[PATCH 13/18] ioat3: support xor via pq descriptors

Dan Williams
2009-09-04T06:46:44Z

If a platform advertises pq capabilities, but not xor, then use
ioat3_prep_pqxor and ioat3_prep_pqxor_val to simulate xor support.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/dma/ioat/dma_v3.c | 49 +++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 49 insertions(+), 0 deletions(-)

diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index ca2af0f..bb57491 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -766,6 +766,44 @@ ioat3_prep_pq_val(struct dma_chan *chan, dma_addr_t *pq, dma_addr_t *src,
flags);
}

+static struct dma_async_tx_descriptor *
+ioat3_prep_pqxor(struct dma_chan *chan, dma_addr_t dst, dma_addr_t *src,
+ unsigned int src_cnt, size_t len, unsigned long flags)
+{
+ unsigned char scf[src_cnt];
+ dma_addr_t pq[2];
+
+ memset(scf, 0, src_cnt);
+ flags |= DMA_PREP_PQ_DISABLE_Q;
+ pq[0] = dst;
+ pq[1] = ~0;
+
+ return __ioat3_prep_pq_lock(chan, NULL, pq, src, src_cnt, scf, len,
+ flags);
+}
+
+struct dma_async_tx_descriptor *
+ioat3_prep_pqxor_val(struct dma_chan *chan, dma_addr_t *src,
+ unsigned int src_cnt, size_t len,
+ enum sum_check_flags *result, unsigned long flags)
+{
+ unsigned char scf[src_cnt];
+ dma_addr_t pq[2];
+
+ /* the cleanup routine only sets bits on validate failure, it
+ * does not clear bits on validate success... so clear it here
+ */
+ *result = 0;
+
+ memset(scf, 0, src_cnt);
+ flags |= DMA_PREP_PQ_DISABLE_Q;
+ pq[0] = src[0];
+ pq[1] = ~0;
+
+ return __ioat3_prep_pq_lock(chan, result, pq, &src[1], src_cnt - 1, scf,
+ len, flags);
+}
+
static void __devinit ioat3_dma_test_callback(void *dma_async_param)
{
struct completion *cmp = dma_async_param;
@@ -1084,6 +1122,17 @@ int __devinit ioat3_dma_probe(struct ioatdma_device *device, int dca)

dma_cap_set(DMA_PQ_VAL, dma->cap_mask);
dma->device_prep_dma_pq_val = ioat3_prep_pq_val;
+
+ if (!(cap & IOAT_CAP_XOR)) {
+ dma->max_xor = 8;
+ dma->xor_align = 2;
+
+ dma_cap_set(DMA_XOR, dma->cap_mask);
+ dma->device_prep_dma_xor = ioat3_prep_pqxor;
+
+ dma_cap_set(DMA_XOR_VAL, dma->cap_mask);
+ dma->device_prep_dma_xor_val = ioat3_prep_pqxor_val;
+ }
}

/* -= IOAT ver.3 workarounds =- */