From: Ritesh Harjani <riteshh@xxxxxxxxxxxxxx>
SDHC core with new 14lpp and later tech DLL should not enable
PWRSAVE_DLL since such controller's internal gating cannot meet
following MCLK requirement:
When MCLK is gated OFF, it is not gated for less than 0.5us and MCLK
must be switched on for at-least 1us before DATA starts coming.
Adding support for this requirement.
Signed-off-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxxx>
Signed-off-by: Veerabhadrarao Badiganti <vbadigan@xxxxxxxxxxxxxx>
--
Changes since V1:
Condition was not correct in V1, which is corrected in V2
--
---
drivers/mmc/host/sdhci-msm.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index c3a160c..aa5b610 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -977,9 +977,21 @@ static int sdhci_msm_cm_dll_sdc4_calibration(struct sdhci_host *host)
goto out;
}
- config = readl_relaxed(host->ioaddr + msm_offset->core_vendor_spec3);
- config |= CORE_PWRSAVE_DLL;
- writel_relaxed(config, host->ioaddr + msm_offset->core_vendor_spec3);
+ /*
+ * Set CORE_PWRSAVE_DLL bit in CORE_VENDOR_SPEC3.
+ * When MCLK is gated OFF, it is not gated for less than 0.5us
+ * and MCLK must be switched on for at-least 1us before DATA
+ * starts coming. Controllers with 14lpp and later tech DLL cannot
+ * guarantee above requirement. So PWRSAVE_DLL should not be
+ * turned on for host controllers using this DLL.
+ */
+ if (!msm_host->use_14lpp_dll_reset) {
+ config = readl_relaxed(host->ioaddr +
+ msm_offset->core_vendor_spec3);
+ config |= CORE_PWRSAVE_DLL;
+ writel_relaxed(config, host->ioaddr +
+ msm_offset->core_vendor_spec3);
+ }
/*
* Drain writebuffer to ensure above DLL calibration
--
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