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mmc: S5P: Support DMA restarts at buffer boundaries 

Currently if a DMA buffer straddles a buffer alignment boundary
(512KiB) then the DMA engine will pause and generate a DMA
interrupt.  Since the DMA interrupt is not enabled it will hang
the MMC driver.

This patch adds support for restarting the DMA transfer.  The
SYSTEM_ADDRESS register contains the next address that would have
been read/written when a boundary is hit.  So we can read that
and write it back.  The write triggers the resumption of the
transfer.

Signed-off-by: Anton Staaf <robotboy@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
Tested-by : Jaehoon Chung <jh80.chung@samsung.com>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
This commit is contained in:
Anton Staaf 2011-06-30 09:55:08 +00:00 committed by Albert ARIBAUD
parent 34d34b88b6
commit 9070872bb3
1 changed files with 11 additions and 4 deletions
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15
drivers/mmc/s5p_mmc.c
View File

@ -232,9 +232,15 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
__func__, mask);
return -1;
} else if (mask & (1 << 3)) {
/* DMA Interrupt */
/*
* DMA Interrupt, restart the transfer where
* it was interrupted.
*/
unsigned int address = readl(&host->reg->sysad);
debug("DMA end\n");
break;
writel((1 << 3), &host->reg->norintsts);
writel(address, &host->reg->sysad);
} else if (mask & (1 << 1)) {
/* Transfer Complete */
debug("r/w is done\n");
@ -425,12 +431,13 @@ static int mmc_core_init(struct mmc *mmc)
* NORMAL Interrupt Status Enable Register init
* [5] ENSTABUFRDRDY : Buffer Read Ready Status Enable
* [4] ENSTABUFWTRDY : Buffer write Ready Status Enable
* [3] ENSTADMAINT : DMA Interrupt Status Enable
* [1] ENSTASTANSCMPLT : Transfre Complete Status Enable
* [0] ENSTACMDCMPLT : Command Complete Status Enable
*/
*/
mask = readl(&host->reg->norintstsen);
mask &= ~(0xffff);
mask |= (1 << 5) | (1 << 4) | (1 << 1) | (1 << 0);
mask |= (1 << 5) | (1 << 4) | (1 << 3) | (1 << 1) | (1 << 0);
writel(mask, &host->reg->norintstsen);
/*