Re: [PATCH v2 2/3] mmc: sdhci: add quirks for be to le byte swapping

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Adrian,

thanks for the feedbacks.

On Tue, Jul 02, 2019 at 12:10:44PM +0300, Adrian Hunter wrote:
On 16/06/19 11:48 PM, Angelo Dureghello wrote:
Some controller as the ColdFire eshdc may require an endianness
byte swap, because DMA read endianness is not configurable.

I would prefer something more generic, like adding another callback
for ->request_done() e.g.


diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index f56ae6f153d4..a63e528cb885 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2729,7 +2729,10 @@ static bool sdhci_request_done(struct sdhci_host *host)
 
 	spin_unlock_irqrestore(&host->lock, flags);
 
-	mmc_request_done(host->mmc, mrq);
+	if (host->ops->request_done)
+		host->ops->request_done(host, mrq);
+	else
+		mmc_request_done(host->mmc, mrq);
 
 	return false;
 }


Then you can use the ->request_done() callback to iterate over the data->sg
and make byte-swaps as needed.

Ok, good to know, will try.


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 59acf8e3331e..f56ae6f153d4 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2600,6 +2600,18 @@ 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                                                              *
@@ -2655,6 +2667,13 @@ 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);
+
 					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 199712e7adbb..be08ff1a8c6f 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -482,6 +482,13 @@ 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 */



Reagrds,
Angelo



[Index of Archives]     [Video for Linux]     [Yosemite News]     [Linux S/390]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux