From: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
---
drivers/mmc/host/atmel-mci-regs.h | 14 ++++++++++++++
drivers/mmc/host/atmel-mci.c | 7 +++++--
2 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/host/atmel-mci-regs.h b/drivers/mmc/host/atmel-mci-regs.h
index 787aba1..ab56f7d 100644
--- a/drivers/mmc/host/atmel-mci-regs.h
+++ b/drivers/mmc/host/atmel-mci-regs.h
@@ -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__ */
diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 2dbfb28..50e8652 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -834,6 +834,7 @@ 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;
@@ -867,16 +868,18 @@ atmci_prepare_data_dma(struct atmel_mci *host, struct mmc_data *data)
if (!chan)
return -ENODEV;
- 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);
--
1.7.5.4
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