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authorDan Williams <dan.j.williams@intel.com>2008-11-11 13:12:33 -0700
committerDan Williams <dan.j.williams@intel.com>2008-11-11 13:12:33 -0700
commit137cb55c6dcd56cb367285adaf15f808a2a9fec7 (patch)
tree4828887b960a451d7ab09a4250b472a2a9f97884 /drivers/dma
parentf21f237cf55494c3a4209de323281a3b0528da10 (diff)
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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')
-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)
int slot_cnt;
int slots_per_op;
dma_cookie_t cookie;
+ dma_addr_t next_dma;
grp_start = sw_desc->group_head;
slot_cnt = grp_start->slot_cnt;
@@ -425,11 +426,11 @@ iop_adma_tx_submit(struct dma_async_tx_descriptor *tx)
&old_chain_tail->chain_node);
/* fix up the hardware chain */
- iop_desc_set_next_desc(old_chain_tail, grp_start->async_tx.phys);
+ next_dma = grp_start->async_tx.phys;
+ iop_desc_set_next_desc(old_chain_tail, next_dma);
+ BUG_ON(iop_desc_get_next_desc(old_chain_tail) != next_dma); /* flush */
- /* 1/ don't add pre-chained descriptors
- * 2/ dummy read to flush next_desc write
- */
+ /* check for pre-chained descriptors */
BUG_ON(iop_desc_get_next_desc(sw_desc));
/* increment the pending count by the number of slots