Commit 9af1f5d8 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'dmaengine-fix-4.7-rc4' of git://git.infradead.org/users/vkoul/slave-dma 

Pull dmaengine fixes from Vinod Koul:
 "Some fixes has piled up, so time to send them upstream.

  These fixes include:
   - at_xdmac fixes for residue and other stuff
   - update MAINTAINERS for dma dt bindings
   - mv_xor fix for incorrect offset"

* tag 'dmaengine-fix-4.7-rc4' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: mv_xor: Fix incorrect offset in dma_map_page()
  dmaengine: at_xdmac: double FIFO flush needed to compute residue
  dmaengine: at_xdmac: fix residue corruption
  dmaengine: at_xdmac: align descriptors on 64 bits
  MAINTAINERS: Add file patterns for dma device tree bindings
parents 049a40c0 51564635

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -3778,6 +3778,7 @@ Q: https://patchwork.kernel.org/project/linux-dmaengine/list/ 
S:	Maintained

F:	drivers/dma/

F:	include/linux/dmaengine.h

F:	Documentation/devicetree/bindings/dma/

F:	Documentation/dmaengine/

T:	git git://git.infradead.org/users/vkoul/slave-dma.git

drivers/dma/at_xdmac.c

+57 −25
Original line number Diff line number Diff line
@@ -242,7 +242,7 @@ struct at_xdmac_lld { 
	u32		mbr_dus;	/* Destination Microblock Stride Register */

};





/* 64-bit alignment needed to update CNDA and CUBC registers in an atomic way. */

struct at_xdmac_desc {

	struct at_xdmac_lld		lld;

	enum dma_transfer_direction	direction;
@@ -253,7 +253,7 @@ struct at_xdmac_desc { 
	unsigned int			xfer_size;

	struct list_head		descs_list;

	struct list_head		xfer_node;

};

} __aligned(sizeof(u64));



static inline void __iomem *at_xdmac_chan_reg_base(struct at_xdmac *atxdmac, unsigned int chan_nb)

{
@@ -1400,6 +1400,7 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, 
	u32			cur_nda, check_nda, cur_ubc, mask, value;

	u8			dwidth = 0;

	unsigned long		flags;

	bool			initd;



	ret = dma_cookie_status(chan, cookie, txstate);

	if (ret == DMA_COMPLETE)
@@ -1424,7 +1425,16 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, 
	residue = desc->xfer_size;

	/*

	 * Flush FIFO: only relevant when the transfer is source peripheral

	 * synchronized.

	 * synchronized. Flush is needed before reading CUBC because data in

	 * the FIFO are not reported by CUBC. Reporting a residue of the

	 * transfer length while we have data in FIFO can cause issue.

	 * Usecase: atmel USART has a timeout which means I have received

	 * characters but there is no more character received for a while. On

	 * timeout, it requests the residue. If the data are in the DMA FIFO,

	 * we will return a residue of the transfer length. It means no data

	 * received. If an application is waiting for these data, it will hang

	 * since we won't have another USART timeout without receiving new

	 * data.

	 */

	mask = AT_XDMAC_CC_TYPE | AT_XDMAC_CC_DSYNC;

	value = AT_XDMAC_CC_TYPE_PER_TRAN | AT_XDMAC_CC_DSYNC_PER2MEM;
@@ -1435,34 +1445,43 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, 
	}



	/*

	 * When processing the residue, we need to read two registers but we

	 * can't do it in an atomic way. AT_XDMAC_CNDA is used to find where

	 * we stand in the descriptor list and AT_XDMAC_CUBC is used

	 * to know how many data are remaining for the current descriptor.

	 * Since the dma channel is not paused to not loose data, between the

	 * AT_XDMAC_CNDA and AT_XDMAC_CUBC read, we may have change of

	 * descriptor.

	 * For that reason, after reading AT_XDMAC_CUBC, we check if we are

	 * still using the same descriptor by reading a second time

	 * AT_XDMAC_CNDA. If AT_XDMAC_CNDA has changed, it means we have to

	 * read again AT_XDMAC_CUBC.

	 * The easiest way to compute the residue should be to pause the DMA

	 * but doing this can lead to miss some data as some devices don't

	 * have FIFO.

	 * We need to read several registers because:

	 * - DMA is running therefore a descriptor change is possible while

	 * reading these registers

	 * - When the block transfer is done, the value of the CUBC register

	 * is set to its initial value until the fetch of the next descriptor.

	 * This value will corrupt the residue calculation so we have to skip

	 * it.

	 *

	 * INITD --------                    ------------

	 *              |____________________|

	 *       _______________________  _______________

	 * NDA       @desc2             \/   @desc3

	 *       _______________________/\_______________

	 *       __________  ___________  _______________

	 * CUBC       0    \/ MAX desc1 \/  MAX desc2

	 *       __________/\___________/\_______________

	 *

	 * Since descriptors are aligned on 64 bits, we can assume that

	 * the update of NDA and CUBC is atomic.

	 * Memory barriers are used to ensure the read order of the registers.

	 * A max number of retries is set because unlikely it can never ends if

	 * we are transferring a lot of data with small buffers.

	 * A max number of retries is set because unlikely it could never ends.

	 */

	cur_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;

	for (retry = 0; retry < AT_XDMAC_RESIDUE_MAX_RETRIES; retry++) {

		check_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;

		rmb();

		initd = !!(at_xdmac_chan_read(atchan, AT_XDMAC_CC) & AT_XDMAC_CC_INITD);

		rmb();

		cur_ubc = at_xdmac_chan_read(atchan, AT_XDMAC_CUBC);

	for (retry = 0; retry < AT_XDMAC_RESIDUE_MAX_RETRIES; retry++) {

		rmb();

		check_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;

		cur_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;

		rmb();



		if (likely(cur_nda == check_nda))

		if ((check_nda == cur_nda) && initd)

			break;



		cur_nda = check_nda;

		rmb();

		cur_ubc = at_xdmac_chan_read(atchan, AT_XDMAC_CUBC);

	}



	if (unlikely(retry >= AT_XDMAC_RESIDUE_MAX_RETRIES)) {
@@ -1470,6 +1489,19 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, 
		goto spin_unlock;

	}



	/*

	 * Flush FIFO: only relevant when the transfer is source peripheral

	 * synchronized. Another flush is needed here because CUBC is updated

	 * when the controller sends the data write command. It can lead to

	 * report data that are not written in the memory or the device. The

	 * FIFO flush ensures that data are really written.

	 */

	if ((desc->lld.mbr_cfg & mask) == value) {

		at_xdmac_write(atxdmac, AT_XDMAC_GSWF, atchan->mask);

		while (!(at_xdmac_chan_read(atchan, AT_XDMAC_CIS) & AT_XDMAC_CIS_FIS))

			cpu_relax();

	}



	/*

	 * Remove size of all microblocks already transferred and the current

	 * one. Then add the remaining size to transfer of the current

drivers/dma/mv_xor.c

+6 −4
Original line number Diff line number Diff line
@@ -703,8 +703,9 @@ static int mv_chan_memcpy_self_test(struct mv_xor_chan *mv_chan) 
		goto free_resources;

	}



	src_dma = dma_map_page(dma_chan->device->dev, virt_to_page(src), 0,

				 PAGE_SIZE, DMA_TO_DEVICE);

	src_dma = dma_map_page(dma_chan->device->dev, virt_to_page(src),

			       (size_t)src & ~PAGE_MASK, PAGE_SIZE,

			       DMA_TO_DEVICE);

	unmap->addr[0] = src_dma;



	ret = dma_mapping_error(dma_chan->device->dev, src_dma);
@@ -714,8 +715,9 @@ static int mv_chan_memcpy_self_test(struct mv_xor_chan *mv_chan) 
	}

	unmap->to_cnt = 1;



	dest_dma = dma_map_page(dma_chan->device->dev, virt_to_page(dest), 0,

				  PAGE_SIZE, DMA_FROM_DEVICE);

	dest_dma = dma_map_page(dma_chan->device->dev, virt_to_page(dest),

				(size_t)dest & ~PAGE_MASK, PAGE_SIZE,

				DMA_FROM_DEVICE);

	unmap->addr[1] = dest_dma;



	ret = dma_mapping_error(dma_chan->device->dev, dest_dma);

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