[Feature]add MT2731_MP2_MR2_SVN388 baseline version
Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/tools/virtio/ringtest/ring.c b/src/kernel/linux/v4.14/tools/virtio/ringtest/ring.c
new file mode 100644
index 0000000..747c5dd
--- /dev/null
+++ b/src/kernel/linux/v4.14/tools/virtio/ringtest/ring.c
@@ -0,0 +1,266 @@
+/*
+ * Copyright (C) 2016 Red Hat, Inc.
+ * Author: Michael S. Tsirkin <mst@redhat.com>
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ *
+ * Simple descriptor-based ring. virtio 0.9 compatible event index is used for
+ * signalling, unconditionally.
+ */
+#define _GNU_SOURCE
+#include "main.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+/* Next - Where next entry will be written.
+ * Prev - "Next" value when event triggered previously.
+ * Event - Peer requested event after writing this entry.
+ */
+static inline bool need_event(unsigned short event,
+ unsigned short next,
+ unsigned short prev)
+{
+ return (unsigned short)(next - event - 1) < (unsigned short)(next - prev);
+}
+
+/* Design:
+ * Guest adds descriptors with unique index values and DESC_HW in flags.
+ * Host overwrites used descriptors with correct len, index, and DESC_HW clear.
+ * Flags are always set last.
+ */
+#define DESC_HW 0x1
+
+struct desc {
+ unsigned short flags;
+ unsigned short index;
+ unsigned len;
+ unsigned long long addr;
+};
+
+/* how much padding is needed to avoid false cache sharing */
+#define HOST_GUEST_PADDING 0x80
+
+/* Mostly read */
+struct event {
+ unsigned short kick_index;
+ unsigned char reserved0[HOST_GUEST_PADDING - 2];
+ unsigned short call_index;
+ unsigned char reserved1[HOST_GUEST_PADDING - 2];
+};
+
+struct data {
+ void *buf; /* descriptor is writeable, we can't get buf from there */
+ void *data;
+} *data;
+
+struct desc *ring;
+struct event *event;
+
+struct guest {
+ unsigned avail_idx;
+ unsigned last_used_idx;
+ unsigned num_free;
+ unsigned kicked_avail_idx;
+ unsigned char reserved[HOST_GUEST_PADDING - 12];
+} guest;
+
+struct host {
+ /* we do not need to track last avail index
+ * unless we have more than one in flight.
+ */
+ unsigned used_idx;
+ unsigned called_used_idx;
+ unsigned char reserved[HOST_GUEST_PADDING - 4];
+} host;
+
+/* implemented by ring */
+void alloc_ring(void)
+{
+ int ret;
+ int i;
+
+ ret = posix_memalign((void **)&ring, 0x1000, ring_size * sizeof *ring);
+ if (ret) {
+ perror("Unable to allocate ring buffer.\n");
+ exit(3);
+ }
+ event = malloc(sizeof *event);
+ if (!event) {
+ perror("Unable to allocate event buffer.\n");
+ exit(3);
+ }
+ memset(event, 0, sizeof *event);
+ guest.avail_idx = 0;
+ guest.kicked_avail_idx = -1;
+ guest.last_used_idx = 0;
+ host.used_idx = 0;
+ host.called_used_idx = -1;
+ for (i = 0; i < ring_size; ++i) {
+ struct desc desc = {
+ .index = i,
+ };
+ ring[i] = desc;
+ }
+ guest.num_free = ring_size;
+ data = malloc(ring_size * sizeof *data);
+ if (!data) {
+ perror("Unable to allocate data buffer.\n");
+ exit(3);
+ }
+ memset(data, 0, ring_size * sizeof *data);
+}
+
+/* guest side */
+int add_inbuf(unsigned len, void *buf, void *datap)
+{
+ unsigned head, index;
+
+ if (!guest.num_free)
+ return -1;
+
+ guest.num_free--;
+ head = (ring_size - 1) & (guest.avail_idx++);
+
+ /* Start with a write. On MESI architectures this helps
+ * avoid a shared state with consumer that is polling this descriptor.
+ */
+ ring[head].addr = (unsigned long)(void*)buf;
+ ring[head].len = len;
+ /* read below might bypass write above. That is OK because it's just an
+ * optimization. If this happens, we will get the cache line in a
+ * shared state which is unfortunate, but probably not worth it to
+ * add an explicit full barrier to avoid this.
+ */
+ barrier();
+ index = ring[head].index;
+ data[index].buf = buf;
+ data[index].data = datap;
+ /* Barrier A (for pairing) */
+ smp_release();
+ ring[head].flags = DESC_HW;
+
+ return 0;
+}
+
+void *get_buf(unsigned *lenp, void **bufp)
+{
+ unsigned head = (ring_size - 1) & guest.last_used_idx;
+ unsigned index;
+ void *datap;
+
+ if (ring[head].flags & DESC_HW)
+ return NULL;
+ /* Barrier B (for pairing) */
+ smp_acquire();
+ *lenp = ring[head].len;
+ index = ring[head].index & (ring_size - 1);
+ datap = data[index].data;
+ *bufp = data[index].buf;
+ data[index].buf = NULL;
+ data[index].data = NULL;
+ guest.num_free++;
+ guest.last_used_idx++;
+ return datap;
+}
+
+bool used_empty()
+{
+ unsigned head = (ring_size - 1) & guest.last_used_idx;
+
+ return (ring[head].flags & DESC_HW);
+}
+
+void disable_call()
+{
+ /* Doing nothing to disable calls might cause
+ * extra interrupts, but reduces the number of cache misses.
+ */
+}
+
+bool enable_call()
+{
+ event->call_index = guest.last_used_idx;
+ /* Flush call index write */
+ /* Barrier D (for pairing) */
+ smp_mb();
+ return used_empty();
+}
+
+void kick_available(void)
+{
+ /* Flush in previous flags write */
+ /* Barrier C (for pairing) */
+ smp_mb();
+ if (!need_event(event->kick_index,
+ guest.avail_idx,
+ guest.kicked_avail_idx))
+ return;
+
+ guest.kicked_avail_idx = guest.avail_idx;
+ kick();
+}
+
+/* host side */
+void disable_kick()
+{
+ /* Doing nothing to disable kicks might cause
+ * extra interrupts, but reduces the number of cache misses.
+ */
+}
+
+bool enable_kick()
+{
+ event->kick_index = host.used_idx;
+ /* Barrier C (for pairing) */
+ smp_mb();
+ return avail_empty();
+}
+
+bool avail_empty()
+{
+ unsigned head = (ring_size - 1) & host.used_idx;
+
+ return !(ring[head].flags & DESC_HW);
+}
+
+bool use_buf(unsigned *lenp, void **bufp)
+{
+ unsigned head = (ring_size - 1) & host.used_idx;
+
+ if (!(ring[head].flags & DESC_HW))
+ return false;
+
+ /* make sure length read below is not speculated */
+ /* Barrier A (for pairing) */
+ smp_acquire();
+
+ /* simple in-order completion: we don't need
+ * to touch index at all. This also means we
+ * can just modify the descriptor in-place.
+ */
+ ring[head].len--;
+ /* Make sure len is valid before flags.
+ * Note: alternative is to write len and flags in one access -
+ * possible on 64 bit architectures but wmb is free on Intel anyway
+ * so I have no way to test whether it's a gain.
+ */
+ /* Barrier B (for pairing) */
+ smp_release();
+ ring[head].flags = 0;
+ host.used_idx++;
+ return true;
+}
+
+void call_used(void)
+{
+ /* Flush in previous flags write */
+ /* Barrier D (for pairing) */
+ smp_mb();
+ if (!need_event(event->call_index,
+ host.used_idx,
+ host.called_used_idx))
+ return;
+
+ host.called_used_idx = host.used_idx;
+ call();
+}