[PATCH 12/18] ioat3: pq support

Dan Williams
2009-09-04T06:46:06Z

ioat3.2 adds support for raid6 syndrome generation (xor sum of galois
field multiplication products) using up to 8 sources. It can also
perform an pq-zero-sum operation to validate whether the syndrome for a
given set of sources matches a previously computed syndrome.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/dma/ioat/dma_v3.c | 265 +++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 264 insertions(+), 1 deletions(-)

diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index 927c08b..ca2af0f 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -69,10 +69,12 @@
#define src_cnt_to_hw(x) ((x) - 2)

/* provide a lookup table for setting the source address in the base or
- * extended descriptor of an xor descriptor
+ * extended descriptor of an xor or pq descriptor
*/
static const u8 xor_idx_to_desc __read_mostly = 0xd0;
static const u8 xor_idx_to_field[] __read_mostly = { 1, 4, 5, 6, 7, 0, 1, 2 };
+static const u8 pq_idx_to_desc __read_mostly = 0xf8;
+static const u8 pq_idx_to_field[] __read_mostly = { 1, 4, 5, 0, 1, 2, 4, 5 };

static dma_addr_t xor_get_src(struct ioat_raw_descriptor *descs[2], int idx)
{
@@ -89,6 +91,23 @@ static void xor_set_src(struct ioat_raw_descriptor *descs[2],
raw->field[xor_idx_to_field[idx]] = addr + offset;
}

+static dma_addr_t pq_get_src(struct ioat_raw_descriptor *descs[2], int idx)
+{
+ struct ioat_raw_descriptor *raw = descs[pq_idx_to_desc >> idx & 1];
+
+ return raw->field[pq_idx_to_field[idx]];
+}
+
+static void pq_set_src(struct ioat_raw_descriptor *descs[2],
+ dma_addr_t addr, u32 offset, u8 coef, int idx)
+{
+ struct ioat_pq_descriptor *pq = (struct ioat_pq_descriptor *) descs[0];
+ struct ioat_raw_descriptor *raw = descs[pq_idx_to_desc >> idx & 1];
+
+ raw->field[pq_idx_to_field[idx]] = addr + offset;
+ pq->coef[idx] = coef;
+}
+
static void ioat3_dma_unmap(struct ioat2_dma_chan *ioat,
struct ioat_ring_ent *desc, int idx)
{
@@ -148,6 +167,58 @@ static void ioat3_dma_unmap(struct ioat2_dma_chan *ioat,
PCI_DMA_FROMDEVICE, flags, 1);
break;
}
+ case IOAT_OP_PQ_VAL:
+ case IOAT_OP_PQ: {
+ struct ioat_pq_descriptor *pq = desc->pq;
+ struct ioat_ring_ent *ext;
+ struct ioat_pq_ext_descriptor *pq_ex = NULL;
+ int src_cnt = src_cnt_to_sw(pq->ctl_f.src_cnt);
+ struct ioat_raw_descriptor *descs[2];
+ int i;
+
+ if (src_cnt > 3) {
+ ext = ioat2_get_ring_ent(ioat, idx + 1);
+ pq_ex = ext->pq_ex;
+ }
+
+ /* in the 'continue' case don't unmap the dests as sources */
+ if (dmaf_p_disabled_continue(flags))
+ src_cnt--;
+ else if (dmaf_continue(flags))
+ src_cnt -= 3;
+
+ if (!(flags & DMA_COMPL_SKIP_SRC_UNMAP)) {
+ descs[0] = (struct ioat_raw_descriptor *) pq;
+ descs[1] = (struct ioat_raw_descriptor *) pq_ex;
+ for (i = 0; i < src_cnt; i++) {
+ dma_addr_t src = pq_get_src(descs, i);
+
+ ioat_unmap(pdev, src - offset, len,
+ PCI_DMA_TODEVICE, flags, 0);
+ }
+
+ /* the dests are sources in pq validate operations */
+ if (pq->ctl_f.op == IOAT_OP_XOR_VAL) {
+ if (!(flags & DMA_PREP_PQ_DISABLE_P))
+ ioat_unmap(pdev, pq->p_addr - offset,
+ len, PCI_DMA_TODEVICE, flags, 0);
+ if (!(flags & DMA_PREP_PQ_DISABLE_Q))
+ ioat_unmap(pdev, pq->q_addr - offset,
+ len, PCI_DMA_TODEVICE, flags, 0);
+ break;
+ }
+ }
+
+ if (!(flags & DMA_COMPL_SKIP_DEST_UNMAP)) {
+ if (!(flags & DMA_PREP_PQ_DISABLE_P))
+ ioat_unmap(pdev, pq->p_addr - offset, len,
+ PCI_DMA_BIDIRECTIONAL, flags, 1);
+ if (!(flags & DMA_PREP_PQ_DISABLE_Q))
+ ioat_unmap(pdev, pq->q_addr - offset, len,
+ PCI_DMA_BIDIRECTIONAL, flags, 1);
+ }
+ break;
+ }
default:
dev_err(&pdev->dev, "%s: unknown op type: %#x\n",
__func__, desc->hw->ctl_f.op);
@@ -164,6 +235,12 @@ static bool desc_has_ext(struct ioat_ring_ent *desc)

if (src_cnt_to_sw(xor->ctl_f.src_cnt) > 5)
return true;
+ } else if (hw->ctl_f.op == IOAT_OP_PQ ||
+ hw->ctl_f.op == IOAT_OP_PQ_VAL) {
+ struct ioat_pq_descriptor *pq = desc->pq;
+
+ if (src_cnt_to_sw(pq->ctl_f.src_cnt) > 3)
+ return true;
}

return false;
@@ -513,6 +590,182 @@ ioat3_prep_xor_val(struct dma_chan *chan, dma_addr_t *src,
src_cnt - 1, len, flags);
}

+static void
+dump_pq_desc_dbg(struct ioat2_dma_chan *ioat, struct ioat_ring_ent *desc, struct ioat_ring_ent *ext)
+{
+ struct device *dev = to_dev(&ioat->base);
+ struct ioat_pq_descriptor *pq = desc->pq;
+ struct ioat_pq_ext_descriptor *pq_ex = ext ? ext->pq_ex : NULL;
+ struct ioat_raw_descriptor *descs[] = { (void *) pq, (void *) pq_ex };
+ int src_cnt = src_cnt_to_sw(pq->ctl_f.src_cnt);
+ int i;
+
+ dev_dbg(dev, "desc[%d]: (%#llx->%#llx) flags: %#x"
+ " sz: %#x ctl: %#x (op: %d int: %d compl: %d pq: '%s%s' src_cnt: %d)\n",
+ desc_id(desc), (unsigned long long) desc->txd.phys,
+ (unsigned long long) (pq_ex ? pq_ex->next : pq->next),
+ desc->txd.flags, pq->size, pq->ctl, pq->ctl_f.op, pq->ctl_f.int_en,
+ pq->ctl_f.compl_write,
+ pq->ctl_f.p_disable ? "" : "p", pq->ctl_f.q_disable ? "" : "q",
+ pq->ctl_f.src_cnt);
+ for (i = 0; i < src_cnt; i++)
+ dev_dbg(dev, "\tsrc[%d]: %#llx coef: %#x\n", i,
+ (unsigned long long) pq_get_src(descs, i), pq->coef[i]);
+ dev_dbg(dev, "\tP: %#llx\n", pq->p_addr);
+ dev_dbg(dev, "\tQ: %#llx\n", pq->q_addr);
+}
+
+static struct dma_async_tx_descriptor *
+__ioat3_prep_pq_lock(struct dma_chan *c, enum sum_check_flags *result,
+ const dma_addr_t *dst, const dma_addr_t *src,
+ unsigned int src_cnt, const unsigned char *scf,
+ size_t len, unsigned long flags)
+{
+ struct ioat2_dma_chan *ioat = to_ioat2_chan(c);
+ struct ioat_chan_common *chan = &ioat->base;
+ struct ioat_ring_ent *compl_desc;
+ struct ioat_ring_ent *desc;
+ struct ioat_ring_ent *ext;
+ size_t total_len = len;
+ struct ioat_pq_descriptor *pq;
+ struct ioat_pq_ext_descriptor *pq_ex = NULL;
+ struct ioat_dma_descriptor *hw;
+ u32 offset = 0;
+ int num_descs;
+ int with_ext;
+ int i, s;
+ u16 idx;
+ u8 op = result ? IOAT_OP_PQ_VAL : IOAT_OP_PQ;
+
+ dev_dbg(to_dev(chan), "%s\n", __func__);
+ /* the engine requires at least two sources (we provide
+ * at least 1 implied source in the DMA_PREP_CONTINUE case)
+ */
+ BUG_ON(src_cnt + dmaf_continue(flags) < 2);
+
+ num_descs = ioat2_xferlen_to_descs(ioat, len);
+ /* we need 2x the number of descriptors to cover greater than 3
+ * sources
+ */
+ if (src_cnt > 3 || flags & DMA_PREP_CONTINUE) {
+ with_ext = 1;
+ num_descs *= 2;
+ } else
+ with_ext = 0;
+
+ /* completion writes from the raid engine may pass completion
+ * writes from the legacy engine, so we need one extra null
+ * (legacy) descriptor to ensure all completion writes arrive in
+ * order.
+ */
+ if (likely(num_descs) &&
+ ioat2_alloc_and_lock(&idx, ioat, num_descs+1) == 0)
+ /* pass */;
+ else
+ return NULL;
+ for (i = 0; i < num_descs; i += 1 + with_ext) {
+ struct ioat_raw_descriptor *descs[2];
+ size_t xfer_size = min_t(size_t, len, 1 << ioat->xfercap_log);
+
+ desc = ioat2_get_ring_ent(ioat, idx + i);
+ pq = desc->pq;
+
+ /* save a branch by unconditionally retrieving the
+ * extended descriptor pq_set_src() knows to not write
+ * to it in the single descriptor case
+ */
+ ext = ioat2_get_ring_ent(ioat, idx + i + with_ext);
+ pq_ex = ext->pq_ex;
+
+ descs[0] = (struct ioat_raw_descriptor *) pq;
+ descs[1] = (struct ioat_raw_descriptor *) pq_ex;
+
+ for (s = 0; s < src_cnt; s++)
+ pq_set_src(descs, src[s], offset, scf[s], s);
+
+ /* see the comment for dma_maxpq in include/linux/dmaengine.h */
+ if (dmaf_p_disabled_continue(flags))
+ pq_set_src(descs, dst[1], offset, 1, s++);
+ else if (dmaf_continue(flags)) {
+ pq_set_src(descs, dst[0], offset, 0, s++);
+ pq_set_src(descs, dst[1], offset, 1, s++);
+ pq_set_src(descs, dst[1], offset, 0, s++);
+ }
+ pq->size = xfer_size;
+ pq->p_addr = dst[0] + offset;
+ pq->q_addr = dst[1] + offset;
+ pq->ctl = 0;
+ pq->ctl_f.op = op;
+ pq->ctl_f.src_cnt = src_cnt_to_hw(s);
+ pq->ctl_f.p_disable = !!(flags & DMA_PREP_PQ_DISABLE_P);
+ pq->ctl_f.q_disable = !!(flags & DMA_PREP_PQ_DISABLE_Q);
+
+ len -= xfer_size;
+ offset += xfer_size;
+ }
+
+ /* last pq descriptor carries the unmap parameters and fence bit */
+ desc->txd.flags = flags;
+ desc->len = total_len;
+ if (result)
+ desc->result = result;
+ pq->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
+ dump_pq_desc_dbg(ioat, desc, ext);
+
+ /* completion descriptor carries interrupt bit */
+ compl_desc = ioat2_get_ring_ent(ioat, idx + i);
+ compl_desc->txd.flags = flags & DMA_PREP_INTERRUPT;
+ hw = compl_desc->hw;
+ hw->ctl = 0;
+ hw->ctl_f.null = 1;
+ hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
+ hw->ctl_f.compl_write = 1;
+ hw->size = NULL_DESC_BUFFER_SIZE;
+ dump_desc_dbg(ioat, compl_desc);
+
+ /* we leave the channel locked to ensure in order submission */
+ return &desc->txd;
+}
+
+static struct dma_async_tx_descriptor *
+ioat3_prep_pq(struct dma_chan *chan, dma_addr_t *dst, dma_addr_t *src,
+ unsigned int src_cnt, const unsigned char *scf, size_t len,
+ unsigned long flags)
+{
+ /* handle the single source multiply case from the raid6
+ * recovery path
+ */
+ if (unlikely((flags & DMA_PREP_PQ_DISABLE_P) && src_cnt == 1)) {
+ dma_addr_t single_source[2];
+ unsigned char single_source_coef[2];
+
+ BUG_ON(flags & DMA_PREP_PQ_DISABLE_Q);
+ single_source[0] = src[0];
+ single_source[1] = src[0];
+ single_source_coef[0] = scf[0];
+ single_source_coef[1] = 0;
+
+ return __ioat3_prep_pq_lock(chan, NULL, dst, single_source, 2,
+ single_source_coef, len, flags);
+ } else
+ return __ioat3_prep_pq_lock(chan, NULL, dst, src, src_cnt, scf,
+ len, flags);
+}
+
+struct dma_async_tx_descriptor *
+ioat3_prep_pq_val(struct dma_chan *chan, dma_addr_t *pq, dma_addr_t *src,
+ unsigned int src_cnt, const unsigned char *scf, size_t len,
+ enum sum_check_flags *pqres, unsigned long flags)
+{
+ /* the cleanup routine only sets bits on validate failure, it
+ * does not clear bits on validate success... so clear it here
+ */
+ *pqres = 0;
+
+ return __ioat3_prep_pq_lock(chan, pqres, pq, src, src_cnt, scf, len,
+ flags);
+}
+
static void __devinit ioat3_dma_test_callback(void *dma_async_param)
{
struct completion *cmp = dma_async_param;
@@ -822,6 +1075,16 @@ int __devinit ioat3_dma_probe(struct ioatdma_device *device, int dca)
dma_cap_set(DMA_XOR_VAL, dma->cap_mask);
dma->device_prep_dma_xor_val = ioat3_prep_xor_val;
}
+ if (cap & IOAT_CAP_PQ) {
+ dma_set_maxpq(dma, 8, 0);
+ dma->pq_align = 2;
+
+ dma_cap_set(DMA_PQ, dma->cap_mask);
+ dma->device_prep_dma_pq = ioat3_prep_pq;
+
+ dma_cap_set(DMA_PQ_VAL, dma->cap_mask);
+ dma->device_prep_dma_pq_val = ioat3_prep_pq_val;
+ }

/* -= IOAT ver.3 workarounds =- */
/* Write CHANERRMSK_INT with 3E07h to mask out the errors