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Subject[PATCH v2] mmc: sdhci-msm: Optionally wait for signal level changes
Date
Not all instances of the SDCC core supports changing signal voltage and
as such will not generate a power interrupt when the software attempts
to change the voltage. This results in probing the eMMC on some devices
to take over 2 minutes.

Check that the SWITCHABLE_SIGNALING_VOLTAGE bit in MCI_GENERICS is set
before waiting for the power interrupt.

Cc: Sahitya Tummala <stummala@codeaurora.org>
Cc: Vijay Viswanath <vviswana@codeaurora.org>
Fixes: c0309b3803fe ("mmc: sdhci-msm: Add sdhci msm register write APIs which wait for pwr irq")
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---

The offending patch is part of your v4.15 pull request, so please pick
this up for the -rcs.

Changes since v1:
- Fixed spelling of swichable...

drivers/mmc/host/sdhci-msm.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index 3fb7d2eec93f..c283291db705 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -29,6 +29,9 @@
#define CORE_VERSION_MAJOR_MASK (0xf << CORE_VERSION_MAJOR_SHIFT)
#define CORE_VERSION_MINOR_MASK 0xff

+#define CORE_MCI_GENERICS 0x70
+#define SWITCHABLE_SIGNALING_VOLTAGE BIT(29)
+
#define CORE_HC_MODE 0x78
#define HC_MODE_EN 0x1
#define CORE_POWER 0x0
@@ -1028,11 +1031,22 @@ static void sdhci_msm_check_power_status(struct sdhci_host *host, u32 req_type)
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
bool done = false;
+ u32 val;

pr_debug("%s: %s: request %d curr_pwr_state %x curr_io_level %x\n",
mmc_hostname(host->mmc), __func__, req_type,
msm_host->curr_pwr_state, msm_host->curr_io_level);

+ /*
+ * The power interrupt will not be generated for signal voltage
+ * switches if SWITCHABLE_SIGNALING_VOLTAGE in MCI_GENERICS is not set.
+ */
+ val = readl(msm_host->core_mem + CORE_MCI_GENERICS);
+ if ((req_type & REQ_IO_HIGH || req_type & REQ_IO_LOW) &&
+ !(val & SWITCHABLE_SIGNALING_VOLTAGE)) {
+ return;
+ }
+
/*
* The IRQ for request type IO High/LOW will be generated when -
* there is a state change in 1.8V enable bit (bit 3) of
--
2.15.0
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