drm/shared-core/via_verifier.c

/*
 * Copyright 2004 The Unichrome Project. All Rights Reserved.
 * Copyright 2005 Thomas Hellstrom. All Rights Reserved.
 *
 * 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 above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * 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 AUTHOR(S), AND/OR THE COPYRIGHT HOLDER(S) 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.
 *
 * Author: Thomas Hellstrom 2004, 2005.
 * This code was written using docs obtained under NDA from VIA Inc.
 *
 * Don't run this code directly on an AGP buffer. Due to cache problems it will
 * be very slow.
 */

#include "via_3d_reg.h"
#include "drmP.h"
#include "drm.h"
#include "via_drm.h"
#include "via_verifier.h"
#include "via_drv.h"

typedef enum {
	state_command,
	state_header2,
	state_header1,
	state_vheader5,
	state_vheader6,
	state_error
} verifier_state_t;

typedef enum {
	no_check = 0,
	check_for_header2,
	check_for_header1,
	check_for_header2_err,
	check_for_header1_err,
	check_for_fire,
	check_z_buffer_addr0,
	check_z_buffer_addr1,
	check_z_buffer_addr_mode,
	check_destination_addr0,
	check_destination_addr1,
	check_destination_addr_mode,
	check_for_dummy,
	check_for_dd,
	check_texture_addr0,
	check_texture_addr1,
	check_texture_addr2,
	check_texture_addr3,
	check_texture_addr4,
	check_texture_addr5,
	check_texture_addr6,
	check_texture_addr7,
	check_texture_addr8,
	check_texture_addr_mode,
	check_for_vertex_count,
	check_number_texunits,
	forbidden_command
} hazard_t;

/*
 * Associates each hazard above with a possible multi-command
 * sequence. For example an address that is split over multiple
 * commands and that needs to be checked at the first command
 * that does not include any part of the address.
 */

static drm_via_sequence_t seqs[] = {
	no_sequence,
	no_sequence,
	no_sequence,
	no_sequence,
	no_sequence,
	no_sequence,
	z_address,
	z_address,
	z_address,
	dest_address,
	dest_address,
	dest_address,
	no_sequence,
	no_sequence,
	tex_address,
	tex_address,
	tex_address,
	tex_address,
	tex_address,
	tex_address,
	tex_address,
	tex_address,
	tex_address,
	tex_address,
	no_sequence
};

typedef struct {
	unsigned int code;
	hazard_t hz;
} hz_init_t;

static hz_init_t init_table1[] = {
	{0xf2, check_for_header2_err},
	{0xf0, check_for_header1_err},
	{0xee, check_for_fire},
	{0xcc, check_for_dummy},
	{0xdd, check_for_dd},
	{0x00, no_check},
	{0x10, check_z_buffer_addr0},
	{0x11, check_z_buffer_addr1},
	{0x12, check_z_buffer_addr_mode},
	{0x13, no_check},
	{0x14, no_check},
	{0x15, no_check},
	{0x23, no_check},
	{0x24, no_check},
	{0x33, no_check},
	{0x34, no_check},
	{0x35, no_check},
	{0x36, no_check},
	{0x37, no_check},
	{0x38, no_check},
	{0x39, no_check},
	{0x3A, no_check},
	{0x3B, no_check},
	{0x3C, no_check},
	{0x3D, no_check},
	{0x3E, no_check},
	{0x40, check_destination_addr0},
	{0x41, check_destination_addr1},
	{0x42, check_destination_addr_mode},
	{0x43, no_check},
	{0x44, no_check},
	{0x50, no_check},
	{0x51, no_check},
	{0x52, no_check},
	{0x53, no_check},
	{0x54, no_check},
	{0x55, no_check},
	{0x56, no_check},
	{0x57, no_check},
	{0x58, no_check},
	{0x70, no_check},
	{0x71, no_check},
	{0x78, no_check},
	{0x79, no_check},
	{0x7A, no_check},
	{0x7B, no_check},
	{0x7C, no_check},
	{0x7D, check_for_vertex_count}
};

static hz_init_t init_table2[] = {
	{0xf2, check_for_header2_err},
	{0xf0, check_for_header1_err},
	{0xee, check_for_fire},
	{0xcc, check_for_dummy},
	{0x00, check_texture_addr0},
	{0x01, check_texture_addr0},
	{0x02, check_texture_addr0},
	{0x03, check_texture_addr0},
	{0x04, check_texture_addr0},
	{0x05, check_texture_addr0},
	{0x06, check_texture_addr0},
	{0x07, check_texture_addr0},
	{0x08, check_texture_addr0},
	{0x09, check_texture_addr0},
	{0x20, check_texture_addr1},
	{0x21, check_texture_addr1},
	{0x22, check_texture_addr1},
	{0x23, check_texture_addr4},
	{0x2B, check_texture_addr3},
	{0x2C, check_texture_addr3},
	{0x2D, check_texture_addr3},
	{0x2E, check_texture_addr3},
	{0x2F, check_texture_addr3},
	{0x30, check_texture_addr3},
	{0x31, check_texture_addr3},
	{0x32, check_texture_addr3},
	{0x33, check_texture_addr3},
	{0x34, check_texture_addr3},
	{0x4B, check_texture_addr5},
	{0x4C, check_texture_addr6},
	{0x51, check_texture_addr7},
	{0x52, check_texture_addr8},
	{0x77, check_texture_addr2},
	{0x78, no_check},
	{0x79, no_check},
	{0x7A, no_check},
	{0x7B, check_texture_addr_mode},
	{0x7C, no_check},
	{0x7D, no_check},
	{0x7E, no_check},
	{0x7F, no_check},
	{0x80, no_check},
	{0x81, no_check},
	{0x82, no_check},
	{0x83, no_check},
	{0x85, no_check},
	{0x86, no_check},
	{0x87, no_check},
	{0x88, no_check},
	{0x89, no_check},
	{0x8A, no_check},
	{0x90, no_check},
	{0x91, no_check},
	{0x92, no_check},
	{0x93, no_check}
};

static hz_init_t init_table3[] = {
	{0xf2, check_for_header2_err},
	{0xf0, check_for_header1_err},
	{0xcc, check_for_dummy},
	{0x00, check_number_texunits}
};

static hazard_t table1[256];
static hazard_t table2[256];
static hazard_t table3[256];

static __inline__ int
eat_words(const uint32_t ** buf, const uint32_t * buf_end, unsigned num_words)
{
	if ((buf_end - *buf) >= num_words) {
		*buf += num_words;
		return 0;
	}
	DRM_ERROR("Illegal termination of DMA command buffer\n");
	return 1;
}

/*
 * Partially stolen from drm_memory.h
 */

static __inline__ drm_local_map_t *via_drm_lookup_agp_map(drm_via_state_t *seq,
							  unsigned long offset,
							  unsigned long size,
							  struct drm_device *dev)
{
#ifdef __linux__
	struct drm_map_list *r_list;
#endif
	drm_local_map_t *map = seq->map_cache;

	if (map && map->offset <= offset
	    && (offset + size) <= (map->offset + map->size)) {
		return map;
	}
#ifdef __linux__
	list_for_each_entry(r_list, &dev->maplist, head) {
		map = r_list->map;
		if (!map)
			continue;
#else
	TAILQ_FOREACH(map, &dev->maplist, link) {
#endif
		if (map->offset <= offset
		    && (offset + size) <= (map->offset + map->size)
		    && !(map->flags & _DRM_RESTRICTED)
		    && (map->type == _DRM_AGP)) {
			seq->map_cache = map;
			return map;
		}
	}
	return NULL;
}

/*
 * Require that all AGP texture levels reside in the same AGP map which should
 * be mappable by the client. This is not a big restriction.
 * FIXME: To actually enforce this security policy strictly, drm_rmmap
 * would have to wait for dma quiescent before removing an AGP map.
 * The via_drm_lookup_agp_map call in reality seems to take
 * very little CPU time.
 */

static __inline__ int finish_current_sequence(drm_via_state_t * cur_seq)
{
	switch (cur_seq->unfinished) {
	case z_address:
		DRM_DEBUG("Z Buffer start address is 0x%x\n", cur_seq->z_addr);
		break;
	case dest_address:
		DRM_DEBUG("Destination start address is 0x%x\n",
			  cur_seq->d_addr);
		break;
	case tex_address:
		if (cur_seq->agp_texture) {
			unsigned start =
			    cur_seq->tex_level_lo[cur_seq->texture];
			unsigned end = cur_seq->tex_level_hi[cur_seq->texture];
			unsigned long lo = ~0, hi = 0, tmp;
			uint32_t *addr, *pitch, *height, tex;
			unsigned i;
			int npot;

			if (end > 9)
				end = 9;
			if (start > 9)
				start = 9;

			addr =
			    &(cur_seq->t_addr[tex = cur_seq->texture][start]);
			pitch = &(cur_seq->pitch[tex][start]);
			height = &(cur_seq->height[tex][start]);
			npot = cur_seq->tex_npot[tex];
			for (i = start; i <= end; ++i) {
				tmp = *addr++;
				if (tmp < lo)
					lo = tmp;
				if (i == 0 && npot)
					tmp += (*height++ * *pitch++);
				else
					tmp += (*height++ << *pitch++);
				if (tmp > hi)
					hi = tmp;
			}

			if (!via_drm_lookup_agp_map
			    (cur_seq, lo, hi - lo, cur_seq->dev)) {
				DRM_ERROR
				    ("AGP texture is not in allowed map\n");
				return 2;
			}
		}
		break;
	default:
		break;
	}
	cur_seq->unfinished = no_sequence;
	return 0;
}

static __inline__ int
investigate_hazard(uint32_t cmd, hazard_t hz, drm_via_state_t * cur_seq)
{
	register uint32_t tmp, *tmp_addr;

	if (cur_seq->unfinished && (cur_seq->unfinished != seqs[hz])) {
		int ret;
		if ((ret = finish_current_sequence(cur_seq)))
			return ret;
	}

	switch (hz) {
	case check_for_header2:
		if (cmd == HALCYON_HEADER2)
			return 1;
		return 0;
	case check_for_header1:
		if ((cmd & HALCYON_HEADER1MASK) == HALCYON_HEADER1)
			return 1;
		return 0;
	case check_for_header2_err:
		if (cmd == HALCYON_HEADER2)
			return 1;
		DRM_ERROR("Illegal DMA HALCYON_HEADER2 command\n");
		break;
	case check_for_header1_err:
		if ((cmd & HALCYON_HEADER1MASK) == HALCYON_HEADER1)
			return 1;
		DRM_ERROR("Illegal DMA HALCYON_HEADER1 command\n");
		break;
	case check_for_fire:
		if ((cmd & HALCYON_FIREMASK) == HALCYON_FIRECMD)
			return 1;
		DRM_ERROR("Illegal DMA HALCYON_FIRECMD command\n");
		break;
	case check_for_dummy:
		if (HC_DUMMY == cmd)
			return 0;
		DRM_ERROR("Illegal DMA HC_DUMMY command\n");
		break;
	case check_for_dd:
		if (0xdddddddd == cmd)
			return 0;
		DRM_ERROR("Illegal DMA 0xdddddddd command\n");
		break;
	case check_z_buffer_addr0:
		cur_seq->unfinished = z_address;
		cur_seq->z_addr = (cur_seq->z_addr & 0xFF000000) |
		    (cmd & 0x00FFFFFF);
		return 0;
	case check_z_buffer_addr1:
		cur_seq->unfinished = z_address;
		cur_seq->z_addr = (cur_seq->z_addr & 0x00FFFFFF) |
		    ((cmd & 0xFF) << 24);
		return 0;
	case check_z_buffer_addr_mode:
		cur_seq->unfinished = z_address;
		if ((cmd & 0x0000C000) == 0)
			return 0;
		DRM_ERROR("Attempt to place Z buffer in system memory\n");
		return 2;
	case check_destination_addr0:
		cur_seq->unfinished = dest_address;
		cur_seq->d_addr = (cur_seq->d_addr & 0xFF000000) |
		    (cmd & 0x00FFFFFF);
		return 0;
	case check_destination_addr1:
		cur_seq->unfinished = dest_address;
		cur_seq->d_addr = (cur_seq->d_addr & 0x00FFFFFF) |
		    ((cmd & 0xFF) << 24);
		return 0;
	case check_destination_addr_mode:
		cur_seq->unfinished = dest_address;
		if ((cmd & 0x0000C000) == 0)
			return 0;
		DRM_ERROR
		    ("Attempt to place 3D drawing buffer in system memory\n");
		return 2;
	case check_texture_addr0:
		cur_seq->unfinished = tex_address;
		tmp = (cmd >> 24);
		tmp_addr = &cur_seq->t_addr[cur_seq->texture][tmp];
		*tmp_addr = (*tmp_addr & 0xFF000000) | (cmd & 0x00FFFFFF);
		return 0;
	case check_texture_addr1:
		cur_seq->unfinished = tex_address;
		tmp = ((cmd >> 24) - 0x20);
		tmp += tmp << 1;
		tmp_addr = &cur_seq->t_addr[cur_seq->texture][tmp];
		*tmp_addr = (*tmp_addr & 0x00FFFFFF) | ((cmd & 0xFF) << 24);
		tmp_addr++;
		*tmp_addr = (*tmp_addr & 0x00FFFFFF) | ((cmd & 0xFF00) << 16);
		tmp_addr++;
		*tmp_addr = (*tmp_addr & 0x00FFFFFF) | ((cmd & 0xFF0000) << 8);
		return 0;
	case check_texture_addr2:
		cur_seq->unfinished = tex_address;
		cur_seq->tex_level_lo[tmp = cur_seq->texture] = cmd & 0x3F;
		cur_seq->tex_level_hi[tmp] = (cmd & 0xFC0) >> 6;
		return 0;
	case check_texture_addr3:
		cur_seq->unfinished = tex_address;
		tmp = ((cmd >> 24) - HC_SubA_HTXnL0Pit);
		if (tmp == 0 &&
		    (cmd & HC_HTXnEnPit_MASK)) {
			cur_seq->pitch[cur_seq->texture][tmp] =
				(cmd & HC_HTXnLnPit_MASK);
			cur_seq->tex_npot[cur_seq->texture] = 1;
		} else {
			cur_seq->pitch[cur_seq->texture][tmp] =
				(cmd & HC_HTXnLnPitE_MASK) >> HC_HTXnLnPitE_SHIFT;
			cur_seq->tex_npot[cur_seq->texture] = 0;
			if (cmd & 0x000FFFFF) {
				DRM_ERROR
					("Unimplemented texture level 0 pitch mode.\n");
				return 2;
			}
		}
		return 0;
	case check_texture_addr4:
		cur_seq->unfinished = tex_address;
		tmp_addr = &cur_seq->t_addr[cur_seq->texture][9];
		*tmp_addr = (*tmp_addr & 0x00FFFFFF) | ((cmd & 0xFF) << 24);
		return 0;
	case check_texture_addr5:
	case check_texture_addr6:
		cur_seq->unfinished = tex_address;
		/*
		 * Texture width. We don't care since we have the pitch.
		 */
		return 0;
	case check_texture_addr7:
		cur_seq->unfinished = tex_address;
		tmp_addr = &(cur_seq->height[cur_seq->texture][0]);
		tmp_addr[5] = 1 << ((cmd & 0x00F00000) >> 20);
		tmp_addr[4] = 1 << ((cmd & 0x000F0000) >> 16);
		tmp_addr[3] = 1 << ((cmd & 0x0000F000) >> 12);
		tmp_addr[2] = 1 << ((cmd & 0x00000F00) >> 8);
		tmp_addr[1] = 1 << ((cmd & 0x000000F0) >> 4);
		tmp_addr[0] = 1 << (cmd & 0x0000000F);
		return 0;
	case check_texture_addr8:
		cur_seq->unfinished = tex_address;
		tmp_addr = &(cur_seq->height[cur_seq->texture][0]);
		tmp_addr[9] = 1 << ((cmd & 0x0000F000) >> 12);
		tmp_addr[8] = 1 << ((cmd & 0x00000F00) >> 8);
		tmp_addr[7] = 1 << ((cmd & 0x000000F0) >> 4);
		tmp_addr[6] = 1 << (cmd & 0x0000000F);
		return 0;
	case check_texture_addr_mode:
		cur_seq->unfinished = tex_address;
		if (2 == (tmp = cmd & 0x00000003)) {
			DRM_ERROR
			    ("Attempt to fetch texture from system memory.\n");
			return 2;
		}
		cur_seq->agp_texture = (tmp == 3);
		cur_seq->tex_palette_size[cur_seq->texture] =
		    (cmd >> 16) & 0x000000007;
		return 0;
	case check_for_vertex_count:
		cur_seq->vertex_count = cmd & 0x0000FFFF;
		return 0;
	case check_number_texunits:
		cur_seq->multitex = (cmd >> 3) & 1;
		return 0;
	default:
		DRM_ERROR("Illegal DMA data: 0x%x\n", cmd);
		return 2;
	}
	return 2;
}

static __inline__ int
via_check_prim_list(uint32_t const **buffer, const uint32_t * buf_end,
		    drm_via_state_t * cur_seq)
{
	drm_via_private_t *dev_priv =
	    (drm_via_private_t *) cur_seq->dev->dev_private;
	uint32_t a_fire, bcmd, dw_count;
	int ret = 0;
	int have_fire;
	const uint32_t *buf = *buffer;

	while (buf < buf_end) {
		have_fire = 0;
		if ((buf_end - buf) < 2) {
			DRM_ERROR
			    ("Unexpected termination of primitive list.\n");
			ret = 1;
			break;
		}
		if ((*buf & HC_ACMD_MASK) != HC_ACMD_HCmdB)
			break;
		bcmd = *buf++;
		if ((*buf & HC_ACMD_MASK) != HC_ACMD_HCmdA) {
			DRM_ERROR("Expected Vertex List A command, got 0x%x\n",
				  *buf);
			ret = 1;
			break;
		}
		a_fire =
		    *buf++ | HC_HPLEND_MASK | HC_HPMValidN_MASK |
		    HC_HE3Fire_MASK;

		/*
		 * How many dwords per vertex ?
		 */

		if (cur_seq->agp && ((bcmd & (0xF << 11)) == 0)) {
			DRM_ERROR("Illegal B command vertex data for AGP.\n");
			ret = 1;
			break;
		}

		dw_count = 0;
		if (bcmd & (1 << 7))
			dw_count += (cur_seq->multitex) ? 2 : 1;
		if (bcmd & (1 << 8))
			dw_count += (cur_seq->multitex) ? 2 : 1;
		if (bcmd & (1 << 9))
			dw_count++;
		if (bcmd & (1 << 10))
			dw_count++;
		if (bcmd & (1 << 11))
			dw_count++;
		if (bcmd & (1 << 12))
			dw_count++;
		if (bcmd & (1 << 13))
			dw_count++;
		if (bcmd & (1 << 14))
			dw_count++;

		while (buf < buf_end) {
			if (*buf == a_fire) {
				if (dev_priv->num_fire_offsets >=
				    VIA_FIRE_BUF_SIZE) {
					DRM_ERROR("Fire offset buffer full.\n");
					ret = 1;
					break;
				}
				dev_priv->fire_offsets[dev_priv->
						       num_fire_offsets++] =
				    buf;
				have_fire = 1;
				buf++;
				if (buf < buf_end && *buf == a_fire)
					buf++;
				break;
			}
			if ((*buf == HALCYON_HEADER2) ||
			    ((*buf & HALCYON_FIREMASK) == HALCYON_FIRECMD)) {
				DRM_ERROR("Missing Vertex Fire command, "
					  "Stray Vertex Fire command  or verifier "
					  "lost sync.\n");
				ret = 1;
				break;
			}
			if ((ret = eat_words(&buf, buf_end, dw_count)))
				break;
		}
		if (buf >= buf_end && !have_fire) {
			DRM_ERROR("Missing Vertex Fire command or verifier "
				  "lost sync.\n");
			ret = 1;
			break;
		}
		if (cur_seq->agp && ((buf - cur_seq->buf_start) & 0x01)) {
			DRM_ERROR("AGP Primitive list end misaligned.\n");
			ret = 1;
			break;
		}
	}
	*buffer = buf;
	return ret;
}

static __inline__ verifier_state_t
via_check_header2(uint32_t const **buffer, const uint32_t * buf_end,
		  drm_via_state_t * hc_state)
{
	uint32_t cmd;
	int hz_mode;
	hazard_t hz;
	const uint32_t *buf = *buffer;
	const hazard_t *hz_table;

	if ((buf_end - buf) < 2) {
		DRM_ERROR
		    ("Illegal termination of DMA HALCYON_HEADER2 sequence.\n");
		return state_error;
	}
	buf++;
	cmd = (*buf++ & 0xFFFF0000) >> 16;

	switch (cmd) {
	case HC_ParaType_CmdVdata:
		if (via_check_prim_list(&buf, buf_end, hc_state))
			return state_error;
		*buffer = buf;
		return state_command;
	case HC_ParaType_NotTex:
		hz_table = table1;
		break;
	case HC_ParaType_Tex:
		hc_state->texture = 0;
		hz_table = table2;
		break;
	case (HC_ParaType_Tex | (HC_SubType_Tex1 << 8)):
		hc_state->texture = 1;
		hz_table = table2;
		break;
	case (HC_ParaType_Tex | (HC_SubType_TexGeneral << 8)):
		hz_table = table3;
		break;
	case HC_ParaType_Auto:
		if (eat_words(&buf, buf_end, 2))
			return state_error;
		*buffer = buf;
		return state_command;
	case (HC_ParaType_Palette | (HC_SubType_Stipple << 8)):
		if (eat_words(&buf, buf_end, 32))
			return state_error;
		*buffer = buf;
		return state_command;
	case (HC_ParaType_Palette | (HC_SubType_TexPalette0 << 8)):
	case (HC_ParaType_Palette | (HC_SubType_TexPalette1 << 8)):
		DRM_ERROR("Texture palettes are rejected because of "
			  "lack of info how to determine their size.\n");
		return state_error;
	case (HC_ParaType_Palette | (HC_SubType_FogTable << 8)):
		DRM_ERROR("Fog factor palettes are rejected because of "
			  "lack of info how to determine their size.\n");
		return state_error;
	default:

		/*
		 * There are some unimplemented HC_ParaTypes here, that
		 * need to be implemented if the Mesa driver is extended.
		 */

		DRM_ERROR("Invalid or unimplemented HALCYON_HEADER2 "
			  "DMA subcommand: 0x%x. Previous dword: 0x%x\n",
			  cmd, *(buf - 2));
		*buffer = buf;
		return state_error;
	}

	while (buf < buf_end) {
		cmd = *buf++;
		if ((hz = hz_table[cmd >> 24])) {
			if ((hz_mode = investigate_hazard(cmd, hz, hc_state))) {
				if (hz_mode == 1) {
					buf--;
					break;
				}
				return state_error;
			}
		} else if (hc_state->unfinished &&
			   finish_current_sequence(hc_state)) {
			return state_error;
		}
	}
	if (hc_state->unfinished && finish_current_sequence(hc_state)) {
		return state_error;
	}
	*buffer = buf;
	return state_command;
}

static __inline__ verifier_state_t
via_parse_header2(drm_via_private_t * dev_priv, uint32_t const **buffer,
		  const uint32_t * buf_end, int *fire_count)
{
	uint32_t cmd;
	const uint32_t *buf = *buffer;
	const uint32_t *next_fire;
	int burst = 0;

	next_fire = dev_priv->fire_offsets[*fire_count];
	buf++;
	cmd = (*buf & 0xFFFF0000) >> 16;
	VIA_WRITE(HC_REG_TRANS_SET + HC_REG_BASE, *buf++);
	switch (cmd) {
	case HC_ParaType_CmdVdata:
		while ((buf < buf_end) &&
		       (*fire_count < dev_priv->num_fire_offsets) &&
		       (*buf & HC_ACMD_MASK) == HC_ACMD_HCmdB) {
			while (buf <= next_fire) {
				VIA_WRITE(HC_REG_TRANS_SPACE + HC_REG_BASE +
					  (burst & 63), *buf++);
				burst += 4;
			}
			if ((buf < buf_end)
			    && ((*buf & HALCYON_FIREMASK) == HALCYON_FIRECMD))
				buf++;

			if (++(*fire_count) < dev_priv->num_fire_offsets)
				next_fire = dev_priv->fire_offsets[*fire_count];
		}
		break;
	default:
		while (buf < buf_end) {

			if (*buf == HC_HEADER2 ||
			    (*buf & HALCYON_HEADER1MASK) == HALCYON_HEADER1 ||
			    (*buf & VIA_VIDEOMASK) == VIA_VIDEO_HEADER5 ||
			    (*buf & VIA_VIDEOMASK) == VIA_VIDEO_HEADER6)
				break;

			VIA_WRITE(HC_REG_TRANS_SPACE + HC_REG_BASE +
				  (burst & 63), *buf++);
			burst += 4;
		}
	}
	*buffer = buf;
	return state_command;
}

static __inline__ int verify_mmio_address(uint32_t address)
{
	if ((address > 0x3FF) && (address < 0xC00)) {
		DRM_ERROR("Invalid VIDEO DMA command. "
			  "Attempt to access 3D- or command burst area.\n");
		return 1;
	} else if ((address > 0xCFF) && (address < 0x1300)) {
		DRM_ERROR("Invalid VIDEO DMA command. "
			  "Attempt to access PCI DMA area.\n");
		return 1;
	} else if (address > 0x13FF) {
		DRM_ERROR("Invalid VIDEO DMA command. "
			  "Attempt to access VGA registers.\n");
		return 1;
	}
	return 0;
}

static __inline__ int
verify_video_tail(uint32_t const **buffer, const uint32_t * buf_end,
		  uint32_t dwords)
{
	const uint32_t *buf = *buffer;

	if (buf_end - buf < dwords) {
		DRM_ERROR("Illegal termination of video command.\n");
		return 1;
	}
	while (dwords--) {
		if (*buf++) {
			DRM_ERROR("Illegal video command tail.\n");
			return 1;
		}
	}
	*buffer = buf;
	return 0;
}

static __inline__ verifier_state_t
via_check_header1(uint32_t const **buffer, const uint32_t * buf_end)
{
	uint32_t cmd;
	const uint32_t *buf = *buffer;
	verifier_state_t ret = state_command;

	while (buf < buf_end) {
		cmd = *buf;
		if ((cmd > ((0x3FF >> 2) | HALCYON_HEADER1)) &&
		    (cmd < ((0xC00 >> 2) | HALCYON_HEADER1))) {
			if ((cmd & HALCYON_HEADER1MASK) != HALCYON_HEADER1)
				break;
			DRM_ERROR("Invalid HALCYON_HEADER1 command. "
				  "Attempt to access 3D- or command burst area.\n");
			ret = state_error;
			break;
		} else if (cmd > ((0xCFF >> 2) | HALCYON_HEADER1)) {
			if ((cmd & HALCYON_HEADER1MASK) != HALCYON_HEADER1)
				break;
			DRM_ERROR("Invalid HALCYON_HEADER1 command. "
				  "Attempt to access VGA registers.\n");
			ret = state_error;
			break;
		} else {
			buf += 2;
		}
	}
	*buffer = buf;
	return ret;
}

static __inline__ verifier_state_t
via_parse_header1(drm_via_private_t * dev_priv, uint32_t const **buffer,
		  const uint32_t * buf_end)
{
	register uint32_t cmd;
	const uint32_t *buf = *buffer;

	while (buf < buf_end) {
		cmd = *buf;
		if ((cmd & HALCYON_HEADER1MASK) != HALCYON_HEADER1)
			break;
		VIA_WRITE((cmd & ~HALCYON_HEADER1MASK) << 2, *++buf);
		buf++;
	}
	*buffer = buf;
	return state_command;
}

static __inline__ verifier_state_t
via_check_vheader5(uint32_t const **buffer, const uint32_t * buf_end)
{
	uint32_t data;
	const uint32_t *buf = *buffer;

	if (buf_end - buf < 4) {
		DRM_ERROR("Illegal termination of video header5 command\n");
		return state_error;
	}

	data = *buf++ & ~VIA_VIDEOMASK;
	if (verify_mmio_address(data))
		return state_error;

	data = *buf++;
	if (*buf++ != 0x00F50000) {
		DRM_ERROR("Illegal header5 header data\n");
		return state_error;
	}
	if (*buf++ != 0x00000000) {
		DRM_ERROR("Illegal header5 header data\n");
		return state_error;
	}
	if (eat_words(&buf, buf_end, data))
		return state_error;
	if ((data & 3) && verify_video_tail(&buf, buf_end, 4 - (data & 3)))
		return state_error;
	*buffer = buf;
	return state_command;

}

static __inline__ verifier_state_t
via_parse_vheader5(drm_via_private_t * dev_priv, uint32_t const **buffer,
		   const uint32_t * buf_end)
{
	uint32_t addr, count, i;
	const uint32_t *buf = *buffer;

	addr = *buf++ & ~VIA_VIDEOMASK;
	i = count = *buf;
	buf += 3;
	while (i--) {
		VIA_WRITE(addr, *buf++);
	}
	if (count & 3)
		buf += 4 - (count & 3);
	*buffer = buf;
	return state_command;
}

static __inline__ verifier_state_t
via_check_vheader6(uint32_t const **buffer, const uint32_t * buf_end)
{
	uint32_t data;
	const uint32_t *buf = *buffer;
	uint32_t i;

	if (buf_end - buf < 4) {
		DRM_ERROR("Illegal termination of video header6 command\n");
		return state_error;
	}
	buf++;
	data = *buf++;
	if (*buf++ != 0x00F60000) {
		DRM_ERROR("Illegal header6 header data\n");
		return state_error;
	}
	if (*buf++ != 0x00000000) {
		DRM_ERROR("Illegal header6 header data\n");
		return state_error;
	}
	if ((buf_end - buf) < (data << 1)) {
		DRM_ERROR("Illegal termination of video header6 command\n");
		return state_error;
	}
	for (i = 0; i < data; ++i) {
		if (verify_mmio_address(*buf++))
			return state_error;
		buf++;
	}
	data <<= 1;
	if ((data & 3) && verify_video_tail(&buf, buf_end, 4 - (data & 3)))
		return state_error;
	*buffer = buf;
	return state_command;
}

static __inline__ verifier_state_t
via_parse_vheader6(drm_via_private_t * dev_priv, uint32_t const **buffer,
		   const uint32_t * buf_end)
{

	uint32_t addr, count, i;
	const uint32_t *buf = *buffer;

	i = count = *++buf;
	buf += 3;
	while (i--) {
		addr = *buf++;
		VIA_WRITE(addr, *buf++);
	}
	count <<= 1;
	if (count & 3)
		buf += 4 - (count & 3);
	*buffer = buf;
	return state_command;
}

int
via_verify_command_stream(const uint32_t * buf, unsigned int size,
			  struct drm_device * dev, int agp)
{

	drm_via_private_t *dev_priv = (drm_via_private_t *) dev->dev_private;
	drm_via_state_t *hc_state = &dev_priv->hc_state;
	drm_via_state_t saved_state = *hc_state;
	uint32_t cmd;
	const uint32_t *buf_end = buf + (size >> 2);
	verifier_state_t state = state_command;
	int cme_video;
	int supported_3d;

	cme_video = (dev_priv->chipset == VIA_PRO_GROUP_A ||
		     dev_priv->chipset == VIA_DX9_0);

	supported_3d = dev_priv->chipset != VIA_DX9_0;

	hc_state->dev = dev;
	hc_state->unfinished = no_sequence;
	hc_state->map_cache = NULL;
	hc_state->agp = agp;
	hc_state->buf_start = buf;
	dev_priv->num_fire_offsets = 0;

	while (buf < buf_end) {

		switch (state) {
		case state_header2:
			state = via_check_header2(&buf, buf_end, hc_state);
			break;
		case state_header1:
			state = via_check_header1(&buf, buf_end);
			break;
		case state_vheader5:
			state = via_check_vheader5(&buf, buf_end);
			break;
		case state_vheader6:
			state = via_check_vheader6(&buf, buf_end);
			break;
		case state_command:
			if ((HALCYON_HEADER2 == (cmd = *buf)) &&
			    supported_3d)
				state = state_header2;
			else if ((cmd & HALCYON_HEADER1MASK) == HALCYON_HEADER1)
				state = state_header1;
			else if (cme_video
				 && (cmd & VIA_VIDEOMASK) == VIA_VIDEO_HEADER5)
				state = state_vheader5;
			else if (cme_video
				 && (cmd & VIA_VIDEOMASK) == VIA_VIDEO_HEADER6)
				state = state_vheader6;
			else if ((cmd == HALCYON_HEADER2) && !supported_3d) {
				DRM_ERROR("Accelerated 3D is not supported on this chipset yet.\n");
				state = state_error;
			} else {
				DRM_ERROR
				    ("Invalid / Unimplemented DMA HEADER command. 0x%x\n",
				     cmd);
				state = state_error;
			}
			break;
		case state_error:
		default:
			*hc_state = saved_state;
			return -EINVAL;
		}
	}
	if (state == state_error) {
		*hc_state = saved_state;
		return -EINVAL;
	}
	return 0;
}

int
via_parse_command_stream(struct drm_device * dev, const uint32_t * buf,
			 unsigned int size)
{

	drm_via_private_t *dev_priv = (drm_via_private_t *) dev->dev_private;
	uint32_t cmd;
	const uint32_t *buf_end = buf + (size >> 2);
	verifier_state_t state = state_command;
	int fire_count = 0;

	while (buf < buf_end) {

		switch (state) {
		case state_header2:
			state =
			    via_parse_header2(dev_priv, &buf, buf_end,
					      &fire_count);
			break;
		case state_header1:
			state = via_parse_header1(dev_priv, &buf, buf_end);
			break;
		case state_vheader5:
			state = via_parse_vheader5(dev_priv, &buf, buf_end);
			break;
		case state_vheader6:
			state = via_parse_vheader6(dev_priv, &buf, buf_end);
			break;
		case state_command:
			if (HALCYON_HEADER2 == (cmd = *buf))
				state = state_header2;
			else if ((cmd & HALCYON_HEADER1MASK) == HALCYON_HEADER1)
				state = state_header1;
			else if ((cmd & VIA_VIDEOMASK) == VIA_VIDEO_HEADER5)
				state = state_vheader5;
			else if ((cmd & VIA_VIDEOMASK) == VIA_VIDEO_HEADER6)
				state = state_vheader6;
			else {
				DRM_ERROR
				    ("Invalid / Unimplemented DMA HEADER command. 0x%x\n",
				     cmd);
				state = state_error;
			}
			break;
		case state_error:
		default:
			return -EINVAL;
		}
	}
	if (state == state_error) {
		return -EINVAL;
	}
	return 0;
}

static void
setup_hazard_table(hz_init_t init_table[], hazard_t table[], int size)
{
	int i;

	for (i = 0; i < 256; ++i) {
		table[i] = forbidden_command;
	}

	for (i = 0; i < size; ++i) {
		table[init_table[i].code] = init_table[i].hz;
	}
}

void via_init_command_verifier(void)
{
	setup_hazard_table(init_table1, table1,
			   sizeof(init_table1) / sizeof(hz_init_t));
	setup_hazard_table(init_table2, table2,
			   sizeof(init_table2) / sizeof(hz_init_t));
	setup_hazard_table(init_table3, table3,
			   sizeof(init_table3) / sizeof(hz_init_t));
}