xref: /linux/drivers/gpu/drm/mxsfb/mxsfb_kms.c (revision 7fc7f25419f5a6b09199ba4b5026b94ef184fa79)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2016 Marek Vasut <marex@denx.de>
4  *
5  * This code is based on drivers/video/fbdev/mxsfb.c :
6  * Copyright (C) 2010 Juergen Beisert, Pengutronix
7  * Copyright (C) 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
8  * Copyright (C) 2008 Embedded Alley Solutions, Inc All Rights Reserved.
9  */
10 
11 #include <linux/clk.h>
12 #include <linux/io.h>
13 #include <linux/iopoll.h>
14 #include <linux/media-bus-format.h>
15 #include <linux/pm_runtime.h>
16 #include <linux/spinlock.h>
17 
18 #include <drm/drm_atomic.h>
19 #include <drm/drm_atomic_helper.h>
20 #include <drm/drm_bridge.h>
21 #include <drm/drm_crtc.h>
22 #include <drm/drm_encoder.h>
23 #include <drm/drm_fb_dma_helper.h>
24 #include <drm/drm_fourcc.h>
25 #include <drm/drm_framebuffer.h>
26 #include <drm/drm_gem_atomic_helper.h>
27 #include <drm/drm_gem_dma_helper.h>
28 #include <drm/drm_plane.h>
29 #include <drm/drm_vblank.h>
30 
31 #include "mxsfb_drv.h"
32 #include "mxsfb_regs.h"
33 
34 /* 1 second delay should be plenty of time for block reset */
35 #define RESET_TIMEOUT		1000000
36 
37 /* -----------------------------------------------------------------------------
38  * CRTC
39  */
40 
41 static u32 set_hsync_pulse_width(struct mxsfb_drm_private *mxsfb, u32 val)
42 {
43 	return (val & mxsfb->devdata->hs_wdth_mask) <<
44 		mxsfb->devdata->hs_wdth_shift;
45 }
46 
47 /*
48  * Setup the MXSFB registers for decoding the pixels out of the framebuffer and
49  * outputting them on the bus.
50  */
51 static void mxsfb_set_formats(struct mxsfb_drm_private *mxsfb,
52 			      const u32 bus_format)
53 {
54 	struct drm_device *drm = mxsfb->drm;
55 	const u32 format = mxsfb->crtc.primary->state->fb->format->format;
56 	u32 ctrl, ctrl1;
57 
58 	DRM_DEV_DEBUG_DRIVER(drm->dev, "Using bus_format: 0x%08X\n",
59 			     bus_format);
60 
61 	ctrl = CTRL_BYPASS_COUNT | CTRL_MASTER;
62 
63 	/* CTRL1 contains IRQ config and status bits, preserve those. */
64 	ctrl1 = readl(mxsfb->base + LCDC_CTRL1);
65 	ctrl1 &= CTRL1_CUR_FRAME_DONE_IRQ_EN | CTRL1_CUR_FRAME_DONE_IRQ;
66 
67 	switch (format) {
68 	case DRM_FORMAT_RGB565:
69 		dev_dbg(drm->dev, "Setting up RGB565 mode\n");
70 		ctrl |= CTRL_WORD_LENGTH_16;
71 		ctrl1 |= CTRL1_SET_BYTE_PACKAGING(0xf);
72 		break;
73 	case DRM_FORMAT_XRGB8888:
74 		dev_dbg(drm->dev, "Setting up XRGB8888 mode\n");
75 		ctrl |= CTRL_WORD_LENGTH_24;
76 		/* Do not use packed pixels = one pixel per word instead. */
77 		ctrl1 |= CTRL1_SET_BYTE_PACKAGING(0x7);
78 		break;
79 	}
80 
81 	switch (bus_format) {
82 	case MEDIA_BUS_FMT_RGB565_1X16:
83 		ctrl |= CTRL_BUS_WIDTH_16;
84 		break;
85 	case MEDIA_BUS_FMT_RGB666_1X18:
86 		ctrl |= CTRL_BUS_WIDTH_18;
87 		break;
88 	case MEDIA_BUS_FMT_RGB888_1X24:
89 		ctrl |= CTRL_BUS_WIDTH_24;
90 		break;
91 	default:
92 		dev_err(drm->dev, "Unknown media bus format 0x%x\n", bus_format);
93 		break;
94 	}
95 
96 	writel(ctrl1, mxsfb->base + LCDC_CTRL1);
97 	writel(ctrl, mxsfb->base + LCDC_CTRL);
98 }
99 
100 static void mxsfb_set_mode(struct mxsfb_drm_private *mxsfb, u32 bus_flags)
101 {
102 	struct drm_display_mode *m = &mxsfb->crtc.state->adjusted_mode;
103 	u32 vdctrl0, vsync_pulse_len, hsync_pulse_len;
104 
105 	writel(TRANSFER_COUNT_SET_VCOUNT(m->crtc_vdisplay) |
106 	       TRANSFER_COUNT_SET_HCOUNT(m->crtc_hdisplay),
107 	       mxsfb->base + mxsfb->devdata->transfer_count);
108 
109 	vsync_pulse_len = m->crtc_vsync_end - m->crtc_vsync_start;
110 
111 	vdctrl0 = VDCTRL0_ENABLE_PRESENT |	/* Always in DOTCLOCK mode */
112 		  VDCTRL0_VSYNC_PERIOD_UNIT |
113 		  VDCTRL0_VSYNC_PULSE_WIDTH_UNIT |
114 		  VDCTRL0_SET_VSYNC_PULSE_WIDTH(vsync_pulse_len);
115 	if (m->flags & DRM_MODE_FLAG_PHSYNC)
116 		vdctrl0 |= VDCTRL0_HSYNC_ACT_HIGH;
117 	if (m->flags & DRM_MODE_FLAG_PVSYNC)
118 		vdctrl0 |= VDCTRL0_VSYNC_ACT_HIGH;
119 	/* Make sure Data Enable is high active by default */
120 	if (!(bus_flags & DRM_BUS_FLAG_DE_LOW))
121 		vdctrl0 |= VDCTRL0_ENABLE_ACT_HIGH;
122 	/*
123 	 * DRM_BUS_FLAG_PIXDATA_DRIVE_ defines are controller centric,
124 	 * controllers VDCTRL0_DOTCLK is display centric.
125 	 * Drive on positive edge       -> display samples on falling edge
126 	 * DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE -> VDCTRL0_DOTCLK_ACT_FALLING
127 	 */
128 	if (bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE)
129 		vdctrl0 |= VDCTRL0_DOTCLK_ACT_FALLING;
130 
131 	writel(vdctrl0, mxsfb->base + LCDC_VDCTRL0);
132 
133 	/* Frame length in lines. */
134 	writel(m->crtc_vtotal, mxsfb->base + LCDC_VDCTRL1);
135 
136 	/* Line length in units of clocks or pixels. */
137 	hsync_pulse_len = m->crtc_hsync_end - m->crtc_hsync_start;
138 	writel(set_hsync_pulse_width(mxsfb, hsync_pulse_len) |
139 	       VDCTRL2_SET_HSYNC_PERIOD(m->crtc_htotal),
140 	       mxsfb->base + LCDC_VDCTRL2);
141 
142 	writel(SET_HOR_WAIT_CNT(m->crtc_htotal - m->crtc_hsync_start) |
143 	       SET_VERT_WAIT_CNT(m->crtc_vtotal - m->crtc_vsync_start),
144 	       mxsfb->base + LCDC_VDCTRL3);
145 
146 	writel(SET_DOTCLK_H_VALID_DATA_CNT(m->hdisplay),
147 	       mxsfb->base + LCDC_VDCTRL4);
148 
149 }
150 
151 static void mxsfb_enable_controller(struct mxsfb_drm_private *mxsfb)
152 {
153 	u32 reg;
154 
155 	if (mxsfb->clk_disp_axi)
156 		clk_prepare_enable(mxsfb->clk_disp_axi);
157 	clk_prepare_enable(mxsfb->clk);
158 
159 	/* Increase number of outstanding requests on all supported IPs */
160 	if (mxsfb->devdata->has_ctrl2) {
161 		reg = readl(mxsfb->base + LCDC_V4_CTRL2);
162 		reg &= ~CTRL2_SET_OUTSTANDING_REQS_MASK;
163 		reg |= CTRL2_SET_OUTSTANDING_REQS_16;
164 		writel(reg, mxsfb->base + LCDC_V4_CTRL2);
165 	}
166 
167 	/* If it was disabled, re-enable the mode again */
168 	writel(CTRL_DOTCLK_MODE, mxsfb->base + LCDC_CTRL + REG_SET);
169 
170 	/* Enable the SYNC signals first, then the DMA engine */
171 	reg = readl(mxsfb->base + LCDC_VDCTRL4);
172 	reg |= VDCTRL4_SYNC_SIGNALS_ON;
173 	writel(reg, mxsfb->base + LCDC_VDCTRL4);
174 
175 	/*
176 	 * Enable recovery on underflow.
177 	 *
178 	 * There is some sort of corner case behavior of the controller,
179 	 * which could rarely be triggered at least on i.MX6SX connected
180 	 * to 800x480 DPI panel and i.MX8MM connected to DPI->DSI->LVDS
181 	 * bridged 1920x1080 panel (and likely on other setups too), where
182 	 * the image on the panel shifts to the right and wraps around.
183 	 * This happens either when the controller is enabled on boot or
184 	 * even later during run time. The condition does not correct
185 	 * itself automatically, i.e. the display image remains shifted.
186 	 *
187 	 * It seems this problem is known and is due to sporadic underflows
188 	 * of the LCDIF FIFO. While the LCDIF IP does have underflow/overflow
189 	 * IRQs, neither of the IRQs trigger and neither IRQ status bit is
190 	 * asserted when this condition occurs.
191 	 *
192 	 * All known revisions of the LCDIF IP have CTRL1 RECOVER_ON_UNDERFLOW
193 	 * bit, which is described in the reference manual since i.MX23 as
194 	 * "
195 	 *   Set this bit to enable the LCDIF block to recover in the next
196 	 *   field/frame if there was an underflow in the current field/frame.
197 	 * "
198 	 * Enable this bit to mitigate the sporadic underflows.
199 	 */
200 	reg = readl(mxsfb->base + LCDC_CTRL1);
201 	reg |= CTRL1_RECOVER_ON_UNDERFLOW;
202 	writel(reg, mxsfb->base + LCDC_CTRL1);
203 
204 	writel(CTRL_RUN, mxsfb->base + LCDC_CTRL + REG_SET);
205 }
206 
207 static void mxsfb_disable_controller(struct mxsfb_drm_private *mxsfb)
208 {
209 	u32 reg;
210 
211 	/*
212 	 * Even if we disable the controller here, it will still continue
213 	 * until its FIFOs are running out of data
214 	 */
215 	writel(CTRL_DOTCLK_MODE, mxsfb->base + LCDC_CTRL + REG_CLR);
216 
217 	readl_poll_timeout(mxsfb->base + LCDC_CTRL, reg, !(reg & CTRL_RUN),
218 			   0, 1000);
219 
220 	reg = readl(mxsfb->base + LCDC_VDCTRL4);
221 	reg &= ~VDCTRL4_SYNC_SIGNALS_ON;
222 	writel(reg, mxsfb->base + LCDC_VDCTRL4);
223 
224 	clk_disable_unprepare(mxsfb->clk);
225 	if (mxsfb->clk_disp_axi)
226 		clk_disable_unprepare(mxsfb->clk_disp_axi);
227 }
228 
229 /*
230  * Clear the bit and poll it cleared.  This is usually called with
231  * a reset address and mask being either SFTRST(bit 31) or CLKGATE
232  * (bit 30).
233  */
234 static int clear_poll_bit(void __iomem *addr, u32 mask)
235 {
236 	u32 reg;
237 
238 	writel(mask, addr + REG_CLR);
239 	return readl_poll_timeout(addr, reg, !(reg & mask), 0, RESET_TIMEOUT);
240 }
241 
242 static int mxsfb_reset_block(struct mxsfb_drm_private *mxsfb)
243 {
244 	int ret;
245 
246 	/*
247 	 * It seems, you can't re-program the controller if it is still
248 	 * running. This may lead to shifted pictures (FIFO issue?), so
249 	 * first stop the controller and drain its FIFOs.
250 	 */
251 
252 	ret = clear_poll_bit(mxsfb->base + LCDC_CTRL, CTRL_SFTRST);
253 	if (ret)
254 		return ret;
255 
256 	writel(CTRL_CLKGATE, mxsfb->base + LCDC_CTRL + REG_CLR);
257 
258 	ret = clear_poll_bit(mxsfb->base + LCDC_CTRL, CTRL_SFTRST);
259 	if (ret)
260 		return ret;
261 
262 	ret = clear_poll_bit(mxsfb->base + LCDC_CTRL, CTRL_CLKGATE);
263 	if (ret)
264 		return ret;
265 
266 	/* Clear the FIFOs */
267 	writel(CTRL1_FIFO_CLEAR, mxsfb->base + LCDC_CTRL1 + REG_SET);
268 	readl(mxsfb->base + LCDC_CTRL1);
269 	writel(CTRL1_FIFO_CLEAR, mxsfb->base + LCDC_CTRL1 + REG_CLR);
270 	readl(mxsfb->base + LCDC_CTRL1);
271 
272 	if (mxsfb->devdata->has_overlay)
273 		writel(0, mxsfb->base + LCDC_AS_CTRL);
274 
275 	return 0;
276 }
277 
278 static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb,
279 				     struct drm_bridge_state *bridge_state,
280 				     const u32 bus_format)
281 {
282 	struct drm_device *drm = mxsfb->crtc.dev;
283 	struct drm_display_mode *m = &mxsfb->crtc.state->adjusted_mode;
284 	u32 bus_flags = mxsfb->connector->display_info.bus_flags;
285 	int err;
286 
287 	if (mxsfb->bridge && mxsfb->bridge->timings)
288 		bus_flags = mxsfb->bridge->timings->input_bus_flags;
289 	else if (bridge_state)
290 		bus_flags = bridge_state->input_bus_cfg.flags;
291 
292 	DRM_DEV_DEBUG_DRIVER(drm->dev, "Pixel clock: %dkHz (actual: %dkHz)\n",
293 			     m->crtc_clock,
294 			     (int)(clk_get_rate(mxsfb->clk) / 1000));
295 	DRM_DEV_DEBUG_DRIVER(drm->dev, "Connector bus_flags: 0x%08X\n",
296 			     bus_flags);
297 	DRM_DEV_DEBUG_DRIVER(drm->dev, "Mode flags: 0x%08X\n", m->flags);
298 
299 	/* Mandatory eLCDIF reset as per the Reference Manual */
300 	err = mxsfb_reset_block(mxsfb);
301 	if (err)
302 		return;
303 
304 	mxsfb_set_formats(mxsfb, bus_format);
305 
306 	clk_set_rate(mxsfb->clk, m->crtc_clock * 1000);
307 
308 	mxsfb_set_mode(mxsfb, bus_flags);
309 }
310 
311 static int mxsfb_crtc_atomic_check(struct drm_crtc *crtc,
312 				   struct drm_atomic_state *state)
313 {
314 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
315 									  crtc);
316 	bool has_primary = crtc_state->plane_mask &
317 			   drm_plane_mask(crtc->primary);
318 
319 	/* The primary plane has to be enabled when the CRTC is active. */
320 	if (crtc_state->active && !has_primary)
321 		return -EINVAL;
322 
323 	/* TODO: Is this needed ? */
324 	return drm_atomic_add_affected_planes(state, crtc);
325 }
326 
327 static void mxsfb_crtc_atomic_flush(struct drm_crtc *crtc,
328 				    struct drm_atomic_state *state)
329 {
330 	struct drm_pending_vblank_event *event;
331 
332 	event = crtc->state->event;
333 	crtc->state->event = NULL;
334 
335 	if (!event)
336 		return;
337 
338 	spin_lock_irq(&crtc->dev->event_lock);
339 	if (drm_crtc_vblank_get(crtc) == 0)
340 		drm_crtc_arm_vblank_event(crtc, event);
341 	else
342 		drm_crtc_send_vblank_event(crtc, event);
343 	spin_unlock_irq(&crtc->dev->event_lock);
344 }
345 
346 static void mxsfb_crtc_atomic_enable(struct drm_crtc *crtc,
347 				     struct drm_atomic_state *state)
348 {
349 	struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(crtc->dev);
350 	struct drm_plane_state *new_pstate = drm_atomic_get_new_plane_state(state,
351 									    crtc->primary);
352 	struct drm_bridge_state *bridge_state = NULL;
353 	struct drm_device *drm = mxsfb->drm;
354 	u32 bus_format = 0;
355 	dma_addr_t dma_addr;
356 
357 	pm_runtime_get_sync(drm->dev);
358 	mxsfb_enable_axi_clk(mxsfb);
359 
360 	drm_crtc_vblank_on(crtc);
361 
362 	/* If there is a bridge attached to the LCDIF, use its bus format */
363 	if (mxsfb->bridge) {
364 		bridge_state =
365 			drm_atomic_get_new_bridge_state(state,
366 							mxsfb->bridge);
367 		if (!bridge_state)
368 			bus_format = MEDIA_BUS_FMT_FIXED;
369 		else
370 			bus_format = bridge_state->input_bus_cfg.format;
371 
372 		if (bus_format == MEDIA_BUS_FMT_FIXED) {
373 			dev_warn_once(drm->dev,
374 				      "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
375 				      "Please fix bridge driver by handling atomic_get_input_bus_fmts.\n");
376 			bus_format = MEDIA_BUS_FMT_RGB888_1X24;
377 		}
378 	}
379 
380 	/* If there is no bridge, use bus format from connector */
381 	if (!bus_format && mxsfb->connector->display_info.num_bus_formats)
382 		bus_format = mxsfb->connector->display_info.bus_formats[0];
383 
384 	/* If all else fails, default to RGB888_1X24 */
385 	if (!bus_format)
386 		bus_format = MEDIA_BUS_FMT_RGB888_1X24;
387 
388 	mxsfb_crtc_mode_set_nofb(mxsfb, bridge_state, bus_format);
389 
390 	/* Write cur_buf as well to avoid an initial corrupt frame */
391 	dma_addr = drm_fb_dma_get_gem_addr(new_pstate->fb, new_pstate, 0);
392 	if (dma_addr) {
393 		writel(dma_addr, mxsfb->base + mxsfb->devdata->cur_buf);
394 		writel(dma_addr, mxsfb->base + mxsfb->devdata->next_buf);
395 	}
396 
397 	mxsfb_enable_controller(mxsfb);
398 }
399 
400 static void mxsfb_crtc_atomic_disable(struct drm_crtc *crtc,
401 				      struct drm_atomic_state *state)
402 {
403 	struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(crtc->dev);
404 	struct drm_device *drm = mxsfb->drm;
405 	struct drm_pending_vblank_event *event;
406 
407 	mxsfb_disable_controller(mxsfb);
408 
409 	spin_lock_irq(&drm->event_lock);
410 	event = crtc->state->event;
411 	if (event) {
412 		crtc->state->event = NULL;
413 		drm_crtc_send_vblank_event(crtc, event);
414 	}
415 	spin_unlock_irq(&drm->event_lock);
416 
417 	drm_crtc_vblank_off(crtc);
418 
419 	mxsfb_disable_axi_clk(mxsfb);
420 	pm_runtime_put_sync(drm->dev);
421 }
422 
423 static int mxsfb_crtc_enable_vblank(struct drm_crtc *crtc)
424 {
425 	struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(crtc->dev);
426 
427 	/* Clear and enable VBLANK IRQ */
428 	writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + REG_CLR);
429 	writel(CTRL1_CUR_FRAME_DONE_IRQ_EN, mxsfb->base + LCDC_CTRL1 + REG_SET);
430 
431 	return 0;
432 }
433 
434 static void mxsfb_crtc_disable_vblank(struct drm_crtc *crtc)
435 {
436 	struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(crtc->dev);
437 
438 	/* Disable and clear VBLANK IRQ */
439 	writel(CTRL1_CUR_FRAME_DONE_IRQ_EN, mxsfb->base + LCDC_CTRL1 + REG_CLR);
440 	writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + REG_CLR);
441 }
442 
443 static int mxsfb_crtc_set_crc_source(struct drm_crtc *crtc, const char *source)
444 {
445 	struct mxsfb_drm_private *mxsfb;
446 
447 	if (!crtc)
448 		return -ENODEV;
449 
450 	mxsfb = to_mxsfb_drm_private(crtc->dev);
451 
452 	if (source && strcmp(source, "auto") == 0)
453 		mxsfb->crc_active = true;
454 	else if (!source)
455 		mxsfb->crc_active = false;
456 	else
457 		return -EINVAL;
458 
459 	return 0;
460 }
461 
462 static int mxsfb_crtc_verify_crc_source(struct drm_crtc *crtc,
463 					const char *source, size_t *values_cnt)
464 {
465 	if (!crtc)
466 		return -ENODEV;
467 
468 	if (source && strcmp(source, "auto") != 0) {
469 		DRM_DEBUG_DRIVER("Unknown CRC source %s for %s\n",
470 				 source, crtc->name);
471 		return -EINVAL;
472 	}
473 
474 	*values_cnt = 1;
475 	return 0;
476 }
477 
478 static const struct drm_crtc_helper_funcs mxsfb_crtc_helper_funcs = {
479 	.atomic_check = mxsfb_crtc_atomic_check,
480 	.atomic_flush = mxsfb_crtc_atomic_flush,
481 	.atomic_enable = mxsfb_crtc_atomic_enable,
482 	.atomic_disable = mxsfb_crtc_atomic_disable,
483 };
484 
485 static const struct drm_crtc_funcs mxsfb_crtc_funcs = {
486 	.reset = drm_atomic_helper_crtc_reset,
487 	.destroy = drm_crtc_cleanup,
488 	.set_config = drm_atomic_helper_set_config,
489 	.page_flip = drm_atomic_helper_page_flip,
490 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
491 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
492 	.enable_vblank = mxsfb_crtc_enable_vblank,
493 	.disable_vblank = mxsfb_crtc_disable_vblank,
494 };
495 
496 static const struct drm_crtc_funcs mxsfb_crtc_with_crc_funcs = {
497 	.reset = drm_atomic_helper_crtc_reset,
498 	.destroy = drm_crtc_cleanup,
499 	.set_config = drm_atomic_helper_set_config,
500 	.page_flip = drm_atomic_helper_page_flip,
501 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
502 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
503 	.enable_vblank = mxsfb_crtc_enable_vblank,
504 	.disable_vblank = mxsfb_crtc_disable_vblank,
505 	.set_crc_source = mxsfb_crtc_set_crc_source,
506 	.verify_crc_source = mxsfb_crtc_verify_crc_source,
507 };
508 
509 /* -----------------------------------------------------------------------------
510  * Encoder
511  */
512 
513 static const struct drm_encoder_funcs mxsfb_encoder_funcs = {
514 	.destroy = drm_encoder_cleanup,
515 };
516 
517 /* -----------------------------------------------------------------------------
518  * Planes
519  */
520 
521 static int mxsfb_plane_atomic_check(struct drm_plane *plane,
522 				    struct drm_atomic_state *state)
523 {
524 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state,
525 									     plane);
526 	struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(plane->dev);
527 	struct drm_crtc_state *crtc_state;
528 
529 	crtc_state = drm_atomic_get_new_crtc_state(state,
530 						   &mxsfb->crtc);
531 
532 	return drm_atomic_helper_check_plane_state(plane_state, crtc_state,
533 						   DRM_PLANE_NO_SCALING,
534 						   DRM_PLANE_NO_SCALING,
535 						   false, true);
536 }
537 
538 static void mxsfb_plane_primary_atomic_update(struct drm_plane *plane,
539 					      struct drm_atomic_state *state)
540 {
541 	struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(plane->dev);
542 	struct drm_plane_state *new_pstate = drm_atomic_get_new_plane_state(state,
543 									    plane);
544 	dma_addr_t dma_addr;
545 
546 	dma_addr = drm_fb_dma_get_gem_addr(new_pstate->fb, new_pstate, 0);
547 	if (dma_addr)
548 		writel(dma_addr, mxsfb->base + mxsfb->devdata->next_buf);
549 }
550 
551 static void mxsfb_plane_overlay_atomic_update(struct drm_plane *plane,
552 					      struct drm_atomic_state *state)
553 {
554 	struct drm_plane_state *old_pstate = drm_atomic_get_old_plane_state(state,
555 									    plane);
556 	struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(plane->dev);
557 	struct drm_plane_state *new_pstate = drm_atomic_get_new_plane_state(state,
558 									    plane);
559 	dma_addr_t dma_addr;
560 	u32 ctrl;
561 
562 	dma_addr = drm_fb_dma_get_gem_addr(new_pstate->fb, new_pstate, 0);
563 	if (!dma_addr) {
564 		writel(0, mxsfb->base + LCDC_AS_CTRL);
565 		return;
566 	}
567 
568 	/*
569 	 * HACK: The hardware seems to output 64 bytes of data of unknown
570 	 * origin, and then to proceed with the framebuffer. Until the reason
571 	 * is understood, live with the 16 initial invalid pixels on the first
572 	 * line and start 64 bytes within the framebuffer.
573 	 */
574 	dma_addr += 64;
575 
576 	writel(dma_addr, mxsfb->base + LCDC_AS_NEXT_BUF);
577 
578 	/*
579 	 * If the plane was previously disabled, write LCDC_AS_BUF as well to
580 	 * provide the first buffer.
581 	 */
582 	if (!old_pstate->fb)
583 		writel(dma_addr, mxsfb->base + LCDC_AS_BUF);
584 
585 	ctrl = AS_CTRL_AS_ENABLE | AS_CTRL_ALPHA(255);
586 
587 	switch (new_pstate->fb->format->format) {
588 	case DRM_FORMAT_XRGB4444:
589 		ctrl |= AS_CTRL_FORMAT_RGB444 | AS_CTRL_ALPHA_CTRL_OVERRIDE;
590 		break;
591 	case DRM_FORMAT_ARGB4444:
592 		ctrl |= AS_CTRL_FORMAT_ARGB4444 | AS_CTRL_ALPHA_CTRL_EMBEDDED;
593 		break;
594 	case DRM_FORMAT_XRGB1555:
595 		ctrl |= AS_CTRL_FORMAT_RGB555 | AS_CTRL_ALPHA_CTRL_OVERRIDE;
596 		break;
597 	case DRM_FORMAT_ARGB1555:
598 		ctrl |= AS_CTRL_FORMAT_ARGB1555 | AS_CTRL_ALPHA_CTRL_EMBEDDED;
599 		break;
600 	case DRM_FORMAT_RGB565:
601 		ctrl |= AS_CTRL_FORMAT_RGB565 | AS_CTRL_ALPHA_CTRL_OVERRIDE;
602 		break;
603 	case DRM_FORMAT_XRGB8888:
604 		ctrl |= AS_CTRL_FORMAT_RGB888 | AS_CTRL_ALPHA_CTRL_OVERRIDE;
605 		break;
606 	case DRM_FORMAT_ARGB8888:
607 		ctrl |= AS_CTRL_FORMAT_ARGB8888 | AS_CTRL_ALPHA_CTRL_EMBEDDED;
608 		break;
609 	}
610 
611 	writel(ctrl, mxsfb->base + LCDC_AS_CTRL);
612 }
613 
614 static bool mxsfb_format_mod_supported(struct drm_plane *plane,
615 				       uint32_t format,
616 				       uint64_t modifier)
617 {
618 	return modifier == DRM_FORMAT_MOD_LINEAR;
619 }
620 
621 static const struct drm_plane_helper_funcs mxsfb_plane_primary_helper_funcs = {
622 	.atomic_check = mxsfb_plane_atomic_check,
623 	.atomic_update = mxsfb_plane_primary_atomic_update,
624 };
625 
626 static const struct drm_plane_helper_funcs mxsfb_plane_overlay_helper_funcs = {
627 	.atomic_check = mxsfb_plane_atomic_check,
628 	.atomic_update = mxsfb_plane_overlay_atomic_update,
629 };
630 
631 static const struct drm_plane_funcs mxsfb_plane_funcs = {
632 	.format_mod_supported	= mxsfb_format_mod_supported,
633 	.update_plane		= drm_atomic_helper_update_plane,
634 	.disable_plane		= drm_atomic_helper_disable_plane,
635 	.destroy		= drm_plane_cleanup,
636 	.reset			= drm_atomic_helper_plane_reset,
637 	.atomic_duplicate_state	= drm_atomic_helper_plane_duplicate_state,
638 	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
639 };
640 
641 static const uint32_t mxsfb_primary_plane_formats[] = {
642 	DRM_FORMAT_RGB565,
643 	DRM_FORMAT_XRGB8888,
644 };
645 
646 static const uint32_t mxsfb_overlay_plane_formats[] = {
647 	DRM_FORMAT_XRGB4444,
648 	DRM_FORMAT_ARGB4444,
649 	DRM_FORMAT_XRGB1555,
650 	DRM_FORMAT_ARGB1555,
651 	DRM_FORMAT_RGB565,
652 	DRM_FORMAT_XRGB8888,
653 	DRM_FORMAT_ARGB8888,
654 };
655 
656 static const uint64_t mxsfb_modifiers[] = {
657 	DRM_FORMAT_MOD_LINEAR,
658 	DRM_FORMAT_MOD_INVALID
659 };
660 
661 /* -----------------------------------------------------------------------------
662  * Initialization
663  */
664 
665 int mxsfb_kms_init(struct mxsfb_drm_private *mxsfb)
666 {
667 	struct drm_encoder *encoder = &mxsfb->encoder;
668 	struct drm_crtc *crtc = &mxsfb->crtc;
669 	int ret;
670 
671 	drm_plane_helper_add(&mxsfb->planes.primary,
672 			     &mxsfb_plane_primary_helper_funcs);
673 	ret = drm_universal_plane_init(mxsfb->drm, &mxsfb->planes.primary, 1,
674 				       &mxsfb_plane_funcs,
675 				       mxsfb_primary_plane_formats,
676 				       ARRAY_SIZE(mxsfb_primary_plane_formats),
677 				       mxsfb_modifiers, DRM_PLANE_TYPE_PRIMARY,
678 				       NULL);
679 	if (ret)
680 		return ret;
681 
682 	if (mxsfb->devdata->has_overlay) {
683 		drm_plane_helper_add(&mxsfb->planes.overlay,
684 				     &mxsfb_plane_overlay_helper_funcs);
685 		ret = drm_universal_plane_init(mxsfb->drm,
686 					       &mxsfb->planes.overlay, 1,
687 					       &mxsfb_plane_funcs,
688 					       mxsfb_overlay_plane_formats,
689 					       ARRAY_SIZE(mxsfb_overlay_plane_formats),
690 					       mxsfb_modifiers, DRM_PLANE_TYPE_OVERLAY,
691 					       NULL);
692 		if (ret)
693 			return ret;
694 	}
695 
696 	drm_crtc_helper_add(crtc, &mxsfb_crtc_helper_funcs);
697 	if (mxsfb->devdata->has_crc32) {
698 		ret = drm_crtc_init_with_planes(mxsfb->drm, crtc,
699 						&mxsfb->planes.primary, NULL,
700 						&mxsfb_crtc_with_crc_funcs,
701 						NULL);
702 	} else {
703 		ret = drm_crtc_init_with_planes(mxsfb->drm, crtc,
704 						&mxsfb->planes.primary, NULL,
705 						&mxsfb_crtc_funcs, NULL);
706 	}
707 	if (ret)
708 		return ret;
709 
710 	encoder->possible_crtcs = drm_crtc_mask(crtc);
711 	return drm_encoder_init(mxsfb->drm, encoder, &mxsfb_encoder_funcs,
712 				DRM_MODE_ENCODER_NONE, NULL);
713 }
714