On Tue, Oct 23, 2012 at 2:39 PM, Chris Ball <[email protected]> wrote: > Dan, maybe you could see if this patch (there's a 1/2 patch too) solves > your UHS problem?
I tested [RFC/PATCH] mmc: core: Fixup signal voltage switch https://patchwork.kernel.org/patch/1514691/ This was previously failing on both XO-1.75 (kernel 3.0) and XO-4 (kernel 3.5) - the 1.8V switch would fail, but it would not successfully switch back to 3.3V. Testing on XO-4, it worked fine: the 1.8V failed switch was detected, it came back as 3.3V and everything was fine. Testing on XO-1.75, it didn't work: it thought that the 1.8V switch was successful so it left it at that, then the card reacted in a very unstable manner (failed/retried reads, huge amount of kernel log spam, etc). So I came up with the attached sdhci patch. That fixes the XO-1.75 case, which now correctly detects the 1.8V switch failure and goes to 3.3V. However, that broke XO-4, which now just does: mmc2: Signal voltage switch failed, power cycling card (retries = 10) mmc2: error -110 whilst initialising SD card (no more time to debug exactly whats happening) All tests with the same 32GB SD storage card. I wonder if this difference in behaviour is related to the difference in kernel versions on each platform (3.0 vs 3.5). I would like to test with 3.5 or newer running on both, but this requires a bit of setup work for the XO-1.75 first (long story). And I'm out of time at this point :( this was a borrowed SD card. Daniel
From 664afe4de295d3783d335a737ce239cebf5885f2 Mon Sep 17 00:00:00 2001 From: Daniel Drake <[email protected]> Date: Tue, 23 Oct 2012 15:58:33 -0600 Subject: [PATCH] update sdhci for voltage changing fixes --- drivers/mmc/host/sdhci.c | 72 +++++++++--------------------------------------- 1 file changed, 13 insertions(+), 59 deletions(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 07a5346..1955406 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -1587,9 +1587,7 @@ static void sdhci_enable_sdio_irq(struct mmc_host *mmc, int enable) static int sdhci_do_start_signal_voltage_switch(struct sdhci_host *host, struct mmc_ios *ios) { - u8 pwr; - u16 clk, ctrl; - u32 present_state; + u16 ctrl; /* * Signal Voltage Switching is only applicable for Host Controllers @@ -1622,62 +1620,9 @@ static int sdhci_do_start_signal_voltage_switch(struct sdhci_host *host, } } else if (!(ctrl & SDHCI_CTRL_VDD_180) && (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180)) { - /* Stop SDCLK */ - clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL); - clk &= ~SDHCI_CLOCK_CARD_EN; - sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL); - - /* Check whether DAT[3:0] is 0000 */ - present_state = sdhci_readl(host, SDHCI_PRESENT_STATE); - if (!((present_state & SDHCI_DATA_LVL_MASK) >> - SDHCI_DATA_LVL_SHIFT)) { - /* - * Enable 1.8V Signal Enable in the Host Control2 - * register - */ - ctrl |= SDHCI_CTRL_VDD_180; - sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2); - - /* Wait for 5ms */ - usleep_range(5000, 5500); - - ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2); - if (ctrl & SDHCI_CTRL_VDD_180) { - /* Provide SDCLK again and wait for 1ms*/ - clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL); - clk |= SDHCI_CLOCK_CARD_EN; - sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL); - usleep_range(1000, 1500); - - /* - * If DAT[3:0] level is 1111b, then the card - * was successfully switched to 1.8V signaling. - */ - present_state = sdhci_readl(host, - SDHCI_PRESENT_STATE); - if ((present_state & SDHCI_DATA_LVL_MASK) == - SDHCI_DATA_LVL_MASK) - return 0; - } - } - - /* - * If we are here, that means the switch to 1.8V signaling - * failed. We power cycle the card, and retry initialization - * sequence by setting S18R to 0. - */ - pwr = sdhci_readb(host, SDHCI_POWER_CONTROL); - pwr &= ~SDHCI_POWER_ON; - sdhci_writeb(host, pwr, SDHCI_POWER_CONTROL); - - /* Wait for 1ms as per the spec */ - usleep_range(1000, 1500); - pwr |= SDHCI_POWER_ON; - sdhci_writeb(host, pwr, SDHCI_POWER_CONTROL); - - pr_info(DRIVER_NAME ": Switching to 1.8V signalling " - "voltage failed, retrying with S18R set to 0\n"); - return -EAGAIN; + ctrl |= SDHCI_CTRL_VDD_180; + sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2); + return 0; } else /* No signal voltage switch required */ return 0; @@ -1931,11 +1876,20 @@ static void sdhci_enable_preset_value(struct mmc_host *mmc, bool enable) sdhci_runtime_pm_put(host); } +static int sdhci_card_busy(struct mmc_host *mmc, int keep_busy) +{ + struct sdhci_host *host = mmc_priv(mmc); + u32 present_state = sdhci_readl(host, SDHCI_PRESENT_STATE); + + return (present_state & SDHCI_DATA_LVL_MASK) != SDHCI_DATA_LVL_MASK; +} + static const struct mmc_host_ops sdhci_ops = { .request = sdhci_request, .set_ios = sdhci_set_ios, .get_ro = sdhci_get_ro, .hw_reset = sdhci_hw_reset, + .card_busy = sdhci_card_busy, .enable_sdio_irq = sdhci_enable_sdio_irq, .start_signal_voltage_switch = sdhci_start_signal_voltage_switch, .execute_tuning = sdhci_execute_tuning, -- 1.7.11.7
