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authorHaavard Skinnemoen <haavard.skinnemoen@atmel.com>2008-07-30 20:29:03 +0200
committerHaavard Skinnemoen <haavard.skinnemoen@atmel.com>2008-10-05 20:39:21 +0200
commit65e8b083fc8ec303499baa1924ae032d46d29990 (patch)
tree4c3e1b4cb6c18e2abe55e590b75e97edf4243cc7 /arch/avr32/mach-at32ap
parent965ebf33ea5afb6386f5b57cc71e6572253746b3 (diff)
downloadop-kernel-dev-65e8b083fc8ec303499baa1924ae032d46d29990.zip
op-kernel-dev-65e8b083fc8ec303499baa1924ae032d46d29990.tar.gz
atmel-mci: Add experimental DMA support
This adds support for DMA transfers through the generic DMA engine framework with the DMA slave extensions. The driver has been tested using mmc-block and ext3fs on several SD, SDHC and MMC+ cards. Reads and writes work fine, with read transfer rates up to 7.5 MiB/s on fast cards with debugging disabled. Unfortunately, the driver has been known to lock up from time to time with DMA enabled, so DMA support is currently optional and marked EXPERIMENTAL. However, I didn't see any problems while testing 13 different cards (MMC, SD and SDHC of different brands and sizes), so I suspect the "Initialize BLKR before sending data transfer command" fix that was posted earlier fixed this as well. Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Diffstat (limited to 'arch/avr32/mach-at32ap')
-rw-r--r--arch/avr32/mach-at32ap/at32ap700x.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/avr32/mach-at32ap/at32ap700x.c b/arch/avr32/mach-at32ap/at32ap700x.c
index 9967d5a..f1b9a3a 100644
--- a/arch/avr32/mach-at32ap/at32ap700x.c
+++ b/arch/avr32/mach-at32ap/at32ap700x.c
@@ -1273,6 +1273,7 @@ struct platform_device *__init
at32_add_device_mci(unsigned int id, struct mci_platform_data *data)
{
struct platform_device *pdev;
+ struct dw_dma_slave *dws;
if (id != 0 || !data)
return NULL;
@@ -1289,6 +1290,21 @@ at32_add_device_mci(unsigned int id, struct mci_platform_data *data)
ARRAY_SIZE(atmel_mci0_resource)))
goto fail;
+ if (data->dma_slave)
+ dws = kmemdup(to_dw_dma_slave(data->dma_slave),
+ sizeof(struct dw_dma_slave), GFP_KERNEL);
+ else
+ dws = kzalloc(sizeof(struct dw_dma_slave), GFP_KERNEL);
+
+ dws->slave.dev = &pdev->dev;
+ dws->slave.dma_dev = &dw_dmac0_device.dev;
+ dws->slave.reg_width = DMA_SLAVE_WIDTH_32BIT;
+ dws->cfg_hi = (DWC_CFGH_SRC_PER(0)
+ | DWC_CFGH_DST_PER(1));
+ dws->cfg_lo &= ~(DWC_CFGL_HS_DST_POL
+ | DWC_CFGL_HS_SRC_POL);
+
+ data->dma_slave = &dws->slave;
if (platform_device_add_data(pdev, data,
sizeof(struct mci_platform_data)))
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