;
if (!mmc_can_reset(card))
return -EOPNOTSUPP;
mmc_host_clk_hold(host);
mmc_set_clock(host, host->f_init);
host->ops->hw_reset(host);
/* If the reset has happened, then a status command will fail */
if (check) {
struct mmc_command cmd = {0};
int err;
cmd.opcode = MMC_SEND_STATUS;
if (!mmc_host_is_spi(card->host))
cmd.arg = card->rca << 16;
cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_AC;
err = mmc_wait_for_cmd(card->host, &cmd, 0);
if (!err) {
mmc_host_clk_release(host);
return -ENOSYS;
}
}
host->card->state &= ~(MMC_STATE_HIGHSPEED | MMC_STATE_HIGHSPEED_DDR);
if (mmc_host_is_spi(host)) {
host->ios.chip_select = MMC_CS_HIGH;
host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
} else {
host->ios.chip_select = MMC_CS_DONTCARE;
host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
}
host->ios.bus_width = MMC_BUS_WIDTH_1;
host->ios.timing = MMC_TIMING_LEGACY;
mmc_set_ios(host);
mmc_host_clk_release(host);
return host->bus_ops->power_restore(host);
}
int mmc_hw_reset(struct mmc_host *host)
{
return mmc_do_hw_reset(host, 0);
}
EXPORT_SYMBOL(mmc_hw_reset);
int mmc_hw_reset_check(struct mmc_host *host)
{
return mmc_do_hw_reset(host, 1);
}
EXPORT_SYMBOL(mmc_hw_reset_check);
static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
{
host->f_init = freq;
@@ -1786,6 +1874,12 @@ static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
#endif
mmc_power_up(host);
/*
* Some eMMCs (with VCCQ always on) may not be reset after power up, so
* do a hardware reset if possible.
*/
mmc_hw_reset_for_init(host);
/*
* sdio_reset sends CMD52 to reset card. Since we do not know
* if the card is being re-initialized, just send it. CMD52

4
drivers/mmc/core/mmc.c
View File

@@ -402,8 +402,10 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
ext_csd[EXT_CSD_TRIM_MULT];
}
if (card->ext_csd.rev >= 5)
if (card->ext_csd.rev >= 5) {
card->ext_csd.rel_param = ext_csd[EXT_CSD_WR_REL_PARAM];
card->ext_csd.rst_n_function = ext_csd[EXT_CSD_RST_N_FUNCTION];
}
if (ext_csd[EXT_CSD_ERASED_MEM_CONT])
card->erased_byte = 0xFF;