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>
diff --git a/drivers/mmc/s5p_mmc.c b/drivers/mmc/s5p_mmc.c
index f136813..7786ecf 100644
--- a/drivers/mmc/s5p_mmc.c
+++ b/drivers/mmc/s5p_mmc.c
@@ -232,9 +232,15 @@
__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 @@
* 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);
/*