From: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx>
SD card read was failing (data crc error)on some cards at
maximum possible frequency on P1010(CCB frequency set to 400MHz).
Some clock deviations are also observed at this frequency.
Hence reduced the mmc clock freq.
Signed-off-by: Priyanka Jain <Priyanka.Jain@xxxxxxxxxxxxx>
Singed-off-by: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx>
CC: Chris Ball <cjb@xxxxxxxxxx>
Acked-by: Anton Vorontsov <cbouatmailru@xxxxxxxxx>
---
changes for v2:
- change the property to compatible for quirks
changes for v3:
- fix one compile error
changes for v4:
- use hooks to suspend/resume the special platform
changes for v5:
- add the Acked-by
changes for v6:
- move the workaround codes to special platform from header file
changes for v7:
- don't use quirks to check the platform support
drivers/mmc/host/sdhci-of-esdhc.c | 19 ++++++++++++++++++-
1 files changed, 18 insertions(+), 1 deletions(-)
drivers/mmc/host/sdhci-of-esdhc.c | 24 ++++++++++++++++++++++--
1 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
index 2ef52f4..acac541 100644
--- a/drivers/mmc/host/sdhci-of-esdhc.c
+++ b/drivers/mmc/host/sdhci-of-esdhc.c
@@ -1,7 +1,7 @@
/*
* Freescale eSDHC controller driver.
*
- * Copyright (c) 2007, 2010 Freescale Semiconductor, Inc.
+ * Copyright (c) 2007, 2010, 2012 Freescale Semiconductor, Inc.
* Copyright (c) 2009 MontaVista Software, Inc.
*
* Authors: Xiaobo Xie <X.Xie@xxxxxxxxxxxxx>
@@ -14,6 +14,7 @@
*/
#include <linux/io.h>
+#include <linux/of.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/mmc/host.h>
@@ -114,6 +115,25 @@ static unsigned int esdhc_of_get_min_clock(struct sdhci_host *host)
return pltfm_host->clock / 256 / 16;
}
+static void esdhc_of_set_clock(struct sdhci_host *host, unsigned int clock)
+{
+ /* Workaround to reduce the clock frequency for p1010 esdhc */
+ if (of_find_compatible_node(NULL, NULL, "fsl,p1010-esdhc")) {
+ if (clock == 0) {
+ host->clock = clock;
+ return;
+ }
+
+ if (clock > 20000000)
+ clock -= 5000000;
+ if (clock > 40000000)
+ clock -= 5000000;
+ }
+
+ /* Set the clock */
+ esdhc_set_clock(host, clock);
+}
+
#ifdef CONFIG_PM
static u32 esdhc_proctl;
static void esdhc_of_suspend(struct sdhci_host *host)
@@ -135,7 +155,7 @@ static struct sdhci_ops sdhci_esdhc_ops = {
.write_l = sdhci_be32bs_writel,
.write_w = esdhc_writew,
.write_b = esdhc_writeb,
- .set_clock = esdhc_set_clock,
+ .set_clock = esdhc_of_set_clock,
.enable_dma = esdhc_of_enable_dma,
.get_max_clock = esdhc_of_get_max_clock,
.get_min_clock = esdhc_of_get_min_clock,
--
1.7.5.4
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