From e5ad0688a6b46f62664bdaad854311017bd039c4 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Mon, 29 Aug 2011 16:42:11 +0300 Subject: 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 Signed-off-by: Chris Ball (cherry picked from commit b2499518b5ad7e28bb3ed348fd3f370eeb1e36c0) --- drivers/mmc/core/core.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++++ drivers/mmc/core/mmc.c | 1 + 2 files changed, 95 insertions(+) (limited to 'drivers') diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 5cbeb1bbf267..96e7d5f894e5 100755 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -1994,6 +1994,94 @@ 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; @@ -2004,6 +2092,12 @@ 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 diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index e450fbc66559..d77872f8f9ba 100755 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -426,6 +426,7 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd) card->ext_csd.raw_erased_mem_count = ext_csd[EXT_CSD_ERASED_MEM_CONT]; 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]; /* check whether the eMMC card supports HPI */ if ((ext_csd[EXT_CSD_HPI_FEATURES] & 0x1) && !(card->quirks & MMC_QUIRK_BROKEN_HPI)) { -- cgit v1.2.3