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authorLinus Torvalds <torvalds@linux-foundation.org>2016-03-11 10:57:18 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-11 10:57:18 -0800
commit20698c922f81047c4d45c7793b7ddce8ff58d10e (patch)
treea24d1fe48615fcf2e33c4136c92b208d624d42f1
parent7ae9c768e19ec8ce1b397a5c4abf88f9ee053e09 (diff)
parent25c5e9626ca4d40928dc9c44f009ce2ed0a739e7 (diff)
downloadlinux-sh-20698c922f81047c4d45c7793b7ddce8ff58d10e.tar.gz
Merge tag 'dmaengine-fix-4.5' of git://git.infradead.org/users/vkoul/slave-dma
Pull dmaengine fixes from Vinod Koul: "Two fixes showed up in last few days, and they should be included in 4.5. Summary: Two more late fixes to drivers, nothing major here: - A memory leak fix in fsdma unmap the dma descriptors on freeup - A fix in xdmac driver for residue calculation of dma descriptor" * tag 'dmaengine-fix-4.5' of git://git.infradead.org/users/vkoul/slave-dma: dmaengine: at_xdmac: fix residue computation dmaengine: fsldma: fix memory leak
-rw-r--r--drivers/dma/at_xdmac.c42
-rw-r--r--drivers/dma/fsldma.c2
2 files changed, 41 insertions, 3 deletions
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index 64f5d1bdbb48..8e304b1befc5 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -176,6 +176,7 @@
#define AT_XDMAC_MAX_CHAN 0x20
#define AT_XDMAC_MAX_CSIZE 16 /* 16 data */
#define AT_XDMAC_MAX_DWIDTH 8 /* 64 bits */
+#define AT_XDMAC_RESIDUE_MAX_RETRIES 5
#define AT_XDMAC_DMA_BUSWIDTHS\
(BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) |\
@@ -1395,8 +1396,8 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
struct at_xdmac_desc *desc, *_desc;
struct list_head *descs_list;
enum dma_status ret;
- int residue;
- u32 cur_nda, mask, value;
+ int residue, retry;
+ u32 cur_nda, check_nda, cur_ubc, mask, value;
u8 dwidth = 0;
unsigned long flags;
@@ -1433,7 +1434,42 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
cpu_relax();
}
+ /*
+ * 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.
+ * 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.
+ */
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();
+ cur_ubc = at_xdmac_chan_read(atchan, AT_XDMAC_CUBC);
+ }
+
+ if (unlikely(retry >= AT_XDMAC_RESIDUE_MAX_RETRIES)) {
+ ret = DMA_ERROR;
+ goto spin_unlock;
+ }
+
/*
* Remove size of all microblocks already transferred and the current
* one. Then add the remaining size to transfer of the current
@@ -1446,7 +1482,7 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
if ((desc->lld.mbr_nda & 0xfffffffc) == cur_nda)
break;
}
- residue += at_xdmac_chan_read(atchan, AT_XDMAC_CUBC) << dwidth;
+ residue += cur_ubc << dwidth;
dma_set_residue(txstate, residue);
diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index 2209f75fdf05..aac85c30c2cf 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -522,6 +522,8 @@ static dma_cookie_t fsldma_run_tx_complete_actions(struct fsldma_chan *chan,
chan_dbg(chan, "LD %p callback\n", desc);
txd->callback(txd->callback_param);
}
+
+ dma_descriptor_unmap(txd);
}
/* Run any dependencies */