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authorDan Williams <dan.j.williams@intel.com>2008-11-11 15:12:33 -0500
committerDan Williams <dan.j.williams@intel.com>2008-11-11 15:12:33 -0500
commit137cb55c6dcd56cb367285adaf15f808a2a9fec7 (patch)
tree4828887b960a451d7ab09a4250b472a2a9f97884 /drivers/dma/iop-adma.c
parentf21f237cf55494c3a4209de323281a3b0528da10 (diff)
iop-adma: add a dummy read to flush next descriptor update
The current dummy read references the wrong address allowing the next descriptor address update to linger in the store buffer and get passed by an 'append' event. This issue was uncovered by the change from strongly-ordered to device memory for the adma registers. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/dma/iop-adma.c')
-rw-r--r--drivers/dma/iop-adma.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/dma/iop-adma.c b/drivers/dma/iop-adma.c
index 71fba82462cb..95f5a9466816 100644
--- a/drivers/dma/iop-adma.c
+++ b/drivers/dma/iop-adma.c
@@ -411,6 +411,7 @@ iop_adma_tx_submit(struct dma_async_tx_descriptor *tx)
411 int slot_cnt; 411 int slot_cnt;
412 int slots_per_op; 412 int slots_per_op;
413 dma_cookie_t cookie; 413 dma_cookie_t cookie;
414 dma_addr_t next_dma;
414 415
415 grp_start = sw_desc->group_head; 416 grp_start = sw_desc->group_head;
416 slot_cnt = grp_start->slot_cnt; 417 slot_cnt = grp_start->slot_cnt;
@@ -425,11 +426,11 @@ iop_adma_tx_submit(struct dma_async_tx_descriptor *tx)
425 &old_chain_tail->chain_node); 426 &old_chain_tail->chain_node);
426 427
427 /* fix up the hardware chain */ 428 /* fix up the hardware chain */
428 iop_desc_set_next_desc(old_chain_tail, grp_start->async_tx.phys); 429 next_dma = grp_start->async_tx.phys;
430 iop_desc_set_next_desc(old_chain_tail, next_dma);
431 BUG_ON(iop_desc_get_next_desc(old_chain_tail) != next_dma); /* flush */
429 432
430 /* 1/ don't add pre-chained descriptors 433 /* check for pre-chained descriptors */
431 * 2/ dummy read to flush next_desc write
432 */
433 BUG_ON(iop_desc_get_next_desc(sw_desc)); 434 BUG_ON(iop_desc_get_next_desc(sw_desc));
434 435
435 /* increment the pending count by the number of slots 436 /* increment the pending count by the number of slots