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mmc: omap: fix the maximum timeout setting 

When running OMAP1 kernel on QEMU, MMC access is annoyingly noisy:

	MMC: CTO of 0xff and 0xfe cannot be used!
	MMC: CTO of 0xff and 0xfe cannot be used!
	MMC: CTO of 0xff and 0xfe cannot be used!
	[ad inf.]

Emulator warnings appear to be valid. The TI document SPRU680 [1]
("OMAP5910 Dual-Core Processor MultiMedia Card/Secure Data Memory Card
(MMC/SD) Reference Guide") page 36 states that the maximum timeout is 253
cycles and "0xff and 0xfe cannot be used".

Fix by using 0xfd as the maximum timeout.

Tested using QEMU 2.5 (Siemens SX1 machine, OMAP310), and also checked on
real hardware using Palm TE (OMAP310), Nokia 770 (OMAP1710) and Nokia N810
(OMAP2420) that MMC works as before.

[1] http://www.ti.com/lit/ug/spru680/spru680.pdf

Fixes: 730c9b7e66 ("[MMC] Add OMAP MMC host driver")
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Aaro Koskinen 2019-02-03 00:14:33 +02:00 committed by Ulf Hansson
parent 3c4019f979
commit a6327b5e57
1 changed files with 1 additions and 1 deletions
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2
drivers/mmc/host/omap.c
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@ -920,7 +920,7 @@ static inline void set_cmd_timeout(struct mmc_omap_host *host, struct mmc_reques
reg &= ~(1 << 5);
OMAP_MMC_WRITE(host, SDIO, reg);
/* Set maximum timeout */
OMAP_MMC_WRITE(host, CTO, 0xff);
OMAP_MMC_WRITE(host, CTO, 0xfd);
}
static inline void set_data_timeout(struct mmc_omap_host *host, struct mmc_request *req)