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authorAdrian Hunter <adrian.hunter@intel.com>2011-08-29 16:42:11 +0300
committerChris Ball <cjb@laptop.org>2011-10-26 16:32:05 -0400
commitb2499518b5ad7e28bb3ed348fd3f370eeb1e36c0 (patch)
treec4c9597d0631554bffeecbcc6a2a7ec3037ea78c /drivers/mmc
parent8e3336b1e4378f7d205af9b25dcc9e645c8a9609 (diff)
mmc: core: add eMMC hardware reset support
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>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/core/core.c94
-rw-r--r--drivers/mmc/core/mmc.c4
2 files changed, 97 insertions, 1 deletions
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 0b4c2ed22bc..da6bd95fa4b 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -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;
@@ -1787,6 +1875,12 @@ static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
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
* should be ignored by SD/eMMC cards.
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index b74e6f14b3a..7adc30da836 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -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;