1 files changed, 95 insertions, 0 deletions
diff --git a/drivers/gpu/drm/vboxvideo/vbox_hgsmi.c b/drivers/gpu/drm/vboxvideo/vbox_hgsmi.c
new file mode 100644
index 000000000..a9ca4d0c3
--- /dev/null
+++ b/drivers/gpu/drm/vboxvideo/vbox_hgsmi.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright (C) 2017 Oracle Corporation
+ * Authors: Hans de Goede <hdegoede@redhat.com>
+ */
+
+#include "vbox_drv.h"
+#include "vboxvideo_vbe.h"
+#include "hgsmi_defs.h"
+
+/* One-at-a-Time Hash from https://www.burtleburtle.net/bob/hash/doobs.html */
+static u32 hgsmi_hash_process(u32 hash, const u8 *data, int size)
+{
+	while (size--) {
+		hash += *data++;
+		hash += (hash << 10);
+		hash ^= (hash >> 6);
+	}
+
+	return hash;
+}
+
+static u32 hgsmi_hash_end(u32 hash)
+{
+	hash += (hash << 3);
+	hash ^= (hash >> 11);
+	hash += (hash << 15);
+
+	return hash;
+}
+
+/* Not really a checksum but that is the naming used in all vbox code */
+static u32 hgsmi_checksum(u32 offset,
+			  const struct hgsmi_buffer_header *header,
+			  const struct hgsmi_buffer_tail *tail)
+{
+	u32 checksum;
+
+	checksum = hgsmi_hash_process(0, (u8 *)&offset, sizeof(offset));
+	checksum = hgsmi_hash_process(checksum, (u8 *)header, sizeof(*header));
+	/* 4 -> Do not checksum the checksum itself */
+	checksum = hgsmi_hash_process(checksum, (u8 *)tail, 4);
+
+	return hgsmi_hash_end(checksum);
+}
+
+void *hgsmi_buffer_alloc(struct gen_pool *guest_pool, size_t size,
+			 u8 channel, u16 channel_info)
+{
+	struct hgsmi_buffer_header *h;
+	struct hgsmi_buffer_tail *t;
+	size_t total_size;
+	dma_addr_t offset;
+
+	total_size = size + sizeof(*h) + sizeof(*t);
+	h = gen_pool_dma_alloc(guest_pool, total_size, &offset);
+	if (!h)
+		return NULL;
+
+	t = (struct hgsmi_buffer_tail *)((u8 *)h + sizeof(*h) + size);
+
+	h->flags = HGSMI_BUFFER_HEADER_F_SEQ_SINGLE;
+	h->data_size = size;
+	h->channel = channel;
+	h->channel_info = channel_info;
+	memset(&h->u.header_data, 0, sizeof(h->u.header_data));
+
+	t->reserved = 0;
+	t->checksum = hgsmi_checksum(offset, h, t);
+
+	return (u8 *)h + sizeof(*h);
+}
+
+void hgsmi_buffer_free(struct gen_pool *guest_pool, void *buf)
+{
+	struct hgsmi_buffer_header *h =
+		(struct hgsmi_buffer_header *)((u8 *)buf - sizeof(*h));
+	size_t total_size = h->data_size + sizeof(*h) +
+					     sizeof(struct hgsmi_buffer_tail);
+
+	gen_pool_free(guest_pool, (unsigned long)h, total_size);
+}
+
+int hgsmi_buffer_submit(struct gen_pool *guest_pool, void *buf)
+{
+	phys_addr_t offset;
+
+	offset = gen_pool_virt_to_phys(guest_pool, (unsigned long)buf -
+				       sizeof(struct hgsmi_buffer_header));
+	outl(offset, VGA_PORT_HGSMI_GUEST);
+	/* Make the compiler aware that the host has changed memory. */
+	mb();
+
+	return 0;
+}