ARM: OMAP: calculate hsmmc data timeout accurately

The data timeout can be calculated from the clock rate and timing values given by the card. At present the timeout is set to the maximum value, about 2.7 secs. When dealing with cards that do have errors, this causes large unnecessary delays because the correct timeout may be around 10 millisecs.

---
drivers/mmc/host/omap_hsmmc.c | 40 ++++++++++++++++++++++++++++++++++++++++

1 files changed, 40 insertions(+), 0 deletions(-)

index 8fb677e..942f68d 100644
@@ -64,6 +64,9 @@

#define ICS 0x2
#define CEN (1<<2)
#define CLKD_MASK 0x0000FFC0
+#define CLKD_SHIFT 6
+#define DTO_MASK 0x000F0000
+#define DTO_SHIFT 16
#define INT_EN_MASK 0x307F0033
#define INIT_STREAM (1<<1)
#define DP_SELECT (1<<21)
@@ -661,6 +664,42 @@ mmc_omap_start_dma_transfer(struct mmc_omap_host *host, struct mmc_request *req)

	return 0;
}

+static void set_data_timeout(struct mmc_omap_host *host,
+ struct mmc_request *req)
+{
+ unsigned int timeout, cycle_ns;
+ uint32_t reg, clkd, dto = 0;
+
+ reg = OMAP_HSMMC_READ(host->base, SYSCTL);
+ clkd = (reg & CLKD_MASK) >> CLKD_SHIFT;
+ if (clkd == 0)
+ clkd = 1;
+
+ cycle_ns = 1000000000 / (clk_get_rate(host->fclk) / clkd);
+ timeout = req->data->timeout_ns / cycle_ns;
+ timeout += req->data->timeout_clks;
+ if (timeout) {
+ while ((timeout & 0x80000000) == 0) {
+ dto += 1;
+ timeout <<= 1;
+ }
+ dto = 31 - dto;
+ timeout <<= 1;
+ if (timeout && dto)
+ dto += 1;
+ if (dto >= 13)
+ dto -= 13;
+ else
+ dto = 0;
+ if (dto > 14)
+ dto = 14;
+ }
+
+ reg &= ~DTO_MASK;
+ reg |= dto << DTO_SHIFT;
+ OMAP_HSMMC_WRITE(host->base, SYSCTL, reg);
+}
+
/*
* Configure block length for MMC/SD cards and initiate the transfer.
*/
@@ -678,6 +717,7 @@ mmc_omap_prepare_data(struct mmc_omap_host *host, struct mmc_request *req)

	OMAP_HSMMC_WRITE(host->base, BLK, (req->data->blksz)
					| (req->data->blocks << 16));

+ set_data_timeout(host, req);

	host->datadir = (req->data->flags & MMC_DATA_WRITE) ?
			OMAP_MMC_DATADIR_WRITE : OMAP_MMC_DATADIR_READ;

1.5.4.3