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Merge branch 'for-linville' of git://github.com/kvalo/ath6kl
[~andy/linux] / drivers / staging / gma500 / psb_irq.c
1 /**************************************************************************
2  * Copyright (c) 2007, Intel Corporation.
3  * All Rights Reserved.
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms and conditions of the GNU General Public License,
7  * version 2, as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12  * more details.
13  *
14  * You should have received a copy of the GNU General Public License along with
15  * this program; if not, write to the Free Software Foundation, Inc.,
16  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
17  *
18  * Intel funded Tungsten Graphics (http://www.tungstengraphics.com) to
19  * develop this driver.
20  *
21  **************************************************************************/
22 /*
23  */
24
25 #include <drm/drmP.h>
26 #include "psb_drv.h"
27 #include "psb_reg.h"
28 #include "psb_intel_reg.h"
29 #include "power.h"
30 #include "mdfld_output.h"
31
32 /*
33  * inline functions
34  */
35
36 static inline u32
37 psb_pipestat(int pipe)
38 {
39         if (pipe == 0)
40                 return PIPEASTAT;
41         if (pipe == 1)
42                 return PIPEBSTAT;
43         if (pipe == 2)
44                 return PIPECSTAT;
45         BUG();
46 }
47
48 static inline u32
49 mid_pipe_event(int pipe)
50 {
51         if (pipe == 0)
52                 return _PSB_PIPEA_EVENT_FLAG;
53         if (pipe == 1)
54                 return _MDFLD_PIPEB_EVENT_FLAG;
55         if (pipe == 2)
56                 return _MDFLD_PIPEC_EVENT_FLAG;
57         BUG();
58 }
59
60 static inline u32
61 mid_pipe_vsync(int pipe)
62 {
63         if (pipe == 0)
64                 return _PSB_VSYNC_PIPEA_FLAG;
65         if (pipe == 1)
66                 return _PSB_VSYNC_PIPEB_FLAG;
67         if (pipe == 2)
68                 return _MDFLD_PIPEC_VBLANK_FLAG;
69         BUG();
70 }
71
72 static inline u32
73 mid_pipeconf(int pipe)
74 {
75         if (pipe == 0)
76                 return PIPEACONF;
77         if (pipe == 1)
78                 return PIPEBCONF;
79         if (pipe == 2)
80                 return PIPECCONF;
81         BUG();
82 }
83
84 void
85 psb_enable_pipestat(struct drm_psb_private *dev_priv, int pipe, u32 mask)
86 {
87         if ((dev_priv->pipestat[pipe] & mask) != mask) {
88                 u32 reg = psb_pipestat(pipe);
89                 dev_priv->pipestat[pipe] |= mask;
90                 /* Enable the interrupt, clear any pending status */
91                 if (gma_power_begin(dev_priv->dev, false)) {
92                         u32 writeVal = PSB_RVDC32(reg);
93                         writeVal |= (mask | (mask >> 16));
94                         PSB_WVDC32(writeVal, reg);
95                         (void) PSB_RVDC32(reg);
96                         gma_power_end(dev_priv->dev);
97                 }
98         }
99 }
100
101 void
102 psb_disable_pipestat(struct drm_psb_private *dev_priv, int pipe, u32 mask)
103 {
104         if ((dev_priv->pipestat[pipe] & mask) != 0) {
105                 u32 reg = psb_pipestat(pipe);
106                 dev_priv->pipestat[pipe] &= ~mask;
107                 if (gma_power_begin(dev_priv->dev, false)) {
108                         u32 writeVal = PSB_RVDC32(reg);
109                         writeVal &= ~mask;
110                         PSB_WVDC32(writeVal, reg);
111                         (void) PSB_RVDC32(reg);
112                         gma_power_end(dev_priv->dev);
113                 }
114         }
115 }
116
117 void mid_enable_pipe_event(struct drm_psb_private *dev_priv, int pipe)
118 {
119         if (gma_power_begin(dev_priv->dev, false)) {
120                 u32 pipe_event = mid_pipe_event(pipe);
121                 dev_priv->vdc_irq_mask |= pipe_event;
122                 PSB_WVDC32(~dev_priv->vdc_irq_mask, PSB_INT_MASK_R);
123                 PSB_WVDC32(dev_priv->vdc_irq_mask, PSB_INT_ENABLE_R);
124                 gma_power_end(dev_priv->dev);
125         }
126 }
127
128 void mid_disable_pipe_event(struct drm_psb_private *dev_priv, int pipe)
129 {
130         if (dev_priv->pipestat[pipe] == 0) {
131                 if (gma_power_begin(dev_priv->dev, false)) {
132                         u32 pipe_event = mid_pipe_event(pipe);
133                         dev_priv->vdc_irq_mask &= ~pipe_event;
134                         PSB_WVDC32(~dev_priv->vdc_irq_mask, PSB_INT_MASK_R);
135                         PSB_WVDC32(dev_priv->vdc_irq_mask, PSB_INT_ENABLE_R);
136                         gma_power_end(dev_priv->dev);
137                 }
138         }
139 }
140
141 /**
142  * Display controller interrupt handler for pipe event.
143  *
144  */
145 static void mid_pipe_event_handler(struct drm_device *dev, int pipe)
146 {
147         struct drm_psb_private *dev_priv =
148             (struct drm_psb_private *) dev->dev_private;
149
150         uint32_t pipe_stat_val = 0;
151         uint32_t pipe_stat_reg = psb_pipestat(pipe);
152         uint32_t pipe_enable = dev_priv->pipestat[pipe];
153         uint32_t pipe_status = dev_priv->pipestat[pipe] >> 16;
154         uint32_t pipe_clear;
155         uint32_t i = 0;
156
157         spin_lock(&dev_priv->irqmask_lock);
158
159         pipe_stat_val = PSB_RVDC32(pipe_stat_reg);
160         pipe_stat_val &= pipe_enable | pipe_status;
161         pipe_stat_val &= pipe_stat_val >> 16;
162
163         spin_unlock(&dev_priv->irqmask_lock);
164
165         /* Clear the 2nd level interrupt status bits
166          * Sometimes the bits are very sticky so we repeat until they unstick */
167         for (i = 0; i < 0xffff; i++) {
168                 PSB_WVDC32(PSB_RVDC32(pipe_stat_reg), pipe_stat_reg);
169                 pipe_clear = PSB_RVDC32(pipe_stat_reg) & pipe_status;
170
171                 if (pipe_clear == 0)
172                         break;
173         }
174
175         if (pipe_clear)
176                 dev_err(dev->dev,
177                 "%s, can't clear status bits for pipe %d, its value = 0x%x.\n",
178                 __func__, pipe, PSB_RVDC32(pipe_stat_reg));
179
180         if (pipe_stat_val & PIPE_VBLANK_STATUS)
181                 drm_handle_vblank(dev, pipe);
182
183         if (pipe_stat_val & PIPE_TE_STATUS)
184                 drm_handle_vblank(dev, pipe);
185 }
186
187 /*
188  * Display controller interrupt handler.
189  */
190 static void psb_vdc_interrupt(struct drm_device *dev, uint32_t vdc_stat)
191 {
192         if (vdc_stat & _PSB_VSYNC_PIPEA_FLAG)
193                 mid_pipe_event_handler(dev, 0);
194
195         if (vdc_stat & _PSB_VSYNC_PIPEB_FLAG)
196                 mid_pipe_event_handler(dev, 1);
197 }
198
199 irqreturn_t psb_irq_handler(DRM_IRQ_ARGS)
200 {
201         struct drm_device *dev = (struct drm_device *) arg;
202         struct drm_psb_private *dev_priv =
203             (struct drm_psb_private *) dev->dev_private;
204
205         uint32_t vdc_stat, dsp_int = 0, sgx_int = 0;
206         int handled = 0;
207
208         spin_lock(&dev_priv->irqmask_lock);
209
210         vdc_stat = PSB_RVDC32(PSB_INT_IDENTITY_R);
211
212         if (vdc_stat & _PSB_PIPE_EVENT_FLAG)
213                 dsp_int = 1;
214
215         /* FIXME: Handle Medfield
216         if (vdc_stat & _MDFLD_DISP_ALL_IRQ_FLAG)
217                 dsp_int = 1;
218         */
219
220         if (vdc_stat & _PSB_IRQ_SGX_FLAG)
221                 sgx_int = 1;
222
223         vdc_stat &= dev_priv->vdc_irq_mask;
224         spin_unlock(&dev_priv->irqmask_lock);
225
226         if (dsp_int && gma_power_is_on(dev)) {
227                 psb_vdc_interrupt(dev, vdc_stat);
228                 handled = 1;
229         }
230
231         if (sgx_int) {
232                 /* Not expected - we have it masked, shut it up */
233                 u32 s, s2;
234                 s = PSB_RSGX32(PSB_CR_EVENT_STATUS);
235                 s2 = PSB_RSGX32(PSB_CR_EVENT_STATUS2);
236                 PSB_WSGX32(s, PSB_CR_EVENT_HOST_CLEAR);
237                 PSB_WSGX32(s2, PSB_CR_EVENT_HOST_CLEAR2);
238                 /* if s & _PSB_CE_TWOD_COMPLETE we have 2D done but
239                    we may as well poll even if we add that ! */
240                 handled = 1;
241         }
242
243         PSB_WVDC32(vdc_stat, PSB_INT_IDENTITY_R);
244         (void) PSB_RVDC32(PSB_INT_IDENTITY_R);
245         DRM_READMEMORYBARRIER();
246
247         if (!handled)
248                 return IRQ_NONE;
249
250         return IRQ_HANDLED;
251 }
252
253 void psb_irq_preinstall(struct drm_device *dev)
254 {
255         struct drm_psb_private *dev_priv =
256             (struct drm_psb_private *) dev->dev_private;
257         unsigned long irqflags;
258
259         spin_lock_irqsave(&dev_priv->irqmask_lock, irqflags);
260
261         if (gma_power_is_on(dev))
262                 PSB_WVDC32(0xFFFFFFFF, PSB_HWSTAM);
263         if (dev->vblank_enabled[0])
264                 dev_priv->vdc_irq_mask |= _PSB_VSYNC_PIPEA_FLAG;
265         if (dev->vblank_enabled[1])
266                 dev_priv->vdc_irq_mask |= _PSB_VSYNC_PIPEB_FLAG;
267
268         /* FIXME: Handle Medfield irq mask
269         if (dev->vblank_enabled[1])
270                 dev_priv->vdc_irq_mask |= _MDFLD_PIPEB_EVENT_FLAG;
271         if (dev->vblank_enabled[2])
272                 dev_priv->vdc_irq_mask |= _MDFLD_PIPEC_EVENT_FLAG;
273         */
274
275         /* This register is safe even if display island is off */
276         PSB_WVDC32(~dev_priv->vdc_irq_mask, PSB_INT_MASK_R);
277         spin_unlock_irqrestore(&dev_priv->irqmask_lock, irqflags);
278 }
279
280 int psb_irq_postinstall(struct drm_device *dev)
281 {
282         struct drm_psb_private *dev_priv =
283             (struct drm_psb_private *) dev->dev_private;
284         unsigned long irqflags;
285
286         spin_lock_irqsave(&dev_priv->irqmask_lock, irqflags);
287
288         /* This register is safe even if display island is off */
289         PSB_WVDC32(dev_priv->vdc_irq_mask, PSB_INT_ENABLE_R);
290         PSB_WVDC32(0xFFFFFFFF, PSB_HWSTAM);
291
292         if (dev->vblank_enabled[0])
293                 psb_enable_pipestat(dev_priv, 0, PIPE_VBLANK_INTERRUPT_ENABLE);
294         else
295                 psb_disable_pipestat(dev_priv, 0, PIPE_VBLANK_INTERRUPT_ENABLE);
296
297         if (dev->vblank_enabled[1])
298                 psb_enable_pipestat(dev_priv, 1, PIPE_VBLANK_INTERRUPT_ENABLE);
299         else
300                 psb_disable_pipestat(dev_priv, 1, PIPE_VBLANK_INTERRUPT_ENABLE);
301
302         if (dev->vblank_enabled[2])
303                 psb_enable_pipestat(dev_priv, 2, PIPE_VBLANK_INTERRUPT_ENABLE);
304         else
305                 psb_disable_pipestat(dev_priv, 2, PIPE_VBLANK_INTERRUPT_ENABLE);
306
307         spin_unlock_irqrestore(&dev_priv->irqmask_lock, irqflags);
308         return 0;
309 }
310
311 void psb_irq_uninstall(struct drm_device *dev)
312 {
313         struct drm_psb_private *dev_priv =
314             (struct drm_psb_private *) dev->dev_private;
315         unsigned long irqflags;
316
317         spin_lock_irqsave(&dev_priv->irqmask_lock, irqflags);
318
319         PSB_WVDC32(0xFFFFFFFF, PSB_HWSTAM);
320
321         if (dev->vblank_enabled[0])
322                 psb_disable_pipestat(dev_priv, 0, PIPE_VBLANK_INTERRUPT_ENABLE);
323
324         if (dev->vblank_enabled[1])
325                 psb_disable_pipestat(dev_priv, 1, PIPE_VBLANK_INTERRUPT_ENABLE);
326
327         if (dev->vblank_enabled[2])
328                 psb_disable_pipestat(dev_priv, 2, PIPE_VBLANK_INTERRUPT_ENABLE);
329
330         dev_priv->vdc_irq_mask &= _PSB_IRQ_SGX_FLAG |
331                                   _PSB_IRQ_MSVDX_FLAG |
332                                   _LNC_IRQ_TOPAZ_FLAG;
333
334         /* These two registers are safe even if display island is off */
335         PSB_WVDC32(~dev_priv->vdc_irq_mask, PSB_INT_MASK_R);
336         PSB_WVDC32(dev_priv->vdc_irq_mask, PSB_INT_ENABLE_R);
337
338         wmb();
339
340         /* This register is safe even if display island is off */
341         PSB_WVDC32(PSB_RVDC32(PSB_INT_IDENTITY_R), PSB_INT_IDENTITY_R);
342         spin_unlock_irqrestore(&dev_priv->irqmask_lock, irqflags);
343 }
344
345 void psb_irq_turn_on_dpst(struct drm_device *dev)
346 {
347         struct drm_psb_private *dev_priv =
348                 (struct drm_psb_private *) dev->dev_private;
349         u32 hist_reg;
350         u32 pwm_reg;
351
352         if (gma_power_begin(dev, false)) {
353                 PSB_WVDC32(1 << 31, HISTOGRAM_LOGIC_CONTROL);
354                 hist_reg = PSB_RVDC32(HISTOGRAM_LOGIC_CONTROL);
355                 PSB_WVDC32(1 << 31, HISTOGRAM_INT_CONTROL);
356                 hist_reg = PSB_RVDC32(HISTOGRAM_INT_CONTROL);
357
358                 PSB_WVDC32(0x80010100, PWM_CONTROL_LOGIC);
359                 pwm_reg = PSB_RVDC32(PWM_CONTROL_LOGIC);
360                 PSB_WVDC32(pwm_reg | PWM_PHASEIN_ENABLE
361                                                 | PWM_PHASEIN_INT_ENABLE,
362                                                            PWM_CONTROL_LOGIC);
363                 pwm_reg = PSB_RVDC32(PWM_CONTROL_LOGIC);
364
365                 psb_enable_pipestat(dev_priv, 0, PIPE_DPST_EVENT_ENABLE);
366
367                 hist_reg = PSB_RVDC32(HISTOGRAM_INT_CONTROL);
368                 PSB_WVDC32(hist_reg | HISTOGRAM_INT_CTRL_CLEAR,
369                                                         HISTOGRAM_INT_CONTROL);
370                 pwm_reg = PSB_RVDC32(PWM_CONTROL_LOGIC);
371                 PSB_WVDC32(pwm_reg | 0x80010100 | PWM_PHASEIN_ENABLE,
372                                                         PWM_CONTROL_LOGIC);
373
374                 gma_power_end(dev);
375         }
376 }
377
378 int psb_irq_enable_dpst(struct drm_device *dev)
379 {
380         struct drm_psb_private *dev_priv =
381                 (struct drm_psb_private *) dev->dev_private;
382         unsigned long irqflags;
383
384         spin_lock_irqsave(&dev_priv->irqmask_lock, irqflags);
385
386         /* enable DPST */
387         mid_enable_pipe_event(dev_priv, 0);
388         psb_irq_turn_on_dpst(dev);
389
390         spin_unlock_irqrestore(&dev_priv->irqmask_lock, irqflags);
391         return 0;
392 }
393
394 void psb_irq_turn_off_dpst(struct drm_device *dev)
395 {
396         struct drm_psb_private *dev_priv =
397             (struct drm_psb_private *) dev->dev_private;
398         u32 hist_reg;
399         u32 pwm_reg;
400
401         if (gma_power_begin(dev, false)) {
402                 PSB_WVDC32(0x00000000, HISTOGRAM_INT_CONTROL);
403                 hist_reg = PSB_RVDC32(HISTOGRAM_INT_CONTROL);
404
405                 psb_disable_pipestat(dev_priv, 0, PIPE_DPST_EVENT_ENABLE);
406
407                 pwm_reg = PSB_RVDC32(PWM_CONTROL_LOGIC);
408                 PSB_WVDC32(pwm_reg & !(PWM_PHASEIN_INT_ENABLE),
409                                                         PWM_CONTROL_LOGIC);
410                 pwm_reg = PSB_RVDC32(PWM_CONTROL_LOGIC);
411
412                 gma_power_end(dev);
413         }
414 }
415
416 int psb_irq_disable_dpst(struct drm_device *dev)
417 {
418         struct drm_psb_private *dev_priv =
419             (struct drm_psb_private *) dev->dev_private;
420         unsigned long irqflags;
421
422         spin_lock_irqsave(&dev_priv->irqmask_lock, irqflags);
423
424         mid_disable_pipe_event(dev_priv, 0);
425         psb_irq_turn_off_dpst(dev);
426
427         spin_unlock_irqrestore(&dev_priv->irqmask_lock, irqflags);
428
429         return 0;
430 }
431
432 #ifdef PSB_FIXME
433 static int psb_vblank_do_wait(struct drm_device *dev,
434                               unsigned int *sequence, atomic_t *counter)
435 {
436         unsigned int cur_vblank;
437         int ret = 0;
438         DRM_WAIT_ON(ret, dev->vbl_queue, 3 * DRM_HZ,
439                     (((cur_vblank = atomic_read(counter))
440                       - *sequence) <= (1 << 23)));
441         *sequence = cur_vblank;
442
443         return ret;
444 }
445 #endif
446
447 /*
448  * It is used to enable VBLANK interrupt
449  */
450 int psb_enable_vblank(struct drm_device *dev, int pipe)
451 {
452         struct drm_psb_private *dev_priv = dev->dev_private;
453         unsigned long irqflags;
454         uint32_t reg_val = 0;
455         uint32_t pipeconf_reg = mid_pipeconf(pipe);
456
457 #if defined(CONFIG_DRM_PSB_MFLD)
458         /* Medfield is different - we should perhaps extract out vblank
459            and blacklight etc ops */
460         if (IS_MFLD(dev) && !mdfld_panel_dpi(dev))
461                 return mdfld_enable_te(dev, pipe);
462 #endif
463         if (gma_power_begin(dev, false)) {
464                 reg_val = REG_READ(pipeconf_reg);
465                 gma_power_end(dev);
466         }
467
468         if (!(reg_val & PIPEACONF_ENABLE))
469                 return -EINVAL;
470
471         spin_lock_irqsave(&dev_priv->irqmask_lock, irqflags);
472
473         if (pipe == 0)
474                 dev_priv->vdc_irq_mask |= _PSB_VSYNC_PIPEA_FLAG;
475         else if (pipe == 1)
476                 dev_priv->vdc_irq_mask |= _PSB_VSYNC_PIPEB_FLAG;
477
478         PSB_WVDC32(~dev_priv->vdc_irq_mask, PSB_INT_MASK_R);
479         PSB_WVDC32(dev_priv->vdc_irq_mask, PSB_INT_ENABLE_R);
480         psb_enable_pipestat(dev_priv, pipe, PIPE_VBLANK_INTERRUPT_ENABLE);
481
482         spin_unlock_irqrestore(&dev_priv->irqmask_lock, irqflags);
483
484         return 0;
485 }
486
487 /*
488  * It is used to disable VBLANK interrupt
489  */
490 void psb_disable_vblank(struct drm_device *dev, int pipe)
491 {
492         struct drm_psb_private *dev_priv = dev->dev_private;
493         unsigned long irqflags;
494
495 #if defined(CONFIG_DRM_PSB_MFLD)
496         if (IS_MFLD(dev) && !mdfld_panel_dpi(dev))
497                 mdfld_disable_te(dev, pipe);
498 #endif
499         spin_lock_irqsave(&dev_priv->irqmask_lock, irqflags);
500
501         if (pipe == 0)
502                 dev_priv->vdc_irq_mask &= ~_PSB_VSYNC_PIPEA_FLAG;
503         else if (pipe == 1)
504                 dev_priv->vdc_irq_mask &= ~_PSB_VSYNC_PIPEB_FLAG;
505
506         PSB_WVDC32(~dev_priv->vdc_irq_mask, PSB_INT_MASK_R);
507         PSB_WVDC32(dev_priv->vdc_irq_mask, PSB_INT_ENABLE_R);
508         psb_disable_pipestat(dev_priv, pipe, PIPE_VBLANK_INTERRUPT_ENABLE);
509
510         spin_unlock_irqrestore(&dev_priv->irqmask_lock, irqflags);
511 }
512
513 /**
514  *      mdfld_enable_te         -       enable TE events
515  *      @dev: our DRM device
516  *      @pipe: which pipe to work on
517  *
518  *      Enable TE events on a Medfield display pipe. Medfield specific.
519  */
520 int mdfld_enable_te(struct drm_device *dev, int pipe)
521 {
522         struct drm_psb_private *dev_priv = dev->dev_private;
523         unsigned long flags;
524         uint32_t reg_val = 0;
525         uint32_t pipeconf_reg = mid_pipeconf(pipe);
526
527         if (gma_power_begin(dev, false)) {
528                 reg_val = REG_READ(pipeconf_reg);
529                 gma_power_end(dev);
530         }
531
532         if (!(reg_val & PIPEACONF_ENABLE))
533                 return -EINVAL;
534
535         spin_lock_irqsave(&dev_priv->irqmask_lock, flags);
536
537         mid_enable_pipe_event(dev_priv, pipe);
538         psb_enable_pipestat(dev_priv, pipe, PIPE_TE_ENABLE);
539
540         spin_unlock_irqrestore(&dev_priv->irqmask_lock, flags);
541
542         return 0;
543 }
544
545 /**
546  *      mdfld_disable_te                -       disable TE events
547  *      @dev: our DRM device
548  *      @pipe: which pipe to work on
549  *
550  *      Disable TE events on a Medfield display pipe. Medfield specific.
551  */
552 void mdfld_disable_te(struct drm_device *dev, int pipe)
553 {
554         struct drm_psb_private *dev_priv = dev->dev_private;
555         unsigned long flags;
556
557         spin_lock_irqsave(&dev_priv->irqmask_lock, flags);
558
559         mid_disable_pipe_event(dev_priv, pipe);
560         psb_disable_pipestat(dev_priv, pipe, PIPE_TE_ENABLE);
561
562         spin_unlock_irqrestore(&dev_priv->irqmask_lock, flags);
563 }
564
565 /* Called from drm generic code, passed a 'crtc', which
566  * we use as a pipe index
567  */
568 u32 psb_get_vblank_counter(struct drm_device *dev, int pipe)
569 {
570         uint32_t high_frame = PIPEAFRAMEHIGH;
571         uint32_t low_frame = PIPEAFRAMEPIXEL;
572         uint32_t pipeconf_reg = PIPEACONF;
573         uint32_t reg_val = 0;
574         uint32_t high1 = 0, high2 = 0, low = 0, count = 0;
575
576         switch (pipe) {
577         case 0:
578                 break;
579         case 1:
580                 high_frame = PIPEBFRAMEHIGH;
581                 low_frame = PIPEBFRAMEPIXEL;
582                 pipeconf_reg = PIPEBCONF;
583                 break;
584         case 2:
585                 high_frame = PIPECFRAMEHIGH;
586                 low_frame = PIPECFRAMEPIXEL;
587                 pipeconf_reg = PIPECCONF;
588                 break;
589         default:
590                 dev_err(dev->dev, "%s, invalid pipe.\n", __func__);
591                 return 0;
592         }
593
594         if (!gma_power_begin(dev, false))
595                 return 0;
596
597         reg_val = REG_READ(pipeconf_reg);
598
599         if (!(reg_val & PIPEACONF_ENABLE)) {
600                 dev_err(dev->dev, "trying to get vblank count for disabled pipe %d\n",
601                                                                 pipe);
602                 goto psb_get_vblank_counter_exit;
603         }
604
605         /*
606          * High & low register fields aren't synchronized, so make sure
607          * we get a low value that's stable across two reads of the high
608          * register.
609          */
610         do {
611                 high1 = ((REG_READ(high_frame) & PIPE_FRAME_HIGH_MASK) >>
612                          PIPE_FRAME_HIGH_SHIFT);
613                 low =  ((REG_READ(low_frame) & PIPE_FRAME_LOW_MASK) >>
614                         PIPE_FRAME_LOW_SHIFT);
615                 high2 = ((REG_READ(high_frame) & PIPE_FRAME_HIGH_MASK) >>
616                          PIPE_FRAME_HIGH_SHIFT);
617         } while (high1 != high2);
618
619         count = (high1 << 8) | low;
620
621 psb_get_vblank_counter_exit:
622
623         gma_power_end(dev);
624
625         return count;
626 }
627