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mmc: atmel-mci: fix burst/chunk size modification

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The use of DMA slave config operation requires that the burst size
(aka chunk size) is specified through this interface.
Modify atmel-mci slave driver to use this specification on its side.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Nicolas Ferre 2012-06-06 12:19:44 +02:00 committed by Chris Ball
parent b87cc1b5d3
commit 693e5e2025
2 changed files with 19 additions and 3 deletions
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14
drivers/mmc/host/atmel-mci-regs.h
View File

@ -140,4 +140,18 @@
#define atmci_writel(port,reg,value) \
__raw_writel((value), (port)->regs + reg)
/*
* Fix sconfig's burst size according to atmel MCI. We need to convert them as:
* 1 -> 0, 4 -> 1, 8 -> 2, 16 -> 3.
*
* This can be done by finding most significant bit set.
*/
static inline unsigned int atmci_convert_chksize(unsigned int maxburst)
{
if (maxburst > 1)
return fls(maxburst) - 2;
else
return 0;
}
#endif /* __DRIVERS_MMC_ATMEL_MCI_H__ */

8
drivers/mmc/host/atmel-mci.c
View File

@ -910,6 +910,7 @@ atmci_prepare_data_dma(struct atmel_mci *host, struct mmc_data *data)
enum dma_data_direction direction;
enum dma_transfer_direction slave_dirn;
unsigned int sglen;
u32 maxburst;
u32 iflags;
data->error = -EINPROGRESS;
@ -943,17 +944,18 @@ atmci_prepare_data_dma(struct atmel_mci *host, struct mmc_data *data)
if (!chan)
return -ENODEV;
if (host->caps.has_dma)
atmci_writel(host, ATMCI_DMA, ATMCI_DMA_CHKSIZE(3) | ATMCI_DMAEN);
if (data->flags & MMC_DATA_READ) {
direction = DMA_FROM_DEVICE;
host->dma_conf.direction = slave_dirn = DMA_DEV_TO_MEM;
maxburst = atmci_convert_chksize(host->dma_conf.src_maxburst);
} else {
direction = DMA_TO_DEVICE;
host->dma_conf.direction = slave_dirn = DMA_MEM_TO_DEV;
maxburst = atmci_convert_chksize(host->dma_conf.dst_maxburst);
}
atmci_writel(host, ATMCI_DMA, ATMCI_DMA_CHKSIZE(maxburst) | ATMCI_DMAEN);
sglen = dma_map_sg(chan->device->dev, data->sg,
data->sg_len, direction);