[dpdk-dev] [PATCH v6 09/16] dma/idxd: add data-path job submission functions

[Kevin Laatz <kevin.laatz@intel.com>]

Add data path functions for enqueuing and submitting operations to DSA
devices.

Documentation updates are included for dmadev library and IDXD driver docs
as appropriate.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Signed-off-by: Kevin Laatz <kevin.laatz@intel.com>
Reviewed-by: Conor Walsh <conor.walsh@intel.com>

---
v6:
  - add references to dmadev lib docs for generic info
  - fix return values in "__idxd_write_desc()"
---
 doc/guides/dmadevs/idxd.rst      |   9 ++
 doc/guides/prog_guide/dmadev.rst |  19 +++++
 drivers/dma/idxd/idxd_common.c   | 136 +++++++++++++++++++++++++++++++
 drivers/dma/idxd/idxd_internal.h |   5 ++
 drivers/dma/idxd/meson.build     |   1 +
 5 files changed, 170 insertions(+)

diff --git a/doc/guides/dmadevs/idxd.rst b/doc/guides/dmadevs/idxd.rst
index da5e51bfa7..b3d78482be 100644
--- a/doc/guides/dmadevs/idxd.rst
+++ b/doc/guides/dmadevs/idxd.rst
@@ -142,3 +142,12 @@ IDXD configuration requirements:
 
 Once configured, the device can then be made ready for use by calling the
 ``rte_dma_start()`` API.
+
+Performing Data Copies
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Refer to the :ref:`Enqueue / Dequeue APIs <dmadev_enqueue_dequeue>` section of the dmadev library
+documentation for details on operation enqueue and submission API usage.
+
+It is expected that, for efficiency reasons, a burst of operations will be enqueued to the
+device via multiple enqueue calls between calls to the ``rte_dma_submit()`` function.
diff --git a/doc/guides/prog_guide/dmadev.rst b/doc/guides/prog_guide/dmadev.rst
index 3612315325..4908e33762 100644
--- a/doc/guides/prog_guide/dmadev.rst
+++ b/doc/guides/prog_guide/dmadev.rst
@@ -108,6 +108,8 @@ can be used to get the device info and supported features.
 Silent mode is a special device capability which does not require the
 application to invoke dequeue APIs.
 
+.. _dmadev_enqueue_dequeue:
+
 
 Enqueue / Dequeue APIs
 ~~~~~~~~~~~~~~~~~~~~~~
@@ -121,6 +123,23 @@ The ``rte_dma_submit`` API is used to issue doorbell to hardware.
 Alternatively the ``RTE_DMA_OP_FLAG_SUBMIT`` flag can be passed to the enqueue
 APIs to also issue the doorbell to hardware.
 
+The following code demonstrates how to enqueue a burst of copies to the
+device and start the hardware processing of them:
+
+.. code-block:: C
+
+   struct rte_mbuf *srcs[DMA_BURST_SZ], *dsts[DMA_BURST_SZ];
+   unsigned int i;
+
+   for (i = 0; i < RTE_DIM(srcs); i++) {
+      if (rte_dma_copy(dev_id, vchan, rte_pktmbuf_iova(srcs),
+            rte_pktmbuf_iova(dsts), COPY_LEN, 0) < 0) {
+         PRINT_ERR("Error with rte_dma_copy for buffer %u\n", i);
+         return -1;
+      }
+   }
+   rte_dma_submit(dev_id, vchan);
+
 There are two dequeue APIs ``rte_dma_completed`` and
 ``rte_dma_completed_status``, these are used to obtain the results of the
 enqueue requests. ``rte_dma_completed`` will return the number of successfully
diff --git a/drivers/dma/idxd/idxd_common.c b/drivers/dma/idxd/idxd_common.c
index 32ddb5f7f8..1580f5029c 100644
--- a/drivers/dma/idxd/idxd_common.c
+++ b/drivers/dma/idxd/idxd_common.c
@@ -2,14 +2,144 @@
  * Copyright 2021 Intel Corporation
  */
 
+#include <x86intrin.h>
+
 #include <rte_dmadev_pmd.h>
 #include <rte_malloc.h>
 #include <rte_common.h>
+#include <rte_prefetch.h>
 
 #include "idxd_internal.h"
 
 #define IDXD_PMD_NAME_STR "dmadev_idxd"
 
+static __rte_always_inline rte_iova_t
+__desc_idx_to_iova(struct idxd_dmadev *idxd, uint16_t n)
+{
+	return idxd->desc_iova + (n * sizeof(struct idxd_hw_desc));
+}
+
+static __rte_always_inline void
+__idxd_movdir64b(volatile void *dst, const struct idxd_hw_desc *src)
+{
+	asm volatile (".byte 0x66, 0x0f, 0x38, 0xf8, 0x02"
+			:
+			: "a" (dst), "d" (src)
+			: "memory");
+}
+
+static __rte_always_inline void
+__submit(struct idxd_dmadev *idxd)
+{
+	rte_prefetch1(&idxd->batch_comp_ring[idxd->batch_idx_read]);
+
+	if (idxd->batch_size == 0)
+		return;
+
+	/* write completion to batch comp ring */
+	rte_iova_t comp_addr = idxd->batch_iova +
+			(idxd->batch_idx_write * sizeof(struct idxd_completion));
+
+	if (idxd->batch_size == 1) {
+		/* submit batch directly */
+		struct idxd_hw_desc desc =
+				idxd->desc_ring[idxd->batch_start & idxd->desc_ring_mask];
+		desc.completion = comp_addr;
+		desc.op_flags |= IDXD_FLAG_REQUEST_COMPLETION;
+		_mm_sfence(); /* fence before writing desc to device */
+		__idxd_movdir64b(idxd->portal, &desc);
+	} else {
+		const struct idxd_hw_desc batch_desc = {
+				.op_flags = (idxd_op_batch << IDXD_CMD_OP_SHIFT) |
+				IDXD_FLAG_COMPLETION_ADDR_VALID |
+				IDXD_FLAG_REQUEST_COMPLETION,
+				.desc_addr = __desc_idx_to_iova(idxd,
+						idxd->batch_start & idxd->desc_ring_mask),
+				.completion = comp_addr,
+				.size = idxd->batch_size,
+		};
+		_mm_sfence(); /* fence before writing desc to device */
+		__idxd_movdir64b(idxd->portal, &batch_desc);
+	}
+
+	if (++idxd->batch_idx_write > idxd->max_batches)
+		idxd->batch_idx_write = 0;
+
+	idxd->batch_start += idxd->batch_size;
+	idxd->batch_size = 0;
+	idxd->batch_idx_ring[idxd->batch_idx_write] = idxd->batch_start;
+	_mm256_store_si256((void *)&idxd->batch_comp_ring[idxd->batch_idx_write],
+			_mm256_setzero_si256());
+}
+
+static __rte_always_inline int
+__idxd_write_desc(struct rte_dma_dev *dev,
+		const uint32_t op_flags,
+		const rte_iova_t src,
+		const rte_iova_t dst,
+		const uint32_t size,
+		const uint32_t flags)
+{
+	struct idxd_dmadev *idxd = dev->dev_private;
+	uint16_t mask = idxd->desc_ring_mask;
+	uint16_t job_id = idxd->batch_start + idxd->batch_size;
+	/* we never wrap batches, so we only mask the start and allow start+size to overflow */
+	uint16_t write_idx = (idxd->batch_start & mask) + idxd->batch_size;
+
+	/* first check batch ring space then desc ring space */
+	if ((idxd->batch_idx_read == 0 && idxd->batch_idx_write == idxd->max_batches) ||
+			idxd->batch_idx_write + 1 == idxd->batch_idx_read)
+		return -ENOSPC;
+	if (((write_idx + 1) & mask) == (idxd->ids_returned & mask))
+		return -ENOSPC;
+
+	/* write desc. Note: descriptors don't wrap, but the completion address does */
+	const uint64_t op_flags64 = (uint64_t)(op_flags | IDXD_FLAG_COMPLETION_ADDR_VALID) << 32;
+	const uint64_t comp_addr = __desc_idx_to_iova(idxd, write_idx & mask);
+	_mm256_store_si256((void *)&idxd->desc_ring[write_idx],
+			_mm256_set_epi64x(dst, src, comp_addr, op_flags64));
+	_mm256_store_si256((void *)&idxd->desc_ring[write_idx].size,
+			_mm256_set_epi64x(0, 0, 0, size));
+
+	idxd->batch_size++;
+
+	rte_prefetch0_write(&idxd->desc_ring[write_idx + 1]);
+
+	if (flags & RTE_DMA_OP_FLAG_SUBMIT)
+		__submit(idxd);
+
+	return job_id;
+}
+
+int
+idxd_enqueue_copy(struct rte_dma_dev *dev, uint16_t qid __rte_unused, rte_iova_t src,
+		rte_iova_t dst, unsigned int length, uint64_t flags)
+{
+	/* we can take advantage of the fact that the fence flag in dmadev and DSA are the same,
+	 * but check it at compile time to be sure.
+	 */
+	RTE_BUILD_BUG_ON(RTE_DMA_OP_FLAG_FENCE != IDXD_FLAG_FENCE);
+	uint32_t memmove = (idxd_op_memmove << IDXD_CMD_OP_SHIFT) |
+			IDXD_FLAG_CACHE_CONTROL | (flags & IDXD_FLAG_FENCE);
+	return __idxd_write_desc(dev, memmove, src, dst, length, flags);
+}
+
+int
+idxd_enqueue_fill(struct rte_dma_dev *dev, uint16_t qid __rte_unused, uint64_t pattern,
+		rte_iova_t dst, unsigned int length, uint64_t flags)
+{
+	uint32_t fill = (idxd_op_fill << IDXD_CMD_OP_SHIFT) |
+			IDXD_FLAG_CACHE_CONTROL | (flags & IDXD_FLAG_FENCE);
+	return __idxd_write_desc(dev, fill, pattern, dst, length, flags);
+}
+
+int
+idxd_submit(struct rte_dma_dev *dev, uint16_t qid __rte_unused)
+{
+	__submit(dev->dev_private);
+	return 0;
+}
+
 int
 idxd_dump(const struct rte_dma_dev *dev, FILE *f)
 {
@@ -139,6 +269,12 @@ idxd_dmadev_create(const char *name, struct rte_device *dev,
 	dmadev->dev_ops = ops;
 	dmadev->device = dev;
 
+	dmadev->copy = idxd_enqueue_copy;
+	dmadev->fill = idxd_enqueue_fill;
+	dmadev->submit = idxd_submit;
+	dmadev->completed = idxd_completed;
+	dmadev->completed_status = idxd_completed_status;
+
 	idxd = dmadev->dev_private;
 	*idxd = *base_idxd; /* copy over the main fields already passed in */
 	idxd->dmadev = dmadev;
diff --git a/drivers/dma/idxd/idxd_internal.h b/drivers/dma/idxd/idxd_internal.h
index fdd018ca35..b66c2d0182 100644
--- a/drivers/dma/idxd/idxd_internal.h
+++ b/drivers/dma/idxd/idxd_internal.h
@@ -88,5 +88,10 @@ int idxd_vchan_setup(struct rte_dma_dev *dev, uint16_t vchan,
 		const struct rte_dma_vchan_conf *qconf, uint32_t qconf_sz);
 int idxd_info_get(const struct rte_dma_dev *dev, struct rte_dma_info *dev_info,
 		uint32_t size);
+int idxd_enqueue_copy(struct rte_dma_dev *dev, uint16_t qid, rte_iova_t src,
+		rte_iova_t dst, unsigned int length, uint64_t flags);
+int idxd_enqueue_fill(struct rte_dma_dev *dev, uint16_t qid, uint64_t pattern,
+		rte_iova_t dst, unsigned int length, uint64_t flags);
+int idxd_submit(struct rte_dma_dev *dev, uint16_t qid);
 
 #endif /* _IDXD_INTERNAL_H_ */
diff --git a/drivers/dma/idxd/meson.build b/drivers/dma/idxd/meson.build
index da5dc2b019..3b5133c578 100644
--- a/drivers/dma/idxd/meson.build
+++ b/drivers/dma/idxd/meson.build
@@ -6,6 +6,7 @@ if is_windows
 endif
 
 deps += ['bus_pci']
+cflags += '-mavx2' # all platforms with idxd HW support AVX
 sources = files(
         'idxd_bus.c',
         'idxd_common.c',
-- 
2.30.2