RE: [PATCH v2] mmc: sdhci-of-esdhc: fixup PRESENT_STATE read

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Am 2016-11-14 04:00, schrieb Y.B. Lu:
-----Original Message-----
From: Michael Walle [mailto:michael@xxxxxxxx]
Sent: Saturday, November 12, 2016 12:04 AM
To: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-mmc@xxxxxxxxxxxxxxx; Ulf Hansson; Adrian Hunter; yangbo lu;
Michael Walle
Subject: [PATCH v2] mmc: sdhci-of-esdhc: fixup PRESENT_STATE read

Since commit 87a18a6a5652 ("mmc: mmc: Use ->card_busy() to detect busy
cards in __mmc_switch()") the ESDHC driver is broken:
  mmc0: Card stuck in programming state! __mmc_switch
  mmc0: error -110 whilst initialising MMC card

Since this commit __mmc_switch() uses ->card_busy(), which is
sdhci_card_busy() for the esdhc driver. sdhci_card_busy() uses the
PRESENT_STATE register, specifically the DAT0 signal level bit. But the ESDHC uses a non-conformant PRESENT_STATE register, thus a read fixup is
required to make the driver work again.

Signed-off-by: Michael Walle <michael@xxxxxxxx>
Fixes: 87a18a6a5652 ("mmc: mmc: Use ->card_busy() to detect busy cards in
__mmc_switch()")
---
v2:
 - use lower bits of the original value (that was actually a typo)
 - add fixes tag
 - fix typo

 drivers/mmc/host/sdhci-of-esdhc.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-
of-esdhc.c
index fb71c86..f9c84bb 100644
--- a/drivers/mmc/host/sdhci-of-esdhc.c
+++ b/drivers/mmc/host/sdhci-of-esdhc.c
@@ -66,6 +66,18 @@ static u32 esdhc_readl_fixup(struct sdhci_host *host,
 			return ret;
 		}
 	}
+	/*
+	 * The DAT[3:0] line signal levels and the CMD line signal level is
+	 * not compatible with standard SDHC register. Move the
corresponding
+	 * bits around.
+	 */
+	if (spec_reg == SDHCI_PRESENT_STATE) {
+		ret = value & ~0xf8000000;

[Lu Yangbo-B47093] I think the bits which should be cleaned before
following '|=' are 0x01f00000 not 0xf8000000, right?
:)

Its neither 0x01f00000 nor 0xf8000000 :( I'll put the bits definition into the comment the next time, so everyone can review them. bit[31:24] are the line DAT[7:0] line signal level. bit[23] is command signal level. All other bits are the same as in the standard SDHC PRESENT_STATE register.

I want to keep all but the upper 9 bits from the original value, therefore, this should be the correct mask:
	ret = value & ~0xff800000;

-michael


+		ret |= (value >> 4) & SDHCI_DATA_LVL_MASK;
+		ret |= (value << 1) & 0x01000000;
+		return ret;
+	}
+
 	ret = value;
 	return ret;
 }
--
2.1.4

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