Hi Olivier,
On Thu, Dec 05, 2013 at 10:45:16AM +0100, Olivier Sobrie wrote:
[...]
> With this patch I'm able to use the wlan sdio module wl1271.
> When you've time, it would be nice to validate or fix this
> patch.
I have tested it and it doesn't solve issue I have with Atheros module.
> Thanks for your help,
>
> Olivier
>
> drivers/mmc/host/atmel-mci.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
> index b86b482..c599731 100644
> --- a/drivers/mmc/host/atmel-mci.c
> +++ b/drivers/mmc/host/atmel-mci.c
> @@ -45,6 +45,7 @@
>
> #define ATMCI_DATA_ERROR_FLAGS (ATMCI_DCRCE | ATMCI_DTOE | ATMCI_OVRE | ATMCI_UNRE)
> #define ATMCI_DMA_THRESHOLD 16
> +#define ATMCI_PDC_MIN_DATASIZE 16
>
> enum {
> EVENT_CMD_RDY = 0,
> @@ -765,7 +766,10 @@ static void atmci_pdc_set_single_buf(struct atmel_mci *host,
> }
>
> if (host->data_size <= buf_size) {
> - if (host->data_size & 0x3) {
> + if ((host->data_size < ATMCI_PDC_MIN_DATASIZE) &&
> + (dir == XFER_TRANSMIT)) {
> + atmci_writel(host, counter_reg, 4);
> + } else if (host->data_size & 0x3) {
I have feedback from people who have issue with atmel-mci driver but not
with at91-mci which has been removed unfortunately (it seems I had the
only sdio wifi module working with atmel-mci driver in pdc mode...). So I
think the 12 bytes value in the errata is correct.
Moreover I am afraid that this patch could cause some other bugs. I mean the
transfer size is 4 bytes, the sg length is 4 bytes too and we will ask
PDC to perform a bigger transfer... With the previous driver it was not a
problem because we didn't use sg directly, they were copied into another
buffer.
Regards
Ludovic
> /* If size is different from modulo 4, transfer bytes */
> atmci_writel(host, counter_reg, host->data_size);
> atmci_writel(host, ATMCI_MR, host->mode_reg | ATMCI_MR_PDCFBYTE);
> --
> 1.7.9.5
>
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