1 /*
2  * Copyright(c) 2011-2016 Intel Corporation. All rights reserved.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice (including the next
12  * paragraph) shall be included in all copies or substantial portions of the
13  * Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21  * SOFTWARE.
22  *
23  * Authors:
24  *    Ke Yu
25  *    Zhiyuan Lv <zhiyuan.lv@intel.com>
26  *
27  * Contributors:
28  *    Terrence Xu <terrence.xu@intel.com>
29  *    Changbin Du <changbin.du@intel.com>
30  *    Bing Niu <bing.niu@intel.com>
31  *    Zhi Wang <zhi.a.wang@intel.com>
32  *
33  */
34 
35 #include "i915_drv.h"
36 #include "gvt.h"
37 
38 #define GMBUS1_TOTAL_BYTES_SHIFT 16
39 #define GMBUS1_TOTAL_BYTES_MASK 0x1ff
40 #define gmbus1_total_byte_count(v) (((v) >> \
41 	GMBUS1_TOTAL_BYTES_SHIFT) & GMBUS1_TOTAL_BYTES_MASK)
42 #define gmbus1_slave_addr(v) (((v) & 0xff) >> 1)
43 #define gmbus1_slave_index(v) (((v) >> 8) & 0xff)
44 #define gmbus1_bus_cycle(v) (((v) >> 25) & 0x7)
45 
46 /* GMBUS0 bits definitions */
47 #define _GMBUS_PIN_SEL_MASK     (0x7)
48 
edid_get_byte(struct intel_vgpu * vgpu)49 static unsigned char edid_get_byte(struct intel_vgpu *vgpu)
50 {
51 	struct intel_vgpu_i2c_edid *edid = &vgpu->display.i2c_edid;
52 	unsigned char chr = 0;
53 
54 	if (edid->state == I2C_NOT_SPECIFIED || !edid->slave_selected) {
55 		gvt_vgpu_err("Driver tries to read EDID without proper sequence!\n");
56 		return 0;
57 	}
58 	if (edid->current_edid_read >= EDID_SIZE) {
59 		gvt_vgpu_err("edid_get_byte() exceeds the size of EDID!\n");
60 		return 0;
61 	}
62 
63 	if (!edid->edid_available) {
64 		gvt_vgpu_err("Reading EDID but EDID is not available!\n");
65 		return 0;
66 	}
67 
68 	if (intel_vgpu_has_monitor_on_port(vgpu, edid->port)) {
69 		struct intel_vgpu_edid_data *edid_data =
70 			intel_vgpu_port(vgpu, edid->port)->edid;
71 
72 		chr = edid_data->edid_block[edid->current_edid_read];
73 		edid->current_edid_read++;
74 	} else {
75 		gvt_vgpu_err("No EDID available during the reading?\n");
76 	}
77 	return chr;
78 }
79 
cnp_get_port_from_gmbus0(u32 gmbus0)80 static inline int cnp_get_port_from_gmbus0(u32 gmbus0)
81 {
82 	int port_select = gmbus0 & _GMBUS_PIN_SEL_MASK;
83 	int port = -EINVAL;
84 
85 	if (port_select == GMBUS_PIN_1_BXT)
86 		port = PORT_B;
87 	else if (port_select == GMBUS_PIN_2_BXT)
88 		port = PORT_C;
89 	else if (port_select == GMBUS_PIN_3_BXT)
90 		port = PORT_D;
91 	else if (port_select == GMBUS_PIN_4_CNP)
92 		port = PORT_E;
93 	return port;
94 }
95 
bxt_get_port_from_gmbus0(u32 gmbus0)96 static inline int bxt_get_port_from_gmbus0(u32 gmbus0)
97 {
98 	int port_select = gmbus0 & _GMBUS_PIN_SEL_MASK;
99 	int port = -EINVAL;
100 
101 	if (port_select == GMBUS_PIN_1_BXT)
102 		port = PORT_B;
103 	else if (port_select == GMBUS_PIN_2_BXT)
104 		port = PORT_C;
105 	else if (port_select == GMBUS_PIN_3_BXT)
106 		port = PORT_D;
107 	return port;
108 }
109 
get_port_from_gmbus0(u32 gmbus0)110 static inline int get_port_from_gmbus0(u32 gmbus0)
111 {
112 	int port_select = gmbus0 & _GMBUS_PIN_SEL_MASK;
113 	int port = -EINVAL;
114 
115 	if (port_select == GMBUS_PIN_VGADDC)
116 		port = PORT_E;
117 	else if (port_select == GMBUS_PIN_DPC)
118 		port = PORT_C;
119 	else if (port_select == GMBUS_PIN_DPB)
120 		port = PORT_B;
121 	else if (port_select == GMBUS_PIN_DPD)
122 		port = PORT_D;
123 	return port;
124 }
125 
reset_gmbus_controller(struct intel_vgpu * vgpu)126 static void reset_gmbus_controller(struct intel_vgpu *vgpu)
127 {
128 	vgpu_vreg_t(vgpu, PCH_GMBUS2) = GMBUS_HW_RDY;
129 	if (!vgpu->display.i2c_edid.edid_available)
130 		vgpu_vreg_t(vgpu, PCH_GMBUS2) |= GMBUS_SATOER;
131 	vgpu->display.i2c_edid.gmbus.phase = GMBUS_IDLE_PHASE;
132 }
133 
134 /* GMBUS0 */
gmbus0_mmio_write(struct intel_vgpu * vgpu,unsigned int offset,void * p_data,unsigned int bytes)135 static int gmbus0_mmio_write(struct intel_vgpu *vgpu,
136 			unsigned int offset, void *p_data, unsigned int bytes)
137 {
138 	struct drm_i915_private *i915 = vgpu->gvt->gt->i915;
139 	int port, pin_select;
140 
141 	memcpy(&vgpu_vreg(vgpu, offset), p_data, bytes);
142 
143 	pin_select = vgpu_vreg(vgpu, offset) & _GMBUS_PIN_SEL_MASK;
144 
145 	intel_vgpu_init_i2c_edid(vgpu);
146 
147 	if (pin_select == 0)
148 		return 0;
149 
150 	if (IS_BROXTON(i915))
151 		port = bxt_get_port_from_gmbus0(pin_select);
152 	else if (IS_COFFEELAKE(i915) || IS_COMETLAKE(i915))
153 		port = cnp_get_port_from_gmbus0(pin_select);
154 	else
155 		port = get_port_from_gmbus0(pin_select);
156 	if (drm_WARN_ON(&i915->drm, port < 0))
157 		return 0;
158 
159 	vgpu->display.i2c_edid.state = I2C_GMBUS;
160 	vgpu->display.i2c_edid.gmbus.phase = GMBUS_IDLE_PHASE;
161 
162 	vgpu_vreg_t(vgpu, PCH_GMBUS2) &= ~GMBUS_ACTIVE;
163 	vgpu_vreg_t(vgpu, PCH_GMBUS2) |= GMBUS_HW_RDY | GMBUS_HW_WAIT_PHASE;
164 
165 	if (intel_vgpu_has_monitor_on_port(vgpu, port) &&
166 			!intel_vgpu_port_is_dp(vgpu, port)) {
167 		vgpu->display.i2c_edid.port = port;
168 		vgpu->display.i2c_edid.edid_available = true;
169 		vgpu_vreg_t(vgpu, PCH_GMBUS2) &= ~GMBUS_SATOER;
170 	} else
171 		vgpu_vreg_t(vgpu, PCH_GMBUS2) |= GMBUS_SATOER;
172 	return 0;
173 }
174 
gmbus1_mmio_write(struct intel_vgpu * vgpu,unsigned int offset,void * p_data,unsigned int bytes)175 static int gmbus1_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
176 		void *p_data, unsigned int bytes)
177 {
178 	struct intel_vgpu_i2c_edid *i2c_edid = &vgpu->display.i2c_edid;
179 	u32 slave_addr;
180 	u32 wvalue = *(u32 *)p_data;
181 
182 	if (vgpu_vreg(vgpu, offset) & GMBUS_SW_CLR_INT) {
183 		if (!(wvalue & GMBUS_SW_CLR_INT)) {
184 			vgpu_vreg(vgpu, offset) &= ~GMBUS_SW_CLR_INT;
185 			reset_gmbus_controller(vgpu);
186 		}
187 		/*
188 		 * TODO: "This bit is cleared to zero when an event
189 		 * causes the HW_RDY bit transition to occur "
190 		 */
191 	} else {
192 		/*
193 		 * per bspec setting this bit can cause:
194 		 * 1) INT status bit cleared
195 		 * 2) HW_RDY bit asserted
196 		 */
197 		if (wvalue & GMBUS_SW_CLR_INT) {
198 			vgpu_vreg_t(vgpu, PCH_GMBUS2) &= ~GMBUS_INT;
199 			vgpu_vreg_t(vgpu, PCH_GMBUS2) |= GMBUS_HW_RDY;
200 		}
201 
202 		/* For virtualization, we suppose that HW is always ready,
203 		 * so GMBUS_SW_RDY should always be cleared
204 		 */
205 		if (wvalue & GMBUS_SW_RDY)
206 			wvalue &= ~GMBUS_SW_RDY;
207 
208 		i2c_edid->gmbus.total_byte_count =
209 			gmbus1_total_byte_count(wvalue);
210 		slave_addr = gmbus1_slave_addr(wvalue);
211 
212 		/* vgpu gmbus only support EDID */
213 		if (slave_addr == EDID_ADDR) {
214 			i2c_edid->slave_selected = true;
215 		} else if (slave_addr != 0) {
216 			gvt_dbg_dpy(
217 				"vgpu%d: unsupported gmbus slave addr(0x%x)\n"
218 				"	gmbus operations will be ignored.\n",
219 					vgpu->id, slave_addr);
220 		}
221 
222 		if (wvalue & GMBUS_CYCLE_INDEX)
223 			i2c_edid->current_edid_read =
224 				gmbus1_slave_index(wvalue);
225 
226 		i2c_edid->gmbus.cycle_type = gmbus1_bus_cycle(wvalue);
227 		switch (gmbus1_bus_cycle(wvalue)) {
228 		case GMBUS_NOCYCLE:
229 			break;
230 		case GMBUS_STOP:
231 			/* From spec:
232 			 * This can only cause a STOP to be generated
233 			 * if a GMBUS cycle is generated, the GMBUS is
234 			 * currently in a data/wait/idle phase, or it is in a
235 			 * WAIT phase
236 			 */
237 			if (gmbus1_bus_cycle(vgpu_vreg(vgpu, offset))
238 				!= GMBUS_NOCYCLE) {
239 				intel_vgpu_init_i2c_edid(vgpu);
240 				/* After the 'stop' cycle, hw state would become
241 				 * 'stop phase' and then 'idle phase' after a
242 				 * few milliseconds. In emulation, we just set
243 				 * it as 'idle phase' ('stop phase' is not
244 				 * visible in gmbus interface)
245 				 */
246 				i2c_edid->gmbus.phase = GMBUS_IDLE_PHASE;
247 				vgpu_vreg_t(vgpu, PCH_GMBUS2) &= ~GMBUS_ACTIVE;
248 			}
249 			break;
250 		case NIDX_NS_W:
251 		case IDX_NS_W:
252 		case NIDX_STOP:
253 		case IDX_STOP:
254 			/* From hw spec the GMBUS phase
255 			 * transition like this:
256 			 * START (-->INDEX) -->DATA
257 			 */
258 			i2c_edid->gmbus.phase = GMBUS_DATA_PHASE;
259 			vgpu_vreg_t(vgpu, PCH_GMBUS2) |= GMBUS_ACTIVE;
260 			break;
261 		default:
262 			gvt_vgpu_err("Unknown/reserved GMBUS cycle detected!\n");
263 			break;
264 		}
265 		/*
266 		 * From hw spec the WAIT state will be
267 		 * cleared:
268 		 * (1) in a new GMBUS cycle
269 		 * (2) by generating a stop
270 		 */
271 		vgpu_vreg(vgpu, offset) = wvalue;
272 	}
273 	return 0;
274 }
275 
gmbus3_mmio_write(struct intel_vgpu * vgpu,unsigned int offset,void * p_data,unsigned int bytes)276 static int gmbus3_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
277 	void *p_data, unsigned int bytes)
278 {
279 	struct drm_i915_private *i915 = vgpu->gvt->gt->i915;
280 
281 	drm_WARN_ON(&i915->drm, 1);
282 	return 0;
283 }
284 
gmbus3_mmio_read(struct intel_vgpu * vgpu,unsigned int offset,void * p_data,unsigned int bytes)285 static int gmbus3_mmio_read(struct intel_vgpu *vgpu, unsigned int offset,
286 		void *p_data, unsigned int bytes)
287 {
288 	int i;
289 	unsigned char byte_data;
290 	struct intel_vgpu_i2c_edid *i2c_edid = &vgpu->display.i2c_edid;
291 	int byte_left = i2c_edid->gmbus.total_byte_count -
292 				i2c_edid->current_edid_read;
293 	int byte_count = byte_left;
294 	u32 reg_data = 0;
295 
296 	/* Data can only be recevied if previous settings correct */
297 	if (vgpu_vreg_t(vgpu, PCH_GMBUS1) & GMBUS_SLAVE_READ) {
298 		if (byte_left <= 0) {
299 			memcpy(p_data, &vgpu_vreg(vgpu, offset), bytes);
300 			return 0;
301 		}
302 
303 		if (byte_count > 4)
304 			byte_count = 4;
305 		for (i = 0; i < byte_count; i++) {
306 			byte_data = edid_get_byte(vgpu);
307 			reg_data |= (byte_data << (i << 3));
308 		}
309 
310 		memcpy(&vgpu_vreg(vgpu, offset), &reg_data, byte_count);
311 		memcpy(p_data, &vgpu_vreg(vgpu, offset), bytes);
312 
313 		if (byte_left <= 4) {
314 			switch (i2c_edid->gmbus.cycle_type) {
315 			case NIDX_STOP:
316 			case IDX_STOP:
317 				i2c_edid->gmbus.phase = GMBUS_IDLE_PHASE;
318 				break;
319 			case NIDX_NS_W:
320 			case IDX_NS_W:
321 			default:
322 				i2c_edid->gmbus.phase = GMBUS_WAIT_PHASE;
323 				break;
324 			}
325 			intel_vgpu_init_i2c_edid(vgpu);
326 		}
327 		/*
328 		 * Read GMBUS3 during send operation,
329 		 * return the latest written value
330 		 */
331 	} else {
332 		memcpy(p_data, &vgpu_vreg(vgpu, offset), bytes);
333 		gvt_vgpu_err("warning: gmbus3 read with nothing returned\n");
334 	}
335 	return 0;
336 }
337 
gmbus2_mmio_read(struct intel_vgpu * vgpu,unsigned int offset,void * p_data,unsigned int bytes)338 static int gmbus2_mmio_read(struct intel_vgpu *vgpu, unsigned int offset,
339 		void *p_data, unsigned int bytes)
340 {
341 	u32 value = vgpu_vreg(vgpu, offset);
342 
343 	if (!(vgpu_vreg(vgpu, offset) & GMBUS_INUSE))
344 		vgpu_vreg(vgpu, offset) |= GMBUS_INUSE;
345 	memcpy(p_data, (void *)&value, bytes);
346 	return 0;
347 }
348 
gmbus2_mmio_write(struct intel_vgpu * vgpu,unsigned int offset,void * p_data,unsigned int bytes)349 static int gmbus2_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
350 		void *p_data, unsigned int bytes)
351 {
352 	u32 wvalue = *(u32 *)p_data;
353 
354 	if (wvalue & GMBUS_INUSE)
355 		vgpu_vreg(vgpu, offset) &= ~GMBUS_INUSE;
356 	/* All other bits are read-only */
357 	return 0;
358 }
359 
360 /**
361  * intel_gvt_i2c_handle_gmbus_read - emulate gmbus register mmio read
362  * @vgpu: a vGPU
363  * @offset: reg offset
364  * @p_data: data return buffer
365  * @bytes: access data length
366  *
367  * This function is used to emulate gmbus register mmio read
368  *
369  * Returns:
370  * Zero on success, negative error code if failed.
371  *
372  */
intel_gvt_i2c_handle_gmbus_read(struct intel_vgpu * vgpu,unsigned int offset,void * p_data,unsigned int bytes)373 int intel_gvt_i2c_handle_gmbus_read(struct intel_vgpu *vgpu,
374 	unsigned int offset, void *p_data, unsigned int bytes)
375 {
376 	struct drm_i915_private *i915 = vgpu->gvt->gt->i915;
377 
378 	if (drm_WARN_ON(&i915->drm, bytes > 8 && (offset & (bytes - 1))))
379 		return -EINVAL;
380 
381 	if (offset == i915_mmio_reg_offset(PCH_GMBUS2))
382 		return gmbus2_mmio_read(vgpu, offset, p_data, bytes);
383 	else if (offset == i915_mmio_reg_offset(PCH_GMBUS3))
384 		return gmbus3_mmio_read(vgpu, offset, p_data, bytes);
385 
386 	memcpy(p_data, &vgpu_vreg(vgpu, offset), bytes);
387 	return 0;
388 }
389 
390 /**
391  * intel_gvt_i2c_handle_gmbus_write - emulate gmbus register mmio write
392  * @vgpu: a vGPU
393  * @offset: reg offset
394  * @p_data: data return buffer
395  * @bytes: access data length
396  *
397  * This function is used to emulate gmbus register mmio write
398  *
399  * Returns:
400  * Zero on success, negative error code if failed.
401  *
402  */
intel_gvt_i2c_handle_gmbus_write(struct intel_vgpu * vgpu,unsigned int offset,void * p_data,unsigned int bytes)403 int intel_gvt_i2c_handle_gmbus_write(struct intel_vgpu *vgpu,
404 		unsigned int offset, void *p_data, unsigned int bytes)
405 {
406 	struct drm_i915_private *i915 = vgpu->gvt->gt->i915;
407 
408 	if (drm_WARN_ON(&i915->drm, bytes > 8 && (offset & (bytes - 1))))
409 		return -EINVAL;
410 
411 	if (offset == i915_mmio_reg_offset(PCH_GMBUS0))
412 		return gmbus0_mmio_write(vgpu, offset, p_data, bytes);
413 	else if (offset == i915_mmio_reg_offset(PCH_GMBUS1))
414 		return gmbus1_mmio_write(vgpu, offset, p_data, bytes);
415 	else if (offset == i915_mmio_reg_offset(PCH_GMBUS2))
416 		return gmbus2_mmio_write(vgpu, offset, p_data, bytes);
417 	else if (offset == i915_mmio_reg_offset(PCH_GMBUS3))
418 		return gmbus3_mmio_write(vgpu, offset, p_data, bytes);
419 
420 	memcpy(&vgpu_vreg(vgpu, offset), p_data, bytes);
421 	return 0;
422 }
423 
424 enum {
425 	AUX_CH_CTL = 0,
426 	AUX_CH_DATA1,
427 	AUX_CH_DATA2,
428 	AUX_CH_DATA3,
429 	AUX_CH_DATA4,
430 	AUX_CH_DATA5
431 };
432 
get_aux_ch_reg(unsigned int offset)433 static inline int get_aux_ch_reg(unsigned int offset)
434 {
435 	int reg;
436 
437 	switch (offset & 0xff) {
438 	case 0x10:
439 		reg = AUX_CH_CTL;
440 		break;
441 	case 0x14:
442 		reg = AUX_CH_DATA1;
443 		break;
444 	case 0x18:
445 		reg = AUX_CH_DATA2;
446 		break;
447 	case 0x1c:
448 		reg = AUX_CH_DATA3;
449 		break;
450 	case 0x20:
451 		reg = AUX_CH_DATA4;
452 		break;
453 	case 0x24:
454 		reg = AUX_CH_DATA5;
455 		break;
456 	default:
457 		reg = -1;
458 		break;
459 	}
460 	return reg;
461 }
462 
463 #define AUX_CTL_MSG_LENGTH(reg) \
464 	((reg & DP_AUX_CH_CTL_MESSAGE_SIZE_MASK) >> \
465 		DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT)
466 
467 /**
468  * intel_gvt_i2c_handle_aux_ch_write - emulate AUX channel register write
469  * @vgpu: a vGPU
470  * @port_idx: port index
471  * @offset: reg offset
472  * @p_data: write ptr
473  *
474  * This function is used to emulate AUX channel register write
475  *
476  */
intel_gvt_i2c_handle_aux_ch_write(struct intel_vgpu * vgpu,int port_idx,unsigned int offset,void * p_data)477 void intel_gvt_i2c_handle_aux_ch_write(struct intel_vgpu *vgpu,
478 				int port_idx,
479 				unsigned int offset,
480 				void *p_data)
481 {
482 	struct drm_i915_private *i915 = vgpu->gvt->gt->i915;
483 	struct intel_vgpu_i2c_edid *i2c_edid = &vgpu->display.i2c_edid;
484 	int msg_length, ret_msg_size;
485 	int msg, addr, ctrl, op;
486 	u32 value = *(u32 *)p_data;
487 	int aux_data_for_write = 0;
488 	int reg = get_aux_ch_reg(offset);
489 
490 	if (reg != AUX_CH_CTL) {
491 		vgpu_vreg(vgpu, offset) = value;
492 		return;
493 	}
494 
495 	msg_length = AUX_CTL_MSG_LENGTH(value);
496 	// check the msg in DATA register.
497 	msg = vgpu_vreg(vgpu, offset + 4);
498 	addr = (msg >> 8) & 0xffff;
499 	ctrl = (msg >> 24) & 0xff;
500 	op = ctrl >> 4;
501 	if (!(value & DP_AUX_CH_CTL_SEND_BUSY)) {
502 		/* The ctl write to clear some states */
503 		return;
504 	}
505 
506 	/* Always set the wanted value for vms. */
507 	ret_msg_size = (((op & 0x1) == GVT_AUX_I2C_READ) ? 2 : 1);
508 	vgpu_vreg(vgpu, offset) =
509 		DP_AUX_CH_CTL_DONE |
510 		((ret_msg_size << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) &
511 		DP_AUX_CH_CTL_MESSAGE_SIZE_MASK);
512 
513 	if (msg_length == 3) {
514 		if (!(op & GVT_AUX_I2C_MOT)) {
515 			/* stop */
516 			intel_vgpu_init_i2c_edid(vgpu);
517 		} else {
518 			/* start or restart */
519 			i2c_edid->aux_ch.i2c_over_aux_ch = true;
520 			i2c_edid->aux_ch.aux_ch_mot = true;
521 			if (addr == 0) {
522 				/* reset the address */
523 				intel_vgpu_init_i2c_edid(vgpu);
524 			} else if (addr == EDID_ADDR) {
525 				i2c_edid->state = I2C_AUX_CH;
526 				i2c_edid->port = port_idx;
527 				i2c_edid->slave_selected = true;
528 				if (intel_vgpu_has_monitor_on_port(vgpu,
529 					port_idx) &&
530 					intel_vgpu_port_is_dp(vgpu, port_idx))
531 					i2c_edid->edid_available = true;
532 			}
533 		}
534 	} else if ((op & 0x1) == GVT_AUX_I2C_WRITE) {
535 		/* TODO
536 		 * We only support EDID reading from I2C_over_AUX. And
537 		 * we do not expect the index mode to be used. Right now
538 		 * the WRITE operation is ignored. It is good enough to
539 		 * support the gfx driver to do EDID access.
540 		 */
541 	} else {
542 		if (drm_WARN_ON(&i915->drm, (op & 0x1) != GVT_AUX_I2C_READ))
543 			return;
544 		if (drm_WARN_ON(&i915->drm, msg_length != 4))
545 			return;
546 		if (i2c_edid->edid_available && i2c_edid->slave_selected) {
547 			unsigned char val = edid_get_byte(vgpu);
548 
549 			aux_data_for_write = (val << 16);
550 		} else
551 			aux_data_for_write = (0xff << 16);
552 	}
553 	/* write the return value in AUX_CH_DATA reg which includes:
554 	 * ACK of I2C_WRITE
555 	 * returned byte if it is READ
556 	 */
557 	aux_data_for_write |= GVT_AUX_I2C_REPLY_ACK << 24;
558 	vgpu_vreg(vgpu, offset + 4) = aux_data_for_write;
559 }
560 
561 /**
562  * intel_vgpu_init_i2c_edid - initialize vGPU i2c edid emulation
563  * @vgpu: a vGPU
564  *
565  * This function is used to initialize vGPU i2c edid emulation stuffs
566  *
567  */
intel_vgpu_init_i2c_edid(struct intel_vgpu * vgpu)568 void intel_vgpu_init_i2c_edid(struct intel_vgpu *vgpu)
569 {
570 	struct intel_vgpu_i2c_edid *edid = &vgpu->display.i2c_edid;
571 
572 	edid->state = I2C_NOT_SPECIFIED;
573 
574 	edid->port = -1;
575 	edid->slave_selected = false;
576 	edid->edid_available = false;
577 	edid->current_edid_read = 0;
578 
579 	memset(&edid->gmbus, 0, sizeof(struct intel_vgpu_i2c_gmbus));
580 
581 	edid->aux_ch.i2c_over_aux_ch = false;
582 	edid->aux_ch.aux_ch_mot = false;
583 }
584