source: vbox/trunk/src/VBox/Additions/linux/drm/vbox_hgsmi.c@ 69206

/** @file
 * VirtualBox Additions Linux kernel video driver hgsmi interface code
 */

/*
 * Copyright (C) 2017 Oracle Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * Authors: Hans de Goede <hdegoede@redhat.com>
 */

#include <HGSMIBase.h>
#include <VBoxVideoVBE.h>

/* One-at-a-Time Hash from http://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 HGSMIBUFFERHEADER *header,
                          const HGSMIBUFFERTAIL *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);
}

#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 13, 0)
void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
{
        unsigned long vaddr = gen_pool_alloc(pool, size);

        if (vaddr)
                *dma = gen_pool_virt_to_phys(pool, vaddr);
        return (void *)vaddr;
}
#endif

void *hgsmi_buffer_alloc(struct gen_pool *guest_pool, size_t size,
                         u8 channel, u16 channel_info)
{
        HGSMIBUFFERHEADER *h;
        HGSMIBUFFERTAIL *t;
        size_t total_size;
        dma_addr_t offset;

        total_size = size + sizeof(HGSMIBUFFERHEADER) + sizeof(HGSMIBUFFERTAIL);
        h = gen_pool_dma_alloc(guest_pool, total_size, &offset);
        if (!h)
                return NULL;

        t = (HGSMIBUFFERTAIL *)((u8 *)h + sizeof(HGSMIBUFFERHEADER) + size);

        h->u8Flags = HGSMI_BUFFER_HEADER_F_SEQ_SINGLE;
        h->u32DataSize = size;
        h->u8Channel = channel;
        h->u16ChannelInfo = channel_info;
        memset(&h->u.au8Union, 0, sizeof(h->u.au8Union));

        t->u32Reserved = 0;
        t->u32Checksum = hgsmi_checksum(offset, h, t);

        return (u8 *)h + sizeof(HGSMIBUFFERHEADER);
}

void hgsmi_buffer_free(struct gen_pool *guest_pool, void *buf)
{
        HGSMIBUFFERHEADER *h =
                (HGSMIBUFFERHEADER *)((u8 *)buf - sizeof(HGSMIBUFFERHEADER));
        size_t total_size = h->u32DataSize + sizeof(HGSMIBUFFERHEADER) +
                                             sizeof(HGSMIBUFFERTAIL);

        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(HGSMIBUFFERHEADER));
        outl(offset, VGA_PORT_HGSMI_GUEST);
        /* Make the compiler aware that the host has changed memory. */
        mb();

        return VINF_SUCCESS;
}