On Tue, Oct 23, 2012 at 2:39 PM, Chris Ball <cjb@xxxxxxxxxx> 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 <dsd@xxxxxxxxxx>
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
