[PATCH] mmc: atmel-mci: fix burst/chunk size modification
From: ludovic.desroches at atmel.com <hidden>
Date: 2012-05-16 14:00:38
Also in:
linux-mmc
Subsystem:
microchip mmc/sd/sdio mci driver, multimedia card (mmc), secure digital (sd) and sdio subsystem, the rest · Maintainers:
Aubin Constans, Ulf Hansson, Linus Torvalds
From: Nicolas Ferre <redacted> 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 <redacted> Signed-off-by: Ludovic Desroches <redacted> --- 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