2 files changed, 222 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/libeth/xsk.c b/drivers/net/ethernet/intel/libeth/xsk.c
index f8f4016d1b25..846e902e31b6 100644
--- a/drivers/net/ethernet/intel/libeth/xsk.c
+++ b/drivers/net/ethernet/intel/libeth/xsk.c
@@ -145,3 +145,127 @@ drop:
 
 	return __ret;
 }
+
+/* Refill */
+
+/**
+ * libeth_xskfq_create - create an XSkFQ
+ * @fq: fill queue to initialize
+ *
+ * Allocates the FQEs and initializes the fields used by libeth_xdp: number
+ * of buffers to refill, refill threshold and buffer len.
+ *
+ * Return: %0 on success, -errno otherwise.
+ */
+int libeth_xskfq_create(struct libeth_xskfq *fq)
+{
+	fq->fqes = kvcalloc_node(fq->count, sizeof(*fq->fqes), GFP_KERNEL,
+				 fq->nid);
+	if (!fq->fqes)
+		return -ENOMEM;
+
+	fq->pending = fq->count;
+	fq->thresh = libeth_xdp_queue_threshold(fq->count);
+	fq->buf_len = xsk_pool_get_rx_frame_size(fq->pool);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(libeth_xskfq_create);
+
+/**
+ * libeth_xskfq_destroy - destroy an XSkFQ
+ * @fq: fill queue to destroy
+ *
+ * Zeroes the used fields and frees the FQEs array.
+ */
+void libeth_xskfq_destroy(struct libeth_xskfq *fq)
+{
+	fq->buf_len = 0;
+	fq->thresh = 0;
+	fq->pending = 0;
+
+	kvfree(fq->fqes);
+}
+EXPORT_SYMBOL_GPL(libeth_xskfq_destroy);
+
+/* .ndo_xsk_wakeup */
+
+static void libeth_xsk_napi_sched(void *info)
+{
+	__napi_schedule_irqoff(info);
+}
+
+/**
+ * libeth_xsk_init_wakeup - initialize libeth XSk wakeup structure
+ * @csd: struct to initialize
+ * @napi: NAPI corresponding to this queue
+ *
+ * libeth_xdp uses inter-processor interrupts to perform XSk wakeups. In order
+ * to do that, the corresponding CSDs must be initialized when creating the
+ * queues.
+ */
+void libeth_xsk_init_wakeup(call_single_data_t *csd, struct napi_struct *napi)
+{
+	INIT_CSD(csd, libeth_xsk_napi_sched, napi);
+}
+EXPORT_SYMBOL_GPL(libeth_xsk_init_wakeup);
+
+/**
+ * libeth_xsk_wakeup - perform an XSk wakeup
+ * @csd: CSD corresponding to the queue
+ * @qid: the stack queue index
+ *
+ * Try to mark the NAPI as missed first, so that it could be rescheduled.
+ * If it's not, schedule it on the corresponding CPU using IPIs (or directly
+ * if already running on it).
+ */
+void libeth_xsk_wakeup(call_single_data_t *csd, u32 qid)
+{
+	struct napi_struct *napi = csd->info;
+
+	if (napi_if_scheduled_mark_missed(napi) ||
+	    unlikely(!napi_schedule_prep(napi)))
+		return;
+
+	if (unlikely(qid >= nr_cpu_ids))
+		qid %= nr_cpu_ids;
+
+	if (qid != raw_smp_processor_id() && cpu_online(qid))
+		smp_call_function_single_async(qid, csd);
+	else
+		__napi_schedule(napi);
+}
+EXPORT_SYMBOL_GPL(libeth_xsk_wakeup);
+
+/* Pool setup */
+
+#define LIBETH_XSK_DMA_ATTR					\
+	(DMA_ATTR_WEAK_ORDERING | DMA_ATTR_SKIP_CPU_SYNC)
+
+/**
+ * libeth_xsk_setup_pool - setup or destroy an XSk pool for a queue
+ * @dev: target &net_device
+ * @qid: stack queue index to configure
+ * @enable: whether to enable or disable the pool
+ *
+ * Check that @qid is valid and then map or unmap the pool.
+ *
+ * Return: %0 on success, -errno otherwise.
+ */
+int libeth_xsk_setup_pool(struct net_device *dev, u32 qid, bool enable)
+{
+	struct xsk_buff_pool *pool;
+
+	pool = xsk_get_pool_from_qid(dev, qid);
+	if (!pool)
+		return -EINVAL;
+
+	if (enable)
+		return xsk_pool_dma_map(pool, dev->dev.parent,
+					LIBETH_XSK_DMA_ATTR);
+	else
+		xsk_pool_dma_unmap(pool, LIBETH_XSK_DMA_ATTR);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(libeth_xsk_setup_pool);
diff --git a/include/net/libeth/xsk.h b/include/net/libeth/xsk.h
index f3f338e566fc..213778a68476 100644
--- a/include/net/libeth/xsk.h
+++ b/include/net/libeth/xsk.h
@@ -584,4 +584,102 @@ __libeth_xsk_run_pass(struct libeth_xdp_buff *xdp,
 #define LIBETH_XSK_DEFINE_FINALIZE(name, flush, finalize)		     \
 	__LIBETH_XDP_DEFINE_FINALIZE(name, flush, finalize, xsk)
 
+/* Refilling */
+
+/**
+ * struct libeth_xskfq - structure representing an XSk buffer (fill) queue
+ * @fp: hotpath part of the structure
+ * @pool: &xsk_buff_pool for buffer management
+ * @fqes: array of XSk buffer pointers
+ * @descs: opaque pointer to the HW descriptor array
+ * @ntu: index of the next buffer to poll
+ * @count: number of descriptors/buffers the queue has
+ * @pending: current number of XSkFQEs to refill
+ * @thresh: threshold below which the queue is refilled
+ * @buf_len: HW-writeable length per each buffer
+ * @nid: ID of the closest NUMA node with memory
+ */
+struct libeth_xskfq {
+	struct_group_tagged(libeth_xskfq_fp, fp,
+		struct xsk_buff_pool	*pool;
+		struct libeth_xdp_buff	**fqes;
+		void			*descs;
+
+		u32			ntu;
+		u32			count;
+	);
+
+	/* Cold fields */
+	u32			pending;
+	u32			thresh;
+
+	u32			buf_len;
+	int			nid;
+};
+
+int libeth_xskfq_create(struct libeth_xskfq *fq);
+void libeth_xskfq_destroy(struct libeth_xskfq *fq);
+
+/**
+ * libeth_xsk_buff_xdp_get_dma - get DMA address of XSk &libeth_xdp_buff
+ * @xdp: buffer to get the DMA addr for
+ */
+#define libeth_xsk_buff_xdp_get_dma(xdp)				     \
+	xsk_buff_xdp_get_dma(&(xdp)->base)
+
+/**
+ * libeth_xskfqe_alloc - allocate @n XSk Rx buffers
+ * @fq: hotpath part of the XSkFQ, usually onstack
+ * @n: number of buffers to allocate
+ * @fill: driver callback to write DMA addresses to HW descriptors
+ *
+ * Note that @fq->ntu gets updated, but ::pending must be recalculated
+ * by the caller.
+ *
+ * Return: number of buffers refilled.
+ */
+static __always_inline u32
+libeth_xskfqe_alloc(struct libeth_xskfq_fp *fq, u32 n,
+		    void (*fill)(const struct libeth_xskfq_fp *fq, u32 i))
+{
+	u32 this, ret, done = 0;
+	struct xdp_buff **xskb;
+
+	this = fq->count - fq->ntu;
+	if (likely(this > n))
+		this = n;
+
+again:
+	xskb = (typeof(xskb))&fq->fqes[fq->ntu];
+	ret = xsk_buff_alloc_batch(fq->pool, xskb, this);
+
+	for (u32 i = 0, ntu = fq->ntu; likely(i < ret); i++)
+		fill(fq, ntu + i);
+
+	done += ret;
+	fq->ntu += ret;
+
+	if (likely(fq->ntu < fq->count) || unlikely(ret < this))
+		goto out;
+
+	fq->ntu = 0;
+
+	if (this < n) {
+		this = n - this;
+		goto again;
+	}
+
+out:
+	return done;
+}
+
+/* .ndo_xsk_wakeup */
+
+void libeth_xsk_init_wakeup(call_single_data_t *csd, struct napi_struct *napi);
+void libeth_xsk_wakeup(call_single_data_t *csd, u32 qid);
+
+/* Pool setup */
+
+int libeth_xsk_setup_pool(struct net_device *dev, u32 qid, bool enable);
+
 #endif /* __LIBETH_XSK_H */