Some controllers require waiting for the bus to become idle
before writing to some registers. I have implemented this
by adding a hook to sd_ctrl_write16() and implementing
a hook for SDHI which waits for the bus to become idle.
Cc: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
Cc: Magnus Damm <magnus.damm@xxxxxxxxx>
Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
---
Dependencies: "mmc: tmio: Share register access functions"
v2:
* Include linux/delay.h instead of asm/delay.h
* Skip write if sh_mobile_sdhi_wait_idle() times out
- The bus will probably be in an inconsistent state and writing
may lock up the bus
* Only set hook if TMIO_MMC_HAS_IDLE_WAIT is set in platform data
rather than checking for TMIO_MMC_HAS_IDLE_WAIT each time the
hook is called.
---
drivers/mmc/host/sh_mobile_sdhi.c | 36 ++++++++++++++++++++++++++++++++++++
drivers/mmc/host/tmio_mmc.h | 5 +++++
include/linux/mfd/tmio.h | 8 ++++++++
include/linux/mmc/tmio.h | 1 +
4 files changed, 50 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/host/sh_mobile_sdhi.c b/drivers/mmc/host/sh_mobile_sdhi.c
index b365429..c8b1f6b 100644
--- a/drivers/mmc/host/sh_mobile_sdhi.c
+++ b/drivers/mmc/host/sh_mobile_sdhi.c
@@ -26,6 +26,7 @@
#include <linux/mmc/sh_mobile_sdhi.h>
#include <linux/mfd/tmio.h>
#include <linux/sh_dma.h>
+#include <linux/delay.h>
#include "tmio_mmc.h"
@@ -55,6 +56,39 @@ static int sh_mobile_sdhi_get_cd(struct platform_device *pdev)
return -ENOSYS;
}
+static int sh_mobile_sdhi_wait_idle(struct tmio_mmc_host *host)
+{
+ int timeout = 1000;
+
+ while (--timeout && !(sd_ctrl_read16(host, CTL_STATUS2) & (1 << 13)))
+ udelay(1);
+
+ if (!timeout) {
+ dev_warn(host->pdata->dev, "timeout waiting for SD bus idle\n");
+ return -EBUSY;
+ }
+
+ return 0;
+}
+
+static int sh_mobile_sdhi_write16_hook(struct tmio_mmc_host *host, int addr)
+{
+ switch (addr)
+ {
+ case CTL_SD_CMD:
+ case CTL_STOP_INTERNAL_ACTION:
+ case CTL_XFER_BLK_COUNT:
+ case CTL_SD_CARD_CLK_CTL:
+ case CTL_SD_XFER_LEN:
+ case CTL_SD_MEM_CARD_OPT:
+ case CTL_TRANSACTION_CTL:
+ case CTL_DMA_ENABLE:
+ return sh_mobile_sdhi_wait_idle(host);
+ }
+
+ return 0;
+}
+
static int __devinit sh_mobile_sdhi_probe(struct platform_device *pdev)
{
struct sh_mobile_sdhi *priv;
@@ -86,6 +120,8 @@ static int __devinit sh_mobile_sdhi_probe(struct platform_device *pdev)
mmc_data->hclk = clk_get_rate(priv->clk);
mmc_data->set_pwr = sh_mobile_sdhi_set_pwr;
mmc_data->get_cd = sh_mobile_sdhi_get_cd;
+ if (mmc_data->flags & TMIO_MMC_HAS_IDLE_WAIT)
+ mmc_data->write16_hook = sh_mobile_sdhi_write16_hook;
mmc_data->capabilities = MMC_CAP_MMC_HIGHSPEED;
if (p) {
mmc_data->flags = p->tmio_flags;
diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
index 0c22df0..211ef6e 100644
--- a/drivers/mmc/host/tmio_mmc.h
+++ b/drivers/mmc/host/tmio_mmc.h
@@ -153,6 +153,11 @@ static inline u32 sd_ctrl_read32(struct tmio_mmc_host *host, int addr)
static inline void sd_ctrl_write16(struct tmio_mmc_host *host, int addr, u16 val)
{
+ /* If there is a hook and it returns non-zero then there
+ * is an error and the write should be skipped
+ */
+ if (host->pdata->write16_hook && host->pdata->write16_hook(host, addr))
+ return;
writew(val, host->ctl + (addr << host->bus_shift));
}
diff --git a/include/linux/mfd/tmio.h b/include/linux/mfd/tmio.h
index 5a90266..0dc9804 100644
--- a/include/linux/mfd/tmio.h
+++ b/include/linux/mfd/tmio.h
@@ -68,6 +68,11 @@
* controller and report the event to the driver.
*/
#define TMIO_MMC_HAS_COLD_CD (1 << 3)
+/*
+ * Some controllers require waiting for the SD bus to become
+ * idle before writing to some registers.
+ */
+#define TMIO_MMC_HAS_IDLE_WAIT (1 << 4)
int tmio_core_mmc_enable(void __iomem *cnf, int shift, unsigned long base);
int tmio_core_mmc_resume(void __iomem *cnf, int shift, unsigned long base);
@@ -80,6 +85,8 @@ struct tmio_mmc_dma {
int alignment_shift;
};
+struct tmio_mmc_host;
+
/*
* data for the MMC controller
*/
@@ -94,6 +101,7 @@ struct tmio_mmc_data {
void (*set_pwr)(struct platform_device *host, int state);
void (*set_clk_div)(struct platform_device *host, int state);
int (*get_cd)(struct platform_device *host);
+ int (*write16_hook)(struct tmio_mmc_host *host, int addr);
};
static inline void tmio_mmc_cd_wakeup(struct tmio_mmc_data *pdata)
diff --git a/include/linux/mmc/tmio.h b/include/linux/mmc/tmio.h
index 0a6e40d..f235757 100644
--- a/include/linux/mmc/tmio.h
+++ b/include/linux/mmc/tmio.h
@@ -21,6 +21,7 @@
#define CTL_XFER_BLK_COUNT 0xa
#define CTL_RESPONSE 0x0c
#define CTL_STATUS 0x1c
+#define CTL_STATUS2 0x1e
#define CTL_IRQ_MASK 0x20
#define CTL_SD_CARD_CLK_CTL 0x24
#define CTL_SD_XFER_LEN 0x26
--
1.7.4.4
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