xref: /linux/drivers/gpu/drm/i915/display/intel_fb_pin.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2021 Intel Corporation
4  */
5 
6 /**
7  * DOC: display pinning helpers
8  */
9 
10 #include "gem/i915_gem_domain.h"
11 #include "gem/i915_gem_object.h"
12 
13 #include "i915_drv.h"
14 #include "intel_atomic_plane.h"
15 #include "intel_display_types.h"
16 #include "intel_dpt.h"
17 #include "intel_fb.h"
18 #include "intel_fb_pin.h"
19 
20 static struct i915_vma *
21 intel_fb_pin_to_dpt(const struct drm_framebuffer *fb,
22 		    const struct i915_gtt_view *view,
23 		    unsigned int alignment,
24 		    unsigned long *out_flags,
25 		    struct i915_address_space *vm)
26 {
27 	struct drm_device *dev = fb->dev;
28 	struct drm_i915_private *dev_priv = to_i915(dev);
29 	struct drm_gem_object *_obj = intel_fb_bo(fb);
30 	struct drm_i915_gem_object *obj = to_intel_bo(_obj);
31 	struct i915_gem_ww_ctx ww;
32 	struct i915_vma *vma;
33 	int ret;
34 
35 	/*
36 	 * We are not syncing against the binding (and potential migrations)
37 	 * below, so this vm must never be async.
38 	 */
39 	if (drm_WARN_ON(&dev_priv->drm, vm->bind_async_flags))
40 		return ERR_PTR(-EINVAL);
41 
42 	if (WARN_ON(!i915_gem_object_is_framebuffer(obj)))
43 		return ERR_PTR(-EINVAL);
44 
45 	atomic_inc(&dev_priv->gpu_error.pending_fb_pin);
46 
47 	for_i915_gem_ww(&ww, ret, true) {
48 		ret = i915_gem_object_lock(obj, &ww);
49 		if (ret)
50 			continue;
51 
52 		if (HAS_LMEM(dev_priv)) {
53 			unsigned int flags = obj->flags;
54 
55 			/*
56 			 * For this type of buffer we need to able to read from the CPU
57 			 * the clear color value found in the buffer, hence we need to
58 			 * ensure it is always in the mappable part of lmem, if this is
59 			 * a small-bar device.
60 			 */
61 			if (intel_fb_rc_ccs_cc_plane(fb) >= 0)
62 				flags &= ~I915_BO_ALLOC_GPU_ONLY;
63 			ret = __i915_gem_object_migrate(obj, &ww, INTEL_REGION_LMEM_0,
64 							flags);
65 			if (ret)
66 				continue;
67 		}
68 
69 		ret = i915_gem_object_set_cache_level(obj, I915_CACHE_NONE);
70 		if (ret)
71 			continue;
72 
73 		vma = i915_vma_instance(obj, vm, view);
74 		if (IS_ERR(vma)) {
75 			ret = PTR_ERR(vma);
76 			continue;
77 		}
78 
79 		if (i915_vma_misplaced(vma, 0, alignment, 0)) {
80 			ret = i915_vma_unbind(vma);
81 			if (ret)
82 				continue;
83 		}
84 
85 		ret = i915_vma_pin_ww(vma, &ww, 0, alignment, PIN_GLOBAL);
86 		if (ret)
87 			continue;
88 	}
89 	if (ret) {
90 		vma = ERR_PTR(ret);
91 		goto err;
92 	}
93 
94 	vma->display_alignment = max(vma->display_alignment, alignment);
95 
96 	i915_gem_object_flush_if_display(obj);
97 
98 	i915_vma_get(vma);
99 err:
100 	atomic_dec(&dev_priv->gpu_error.pending_fb_pin);
101 
102 	return vma;
103 }
104 
105 struct i915_vma *
106 intel_fb_pin_to_ggtt(const struct drm_framebuffer *fb,
107 		     const struct i915_gtt_view *view,
108 		     unsigned int alignment,
109 		     unsigned int phys_alignment,
110 		     bool uses_fence,
111 		     unsigned long *out_flags)
112 {
113 	struct drm_device *dev = fb->dev;
114 	struct drm_i915_private *dev_priv = to_i915(dev);
115 	struct drm_gem_object *_obj = intel_fb_bo(fb);
116 	struct drm_i915_gem_object *obj = to_intel_bo(_obj);
117 	intel_wakeref_t wakeref;
118 	struct i915_gem_ww_ctx ww;
119 	struct i915_vma *vma;
120 	unsigned int pinctl;
121 	int ret;
122 
123 	if (drm_WARN_ON(dev, !i915_gem_object_is_framebuffer(obj)))
124 		return ERR_PTR(-EINVAL);
125 
126 	if (drm_WARN_ON(dev, alignment && !is_power_of_2(alignment)))
127 		return ERR_PTR(-EINVAL);
128 
129 	/* Note that the w/a also requires 64 PTE of padding following the
130 	 * bo. We currently fill all unused PTE with the shadow page and so
131 	 * we should always have valid PTE following the scanout preventing
132 	 * the VT-d warning.
133 	 */
134 	if (intel_scanout_needs_vtd_wa(dev_priv) && alignment < 256 * 1024)
135 		alignment = 256 * 1024;
136 
137 	/*
138 	 * Global gtt pte registers are special registers which actually forward
139 	 * writes to a chunk of system memory. Which means that there is no risk
140 	 * that the register values disappear as soon as we call
141 	 * intel_runtime_pm_put(), so it is correct to wrap only the
142 	 * pin/unpin/fence and not more.
143 	 */
144 	wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
145 
146 	atomic_inc(&dev_priv->gpu_error.pending_fb_pin);
147 
148 	/*
149 	 * Valleyview is definitely limited to scanning out the first
150 	 * 512MiB. Lets presume this behaviour was inherited from the
151 	 * g4x display engine and that all earlier gen are similarly
152 	 * limited. Testing suggests that it is a little more
153 	 * complicated than this. For example, Cherryview appears quite
154 	 * happy to scanout from anywhere within its global aperture.
155 	 */
156 	pinctl = 0;
157 	if (HAS_GMCH(dev_priv))
158 		pinctl |= PIN_MAPPABLE;
159 
160 	i915_gem_ww_ctx_init(&ww, true);
161 retry:
162 	ret = i915_gem_object_lock(obj, &ww);
163 	if (!ret && phys_alignment)
164 		ret = i915_gem_object_attach_phys(obj, phys_alignment);
165 	else if (!ret && HAS_LMEM(dev_priv))
166 		ret = i915_gem_object_migrate(obj, &ww, INTEL_REGION_LMEM_0);
167 	if (!ret)
168 		ret = i915_gem_object_pin_pages(obj);
169 	if (ret)
170 		goto err;
171 
172 	vma = i915_gem_object_pin_to_display_plane(obj, &ww, alignment,
173 						   view, pinctl);
174 	if (IS_ERR(vma)) {
175 		ret = PTR_ERR(vma);
176 		goto err_unpin;
177 	}
178 
179 	if (uses_fence && i915_vma_is_map_and_fenceable(vma)) {
180 		/*
181 		 * Install a fence for tiled scan-out. Pre-i965 always needs a
182 		 * fence, whereas 965+ only requires a fence if using
183 		 * framebuffer compression.  For simplicity, we always, when
184 		 * possible, install a fence as the cost is not that onerous.
185 		 *
186 		 * If we fail to fence the tiled scanout, then either the
187 		 * modeset will reject the change (which is highly unlikely as
188 		 * the affected systems, all but one, do not have unmappable
189 		 * space) or we will not be able to enable full powersaving
190 		 * techniques (also likely not to apply due to various limits
191 		 * FBC and the like impose on the size of the buffer, which
192 		 * presumably we violated anyway with this unmappable buffer).
193 		 * Anyway, it is presumably better to stumble onwards with
194 		 * something and try to run the system in a "less than optimal"
195 		 * mode that matches the user configuration.
196 		 */
197 		ret = i915_vma_pin_fence(vma);
198 		if (ret != 0 && DISPLAY_VER(dev_priv) < 4) {
199 			i915_vma_unpin(vma);
200 			goto err_unpin;
201 		}
202 		ret = 0;
203 
204 		if (vma->fence)
205 			*out_flags |= PLANE_HAS_FENCE;
206 	}
207 
208 	i915_vma_get(vma);
209 
210 err_unpin:
211 	i915_gem_object_unpin_pages(obj);
212 err:
213 	if (ret == -EDEADLK) {
214 		ret = i915_gem_ww_ctx_backoff(&ww);
215 		if (!ret)
216 			goto retry;
217 	}
218 	i915_gem_ww_ctx_fini(&ww);
219 	if (ret)
220 		vma = ERR_PTR(ret);
221 
222 	atomic_dec(&dev_priv->gpu_error.pending_fb_pin);
223 	intel_runtime_pm_put(&dev_priv->runtime_pm, wakeref);
224 	return vma;
225 }
226 
227 void intel_fb_unpin_vma(struct i915_vma *vma, unsigned long flags)
228 {
229 	if (flags & PLANE_HAS_FENCE)
230 		i915_vma_unpin_fence(vma);
231 	i915_vma_unpin(vma);
232 	i915_vma_put(vma);
233 }
234 
235 static unsigned int
236 intel_plane_fb_min_alignment(const struct intel_plane_state *plane_state)
237 {
238 	const struct intel_framebuffer *fb = to_intel_framebuffer(plane_state->hw.fb);
239 
240 	return fb->min_alignment;
241 }
242 
243 static unsigned int
244 intel_plane_fb_min_phys_alignment(const struct intel_plane_state *plane_state)
245 {
246 	struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
247 	const struct drm_framebuffer *fb = plane_state->hw.fb;
248 
249 	if (!intel_plane_needs_physical(plane))
250 		return 0;
251 
252 	return plane->min_alignment(plane, fb, 0);
253 }
254 
255 int intel_plane_pin_fb(struct intel_plane_state *plane_state)
256 {
257 	struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
258 	const struct intel_framebuffer *fb =
259 		to_intel_framebuffer(plane_state->hw.fb);
260 	struct i915_vma *vma;
261 
262 	if (!intel_fb_uses_dpt(&fb->base)) {
263 		vma = intel_fb_pin_to_ggtt(&fb->base, &plane_state->view.gtt,
264 					   intel_plane_fb_min_alignment(plane_state),
265 					   intel_plane_fb_min_phys_alignment(plane_state),
266 					   intel_plane_uses_fence(plane_state),
267 					   &plane_state->flags);
268 		if (IS_ERR(vma))
269 			return PTR_ERR(vma);
270 
271 		plane_state->ggtt_vma = vma;
272 
273 		/*
274 		 * Pre-populate the dma address before we enter the vblank
275 		 * evade critical section as i915_gem_object_get_dma_address()
276 		 * will trigger might_sleep() even if it won't actually sleep,
277 		 * which is the case when the fb has already been pinned.
278 		 */
279 		if (intel_plane_needs_physical(plane)) {
280 			struct drm_i915_gem_object *obj = to_intel_bo(intel_fb_bo(&fb->base));
281 
282 			plane_state->phys_dma_addr = i915_gem_object_get_dma_address(obj, 0);
283 		}
284 	} else {
285 		unsigned int alignment = intel_plane_fb_min_alignment(plane_state);
286 
287 		vma = intel_dpt_pin_to_ggtt(fb->dpt_vm, alignment / 512);
288 		if (IS_ERR(vma))
289 			return PTR_ERR(vma);
290 
291 		plane_state->ggtt_vma = vma;
292 
293 		vma = intel_fb_pin_to_dpt(&fb->base, &plane_state->view.gtt,
294 					  alignment, &plane_state->flags,
295 					  fb->dpt_vm);
296 		if (IS_ERR(vma)) {
297 			intel_dpt_unpin_from_ggtt(fb->dpt_vm);
298 			plane_state->ggtt_vma = NULL;
299 			return PTR_ERR(vma);
300 		}
301 
302 		plane_state->dpt_vma = vma;
303 
304 		WARN_ON(plane_state->ggtt_vma == plane_state->dpt_vma);
305 	}
306 
307 	return 0;
308 }
309 
310 void intel_plane_unpin_fb(struct intel_plane_state *old_plane_state)
311 {
312 	const struct intel_framebuffer *fb =
313 		to_intel_framebuffer(old_plane_state->hw.fb);
314 	struct i915_vma *vma;
315 
316 	if (!intel_fb_uses_dpt(&fb->base)) {
317 		vma = fetch_and_zero(&old_plane_state->ggtt_vma);
318 		if (vma)
319 			intel_fb_unpin_vma(vma, old_plane_state->flags);
320 	} else {
321 		vma = fetch_and_zero(&old_plane_state->dpt_vma);
322 		if (vma)
323 			intel_fb_unpin_vma(vma, old_plane_state->flags);
324 
325 		vma = fetch_and_zero(&old_plane_state->ggtt_vma);
326 		if (vma)
327 			intel_dpt_unpin_from_ggtt(fb->dpt_vm);
328 	}
329 }
330