1/* via_dma.c -- DMA support for the VIA Unichrome/Pro
2 *
3 * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
4 * All Rights Reserved.
5 *
6 * Copyright 2004 Digeo, Inc., Palo Alto, CA, U.S.A.
7 * All Rights Reserved.
8 *
9 * Copyright 2004 The Unichrome project.
10 * All Rights Reserved.
11 *
12 * Permission is hereby granted, free of charge, to any person obtaining a
13 * copy of this software and associated documentation files (the "Software"),
14 * to deal in the Software without restriction, including without limitation
15 * the rights to use, copy, modify, merge, publish, distribute, sub license,
16 * and/or sell copies of the Software, and to permit persons to whom the
17 * Software is furnished to do so, subject to the following conditions:
18 *
19 * The above copyright notice and this permission notice (including the
20 * next paragraph) shall be included in all copies or substantial portions
21 * of the Software.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
26 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
27 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
28 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
29 * USE OR OTHER DEALINGS IN THE SOFTWARE.
30 *
31 * Authors:
32 *    Tungsten Graphics,
33 *    Erdi Chen,
34 *    Thomas Hellstrom.
35 */
36
37#include <drm/drmP.h>
38#include <drm/via_drm.h>
39#include "via_drv.h"
40#include "via_3d_reg.h"
41
42#define CMDBUF_ALIGNMENT_SIZE   (0x100)
43#define CMDBUF_ALIGNMENT_MASK   (0x0ff)
44
45/* defines for VIA 3D registers */
46#define VIA_REG_STATUS          0x400
47#define VIA_REG_TRANSET         0x43C
48#define VIA_REG_TRANSPACE       0x440
49
50/* VIA_REG_STATUS(0x400): Engine Status */
51#define VIA_CMD_RGTR_BUSY       0x00000080	/* Command Regulator is busy */
52#define VIA_2D_ENG_BUSY         0x00000001	/* 2D Engine is busy */
53#define VIA_3D_ENG_BUSY         0x00000002	/* 3D Engine is busy */
54#define VIA_VR_QUEUE_BUSY       0x00020000	/* Virtual Queue is busy */
55
56#define SetReg2DAGP(nReg, nData) {				\
57	*((uint32_t *)(vb)) = ((nReg) >> 2) | HALCYON_HEADER1;	\
58	*((uint32_t *)(vb) + 1) = (nData);			\
59	vb = ((uint32_t *)vb) + 2;				\
60	dev_priv->dma_low += 8;					\
61}
62
63#define via_flush_write_combine() mb()
64
65#define VIA_OUT_RING_QW(w1, w2)	do {		\
66	*vb++ = (w1);				\
67	*vb++ = (w2);				\
68	dev_priv->dma_low += 8;			\
69} while (0)
70
71static void via_cmdbuf_start(drm_via_private_t *dev_priv);
72static void via_cmdbuf_pause(drm_via_private_t *dev_priv);
73static void via_cmdbuf_reset(drm_via_private_t *dev_priv);
74static void via_cmdbuf_rewind(drm_via_private_t *dev_priv);
75static int via_wait_idle(drm_via_private_t *dev_priv);
76static void via_pad_cache(drm_via_private_t *dev_priv, int qwords);
77
78/*
79 * Free space in command buffer.
80 */
81
82static uint32_t via_cmdbuf_space(drm_via_private_t *dev_priv)
83{
84	uint32_t agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
85	uint32_t hw_addr = *(dev_priv->hw_addr_ptr) - agp_base;
86
87	return ((hw_addr <= dev_priv->dma_low) ?
88		(dev_priv->dma_high + hw_addr - dev_priv->dma_low) :
89		(hw_addr - dev_priv->dma_low));
90}
91
92/*
93 * How much does the command regulator lag behind?
94 */
95
96static uint32_t via_cmdbuf_lag(drm_via_private_t *dev_priv)
97{
98	uint32_t agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
99	uint32_t hw_addr = *(dev_priv->hw_addr_ptr) - agp_base;
100
101	return ((hw_addr <= dev_priv->dma_low) ?
102		(dev_priv->dma_low - hw_addr) :
103		(dev_priv->dma_wrap + dev_priv->dma_low - hw_addr));
104}
105
106/*
107 * Check that the given size fits in the buffer, otherwise wait.
108 */
109
110static inline int
111via_cmdbuf_wait(drm_via_private_t *dev_priv, unsigned int size)
112{
113	uint32_t agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
114	uint32_t cur_addr, hw_addr, next_addr;
115	volatile uint32_t *hw_addr_ptr;
116	uint32_t count;
117	hw_addr_ptr = dev_priv->hw_addr_ptr;
118	cur_addr = dev_priv->dma_low;
119	next_addr = cur_addr + size + 512 * 1024;
120	count = 1000000;
121	do {
122		hw_addr = *hw_addr_ptr - agp_base;
123		if (count-- == 0) {
124			DRM_ERROR
125			    ("via_cmdbuf_wait timed out hw %x cur_addr %x next_addr %x\n",
126			     hw_addr, cur_addr, next_addr);
127			return -1;
128		}
129		if  ((cur_addr < hw_addr) && (next_addr >= hw_addr))
130			msleep(1);
131	} while ((cur_addr < hw_addr) && (next_addr >= hw_addr));
132	return 0;
133}
134
135/*
136 * Checks whether buffer head has reach the end. Rewind the ring buffer
137 * when necessary.
138 *
139 * Returns virtual pointer to ring buffer.
140 */
141
142static inline uint32_t *via_check_dma(drm_via_private_t * dev_priv,
143				      unsigned int size)
144{
145	if ((dev_priv->dma_low + size + 4 * CMDBUF_ALIGNMENT_SIZE) >
146	    dev_priv->dma_high) {
147		via_cmdbuf_rewind(dev_priv);
148	}
149	if (via_cmdbuf_wait(dev_priv, size) != 0)
150		return NULL;
151
152	return (uint32_t *) (dev_priv->dma_ptr + dev_priv->dma_low);
153}
154
155int via_dma_cleanup(struct drm_device *dev)
156{
157	if (dev->dev_private) {
158		drm_via_private_t *dev_priv =
159		    (drm_via_private_t *) dev->dev_private;
160
161		if (dev_priv->ring.virtual_start) {
162			via_cmdbuf_reset(dev_priv);
163
164			drm_legacy_ioremapfree(&dev_priv->ring.map, dev);
165			dev_priv->ring.virtual_start = NULL;
166		}
167
168	}
169
170	return 0;
171}
172
173static int via_initialize(struct drm_device *dev,
174			  drm_via_private_t *dev_priv,
175			  drm_via_dma_init_t *init)
176{
177	if (!dev_priv || !dev_priv->mmio) {
178		DRM_ERROR("via_dma_init called before via_map_init\n");
179		return -EFAULT;
180	}
181
182	if (dev_priv->ring.virtual_start != NULL) {
183		DRM_ERROR("called again without calling cleanup\n");
184		return -EFAULT;
185	}
186
187	if (!dev->agp || !dev->agp->base) {
188		DRM_ERROR("called with no agp memory available\n");
189		return -EFAULT;
190	}
191
192	if (dev_priv->chipset == VIA_DX9_0) {
193		DRM_ERROR("AGP DMA is not supported on this chip\n");
194		return -EINVAL;
195	}
196
197	dev_priv->ring.map.offset = dev->agp->base + init->offset;
198	dev_priv->ring.map.size = init->size;
199	dev_priv->ring.map.type = 0;
200	dev_priv->ring.map.flags = 0;
201	dev_priv->ring.map.mtrr = 0;
202
203	drm_legacy_ioremap(&dev_priv->ring.map, dev);
204
205	if (dev_priv->ring.map.handle == NULL) {
206		via_dma_cleanup(dev);
207		DRM_ERROR("can not ioremap virtual address for"
208			  " ring buffer\n");
209		return -ENOMEM;
210	}
211
212	dev_priv->ring.virtual_start = dev_priv->ring.map.handle;
213
214	dev_priv->dma_ptr = dev_priv->ring.virtual_start;
215	dev_priv->dma_low = 0;
216	dev_priv->dma_high = init->size;
217	dev_priv->dma_wrap = init->size;
218	dev_priv->dma_offset = init->offset;
219	dev_priv->last_pause_ptr = NULL;
220	dev_priv->hw_addr_ptr =
221		(volatile uint32_t *)((char *)dev_priv->mmio->handle +
222		init->reg_pause_addr);
223
224	via_cmdbuf_start(dev_priv);
225
226	return 0;
227}
228
229static int via_dma_init(struct drm_device *dev, void *data, struct drm_file *file_priv)
230{
231	drm_via_private_t *dev_priv = (drm_via_private_t *) dev->dev_private;
232	drm_via_dma_init_t *init = data;
233	int retcode = 0;
234
235	switch (init->func) {
236	case VIA_INIT_DMA:
237		if (!capable(CAP_SYS_ADMIN))
238			retcode = -EPERM;
239		else
240			retcode = via_initialize(dev, dev_priv, init);
241		break;
242	case VIA_CLEANUP_DMA:
243		if (!capable(CAP_SYS_ADMIN))
244			retcode = -EPERM;
245		else
246			retcode = via_dma_cleanup(dev);
247		break;
248	case VIA_DMA_INITIALIZED:
249		retcode = (dev_priv->ring.virtual_start != NULL) ?
250			0 : -EFAULT;
251		break;
252	default:
253		retcode = -EINVAL;
254		break;
255	}
256
257	return retcode;
258}
259
260static int via_dispatch_cmdbuffer(struct drm_device *dev, drm_via_cmdbuffer_t *cmd)
261{
262	drm_via_private_t *dev_priv;
263	uint32_t *vb;
264	int ret;
265
266	dev_priv = (drm_via_private_t *) dev->dev_private;
267
268	if (dev_priv->ring.virtual_start == NULL) {
269		DRM_ERROR("called without initializing AGP ring buffer.\n");
270		return -EFAULT;
271	}
272
273	if (cmd->size > VIA_PCI_BUF_SIZE)
274		return -ENOMEM;
275
276	if (copy_from_user(dev_priv->pci_buf, cmd->buf, cmd->size))
277		return -EFAULT;
278
279	/*
280	 * Running this function on AGP memory is dead slow. Therefore
281	 * we run it on a temporary cacheable system memory buffer and
282	 * copy it to AGP memory when ready.
283	 */
284
285	if ((ret =
286	     via_verify_command_stream((uint32_t *) dev_priv->pci_buf,
287				       cmd->size, dev, 1))) {
288		return ret;
289	}
290
291	vb = via_check_dma(dev_priv, (cmd->size < 0x100) ? 0x102 : cmd->size);
292	if (vb == NULL)
293		return -EAGAIN;
294
295	memcpy(vb, dev_priv->pci_buf, cmd->size);
296
297	dev_priv->dma_low += cmd->size;
298
299	/*
300	 * Small submissions somehow stalls the CPU. (AGP cache effects?)
301	 * pad to greater size.
302	 */
303
304	if (cmd->size < 0x100)
305		via_pad_cache(dev_priv, (0x100 - cmd->size) >> 3);
306	via_cmdbuf_pause(dev_priv);
307
308	return 0;
309}
310
311int via_driver_dma_quiescent(struct drm_device *dev)
312{
313	drm_via_private_t *dev_priv = dev->dev_private;
314
315	if (!via_wait_idle(dev_priv))
316		return -EBUSY;
317	return 0;
318}
319
320static int via_flush_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv)
321{
322
323	LOCK_TEST_WITH_RETURN(dev, file_priv);
324
325	return via_driver_dma_quiescent(dev);
326}
327
328static int via_cmdbuffer(struct drm_device *dev, void *data, struct drm_file *file_priv)
329{
330	drm_via_cmdbuffer_t *cmdbuf = data;
331	int ret;
332
333	LOCK_TEST_WITH_RETURN(dev, file_priv);
334
335	DRM_DEBUG("buf %p size %lu\n", cmdbuf->buf, cmdbuf->size);
336
337	ret = via_dispatch_cmdbuffer(dev, cmdbuf);
338	return ret;
339}
340
341static int via_dispatch_pci_cmdbuffer(struct drm_device *dev,
342				      drm_via_cmdbuffer_t *cmd)
343{
344	drm_via_private_t *dev_priv = dev->dev_private;
345	int ret;
346
347	if (cmd->size > VIA_PCI_BUF_SIZE)
348		return -ENOMEM;
349	if (copy_from_user(dev_priv->pci_buf, cmd->buf, cmd->size))
350		return -EFAULT;
351
352	if ((ret =
353	     via_verify_command_stream((uint32_t *) dev_priv->pci_buf,
354				       cmd->size, dev, 0))) {
355		return ret;
356	}
357
358	ret =
359	    via_parse_command_stream(dev, (const uint32_t *)dev_priv->pci_buf,
360				     cmd->size);
361	return ret;
362}
363
364static int via_pci_cmdbuffer(struct drm_device *dev, void *data, struct drm_file *file_priv)
365{
366	drm_via_cmdbuffer_t *cmdbuf = data;
367	int ret;
368
369	LOCK_TEST_WITH_RETURN(dev, file_priv);
370
371	DRM_DEBUG("buf %p size %lu\n", cmdbuf->buf, cmdbuf->size);
372
373	ret = via_dispatch_pci_cmdbuffer(dev, cmdbuf);
374	return ret;
375}
376
377static inline uint32_t *via_align_buffer(drm_via_private_t *dev_priv,
378					 uint32_t * vb, int qw_count)
379{
380	for (; qw_count > 0; --qw_count)
381		VIA_OUT_RING_QW(HC_DUMMY, HC_DUMMY);
382	return vb;
383}
384
385/*
386 * This function is used internally by ring buffer management code.
387 *
388 * Returns virtual pointer to ring buffer.
389 */
390static inline uint32_t *via_get_dma(drm_via_private_t *dev_priv)
391{
392	return (uint32_t *) (dev_priv->dma_ptr + dev_priv->dma_low);
393}
394
395/*
396 * Hooks a segment of data into the tail of the ring-buffer by
397 * modifying the pause address stored in the buffer itself. If
398 * the regulator has already paused, restart it.
399 */
400static int via_hook_segment(drm_via_private_t *dev_priv,
401			    uint32_t pause_addr_hi, uint32_t pause_addr_lo,
402			    int no_pci_fire)
403{
404	int paused, count;
405	volatile uint32_t *paused_at = dev_priv->last_pause_ptr;
406	uint32_t reader, ptr;
407	uint32_t diff;
408
409	paused = 0;
410	via_flush_write_combine();
411	(void) *(volatile uint32_t *)(via_get_dma(dev_priv) - 1);
412
413	*paused_at = pause_addr_lo;
414	via_flush_write_combine();
415	(void) *paused_at;
416
417	reader = *(dev_priv->hw_addr_ptr);
418	ptr = ((volatile char *)paused_at - dev_priv->dma_ptr) +
419		dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr + 4;
420
421	dev_priv->last_pause_ptr = via_get_dma(dev_priv) - 1;
422
423	/*
424	 * If there is a possibility that the command reader will
425	 * miss the new pause address and pause on the old one,
426	 * In that case we need to program the new start address
427	 * using PCI.
428	 */
429
430	diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
431	count = 10000000;
432	while (diff == 0 && count--) {
433		paused = (VIA_READ(0x41c) & 0x80000000);
434		if (paused)
435			break;
436		reader = *(dev_priv->hw_addr_ptr);
437		diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
438	}
439
440	paused = VIA_READ(0x41c) & 0x80000000;
441
442	if (paused && !no_pci_fire) {
443		reader = *(dev_priv->hw_addr_ptr);
444		diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
445		diff &= (dev_priv->dma_high - 1);
446		if (diff != 0 && diff < (dev_priv->dma_high >> 1)) {
447			DRM_ERROR("Paused at incorrect address. "
448				  "0x%08x, 0x%08x 0x%08x\n",
449				  ptr, reader, dev_priv->dma_diff);
450		} else if (diff == 0) {
451			/*
452			 * There is a concern that these writes may stall the PCI bus
453			 * if the GPU is not idle. However, idling the GPU first
454			 * doesn't make a difference.
455			 */
456
457			VIA_WRITE(VIA_REG_TRANSET, (HC_ParaType_PreCR << 16));
458			VIA_WRITE(VIA_REG_TRANSPACE, pause_addr_hi);
459			VIA_WRITE(VIA_REG_TRANSPACE, pause_addr_lo);
460			VIA_READ(VIA_REG_TRANSPACE);
461		}
462	}
463	return paused;
464}
465
466static int via_wait_idle(drm_via_private_t *dev_priv)
467{
468	int count = 10000000;
469
470	while (!(VIA_READ(VIA_REG_STATUS) & VIA_VR_QUEUE_BUSY) && --count)
471		;
472
473	while (count && (VIA_READ(VIA_REG_STATUS) &
474			   (VIA_CMD_RGTR_BUSY | VIA_2D_ENG_BUSY |
475			    VIA_3D_ENG_BUSY)))
476		--count;
477	return count;
478}
479
480static uint32_t *via_align_cmd(drm_via_private_t *dev_priv, uint32_t cmd_type,
481			       uint32_t addr, uint32_t *cmd_addr_hi,
482			       uint32_t *cmd_addr_lo, int skip_wait)
483{
484	uint32_t agp_base;
485	uint32_t cmd_addr, addr_lo, addr_hi;
486	uint32_t *vb;
487	uint32_t qw_pad_count;
488
489	if (!skip_wait)
490		via_cmdbuf_wait(dev_priv, 2 * CMDBUF_ALIGNMENT_SIZE);
491
492	vb = via_get_dma(dev_priv);
493	VIA_OUT_RING_QW(HC_HEADER2 | ((VIA_REG_TRANSET >> 2) << 12) |
494			(VIA_REG_TRANSPACE >> 2), HC_ParaType_PreCR << 16);
495	agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
496	qw_pad_count = (CMDBUF_ALIGNMENT_SIZE >> 3) -
497	    ((dev_priv->dma_low & CMDBUF_ALIGNMENT_MASK) >> 3);
498
499	cmd_addr = (addr) ? addr :
500	    agp_base + dev_priv->dma_low - 8 + (qw_pad_count << 3);
501	addr_lo = ((HC_SubA_HAGPBpL << 24) | (cmd_type & HC_HAGPBpID_MASK) |
502		   (cmd_addr & HC_HAGPBpL_MASK));
503	addr_hi = ((HC_SubA_HAGPBpH << 24) | (cmd_addr >> 24));
504
505	vb = via_align_buffer(dev_priv, vb, qw_pad_count - 1);
506	VIA_OUT_RING_QW(*cmd_addr_hi = addr_hi, *cmd_addr_lo = addr_lo);
507	return vb;
508}
509
510static void via_cmdbuf_start(drm_via_private_t *dev_priv)
511{
512	uint32_t pause_addr_lo, pause_addr_hi;
513	uint32_t start_addr, start_addr_lo;
514	uint32_t end_addr, end_addr_lo;
515	uint32_t command;
516	uint32_t agp_base;
517	uint32_t ptr;
518	uint32_t reader;
519	int count;
520
521	dev_priv->dma_low = 0;
522
523	agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
524	start_addr = agp_base;
525	end_addr = agp_base + dev_priv->dma_high;
526
527	start_addr_lo = ((HC_SubA_HAGPBstL << 24) | (start_addr & 0xFFFFFF));
528	end_addr_lo = ((HC_SubA_HAGPBendL << 24) | (end_addr & 0xFFFFFF));
529	command = ((HC_SubA_HAGPCMNT << 24) | (start_addr >> 24) |
530		   ((end_addr & 0xff000000) >> 16));
531
532	dev_priv->last_pause_ptr =
533	    via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0,
534			  &pause_addr_hi, &pause_addr_lo, 1) - 1;
535
536	via_flush_write_combine();
537	(void) *(volatile uint32_t *)dev_priv->last_pause_ptr;
538
539	VIA_WRITE(VIA_REG_TRANSET, (HC_ParaType_PreCR << 16));
540	VIA_WRITE(VIA_REG_TRANSPACE, command);
541	VIA_WRITE(VIA_REG_TRANSPACE, start_addr_lo);
542	VIA_WRITE(VIA_REG_TRANSPACE, end_addr_lo);
543
544	VIA_WRITE(VIA_REG_TRANSPACE, pause_addr_hi);
545	VIA_WRITE(VIA_REG_TRANSPACE, pause_addr_lo);
546	wmb();
547	VIA_WRITE(VIA_REG_TRANSPACE, command | HC_HAGPCMNT_MASK);
548	VIA_READ(VIA_REG_TRANSPACE);
549
550	dev_priv->dma_diff = 0;
551
552	count = 10000000;
553	while (!(VIA_READ(0x41c) & 0x80000000) && count--);
554
555	reader = *(dev_priv->hw_addr_ptr);
556	ptr = ((volatile char *)dev_priv->last_pause_ptr - dev_priv->dma_ptr) +
557	    dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr + 4;
558
559	/*
560	 * This is the difference between where we tell the
561	 * command reader to pause and where it actually pauses.
562	 * This differs between hw implementation so we need to
563	 * detect it.
564	 */
565
566	dev_priv->dma_diff = ptr - reader;
567}
568
569static void via_pad_cache(drm_via_private_t *dev_priv, int qwords)
570{
571	uint32_t *vb;
572
573	via_cmdbuf_wait(dev_priv, qwords + 2);
574	vb = via_get_dma(dev_priv);
575	VIA_OUT_RING_QW(HC_HEADER2, HC_ParaType_NotTex << 16);
576	via_align_buffer(dev_priv, vb, qwords);
577}
578
579static inline void via_dummy_bitblt(drm_via_private_t *dev_priv)
580{
581	uint32_t *vb = via_get_dma(dev_priv);
582	SetReg2DAGP(0x0C, (0 | (0 << 16)));
583	SetReg2DAGP(0x10, 0 | (0 << 16));
584	SetReg2DAGP(0x0, 0x1 | 0x2000 | 0xAA000000);
585}
586
587static void via_cmdbuf_jump(drm_via_private_t *dev_priv)
588{
589	uint32_t agp_base;
590	uint32_t pause_addr_lo, pause_addr_hi;
591	uint32_t jump_addr_lo, jump_addr_hi;
592	volatile uint32_t *last_pause_ptr;
593	uint32_t dma_low_save1, dma_low_save2;
594
595	agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
596	via_align_cmd(dev_priv, HC_HAGPBpID_JUMP, 0, &jump_addr_hi,
597		      &jump_addr_lo, 0);
598
599	dev_priv->dma_wrap = dev_priv->dma_low;
600
601	/*
602	 * Wrap command buffer to the beginning.
603	 */
604
605	dev_priv->dma_low = 0;
606	if (via_cmdbuf_wait(dev_priv, CMDBUF_ALIGNMENT_SIZE) != 0)
607		DRM_ERROR("via_cmdbuf_jump failed\n");
608
609	via_dummy_bitblt(dev_priv);
610	via_dummy_bitblt(dev_priv);
611
612	last_pause_ptr =
613	    via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0, &pause_addr_hi,
614			  &pause_addr_lo, 0) - 1;
615	via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0, &pause_addr_hi,
616		      &pause_addr_lo, 0);
617
618	*last_pause_ptr = pause_addr_lo;
619	dma_low_save1 = dev_priv->dma_low;
620
621	/*
622	 * Now, set a trap that will pause the regulator if it tries to rerun the old
623	 * command buffer. (Which may happen if via_hook_segment detecs a command regulator pause
624	 * and reissues the jump command over PCI, while the regulator has already taken the jump
625	 * and actually paused at the current buffer end).
626	 * There appears to be no other way to detect this condition, since the hw_addr_pointer
627	 * does not seem to get updated immediately when a jump occurs.
628	 */
629
630	last_pause_ptr =
631		via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0, &pause_addr_hi,
632			      &pause_addr_lo, 0) - 1;
633	via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0, &pause_addr_hi,
634		      &pause_addr_lo, 0);
635	*last_pause_ptr = pause_addr_lo;
636
637	dma_low_save2 = dev_priv->dma_low;
638	dev_priv->dma_low = dma_low_save1;
639	via_hook_segment(dev_priv, jump_addr_hi, jump_addr_lo, 0);
640	dev_priv->dma_low = dma_low_save2;
641	via_hook_segment(dev_priv, pause_addr_hi, pause_addr_lo, 0);
642}
643
644
645static void via_cmdbuf_rewind(drm_via_private_t *dev_priv)
646{
647	via_cmdbuf_jump(dev_priv);
648}
649
650static void via_cmdbuf_flush(drm_via_private_t *dev_priv, uint32_t cmd_type)
651{
652	uint32_t pause_addr_lo, pause_addr_hi;
653
654	via_align_cmd(dev_priv, cmd_type, 0, &pause_addr_hi, &pause_addr_lo, 0);
655	via_hook_segment(dev_priv, pause_addr_hi, pause_addr_lo, 0);
656}
657
658static void via_cmdbuf_pause(drm_via_private_t *dev_priv)
659{
660	via_cmdbuf_flush(dev_priv, HC_HAGPBpID_PAUSE);
661}
662
663static void via_cmdbuf_reset(drm_via_private_t *dev_priv)
664{
665	via_cmdbuf_flush(dev_priv, HC_HAGPBpID_STOP);
666	via_wait_idle(dev_priv);
667}
668
669/*
670 * User interface to the space and lag functions.
671 */
672
673static int via_cmdbuf_size(struct drm_device *dev, void *data, struct drm_file *file_priv)
674{
675	drm_via_cmdbuf_size_t *d_siz = data;
676	int ret = 0;
677	uint32_t tmp_size, count;
678	drm_via_private_t *dev_priv;
679
680	DRM_DEBUG("\n");
681	LOCK_TEST_WITH_RETURN(dev, file_priv);
682
683	dev_priv = (drm_via_private_t *) dev->dev_private;
684
685	if (dev_priv->ring.virtual_start == NULL) {
686		DRM_ERROR("called without initializing AGP ring buffer.\n");
687		return -EFAULT;
688	}
689
690	count = 1000000;
691	tmp_size = d_siz->size;
692	switch (d_siz->func) {
693	case VIA_CMDBUF_SPACE:
694		while (((tmp_size = via_cmdbuf_space(dev_priv)) < d_siz->size)
695		       && --count) {
696			if (!d_siz->wait)
697				break;
698		}
699		if (!count) {
700			DRM_ERROR("VIA_CMDBUF_SPACE timed out.\n");
701			ret = -EAGAIN;
702		}
703		break;
704	case VIA_CMDBUF_LAG:
705		while (((tmp_size = via_cmdbuf_lag(dev_priv)) > d_siz->size)
706		       && --count) {
707			if (!d_siz->wait)
708				break;
709		}
710		if (!count) {
711			DRM_ERROR("VIA_CMDBUF_LAG timed out.\n");
712			ret = -EAGAIN;
713		}
714		break;
715	default:
716		ret = -EFAULT;
717	}
718	d_siz->size = tmp_size;
719
720	return ret;
721}
722
723const struct drm_ioctl_desc via_ioctls[] = {
724	DRM_IOCTL_DEF_DRV(VIA_ALLOCMEM, via_mem_alloc, DRM_AUTH),
725	DRM_IOCTL_DEF_DRV(VIA_FREEMEM, via_mem_free, DRM_AUTH),
726	DRM_IOCTL_DEF_DRV(VIA_AGP_INIT, via_agp_init, DRM_AUTH|DRM_MASTER),
727	DRM_IOCTL_DEF_DRV(VIA_FB_INIT, via_fb_init, DRM_AUTH|DRM_MASTER),
728	DRM_IOCTL_DEF_DRV(VIA_MAP_INIT, via_map_init, DRM_AUTH|DRM_MASTER),
729	DRM_IOCTL_DEF_DRV(VIA_DEC_FUTEX, via_decoder_futex, DRM_AUTH),
730	DRM_IOCTL_DEF_DRV(VIA_DMA_INIT, via_dma_init, DRM_AUTH),
731	DRM_IOCTL_DEF_DRV(VIA_CMDBUFFER, via_cmdbuffer, DRM_AUTH),
732	DRM_IOCTL_DEF_DRV(VIA_FLUSH, via_flush_ioctl, DRM_AUTH),
733	DRM_IOCTL_DEF_DRV(VIA_PCICMD, via_pci_cmdbuffer, DRM_AUTH),
734	DRM_IOCTL_DEF_DRV(VIA_CMDBUF_SIZE, via_cmdbuf_size, DRM_AUTH),
735	DRM_IOCTL_DEF_DRV(VIA_WAIT_IRQ, via_wait_irq, DRM_AUTH),
736	DRM_IOCTL_DEF_DRV(VIA_DMA_BLIT, via_dma_blit, DRM_AUTH),
737	DRM_IOCTL_DEF_DRV(VIA_BLIT_SYNC, via_dma_blit_sync, DRM_AUTH)
738};
739
740int via_max_ioctl = ARRAY_SIZE(via_ioctls);
741