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