[xen] Add support for Xen netfront virtual NICs

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 153 insertions, 0 deletions

diff --git a/src/drivers/net/netfront.h b/src/drivers/net/netfront.h
new file mode 100644
index 00000000..b3f899f3
--- /dev/null
+++ b/src/drivers/net/netfront.h
@@ -0,0 +1,153 @@
+#ifndef _NETFRONT_H
+#define _NETFRONT_H
+
+/** @file
+ *
+ * Xen netfront driver
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <ipxe/xen.h>
+#include <xen/io/netif.h>
+
+/** Number of transmit ring entries */
+#define NETFRONT_NUM_TX_DESC 16
+
+/** Number of receive ring entries */
+#define NETFRONT_NUM_RX_DESC 8
+
+/** Grant reference indices */
+enum netfront_ref_index {
+	/** Transmit ring grant reference index */
+	NETFRONT_REF_TX_RING = 0,
+	/** Transmit descriptor grant reference base index */
+	NETFRONT_REF_TX_BASE,
+	/** Receive ring grant reference index */
+	NETFRONT_REF_RX_RING = ( NETFRONT_REF_TX_BASE + NETFRONT_NUM_TX_DESC ),
+	/** Receive descriptor grant reference base index */
+	NETFRONT_REF_RX_BASE,
+	/** Total number of grant references required */
+	NETFRONT_REF_COUNT = ( NETFRONT_REF_RX_BASE + NETFRONT_NUM_RX_DESC )
+};
+
+/** A netfront descriptor ring */
+struct netfront_ring {
+	/** Shared ring */
+	union {
+		/** Transmit shared ring */
+		netif_tx_sring_t *tx;
+		/** Receive shared ring */
+		netif_rx_sring_t *rx;
+		/** Raw pointer */
+		void *raw;
+	} sring;
+	/** Shared ring grant reference key */
+	const char *ref_key;
+	/** Shared ring grant reference */
+	grant_ref_t ref;
+
+	/** Maximum number of used descriptors */
+	size_t count;
+	/** I/O buffers, indexed by buffer ID */
+	struct io_buffer **iobufs;
+	/** I/O buffer grant references, indexed by buffer ID */
+	grant_ref_t *refs;
+
+	/** Buffer ID ring */
+	uint8_t *ids;
+	/** Buffer ID ring producer counter */
+	unsigned int id_prod;
+	/** Buffer ID ring consumer counter */
+	unsigned int id_cons;
+};
+
+/**
+ * Initialise descriptor ring
+ *
+ * @v ring		Descriptor ring
+ * @v ref_key		Shared ring grant reference key
+ * @v ref		Shared ring grant reference
+ * @v count		Maxium number of used descriptors
+ * @v iobufs		I/O buffers
+ * @v refs		I/O buffer grant references
+ * @v ids		Buffer IDs
+ */
+static inline __attribute__ (( always_inline )) void
+netfront_init_ring ( struct netfront_ring *ring, const char *ref_key,
+		     grant_ref_t ref, unsigned int count,
+		     struct io_buffer **iobufs, grant_ref_t *refs,
+		     uint8_t *ids ) {
+
+	ring->ref_key = ref_key;
+	ring->ref = ref;
+	ring->count = count;
+	ring->iobufs = iobufs;
+	ring->refs = refs;
+	ring->ids = ids;
+}
+
+/**
+ * Check whether or not descriptor ring is full
+ *
+ * @v ring		Descriptor ring
+ * @v is_full		Ring is full
+ */
+static inline __attribute__ (( always_inline )) int
+netfront_ring_is_full ( struct netfront_ring *ring ) {
+	unsigned int fill_level;
+
+	fill_level = ( ring->id_prod - ring->id_cons );
+	assert ( fill_level <= ring->count );
+	return ( fill_level >= ring->count );
+}
+
+/**
+ * Check whether or not descriptor ring is empty
+ *
+ * @v ring		Descriptor ring
+ * @v is_empty		Ring is empty
+ */
+static inline __attribute__ (( always_inline )) int
+netfront_ring_is_empty ( struct netfront_ring *ring ) {
+
+	return ( ring->id_prod == ring->id_cons );
+}
+
+/** A netfront NIC */
+struct netfront_nic {
+	/** Xen device */
+	struct xen_device *xendev;
+	/** Grant references */
+	grant_ref_t refs[NETFRONT_REF_COUNT];
+
+	/** Transmit ring */
+	struct netfront_ring tx;
+	/** Transmit front ring */
+	netif_tx_front_ring_t tx_fring;
+	/** Transmit I/O buffers */
+	struct io_buffer *tx_iobufs[NETFRONT_NUM_TX_DESC];
+	/** Transmit I/O buffer IDs */
+	uint8_t tx_ids[NETFRONT_NUM_TX_DESC];
+
+	/** Receive ring */
+	struct netfront_ring rx;
+	/** Receive front ring */
+	netif_rx_front_ring_t rx_fring;
+	/** Receive I/O buffers */
+	struct io_buffer *rx_iobufs[NETFRONT_NUM_RX_DESC];
+	/** Receive I/O buffer IDs */
+	uint8_t rx_ids[NETFRONT_NUM_RX_DESC];
+
+	/** Event channel */
+	struct evtchn_send event;
+};
+
+/** Transmit shared ring field */
+#define tx_sring tx.sring.tx
+
+/** Receive shared ring field */
+#define rx_sring rx.sring.rx
+
+#endif /* _NETFRONT_H */