Hi,
On Wed, May 16 2012, ludovic.desroches@xxxxxxxxx wrote:
> 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(-)
This doesn't apply:
> 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);
> -
.. because mainline actually looks like:
if (host->caps.has_dma)
atmci_writel(host, ATMCI_DMA, ATMCI_DMA_CHKSIZE(3) | ATMCI_DMAEN);
and has done since 2011-08-11. Maybe this was created against the wrong
kernel version -- want to resend?
> 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);
Thanks,
- Chris.
--
Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/>
One Laptop Per Child
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