This can now be supported even for devices that complete operations out
of order. Add support for directly polling transactions.
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Signed-off-by: Ben Walker <benjamin.walker@xxxxxxxxx>
---
drivers/dma/idxd/device.c | 1 +
drivers/dma/idxd/dma.c | 85 ++++++++++++++++++++++++++++++++++++++-
drivers/dma/idxd/idxd.h | 1 +
3 files changed, 85 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 5a8cc52c1abfd..752544bef4551 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -148,6 +148,7 @@ int idxd_wq_alloc_resources(struct idxd_wq *wq)
desc->iax_completion = &wq->iax_compls[i];
desc->compl_dma = wq->compls_addr + idxd->data->compl_size * i;
desc->id = i;
+ desc->gen = 1;
desc->wq = wq;
desc->cpu = -1;
}
diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
index e0874cb4721c8..dda5342d273f4 100644
--- a/drivers/dma/idxd/dma.c
+++ b/drivers/dma/idxd/dma.c
@@ -12,6 +12,23 @@
#include "registers.h"
#include "idxd.h"
+
+#define DMA_COOKIE_BITS (sizeof(dma_cookie_t) * 8)
+/*
+ * The descriptor id takes the lower 16 bits of the cookie.
+ */
+#define DESC_ID_BITS 16
+#define DESC_ID_MASK ((1 << DESC_ID_BITS) - 1)
+/*
+ * The 'generation' is in the upper half of the cookie. But dma_cookie_t
+ * is signed, so we leave the upper-most bit for the sign. Further, we
+ * need to flag whether a cookie corresponds to an operation that is
+ * being completed via interrupt to avoid polling it, which takes
+ * the second most upper bit. So we subtract two bits from the upper half.
+ */
+#define DESC_GEN_MAX ((1 << (DMA_COOKIE_BITS - DESC_ID_BITS - 2)) - 1)
+#define DESC_INTERRUPT_FLAG (1 << (DMA_COOKIE_BITS - 2))
+
static inline struct idxd_wq *to_idxd_wq(struct dma_chan *c)
{
struct idxd_dma_chan *idxd_chan;
@@ -158,13 +175,67 @@ static void idxd_dma_free_chan_resources(struct dma_chan *chan)
idxd_wq_refcount(wq));
}
+
static enum dma_status idxd_dma_tx_status(struct dma_chan *dma_chan,
dma_cookie_t cookie,
struct dma_tx_state *txstate)
{
- return DMA_OUT_OF_ORDER;
+ u8 status;
+ struct idxd_wq *wq;
+ struct idxd_desc *desc;
+ u32 idx;
+
+ memset(txstate, 0, sizeof(*txstate));
+
+ if (dma_submit_error(cookie))
+ return DMA_ERROR;
+
+ wq = to_idxd_wq(dma_chan);
+
+ idx = cookie & DESC_ID_MASK;
+ if (idx >= wq->num_descs)
+ return DMA_ERROR;
+
+ desc = wq->descs[idx];
+
+ if (desc->txd.cookie != cookie) {
+ /*
+ * The user asked about an old transaction
+ */
+ return DMA_COMPLETE;
+ }
+
+ /*
+ * For descriptors completed via interrupt, we can't go
+ * look at the completion status directly because it races
+ * with the IRQ handler recyling the descriptor. However,
+ * since in this case we can rely on the interrupt handler
+ * to invalidate the cookie when the command completes we
+ * know that if we get here, the command is still in
+ * progress.
+ */
+ if ((cookie & DESC_INTERRUPT_FLAG) != 0)
+ return DMA_IN_PROGRESS;
+
+ status = desc->completion->status & DSA_COMP_STATUS_MASK;
+
+ if (status) {
+ /*
+ * Check against the original status as ABORT is software defined
+ * and 0xff, which DSA_COMP_STATUS_MASK can mask out.
+ */
+ if (unlikely(desc->completion->status == IDXD_COMP_DESC_ABORT))
+ idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, true);
+ else
+ idxd_dma_complete_txd(desc, IDXD_COMPLETE_NORMAL, true);
+
+ return DMA_COMPLETE;
+ }
+
+ return DMA_IN_PROGRESS;
}
+
/*
* issue_pending() does not need to do anything since tx_submit() does the job
* already.
@@ -181,7 +252,17 @@ static dma_cookie_t idxd_dma_tx_submit(struct dma_async_tx_descriptor *tx)
int rc;
struct idxd_desc *desc = container_of(tx, struct idxd_desc, txd);
- cookie = dma_cookie_assign(tx);
+ cookie = (desc->gen << DESC_ID_BITS) | (desc->id & DESC_ID_MASK);
+
+ if ((desc->hw->flags & IDXD_OP_FLAG_RCI) != 0)
+ cookie |= DESC_INTERRUPT_FLAG;
+
+ if (desc->gen == DESC_GEN_MAX)
+ desc->gen = 1;
+ else
+ desc->gen++;
+
+ tx->cookie = cookie;
rc = idxd_submit_desc(wq, desc);
if (rc < 0) {
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index bd93ada32c89d..d4f0227895075 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -326,6 +326,7 @@ struct idxd_desc {
struct llist_node llnode;
struct list_head list;
u16 id;
+ u16 gen;
int cpu;
struct idxd_wq *wq;
};
--
2.37.1
