xref: /rk3399_rockchip-uboot/drivers/video/tegra.c (revision bfda03770cc9a05be89d03e90c275e88f12e4174)
1 /*
2  * Copyright (c) 2011 The Chromium OS Authors.
3  * SPDX-License-Identifier:	GPL-2.0+
4  */
5 
6 #include <common.h>
7 #include <dm.h>
8 #include <fdtdec.h>
9 #include <video.h>
10 #include <asm/system.h>
11 #include <asm/gpio.h>
12 #include <asm/io.h>
13 
14 #include <asm/arch/clock.h>
15 #include <asm/arch/funcmux.h>
16 #include <asm/arch/pinmux.h>
17 #include <asm/arch/pwm.h>
18 #include <asm/arch/display.h>
19 #include <asm/arch-tegra/timer.h>
20 
21 DECLARE_GLOBAL_DATA_PTR;
22 
23 /* These are the stages we go throuh in enabling the LCD */
24 enum stage_t {
25 	STAGE_START,
26 	STAGE_PANEL_VDD,
27 	STAGE_LVDS,
28 	STAGE_BACKLIGHT_VDD,
29 	STAGE_PWM,
30 	STAGE_BACKLIGHT_EN,
31 	STAGE_DONE,
32 };
33 
34 #define FDT_LCD_TIMINGS	4
35 
36 enum {
37 	FDT_LCD_TIMING_REF_TO_SYNC,
38 	FDT_LCD_TIMING_SYNC_WIDTH,
39 	FDT_LCD_TIMING_BACK_PORCH,
40 	FDT_LCD_TIMING_FRONT_PORCH,
41 
42 	FDT_LCD_TIMING_COUNT,
43 };
44 
45 enum lcd_cache_t {
46 	FDT_LCD_CACHE_OFF		= 0,
47 	FDT_LCD_CACHE_WRITE_THROUGH	= 1 << 0,
48 	FDT_LCD_CACHE_WRITE_BACK	= 1 << 1,
49 	FDT_LCD_CACHE_FLUSH		= 1 << 2,
50 	FDT_LCD_CACHE_WRITE_BACK_FLUSH	= FDT_LCD_CACHE_WRITE_BACK |
51 						FDT_LCD_CACHE_FLUSH,
52 };
53 
54 /* Information about the display controller */
55 struct tegra_lcd_priv {
56 	enum stage_t stage;	/* Current stage we are at */
57 	unsigned long timer_next; /* Time we can move onto next stage */
58 	int width;			/* width in pixels */
59 	int height;			/* height in pixels */
60 	int bpp;			/* number of bits per pixel */
61 
62 	/*
63 	 * log2 of number of bpp, in general, unless it bpp is 24 in which
64 	 * case this field holds 24 also! This is a U-Boot thing.
65 	 */
66 	int log2_bpp;
67 	struct disp_ctlr *disp;		/* Display controller to use */
68 	fdt_addr_t frame_buffer;	/* Address of frame buffer */
69 	unsigned pixel_clock;		/* Pixel clock in Hz */
70 	uint horiz_timing[FDT_LCD_TIMING_COUNT];	/* Horizontal timing */
71 	uint vert_timing[FDT_LCD_TIMING_COUNT];		/* Vertical timing */
72 	int panel_node;			/* node offset of panel information */
73 	int pwm_channel;		/* PWM channel to use for backlight */
74 	enum lcd_cache_t cache_type;
75 
76 	struct gpio_desc backlight_en;	/* GPIO for backlight enable */
77 	struct gpio_desc lvds_shutdown;	/* GPIO for lvds shutdown */
78 	struct gpio_desc backlight_vdd;	/* GPIO for backlight vdd */
79 	struct gpio_desc panel_vdd;	/* GPIO for panel vdd */
80 	/*
81 	 * Panel required timings
82 	 * Timing 1: delay between panel_vdd-rise and data-rise
83 	 * Timing 2: delay between data-rise and backlight_vdd-rise
84 	 * Timing 3: delay between backlight_vdd and pwm-rise
85 	 * Timing 4: delay between pwm-rise and backlight_en-rise
86 	 */
87 	uint panel_timings[FDT_LCD_TIMINGS];
88 };
89 
90 enum {
91 	/* Maximum LCD size we support */
92 	LCD_MAX_WIDTH		= 1366,
93 	LCD_MAX_HEIGHT		= 768,
94 	LCD_MAX_LOG2_BPP	= VIDEO_BPP16,
95 };
96 
97 static void update_window(struct dc_ctlr *dc, struct disp_ctl_win *win)
98 {
99 	unsigned h_dda, v_dda;
100 	unsigned long val;
101 
102 	val = readl(&dc->cmd.disp_win_header);
103 	val |= WINDOW_A_SELECT;
104 	writel(val, &dc->cmd.disp_win_header);
105 
106 	writel(win->fmt, &dc->win.color_depth);
107 
108 	clrsetbits_le32(&dc->win.byte_swap, BYTE_SWAP_MASK,
109 			BYTE_SWAP_NOSWAP << BYTE_SWAP_SHIFT);
110 
111 	val = win->out_x << H_POSITION_SHIFT;
112 	val |= win->out_y << V_POSITION_SHIFT;
113 	writel(val, &dc->win.pos);
114 
115 	val = win->out_w << H_SIZE_SHIFT;
116 	val |= win->out_h << V_SIZE_SHIFT;
117 	writel(val, &dc->win.size);
118 
119 	val = (win->w * win->bpp / 8) << H_PRESCALED_SIZE_SHIFT;
120 	val |= win->h << V_PRESCALED_SIZE_SHIFT;
121 	writel(val, &dc->win.prescaled_size);
122 
123 	writel(0, &dc->win.h_initial_dda);
124 	writel(0, &dc->win.v_initial_dda);
125 
126 	h_dda = (win->w * 0x1000) / max(win->out_w - 1, 1U);
127 	v_dda = (win->h * 0x1000) / max(win->out_h - 1, 1U);
128 
129 	val = h_dda << H_DDA_INC_SHIFT;
130 	val |= v_dda << V_DDA_INC_SHIFT;
131 	writel(val, &dc->win.dda_increment);
132 
133 	writel(win->stride, &dc->win.line_stride);
134 	writel(0, &dc->win.buf_stride);
135 
136 	val = WIN_ENABLE;
137 	if (win->bpp < 24)
138 		val |= COLOR_EXPAND;
139 	writel(val, &dc->win.win_opt);
140 
141 	writel((unsigned long)win->phys_addr, &dc->winbuf.start_addr);
142 	writel(win->x, &dc->winbuf.addr_h_offset);
143 	writel(win->y, &dc->winbuf.addr_v_offset);
144 
145 	writel(0xff00, &dc->win.blend_nokey);
146 	writel(0xff00, &dc->win.blend_1win);
147 
148 	val = GENERAL_ACT_REQ | WIN_A_ACT_REQ;
149 	val |= GENERAL_UPDATE | WIN_A_UPDATE;
150 	writel(val, &dc->cmd.state_ctrl);
151 }
152 
153 static void write_pair(struct tegra_lcd_priv *priv, int item, u32 *reg)
154 {
155 	writel(priv->horiz_timing[item] |
156 			(priv->vert_timing[item] << 16), reg);
157 }
158 
159 static int update_display_mode(struct dc_disp_reg *disp,
160 			       struct tegra_lcd_priv *priv)
161 {
162 	unsigned long val;
163 	unsigned long rate;
164 	unsigned long div;
165 
166 	writel(0x0, &disp->disp_timing_opt);
167 	write_pair(priv, FDT_LCD_TIMING_REF_TO_SYNC, &disp->ref_to_sync);
168 	write_pair(priv, FDT_LCD_TIMING_SYNC_WIDTH, &disp->sync_width);
169 	write_pair(priv, FDT_LCD_TIMING_BACK_PORCH, &disp->back_porch);
170 	write_pair(priv, FDT_LCD_TIMING_FRONT_PORCH, &disp->front_porch);
171 
172 	writel(priv->width | (priv->height << 16), &disp->disp_active);
173 
174 	val = DE_SELECT_ACTIVE << DE_SELECT_SHIFT;
175 	val |= DE_CONTROL_NORMAL << DE_CONTROL_SHIFT;
176 	writel(val, &disp->data_enable_opt);
177 
178 	val = DATA_FORMAT_DF1P1C << DATA_FORMAT_SHIFT;
179 	val |= DATA_ALIGNMENT_MSB << DATA_ALIGNMENT_SHIFT;
180 	val |= DATA_ORDER_RED_BLUE << DATA_ORDER_SHIFT;
181 	writel(val, &disp->disp_interface_ctrl);
182 
183 	/*
184 	 * The pixel clock divider is in 7.1 format (where the bottom bit
185 	 * represents 0.5). Here we calculate the divider needed to get from
186 	 * the display clock (typically 600MHz) to the pixel clock. We round
187 	 * up or down as requried.
188 	 */
189 	rate = clock_get_periph_rate(PERIPH_ID_DISP1, CLOCK_ID_CGENERAL);
190 	div = ((rate * 2 + priv->pixel_clock / 2) / priv->pixel_clock) - 2;
191 	debug("Display clock %lu, divider %lu\n", rate, div);
192 
193 	writel(0x00010001, &disp->shift_clk_opt);
194 
195 	val = PIXEL_CLK_DIVIDER_PCD1 << PIXEL_CLK_DIVIDER_SHIFT;
196 	val |= div << SHIFT_CLK_DIVIDER_SHIFT;
197 	writel(val, &disp->disp_clk_ctrl);
198 
199 	return 0;
200 }
201 
202 /* Start up the display and turn on power to PWMs */
203 static void basic_init(struct dc_cmd_reg *cmd)
204 {
205 	u32 val;
206 
207 	writel(0x00000100, &cmd->gen_incr_syncpt_ctrl);
208 	writel(0x0000011a, &cmd->cont_syncpt_vsync);
209 	writel(0x00000000, &cmd->int_type);
210 	writel(0x00000000, &cmd->int_polarity);
211 	writel(0x00000000, &cmd->int_mask);
212 	writel(0x00000000, &cmd->int_enb);
213 
214 	val = PW0_ENABLE | PW1_ENABLE | PW2_ENABLE;
215 	val |= PW3_ENABLE | PW4_ENABLE | PM0_ENABLE;
216 	val |= PM1_ENABLE;
217 	writel(val, &cmd->disp_pow_ctrl);
218 
219 	val = readl(&cmd->disp_cmd);
220 	val |= CTRL_MODE_C_DISPLAY << CTRL_MODE_SHIFT;
221 	writel(val, &cmd->disp_cmd);
222 }
223 
224 static void basic_init_timer(struct dc_disp_reg *disp)
225 {
226 	writel(0x00000020, &disp->mem_high_pri);
227 	writel(0x00000001, &disp->mem_high_pri_timer);
228 }
229 
230 static const u32 rgb_enb_tab[PIN_REG_COUNT] = {
231 	0x00000000,
232 	0x00000000,
233 	0x00000000,
234 	0x00000000,
235 };
236 
237 static const u32 rgb_polarity_tab[PIN_REG_COUNT] = {
238 	0x00000000,
239 	0x01000000,
240 	0x00000000,
241 	0x00000000,
242 };
243 
244 static const u32 rgb_data_tab[PIN_REG_COUNT] = {
245 	0x00000000,
246 	0x00000000,
247 	0x00000000,
248 	0x00000000,
249 };
250 
251 static const u32 rgb_sel_tab[PIN_OUTPUT_SEL_COUNT] = {
252 	0x00000000,
253 	0x00000000,
254 	0x00000000,
255 	0x00000000,
256 	0x00210222,
257 	0x00002200,
258 	0x00020000,
259 };
260 
261 static void rgb_enable(struct dc_com_reg *com)
262 {
263 	int i;
264 
265 	for (i = 0; i < PIN_REG_COUNT; i++) {
266 		writel(rgb_enb_tab[i], &com->pin_output_enb[i]);
267 		writel(rgb_polarity_tab[i], &com->pin_output_polarity[i]);
268 		writel(rgb_data_tab[i], &com->pin_output_data[i]);
269 	}
270 
271 	for (i = 0; i < PIN_OUTPUT_SEL_COUNT; i++)
272 		writel(rgb_sel_tab[i], &com->pin_output_sel[i]);
273 }
274 
275 static int setup_window(struct disp_ctl_win *win,
276 			struct tegra_lcd_priv *priv)
277 {
278 	win->x = 0;
279 	win->y = 0;
280 	win->w = priv->width;
281 	win->h = priv->height;
282 	win->out_x = 0;
283 	win->out_y = 0;
284 	win->out_w = priv->width;
285 	win->out_h = priv->height;
286 	win->phys_addr = priv->frame_buffer;
287 	win->stride = priv->width * (1 << priv->log2_bpp) / 8;
288 	debug("%s: depth = %d\n", __func__, priv->log2_bpp);
289 	switch (priv->log2_bpp) {
290 	case 5:
291 	case 24:
292 		win->fmt = COLOR_DEPTH_R8G8B8A8;
293 		win->bpp = 32;
294 		break;
295 	case 4:
296 		win->fmt = COLOR_DEPTH_B5G6R5;
297 		win->bpp = 16;
298 		break;
299 
300 	default:
301 		debug("Unsupported LCD bit depth");
302 		return -1;
303 	}
304 
305 	return 0;
306 }
307 
308 static void debug_timing(const char *name, unsigned int timing[])
309 {
310 #ifdef DEBUG
311 	int i;
312 
313 	debug("%s timing: ", name);
314 	for (i = 0; i < FDT_LCD_TIMING_COUNT; i++)
315 		debug("%d ", timing[i]);
316 	debug("\n");
317 #endif
318 }
319 
320 /**
321  * Decode panel information from the fdt, according to a standard binding
322  *
323  * @param blob		fdt blob
324  * @param node		offset of fdt node to read from
325  * @param priv		structure to store fdt config into
326  * @return 0 if ok, -ve on error
327  */
328 static int tegra_decode_panel(const void *blob, int node,
329 			      struct tegra_lcd_priv *priv)
330 {
331 	int front, back, ref;
332 
333 	priv->width = fdtdec_get_int(blob, node, "xres", -1);
334 	priv->height = fdtdec_get_int(blob, node, "yres", -1);
335 	priv->pixel_clock = fdtdec_get_int(blob, node, "clock", 0);
336 	if (!priv->pixel_clock || priv->width == -1 || priv->height == -1) {
337 		debug("%s: Pixel parameters missing\n", __func__);
338 		return -FDT_ERR_NOTFOUND;
339 	}
340 
341 	back = fdtdec_get_int(blob, node, "left-margin", -1);
342 	front = fdtdec_get_int(blob, node, "right-margin", -1);
343 	ref = fdtdec_get_int(blob, node, "hsync-len", -1);
344 	if ((back | front | ref) == -1) {
345 		debug("%s: Horizontal parameters missing\n", __func__);
346 		return -FDT_ERR_NOTFOUND;
347 	}
348 
349 	/* Use a ref-to-sync of 1 always, and take this from the front porch */
350 	priv->horiz_timing[FDT_LCD_TIMING_REF_TO_SYNC] = 1;
351 	priv->horiz_timing[FDT_LCD_TIMING_SYNC_WIDTH] = ref;
352 	priv->horiz_timing[FDT_LCD_TIMING_BACK_PORCH] = back;
353 	priv->horiz_timing[FDT_LCD_TIMING_FRONT_PORCH] = front -
354 		priv->horiz_timing[FDT_LCD_TIMING_REF_TO_SYNC];
355 	debug_timing("horiz", priv->horiz_timing);
356 
357 	back = fdtdec_get_int(blob, node, "upper-margin", -1);
358 	front = fdtdec_get_int(blob, node, "lower-margin", -1);
359 	ref = fdtdec_get_int(blob, node, "vsync-len", -1);
360 	if ((back | front | ref) == -1) {
361 		debug("%s: Vertical parameters missing\n", __func__);
362 		return -FDT_ERR_NOTFOUND;
363 	}
364 
365 	priv->vert_timing[FDT_LCD_TIMING_REF_TO_SYNC] = 1;
366 	priv->vert_timing[FDT_LCD_TIMING_SYNC_WIDTH] = ref;
367 	priv->vert_timing[FDT_LCD_TIMING_BACK_PORCH] = back;
368 	priv->vert_timing[FDT_LCD_TIMING_FRONT_PORCH] = front -
369 		priv->vert_timing[FDT_LCD_TIMING_REF_TO_SYNC];
370 	debug_timing("vert", priv->vert_timing);
371 
372 	return 0;
373 }
374 
375 /**
376  * Decode the display controller information from the fdt.
377  *
378  * @param blob		fdt blob
379  * @param priv		structure to store fdt priv into
380  * @return 0 if ok, -ve on error
381  */
382 static int tegra_display_decode_config(const void *blob, int node,
383 				       struct tegra_lcd_priv *priv)
384 {
385 	int rgb;
386 	int bpp, bit;
387 
388 	priv->disp = (struct disp_ctlr *)fdtdec_get_addr(blob, node, "reg");
389 	if (!priv->disp) {
390 		debug("%s: No display controller address\n", __func__);
391 		return -1;
392 	}
393 
394 	rgb = fdt_subnode_offset(blob, node, "rgb");
395 
396 	priv->panel_node = fdtdec_lookup_phandle(blob, rgb, "nvidia,panel");
397 	if (priv->panel_node < 0) {
398 		debug("%s: Cannot find panel information\n", __func__);
399 		return -1;
400 	}
401 
402 	if (tegra_decode_panel(blob, priv->panel_node, priv)) {
403 		debug("%s: Failed to decode panel information\n", __func__);
404 		return -1;
405 	}
406 
407 	bpp = fdtdec_get_int(blob, priv->panel_node, "nvidia,bits-per-pixel",
408 			     -1);
409 	bit = ffs(bpp) - 1;
410 	if (bpp == (1 << bit))
411 		priv->log2_bpp = bit;
412 	else
413 		priv->log2_bpp = bpp;
414 	if (bpp == -1) {
415 		debug("%s: Pixel bpp parameters missing\n", __func__);
416 		return -FDT_ERR_NOTFOUND;
417 	}
418 	priv->bpp = bpp;
419 
420 	return 0;
421 }
422 
423 /**
424  * Register a new display based on device tree configuration.
425  *
426  * The frame buffer can be positioned by U-Boot or overriden by the fdt.
427  * You should pass in the U-Boot address here, and check the contents of
428  * struct tegra_lcd_priv to see what was actually chosen.
429  *
430  * @param blob			Device tree blob
431  * @param priv			Driver's private data
432  * @param default_lcd_base	Default address of LCD frame buffer
433  * @return 0 if ok, -1 on error (unsupported bits per pixel)
434  */
435 static int tegra_display_probe(const void *blob, struct tegra_lcd_priv *priv,
436 			       void *default_lcd_base)
437 {
438 	struct disp_ctl_win window;
439 	struct dc_ctlr *dc;
440 
441 	priv->frame_buffer = (u32)default_lcd_base;
442 
443 	dc = (struct dc_ctlr *)priv->disp;
444 
445 	/*
446 	 * A header file for clock constants was NAKed upstream.
447 	 * TODO: Put this into the FDT and fdt_lcd struct when we have clock
448 	 * support there
449 	 */
450 	clock_start_periph_pll(PERIPH_ID_HOST1X, CLOCK_ID_PERIPH,
451 			       144 * 1000000);
452 	clock_start_periph_pll(PERIPH_ID_DISP1, CLOCK_ID_CGENERAL,
453 			       600 * 1000000);
454 	basic_init(&dc->cmd);
455 	basic_init_timer(&dc->disp);
456 	rgb_enable(&dc->com);
457 
458 	if (priv->pixel_clock)
459 		update_display_mode(&dc->disp, priv);
460 
461 	if (setup_window(&window, priv))
462 		return -1;
463 
464 	update_window(dc, &window);
465 
466 	return 0;
467 }
468 
469 /**
470  * Decode the panel information from the fdt.
471  *
472  * @param blob		fdt blob
473  * @param priv		structure to store fdt config into
474  * @return 0 if ok, -ve on error
475  */
476 static int fdt_decode_lcd(const void *blob, struct tegra_lcd_priv *priv)
477 {
478 	int display_node;
479 
480 	display_node = priv->panel_node;
481 	if (display_node < 0) {
482 		debug("%s: No panel configuration available\n", __func__);
483 		return -1;
484 	}
485 
486 	priv->pwm_channel = pwm_request(blob, display_node, "nvidia,pwm");
487 	if (priv->pwm_channel < 0) {
488 		debug("%s: Unable to request PWM channel\n", __func__);
489 		return -1;
490 	}
491 
492 	priv->cache_type = fdtdec_get_int(blob, display_node,
493 					    "nvidia,cache-type",
494 					    FDT_LCD_CACHE_WRITE_BACK_FLUSH);
495 
496 	/* These GPIOs are all optional */
497 	gpio_request_by_name_nodev(blob, display_node,
498 				   "nvidia,backlight-enable-gpios", 0,
499 				   &priv->backlight_en, GPIOD_IS_OUT);
500 	gpio_request_by_name_nodev(blob, display_node,
501 				   "nvidia,lvds-shutdown-gpios", 0,
502 				   &priv->lvds_shutdown, GPIOD_IS_OUT);
503 	gpio_request_by_name_nodev(blob, display_node,
504 				   "nvidia,backlight-vdd-gpios", 0,
505 				   &priv->backlight_vdd, GPIOD_IS_OUT);
506 	gpio_request_by_name_nodev(blob, display_node,
507 				   "nvidia,panel-vdd-gpios", 0,
508 				   &priv->panel_vdd, GPIOD_IS_OUT);
509 
510 	return fdtdec_get_int_array(blob, display_node, "nvidia,panel-timings",
511 			priv->panel_timings, FDT_LCD_TIMINGS);
512 }
513 
514 /**
515  * Handle the next stage of device init
516  */
517 static int handle_stage(const void *blob, struct tegra_lcd_priv *priv)
518 {
519 	debug("%s: stage %d\n", __func__, priv->stage);
520 
521 	/* do the things for this stage */
522 	switch (priv->stage) {
523 	case STAGE_START:
524 		/*
525 		 * It is possible that the FDT has requested that the LCD be
526 		 * disabled. We currently don't support this. It would require
527 		 * changes to U-Boot LCD subsystem to have LCD support
528 		 * compiled in but not used. An easier option might be to
529 		 * still have a frame buffer, but leave the backlight off and
530 		 * remove all mention of lcd in the stdout environment
531 		 * variable.
532 		 */
533 
534 		funcmux_select(PERIPH_ID_DISP1, FUNCMUX_DEFAULT);
535 		break;
536 	case STAGE_PANEL_VDD:
537 		if (dm_gpio_is_valid(&priv->panel_vdd))
538 			dm_gpio_set_value(&priv->panel_vdd, 1);
539 		break;
540 	case STAGE_LVDS:
541 		if (dm_gpio_is_valid(&priv->lvds_shutdown))
542 			dm_gpio_set_value(&priv->lvds_shutdown, 1);
543 		break;
544 	case STAGE_BACKLIGHT_VDD:
545 		if (dm_gpio_is_valid(&priv->backlight_vdd))
546 			dm_gpio_set_value(&priv->backlight_vdd, 1);
547 		break;
548 	case STAGE_PWM:
549 		/* Enable PWM at 15/16 high, 32768 Hz with divider 1 */
550 		pinmux_set_func(PMUX_PINGRP_GPU, PMUX_FUNC_PWM);
551 		pinmux_tristate_disable(PMUX_PINGRP_GPU);
552 
553 		pwm_enable(priv->pwm_channel, 32768, 0xdf, 1);
554 		break;
555 	case STAGE_BACKLIGHT_EN:
556 		if (dm_gpio_is_valid(&priv->backlight_en))
557 			dm_gpio_set_value(&priv->backlight_en, 1);
558 		break;
559 	case STAGE_DONE:
560 		break;
561 	}
562 
563 	/* set up timer for next stage */
564 	priv->timer_next = timer_get_us();
565 	if (priv->stage < FDT_LCD_TIMINGS)
566 		priv->timer_next += priv->panel_timings[priv->stage] * 1000;
567 
568 	/* move to next stage */
569 	priv->stage++;
570 	return 0;
571 }
572 
573 /**
574  * Perform the next stage of the LCD init if it is time to do so.
575  *
576  * LCD init can be time-consuming because of the number of delays we need
577  * while waiting for the backlight power supply, etc. This function can
578  * be called at various times during U-Boot operation to advance the
579  * initialization of the LCD to the next stage if sufficient time has
580  * passed since the last stage. It keeps track of what stage it is up to
581  * and the time that it is permitted to move to the next stage.
582  *
583  * The final call should have wait=1 to complete the init.
584  *
585  * @param blob	fdt blob containing LCD information
586  * @param wait	1 to wait until all init is complete, and then return
587  *		0 to return immediately, potentially doing nothing if it is
588  *		not yet time for the next init.
589  */
590 static int tegra_lcd_check_next_stage(const void *blob,
591 				      struct tegra_lcd_priv *priv, int wait)
592 {
593 	if (priv->stage == STAGE_DONE)
594 		return 0;
595 
596 	do {
597 		/* wait if we need to */
598 		debug("%s: stage %d\n", __func__, priv->stage);
599 		if (priv->stage != STAGE_START) {
600 			int delay = priv->timer_next - timer_get_us();
601 
602 			if (delay > 0) {
603 				if (wait)
604 					udelay(delay);
605 				else
606 					return 0;
607 			}
608 		}
609 
610 		if (handle_stage(blob, priv))
611 			return -1;
612 	} while (wait && priv->stage != STAGE_DONE);
613 	if (priv->stage == STAGE_DONE)
614 		debug("%s: LCD init complete\n", __func__);
615 
616 	return 0;
617 }
618 
619 static int tegra_lcd_probe(struct udevice *dev)
620 {
621 	struct video_uc_platdata *plat = dev_get_uclass_platdata(dev);
622 	struct video_priv *uc_priv = dev_get_uclass_priv(dev);
623 	struct tegra_lcd_priv *priv = dev_get_priv(dev);
624 	const void *blob = gd->fdt_blob;
625 	int type = DCACHE_OFF;
626 
627 	if (tegra_display_decode_config(blob, dev->of_offset, priv))
628 		return -1;
629 
630 	/* get panel details */
631 	if (fdt_decode_lcd(blob, priv)) {
632 		printf("No valid LCD information in device tree\n");
633 		return -1;
634 	}
635 
636 	/* Initialize the Tegra display controller */
637 	if (tegra_display_probe(blob, priv, (void *)plat->base)) {
638 		printf("%s: Failed to probe display driver\n", __func__);
639 		return -1;
640 	}
641 
642 	tegra_lcd_check_next_stage(blob, priv, 1);
643 
644 	/* Set up the LCD caching as requested */
645 	if (priv->cache_type & FDT_LCD_CACHE_WRITE_THROUGH)
646 		type = DCACHE_WRITETHROUGH;
647 	else if (priv->cache_type & FDT_LCD_CACHE_WRITE_BACK)
648 		type = DCACHE_WRITEBACK;
649 	mmu_set_region_dcache_behaviour(priv->frame_buffer, plat->size, type);
650 
651 	/* Enable flushing after LCD writes if requested */
652 	video_set_flush_dcache(dev, priv->cache_type & FDT_LCD_CACHE_FLUSH);
653 
654 	uc_priv->xsize = priv->width;
655 	uc_priv->ysize = priv->height;
656 	uc_priv->bpix = priv->log2_bpp;
657 	debug("LCD frame buffer at %pa, size %x\n", &priv->frame_buffer,
658 	      plat->size);
659 
660 	return 0;
661 }
662 
663 static int tegra_lcd_bind(struct udevice *dev)
664 {
665 	struct video_uc_platdata *plat = dev_get_uclass_platdata(dev);
666 
667 	plat->size = LCD_MAX_WIDTH * LCD_MAX_HEIGHT *
668 		(1 << LCD_MAX_LOG2_BPP) / 8;
669 
670 	return 0;
671 }
672 
673 static const struct video_ops tegra_lcd_ops = {
674 };
675 
676 static const struct udevice_id tegra_lcd_ids[] = {
677 	{ .compatible = "nvidia,tegra20-dc" },
678 	{ }
679 };
680 
681 U_BOOT_DRIVER(tegra_lcd) = {
682 	.name	= "tegra_lcd",
683 	.id	= UCLASS_VIDEO,
684 	.of_match = tegra_lcd_ids,
685 	.ops	= &tegra_lcd_ops,
686 	.bind	= tegra_lcd_bind,
687 	.probe	= tegra_lcd_probe,
688 	.priv_auto_alloc_size	= sizeof(struct tegra_lcd_priv),
689 };
690