Hi Adrian,
On Wed, Jun 12, 2019 at 09:42:27AM +0300, Adrian Hunter wrote:
On 12/05/19 10:41 PM, Angelo Dureghello wrote:
Some controller as the ColdFire eshdc may require an endianness
byte swap, becouse DMA read endianness is not configurable.
becouse -> because
ok
Do any other drivers have this issue?
host/mxcmmc.c for PPC devices is doing a similar swap (buffer_swap32).
Signed-off-by: Angelo Dureghello <angelo@xxxxxxxx>
---
drivers/mmc/host/sdhci.c | 19 +++++++++++++++++++
drivers/mmc/host/sdhci.h | 7 +++++++
2 files changed, 26 insertions(+)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 97158344b862..317dcfb4bb4c 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2592,6 +2592,18 @@ static const struct mmc_host_ops sdhci_ops = {
.card_busy = sdhci_card_busy,
};
+static void sdhci_be_to_le(char *buff, u32 length)
+{
+ int i, size = length >> 2;
+ u32 *buffer = (u32 *)buff;
+ u32 temp;
+
+ for (i = 0; i < size; i++) {
+ temp = *buffer;
+ *buffer++ = __le32_to_cpu(temp);
+ }
+}
+
/*****************************************************************************\
* *
* Request done *
@@ -2647,6 +2659,13 @@ static bool sdhci_request_done(struct sdhci_host *host)
host->bounce_addr,
host->bounce_buffer_size,
DMA_FROM_DEVICE);
+
+ if (host->quirks2 &
+ SDHCI_QUIRK2_USE_32BIT_BE_DMA_SWAP)
+ sdhci_be_to_le(
+ host->bounce_buffer,
+ length);
How come it only affects the bounce buffer? What about if there is no
bounce buffer?
Right, Will check where how to apply the swap also without bounce buffer.
+
sg_copy_from_buffer(data->sg,
data->sg_len,
host->bounce_buffer,
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index d6bcc584c92b..38fa69678cec 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -486,6 +486,13 @@ struct sdhci_host {
*/
#define SDHCI_QUIRK2_USE_32BIT_BLK_CNT (1<<18)
+/*
+ * On some architectures, as ColdFire/m68k, native endianness is big endian,
+ * and the dma buffer is filled in big endian order only (no other options).
+ * So, a swap is needed for these specific cases.
+ */
+#define SDHCI_QUIRK2_USE_32BIT_BE_DMA_SWAP (1<<19)
+
int irq; /* Device IRQ */
void __iomem *ioaddr; /* Mapped address */
char *bounce_buffer; /* For packing SDMA reads/writes */
Regards,
Angelo
