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ARM: 7552/1: mmc: mmci: Switching off HWFC for SDIO depends on MCLK

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For writes, HWFC shall be switched off when transfer size <= 8
bytes and when MCLK rate is above 50 MHz. For 50MHz and below
it shall be switched off when transfer size < 8 bytes.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Johan Rudholm <johan.rudholm@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Ulf Hansson 2012-10-12 14:07:36 +01:00 committed by Russell King
parent 06c1a12180
commit 70ac09358c
1 changed files with 7 additions and 5 deletions
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12
drivers/mmc/host/mmci.c
View file

@ -664,12 +664,14 @@ static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
datactrl |= MCI_ST_DPSM_SDIOEN;
/*
* The ST Micro variant for SDIO transfer sizes
* less then 8 bytes should have clock H/W flow
* control disabled.
* The ST Micro variant for SDIO small write transfers
* needs to have clock H/W flow control disabled,
* otherwise the transfer will not start. The threshold
* depends on the rate of MCLK.
*/
if ((host->size < 8) &&
(data->flags & MMC_DATA_WRITE))
if (data->flags & MMC_DATA_WRITE &&
(host->size < 8 ||
(host->size <= 8 && host->mclk > 50000000)))
clk = host->clk_reg & ~variant->clkreg_enable;
else
clk = host->clk_reg | variant->clkreg_enable;