Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 03e8cb53 authored by James Hogan's avatar James Hogan Committed by Chris Ball
Browse files

mmc: dw_mmc: fix stop when fallen back to PIO 



There are several situations when dw_mci_submit_data_dma() decides to
fall back to PIO mode instead of using DMA, due to a short (to avoid
overhead) or "complex" (e.g. with unaligned buffers) transaction, even
though host->use_dma is set. However dw_mci_stop_dma() decides whether
to stop DMA or set the EVENT_XFER_COMPLETE event based on host->use_dma.
When falling back to PIO mode this results in data timeout errors
getting missed and the driver locking up.

Therefore add host->using_dma to indicate whether the current
transaction is using dma or not, and adjust dw_mci_stop_dma() to use
that instead.

Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Acked-by: default avatarWill Newton <will.newton@imgtec.com>
Tested-by: default avatarJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 65d13516

drivers/mmc/host/dw_mmc.c

+5 −1
Original line number Diff line number Diff line
@@ -287,7 +287,7 @@ static void send_stop_cmd(struct dw_mci *host, struct mmc_data *data) 
/* DMA interface functions */

static void dw_mci_stop_dma(struct dw_mci *host)

{

	if (host->use_dma) {

	if (host->using_dma) {

		host->dma_ops->stop(host);

		host->dma_ops->cleanup(host);

	} else {
@@ -435,6 +435,8 @@ static int dw_mci_submit_data_dma(struct dw_mci *host, struct mmc_data *data) 
	unsigned int i, direction, sg_len;

	u32 temp;



	host->using_dma = 0;



	/* If we don't have a channel, we can't do DMA */

	if (!host->use_dma)

		return -ENODEV;
@@ -454,6 +456,8 @@ static int dw_mci_submit_data_dma(struct dw_mci *host, struct mmc_data *data) 
			return -EINVAL;

	}



	host->using_dma = 1;



	if (data->flags & MMC_DATA_READ)

		direction = DMA_FROM_DEVICE;

	else

include/linux/mmc/dw_mmc.h

+2 −0
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ struct mmc_data; 
 * @data: The data currently being transferred, or NULL if no data

 *	transfer is in progress.

 * @use_dma: Whether DMA channel is initialized or not.

 * @using_dma: Whether DMA is in use for the current transfer.

 * @sg_dma: Bus address of DMA buffer.

 * @sg_cpu: Virtual address of DMA buffer.

 * @dma_ops: Pointer to platform-specific DMA callbacks.
@@ -121,6 +122,7 @@ struct dw_mci { 


	/* DMA interface members*/

	int			use_dma;

	int			using_dma;



	dma_addr_t		sg_dma;

	void			*sg_cpu;