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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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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
+41
-3
+39
-3
drivers/dma/at_xdmac.c
+39
-3
drivers/dma/at_xdmac.c
···
176
176
#define AT_XDMAC_MAX_CHAN 0x20
177
177
#define AT_XDMAC_MAX_CSIZE 16 /* 16 data */
178
178
#define AT_XDMAC_MAX_DWIDTH 8 /* 64 bits */
179
+
#define AT_XDMAC_RESIDUE_MAX_RETRIES 5
179
180
180
181
#define AT_XDMAC_DMA_BUSWIDTHS\
181
182
(BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) |\
···
1396
1395
struct at_xdmac_desc *desc, *_desc;
1397
1396
struct list_head *descs_list;
1398
1397
enum dma_status ret;
1399
-
int residue;
1400
-
u32 cur_nda, mask, value;
1398
+
int residue, retry;
1399
+
u32 cur_nda, check_nda, cur_ubc, mask, value;
1401
1400
u8 dwidth = 0;
1402
1401
unsigned long flags;
1403
1402
···
1434
1433
cpu_relax();
1435
1434
}
1436
1435
1436
+
/*
1437
+
* When processing the residue, we need to read two registers but we
1438
+
* can't do it in an atomic way. AT_XDMAC_CNDA is used to find where
1439
+
* we stand in the descriptor list and AT_XDMAC_CUBC is used
1440
+
* to know how many data are remaining for the current descriptor.
1441
+
* Since the dma channel is not paused to not loose data, between the
1442
+
* AT_XDMAC_CNDA and AT_XDMAC_CUBC read, we may have change of
1443
+
* descriptor.
1444
+
* For that reason, after reading AT_XDMAC_CUBC, we check if we are
1445
+
* still using the same descriptor by reading a second time
1446
+
* AT_XDMAC_CNDA. If AT_XDMAC_CNDA has changed, it means we have to
1447
+
* read again AT_XDMAC_CUBC.
1448
+
* Memory barriers are used to ensure the read order of the registers.
1449
+
* A max number of retries is set because unlikely it can never ends if
1450
+
* we are transferring a lot of data with small buffers.
1451
+
*/
1437
1452
cur_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;
1453
+
rmb();
1454
+
cur_ubc = at_xdmac_chan_read(atchan, AT_XDMAC_CUBC);
1455
+
for (retry = 0; retry < AT_XDMAC_RESIDUE_MAX_RETRIES; retry++) {
1456
+
rmb();
1457
+
check_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;
1458
+
1459
+
if (likely(cur_nda == check_nda))
1460
+
break;
1461
+
1462
+
cur_nda = check_nda;
1463
+
rmb();
1464
+
cur_ubc = at_xdmac_chan_read(atchan, AT_XDMAC_CUBC);
1465
+
}
1466
+
1467
+
if (unlikely(retry >= AT_XDMAC_RESIDUE_MAX_RETRIES)) {
1468
+
ret = DMA_ERROR;
1469
+
goto spin_unlock;
1470
+
}
1471
+
1438
1472
/*
1439
1473
* Remove size of all microblocks already transferred and the current
1440
1474
* one. Then add the remaining size to transfer of the current
···
1482
1446
if ((desc->lld.mbr_nda & 0xfffffffc) == cur_nda)
1483
1447
break;
1484
1448
}
1485
-
residue += at_xdmac_chan_read(atchan, AT_XDMAC_CUBC) << dwidth;
1449
+
residue += cur_ubc << dwidth;
1486
1450
1487
1451
dma_set_residue(txstate, residue);
1488
1452