1 files changed, 259 insertions, 0 deletions
diff --git a/drivers/net/ethernet/intel/libeth/rx.c b/drivers/net/ethernet/intel/libeth/rx.c
new file mode 100644
index 000000000000..66d1d23b8ad2
--- /dev/null
+++ b/drivers/net/ethernet/intel/libeth/rx.c
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2024 Intel Corporation */
+
+#include <net/libeth/rx.h>
+
+/* Rx buffer management */
+
+/**
+ * libeth_rx_hw_len_mtu - get the actual buffer size to be passed to HW
+ * @pp: &page_pool_params of the netdev to calculate the size for
+ * @max_len: maximum buffer size for a single descriptor
+ *
+ * Return: HW-writeable length per one buffer to pass it to the HW accounting:
+ * MTU the @dev has, HW required alignment, minimum and maximum allowed values,
+ * and system's page size.
+ */
+static u32 libeth_rx_hw_len_mtu(const struct page_pool_params *pp, u32 max_len)
+{
+	u32 len;
+
+	len = READ_ONCE(pp->netdev->mtu) + LIBETH_RX_LL_LEN;
+	len = ALIGN(len, LIBETH_RX_BUF_STRIDE);
+	len = min3(len, ALIGN_DOWN(max_len ? : U32_MAX, LIBETH_RX_BUF_STRIDE),
+		   pp->max_len);
+
+	return len;
+}
+
+/**
+ * libeth_rx_hw_len_truesize - get the short buffer size to be passed to HW
+ * @pp: &page_pool_params of the netdev to calculate the size for
+ * @max_len: maximum buffer size for a single descriptor
+ * @truesize: desired truesize for the buffers
+ *
+ * Return: HW-writeable length per one buffer to pass it to the HW ignoring the
+ * MTU and closest to the passed truesize. Can be used for "short" buffer
+ * queues to fragment pages more efficiently.
+ */
+static u32 libeth_rx_hw_len_truesize(const struct page_pool_params *pp,
+				     u32 max_len, u32 truesize)
+{
+	u32 min, len;
+
+	min = SKB_HEAD_ALIGN(pp->offset + LIBETH_RX_BUF_STRIDE);
+	truesize = clamp(roundup_pow_of_two(truesize), roundup_pow_of_two(min),
+			 PAGE_SIZE << LIBETH_RX_PAGE_ORDER);
+
+	len = SKB_WITH_OVERHEAD(truesize - pp->offset);
+	len = ALIGN_DOWN(len, LIBETH_RX_BUF_STRIDE) ? : LIBETH_RX_BUF_STRIDE;
+	len = min3(len, ALIGN_DOWN(max_len ? : U32_MAX, LIBETH_RX_BUF_STRIDE),
+		   pp->max_len);
+
+	return len;
+}
+
+/**
+ * libeth_rx_page_pool_params - calculate params with the stack overhead
+ * @fq: buffer queue to calculate the size for
+ * @pp: &page_pool_params of the netdev
+ *
+ * Set the PP params to will all needed stack overhead (headroom, tailroom) and
+ * both the HW buffer length and the truesize for all types of buffers. For
+ * "short" buffers, truesize never exceeds the "wanted" one; for the rest,
+ * it can be up to the page size.
+ *
+ * Return: true on success, false on invalid input params.
+ */
+static bool libeth_rx_page_pool_params(struct libeth_fq *fq,
+				       struct page_pool_params *pp)
+{
+	pp->offset = LIBETH_SKB_HEADROOM;
+	/* HW-writeable / syncable length per one page */
+	pp->max_len = LIBETH_RX_PAGE_LEN(pp->offset);
+
+	/* HW-writeable length per buffer */
+	switch (fq->type) {
+	case LIBETH_FQE_MTU:
+		fq->buf_len = libeth_rx_hw_len_mtu(pp, fq->buf_len);
+		break;
+	case LIBETH_FQE_SHORT:
+		fq->buf_len = libeth_rx_hw_len_truesize(pp, fq->buf_len,
+							fq->truesize);
+		break;
+	case LIBETH_FQE_HDR:
+		fq->buf_len = ALIGN(LIBETH_MAX_HEAD, LIBETH_RX_BUF_STRIDE);
+		break;
+	default:
+		return false;
+	}
+
+	/* Buffer size to allocate */
+	fq->truesize = roundup_pow_of_two(SKB_HEAD_ALIGN(pp->offset +
+							 fq->buf_len));
+
+	return true;
+}
+
+/**
+ * libeth_rx_page_pool_params_zc - calculate params without the stack overhead
+ * @fq: buffer queue to calculate the size for
+ * @pp: &page_pool_params of the netdev
+ *
+ * Set the PP params to exclude the stack overhead and both the buffer length
+ * and the truesize, which are equal for the data buffers. Note that this
+ * requires separate header buffers to be always active and account the
+ * overhead.
+ * With the MTU == ``PAGE_SIZE``, this allows the kernel to enable the zerocopy
+ * mode.
+ *
+ * Return: true on success, false on invalid input params.
+ */
+static bool libeth_rx_page_pool_params_zc(struct libeth_fq *fq,
+					  struct page_pool_params *pp)
+{
+	u32 mtu, max;
+
+	pp->offset = 0;
+	pp->max_len = PAGE_SIZE << LIBETH_RX_PAGE_ORDER;
+
+	switch (fq->type) {
+	case LIBETH_FQE_MTU:
+		mtu = READ_ONCE(pp->netdev->mtu);
+		break;
+	case LIBETH_FQE_SHORT:
+		mtu = fq->truesize;
+		break;
+	default:
+		return false;
+	}
+
+	mtu = roundup_pow_of_two(mtu);
+	max = min(rounddown_pow_of_two(fq->buf_len ? : U32_MAX),
+		  pp->max_len);
+
+	fq->buf_len = clamp(mtu, LIBETH_RX_BUF_STRIDE, max);
+	fq->truesize = fq->buf_len;
+
+	return true;
+}
+
+/**
+ * libeth_rx_fq_create - create a PP with the default libeth settings
+ * @fq: buffer queue struct to fill
+ * @napi: &napi_struct covering this PP (no usage outside its poll loops)
+ *
+ * Return: %0 on success, -%errno on failure.
+ */
+int libeth_rx_fq_create(struct libeth_fq *fq, struct napi_struct *napi)
+{
+	struct page_pool_params pp = {
+		.flags		= PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV,
+		.order		= LIBETH_RX_PAGE_ORDER,
+		.pool_size	= fq->count,
+		.nid		= fq->nid,
+		.dev		= napi->dev->dev.parent,
+		.netdev		= napi->dev,
+		.napi		= napi,
+		.dma_dir	= DMA_FROM_DEVICE,
+	};
+	struct libeth_fqe *fqes;
+	struct page_pool *pool;
+	bool ret;
+
+	if (!fq->hsplit)
+		ret = libeth_rx_page_pool_params(fq, &pp);
+	else
+		ret = libeth_rx_page_pool_params_zc(fq, &pp);
+	if (!ret)
+		return -EINVAL;
+
+	pool = page_pool_create(&pp);
+	if (IS_ERR(pool))
+		return PTR_ERR(pool);
+
+	fqes = kvcalloc_node(fq->count, sizeof(*fqes), GFP_KERNEL, fq->nid);
+	if (!fqes)
+		goto err_buf;
+
+	fq->fqes = fqes;
+	fq->pp = pool;
+
+	return 0;
+
+err_buf:
+	page_pool_destroy(pool);
+
+	return -ENOMEM;
+}
+EXPORT_SYMBOL_NS_GPL(libeth_rx_fq_create, "LIBETH");
+
+/**
+ * libeth_rx_fq_destroy - destroy a &page_pool created by libeth
+ * @fq: buffer queue to process
+ */
+void libeth_rx_fq_destroy(struct libeth_fq *fq)
+{
+	kvfree(fq->fqes);
+	page_pool_destroy(fq->pp);
+}
+EXPORT_SYMBOL_NS_GPL(libeth_rx_fq_destroy, "LIBETH");
+
+/**
+ * libeth_rx_recycle_slow - recycle a libeth page from the NAPI context
+ * @page: page to recycle
+ *
+ * To be used on exceptions or rare cases not requiring fast inline recycling.
+ */
+void libeth_rx_recycle_slow(struct page *page)
+{
+	page_pool_recycle_direct(page->pp, page);
+}
+EXPORT_SYMBOL_NS_GPL(libeth_rx_recycle_slow, "LIBETH");
+
+/* Converting abstract packet type numbers into a software structure with
+ * the packet parameters to do O(1) lookup on Rx.
+ */
+
+static const u16 libeth_rx_pt_xdp_oip[] = {
+	[LIBETH_RX_PT_OUTER_L2]		= XDP_RSS_TYPE_NONE,
+	[LIBETH_RX_PT_OUTER_IPV4]	= XDP_RSS_L3_IPV4,
+	[LIBETH_RX_PT_OUTER_IPV6]	= XDP_RSS_L3_IPV6,
+};
+
+static const u16 libeth_rx_pt_xdp_iprot[] = {
+	[LIBETH_RX_PT_INNER_NONE]	= XDP_RSS_TYPE_NONE,
+	[LIBETH_RX_PT_INNER_UDP]	= XDP_RSS_L4_UDP,
+	[LIBETH_RX_PT_INNER_TCP]	= XDP_RSS_L4_TCP,
+	[LIBETH_RX_PT_INNER_SCTP]	= XDP_RSS_L4_SCTP,
+	[LIBETH_RX_PT_INNER_ICMP]	= XDP_RSS_L4_ICMP,
+	[LIBETH_RX_PT_INNER_TIMESYNC]	= XDP_RSS_TYPE_NONE,
+};
+
+static const u16 libeth_rx_pt_xdp_pl[] = {
+	[LIBETH_RX_PT_PAYLOAD_NONE]	= XDP_RSS_TYPE_NONE,
+	[LIBETH_RX_PT_PAYLOAD_L2]	= XDP_RSS_TYPE_NONE,
+	[LIBETH_RX_PT_PAYLOAD_L3]	= XDP_RSS_TYPE_NONE,
+	[LIBETH_RX_PT_PAYLOAD_L4]	= XDP_RSS_L4,
+};
+
+/**
+ * libeth_rx_pt_gen_hash_type - generate an XDP RSS hash type for a PT
+ * @pt: PT structure to evaluate
+ *
+ * Generates ```hash_type``` field with XDP RSS type values from the parsed
+ * packet parameters if they're obtained dynamically at runtime.
+ */
+void libeth_rx_pt_gen_hash_type(struct libeth_rx_pt *pt)
+{
+	pt->hash_type = 0;
+	pt->hash_type |= libeth_rx_pt_xdp_oip[pt->outer_ip];
+	pt->hash_type |= libeth_rx_pt_xdp_iprot[pt->inner_prot];
+	pt->hash_type |= libeth_rx_pt_xdp_pl[pt->payload_layer];
+}
+EXPORT_SYMBOL_NS_GPL(libeth_rx_pt_gen_hash_type, "LIBETH");
+
+/* Module */
+
+MODULE_DESCRIPTION("Common Ethernet library");
+MODULE_LICENSE("GPL");