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dmaengine fixes for 4.7-rc4

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This fixes include:
  - at_xdmac fixes for residue and other stuff
  - update MAINTAINERS for dma dt bindings
  - mv_xor fix for incorrect offset
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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
This commit is contained in:
Linus Torvalds 2016-06-19 06:52:20 -10:00
commit 9af1f5d8f2
3 changed files with 64 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
MAINTAINERS
View File

@ -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

82
drivers/dma/at_xdmac.c
View File

@ -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;
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;
if (likely(cur_nda == check_nda))
break;
cur_nda = check_nda;
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);
rmb();
cur_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;
rmb();
if ((check_nda == cur_nda) && initd)
break;
}
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

10
drivers/dma/mv_xor.c
View File

@ -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);