* With certain SD cards timeouts like the following have been seen
due to an improper calculation of the dto value:
mmcblk0: error -110 transferring data, sector 4126233, nr 8,
card status 0xc00
* By removing the dto calculation and setting the timeout value
to the maximum specified by the SD card specification part A2
section 2.2.15 these timeouts can be avoided.
* This change has been used by beagleboard users as well as the
Texas Instruments SDK without a negative impact.
* There are multiple discussion threads about this but the most
relevant ones are:
* http://talk.maemo.org/showthread.php?p=1000707#post1000707
* http://www.mail-archive.com/[email protected]/msg42213.html
* Original proposal for this fix was done by Sukumar Ghoral of
Texas Instruments
* Tested using a Texas Instruments AM335x EVM
Signed-off-by: Chase Maupin <[email protected]>
---
drivers/mmc/host/omap_hsmmc.c | 30 +++++-------------------------
1 files changed, 5 insertions(+), 25 deletions(-)
diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index fd0c661..afd7292 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -1481,11 +1481,8 @@ static int omap_hsmmc_start_dma_transfer(struct
omap_hsmmc_host *host,
return 0;
}
-static void set_data_timeout(struct omap_hsmmc_host *host,
- unsigned int timeout_ns,
- unsigned int timeout_clks)
+static void set_data_timeout(struct omap_hsmmc_host *host)
{
- unsigned int timeout, cycle_ns;
uint32_t reg, clkd, dto = 0;
reg = OMAP_HSMMC_READ(host->base, SYSCTL);
@@ -1493,25 +1490,8 @@ static void set_data_timeout(struct omap_hsmmc_host
*host,
if (clkd == 0)
clkd = 1;
- cycle_ns = 1000000000 / (clk_get_rate(host->fclk) / clkd);
- timeout = timeout_ns / cycle_ns;
- timeout += 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;
- }
+ /* Use the maximum timeout value allowed in the standard of 14 or 0xE */
+ dto = 14;
reg &= ~DTO_MASK;
reg |= dto << DTO_SHIFT;
@@ -1534,13 +1514,13 @@ omap_hsmmc_prepare_data(struct omap_hsmmc_host *host,
struct mmc_request *req)
* busy signal.
*/
if (req->cmd->flags & MMC_RSP_BUSY)
- set_data_timeout(host, 100000000U, 0);
+ set_data_timeout(host);
return 0;
}
OMAP_HSMMC_WRITE(host->base, BLK, (req->data->blksz)
| (req->data->blocks << 16));
- set_data_timeout(host, req->data->timeout_ns, req->data->timeout_clks);
+ set_data_timeout(host);
if (host->use_dma) {
ret = omap_hsmmc_start_dma_transfer(host, req);
--
1.7.0.4
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