1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2011 Texas Instruments Incorporated - https://www.ti.com/
4 * Author: Rob Clark <rob@ti.com>
5 */
6
7#include <linux/fb.h>
8
9#include <drm/drm_drv.h>
10#include <drm/drm_crtc_helper.h>
11#include <drm/drm_fb_helper.h>
12#include <drm/drm_file.h>
13#include <drm/drm_fourcc.h>
14#include <drm/drm_framebuffer.h>
15#include <drm/drm_gem_framebuffer_helper.h>
16#include <drm/drm_util.h>
17
18#include "omap_drv.h"
19#include "omap_fbdev.h"
20
21MODULE_PARM_DESC(ywrap, "Enable ywrap scrolling (omap44xx and later, default 'y')");
22static bool ywrap_enabled = true;
23module_param_named(ywrap, ywrap_enabled, bool, 0644);
24
25/*
26 * fbdev funcs, to implement legacy fbdev interface on top of drm driver
27 */
28
29#define to_omap_fbdev(x) container_of(x, struct omap_fbdev, base)
30
31struct omap_fbdev {
32	struct drm_fb_helper base;
33	bool ywrap_enabled;
34
35	/* for deferred dmm roll when getting called in atomic ctx */
36	struct work_struct work;
37};
38
39static struct drm_fb_helper *get_fb(struct fb_info *fbi);
40
41static void pan_worker(struct work_struct *work)
42{
43	struct omap_fbdev *fbdev = container_of(work, struct omap_fbdev, work);
44	struct drm_fb_helper *helper = &fbdev->base;
45	struct fb_info *fbi = helper->info;
46	struct drm_gem_object *bo = drm_gem_fb_get_obj(helper->fb, 0);
47	int npages;
48
49	/* DMM roll shifts in 4K pages: */
50	npages = fbi->fix.line_length >> PAGE_SHIFT;
51	omap_gem_roll(bo, fbi->var.yoffset * npages);
52}
53
54static int omap_fbdev_pan_display(struct fb_var_screeninfo *var,
55		struct fb_info *fbi)
56{
57	struct drm_fb_helper *helper = get_fb(fbi);
58	struct omap_fbdev *fbdev = to_omap_fbdev(helper);
59
60	if (!helper)
61		goto fallback;
62
63	if (!fbdev->ywrap_enabled)
64		goto fallback;
65
66	if (drm_can_sleep()) {
67		pan_worker(&fbdev->work);
68	} else {
69		struct omap_drm_private *priv = helper->dev->dev_private;
70		queue_work(priv->wq, &fbdev->work);
71	}
72
73	return 0;
74
75fallback:
76	return drm_fb_helper_pan_display(var, fbi);
77}
78
79static int omap_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
80{
81	struct drm_fb_helper *helper = info->par;
82	struct drm_framebuffer *fb = helper->fb;
83	struct drm_gem_object *bo = drm_gem_fb_get_obj(fb, 0);
84
85	return drm_gem_mmap_obj(bo, omap_gem_mmap_size(bo), vma);
86}
87
88static void omap_fbdev_fb_destroy(struct fb_info *info)
89{
90	struct drm_fb_helper *helper = info->par;
91	struct drm_framebuffer *fb = helper->fb;
92	struct drm_gem_object *bo = drm_gem_fb_get_obj(fb, 0);
93	struct omap_fbdev *fbdev = to_omap_fbdev(helper);
94
95	DBG();
96
97	drm_fb_helper_fini(helper);
98
99	omap_gem_unpin(bo);
100	drm_framebuffer_remove(fb);
101
102	drm_client_release(&helper->client);
103	drm_fb_helper_unprepare(helper);
104	kfree(fbdev);
105}
106
107static const struct fb_ops omap_fb_ops = {
108	.owner = THIS_MODULE,
109	__FB_DEFAULT_DMAMEM_OPS_RDWR,
110	.fb_check_var	= drm_fb_helper_check_var,
111	.fb_set_par	= drm_fb_helper_set_par,
112	.fb_setcmap	= drm_fb_helper_setcmap,
113	.fb_blank	= drm_fb_helper_blank,
114	.fb_pan_display = omap_fbdev_pan_display,
115	__FB_DEFAULT_DMAMEM_OPS_DRAW,
116	.fb_ioctl	= drm_fb_helper_ioctl,
117	.fb_mmap	= omap_fbdev_fb_mmap,
118	.fb_destroy	= omap_fbdev_fb_destroy,
119};
120
121static int omap_fbdev_create(struct drm_fb_helper *helper,
122		struct drm_fb_helper_surface_size *sizes)
123{
124	struct omap_fbdev *fbdev = to_omap_fbdev(helper);
125	struct drm_device *dev = helper->dev;
126	struct omap_drm_private *priv = dev->dev_private;
127	struct drm_framebuffer *fb = NULL;
128	union omap_gem_size gsize;
129	struct fb_info *fbi = NULL;
130	struct drm_mode_fb_cmd2 mode_cmd = {0};
131	struct drm_gem_object *bo;
132	dma_addr_t dma_addr;
133	int ret;
134
135	sizes->surface_bpp = 32;
136	sizes->surface_depth = 24;
137
138	DBG("create fbdev: %dx%d@%d (%dx%d)", sizes->surface_width,
139			sizes->surface_height, sizes->surface_bpp,
140			sizes->fb_width, sizes->fb_height);
141
142	mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
143			sizes->surface_depth);
144
145	mode_cmd.width = sizes->surface_width;
146	mode_cmd.height = sizes->surface_height;
147
148	mode_cmd.pitches[0] =
149			DIV_ROUND_UP(mode_cmd.width * sizes->surface_bpp, 8);
150
151	fbdev->ywrap_enabled = priv->has_dmm && ywrap_enabled;
152	if (fbdev->ywrap_enabled) {
153		/* need to align pitch to page size if using DMM scrolling */
154		mode_cmd.pitches[0] = PAGE_ALIGN(mode_cmd.pitches[0]);
155	}
156
157	/* allocate backing bo */
158	gsize = (union omap_gem_size){
159		.bytes = PAGE_ALIGN(mode_cmd.pitches[0] * mode_cmd.height),
160	};
161	DBG("allocating %d bytes for fb %d", gsize.bytes, dev->primary->index);
162	bo = omap_gem_new(dev, gsize, OMAP_BO_SCANOUT | OMAP_BO_WC);
163	if (!bo) {
164		dev_err(dev->dev, "failed to allocate buffer object\n");
165		ret = -ENOMEM;
166		goto fail;
167	}
168
169	fb = omap_framebuffer_init(dev, &mode_cmd, &bo);
170	if (IS_ERR(fb)) {
171		dev_err(dev->dev, "failed to allocate fb\n");
172		/* note: if fb creation failed, we can't rely on fb destroy
173		 * to unref the bo:
174		 */
175		drm_gem_object_put(bo);
176		ret = PTR_ERR(fb);
177		goto fail;
178	}
179
180	/* note: this keeps the bo pinned.. which is perhaps not ideal,
181	 * but is needed as long as we use fb_mmap() to mmap to userspace
182	 * (since this happens using fix.smem_start).  Possibly we could
183	 * implement our own mmap using GEM mmap support to avoid this
184	 * (non-tiled buffer doesn't need to be pinned for fbcon to write
185	 * to it).  Then we just need to be sure that we are able to re-
186	 * pin it in case of an opps.
187	 */
188	ret = omap_gem_pin(bo, &dma_addr);
189	if (ret) {
190		dev_err(dev->dev, "could not pin framebuffer\n");
191		ret = -ENOMEM;
192		goto fail;
193	}
194
195	fbi = drm_fb_helper_alloc_info(helper);
196	if (IS_ERR(fbi)) {
197		dev_err(dev->dev, "failed to allocate fb info\n");
198		ret = PTR_ERR(fbi);
199		goto fail;
200	}
201
202	DBG("fbi=%p, dev=%p", fbi, dev);
203
204	helper->fb = fb;
205
206	fbi->fbops = &omap_fb_ops;
207
208	drm_fb_helper_fill_info(fbi, helper, sizes);
209
210	fbi->flags |= FBINFO_VIRTFB;
211	fbi->screen_buffer = omap_gem_vaddr(bo);
212	fbi->screen_size = bo->size;
213	fbi->fix.smem_start = dma_addr;
214	fbi->fix.smem_len = bo->size;
215
216	/* if we have DMM, then we can use it for scrolling by just
217	 * shuffling pages around in DMM rather than doing sw blit.
218	 */
219	if (fbdev->ywrap_enabled) {
220		DRM_INFO("Enabling DMM ywrap scrolling\n");
221		fbi->flags |= FBINFO_HWACCEL_YWRAP | FBINFO_READS_FAST;
222		fbi->fix.ywrapstep = 1;
223	}
224
225
226	DBG("par=%p, %dx%d", fbi->par, fbi->var.xres, fbi->var.yres);
227	DBG("allocated %dx%d fb", fb->width, fb->height);
228
229	return 0;
230
231fail:
232
233	if (ret) {
234		if (fb)
235			drm_framebuffer_remove(fb);
236	}
237
238	return ret;
239}
240
241static const struct drm_fb_helper_funcs omap_fb_helper_funcs = {
242	.fb_probe = omap_fbdev_create,
243};
244
245static struct drm_fb_helper *get_fb(struct fb_info *fbi)
246{
247	if (!fbi || strcmp(fbi->fix.id, MODULE_NAME)) {
248		/* these are not the fb's you're looking for */
249		return NULL;
250	}
251	return fbi->par;
252}
253
254/*
255 * struct drm_client
256 */
257
258static void omap_fbdev_client_unregister(struct drm_client_dev *client)
259{
260	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
261
262	if (fb_helper->info) {
263		drm_fb_helper_unregister_info(fb_helper);
264	} else {
265		drm_client_release(&fb_helper->client);
266		drm_fb_helper_unprepare(fb_helper);
267		kfree(fb_helper);
268	}
269}
270
271static int omap_fbdev_client_restore(struct drm_client_dev *client)
272{
273	drm_fb_helper_lastclose(client->dev);
274
275	return 0;
276}
277
278static int omap_fbdev_client_hotplug(struct drm_client_dev *client)
279{
280	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
281	struct drm_device *dev = client->dev;
282	int ret;
283
284	if (dev->fb_helper)
285		return drm_fb_helper_hotplug_event(dev->fb_helper);
286
287	ret = drm_fb_helper_init(dev, fb_helper);
288	if (ret)
289		goto err_drm_err;
290
291	ret = drm_fb_helper_initial_config(fb_helper);
292	if (ret)
293		goto err_drm_fb_helper_fini;
294
295	return 0;
296
297err_drm_fb_helper_fini:
298	drm_fb_helper_fini(fb_helper);
299err_drm_err:
300	drm_err(dev, "Failed to setup fbdev emulation (ret=%d)\n", ret);
301	return ret;
302}
303
304static const struct drm_client_funcs omap_fbdev_client_funcs = {
305	.owner		= THIS_MODULE,
306	.unregister	= omap_fbdev_client_unregister,
307	.restore	= omap_fbdev_client_restore,
308	.hotplug	= omap_fbdev_client_hotplug,
309};
310
311void omap_fbdev_setup(struct drm_device *dev)
312{
313	struct omap_fbdev *fbdev;
314	struct drm_fb_helper *helper;
315	int ret;
316
317	drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
318	drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
319
320	fbdev = kzalloc(sizeof(*fbdev), GFP_KERNEL);
321	if (!fbdev)
322		return;
323	helper = &fbdev->base;
324
325	drm_fb_helper_prepare(dev, helper, 32, &omap_fb_helper_funcs);
326
327	ret = drm_client_init(dev, &helper->client, "fbdev", &omap_fbdev_client_funcs);
328	if (ret)
329		goto err_drm_client_init;
330
331	INIT_WORK(&fbdev->work, pan_worker);
332
333	drm_client_register(&helper->client);
334
335	return;
336
337err_drm_client_init:
338	drm_fb_helper_unprepare(helper);
339	kfree(fbdev);
340}
341