From: Ritesh Harjani <riteshh@xxxxxxxxxxxxxx>
To allow UHS mode to work properly, we need to implement a Qualcomm
specific set_uhs_signaling() callback function. This function differs
from the sdhci_set_uhs_signaling() in that we need check the clock
rate and enable UHS timing only if the frequency is above 100MHz.
Signed-off-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxxx>
Signed-off-by: Georgi Djakov <georgi.djakov@xxxxxxxxxx>
---
This patch resolves the mmc_select_hs200 timeouts noticed after merging
commit a5c1f3e55c99 ("mmc: mmc: do not use CMD13 to get status after
speed mode switch")
mmc0: mmc_select_hs200 failed, error -110
mmc0: error -110 whilst initialising MMC card
mmc0: Reset 0x1 never completed.
sdhci: =========== REGISTER DUMP (mmc0)===========
sdhci: Sys addr: 0x00000000 | Version: 0x00002e02
sdhci: Blk size: 0x00004000 | Blk cnt: 0x00000000
sdhci: Argument: 0x00000000 | Trn mode: 0x00000000
sdhci: Present: 0x01f80000 | Host ctl: 0x00000000
sdhci: Power: 0x00000000 | Blk gap: 0x00000000
sdhci: Wake-up: 0x00000000 | Clock: 0x00000003
sdhci: Timeout: 0x00000000 | Int stat: 0x00000000
sdhci: Int enab: 0x00000000 | Sig enab: 0x00000000
sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000
sdhci: Caps: 0x322dc8b2 | Caps_1: 0x00008007
sdhci: Cmd: 0x00000000 | Max curr: 0x00000000
sdhci: Host ctl2: 0x00000000
sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x0000000000000000
sdhci: ===========================================
drivers/mmc/host/sdhci-msm.c | 48 +++++++++++++++++++++++++++++++++++++++++-
1 file changed, 47 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index 343e4bd4dc08..d1fce941cdd4 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -410,6 +410,52 @@ retry:
return rc;
}
+static void sdhci_msm_set_uhs_signaling(struct sdhci_host *host,
+ unsigned int uhs)
+{
+ struct mmc_host *mmc = host->mmc;
+ u16 ctrl_2;
+
+ ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+ /* Select Bus Speed Mode for host */
+ ctrl_2 &= ~SDHCI_CTRL_UHS_MASK;
+ switch (uhs) {
+ case MMC_TIMING_UHS_SDR12:
+ ctrl_2 |= SDHCI_CTRL_UHS_SDR12;
+ break;
+ case MMC_TIMING_UHS_SDR25:
+ ctrl_2 |= SDHCI_CTRL_UHS_SDR25;
+ break;
+ case MMC_TIMING_UHS_SDR50:
+ ctrl_2 |= SDHCI_CTRL_UHS_SDR50;
+ break;
+ case MMC_TIMING_MMC_HS200:
+ case MMC_TIMING_UHS_SDR104:
+ ctrl_2 |= SDHCI_CTRL_UHS_SDR104;
+ break;
+ case MMC_TIMING_UHS_DDR50:
+ case MMC_TIMING_MMC_DDR52:
+ ctrl_2 |= SDHCI_CTRL_UHS_DDR50;
+ break;
+ }
+
+ /*
+ * When clock frequency is less than 100MHz, the feedback clock must be
+ * provided and DLL must not be used so that tuning can be skipped. To
+ * provide feedback clock, the mode selection can be any value less
+ * than 3'b011 in bits [2:0] of HOST CONTROL2 register.
+ */
+ if (host->clock <= 100000000 &&
+ (uhs == MMC_TIMING_MMC_HS400 ||
+ uhs == MMC_TIMING_MMC_HS200 ||
+ uhs == MMC_TIMING_UHS_SDR104))
+ ctrl_2 &= ~SDHCI_CTRL_UHS_MASK;
+
+ dev_dbg(mmc_dev(mmc), "%s: clock=%u uhs=%u ctrl_2=0x%x\n",
+ mmc_hostname(host->mmc), host->clock, uhs, ctrl_2);
+ sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
+}
+
static const struct of_device_id sdhci_msm_dt_match[] = {
{ .compatible = "qcom,sdhci-msm-v4" },
{},
@@ -422,7 +468,7 @@ static const struct sdhci_ops sdhci_msm_ops = {
.reset = sdhci_reset,
.set_clock = sdhci_set_clock,
.set_bus_width = sdhci_set_bus_width,
- .set_uhs_signaling = sdhci_set_uhs_signaling,
+ .set_uhs_signaling = sdhci_msm_set_uhs_signaling,
};
static const struct sdhci_pltfm_data sdhci_msm_pdata = {
--
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