1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2022 Intel Corporation
4  */
5 
6 #include "hsw_ips.h"
7 #include "i915_drv.h"
8 #include "i915_reg.h"
9 #include "intel_de.h"
10 #include "intel_display_types.h"
11 #include "intel_pcode.h"
12 
13 static void hsw_ips_enable(const struct intel_crtc_state *crtc_state)
14 {
15 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
16 	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
17 
18 	if (!crtc_state->ips_enabled)
19 		return;
20 
21 	/*
22 	 * We can only enable IPS after we enable a plane and wait for a vblank
23 	 * This function is called from post_plane_update, which is run after
24 	 * a vblank wait.
25 	 */
26 	drm_WARN_ON(&i915->drm,
27 		    !(crtc_state->active_planes & ~BIT(PLANE_CURSOR)));
28 
29 	if (IS_BROADWELL(i915)) {
30 		drm_WARN_ON(&i915->drm,
31 			    snb_pcode_write(&i915->uncore, DISPLAY_IPS_CONTROL,
32 					    IPS_ENABLE | IPS_PCODE_CONTROL));
33 		/*
34 		 * Quoting Art Runyan: "its not safe to expect any particular
35 		 * value in IPS_CTL bit 31 after enabling IPS through the
36 		 * mailbox." Moreover, the mailbox may return a bogus state,
37 		 * so we need to just enable it and continue on.
38 		 */
39 	} else {
40 		intel_de_write(i915, IPS_CTL, IPS_ENABLE);
41 		/*
42 		 * The bit only becomes 1 in the next vblank, so this wait here
43 		 * is essentially intel_wait_for_vblank. If we don't have this
44 		 * and don't wait for vblanks until the end of crtc_enable, then
45 		 * the HW state readout code will complain that the expected
46 		 * IPS_CTL value is not the one we read.
47 		 */
48 		if (intel_de_wait_for_set(i915, IPS_CTL, IPS_ENABLE, 50))
49 			drm_err(&i915->drm,
50 				"Timed out waiting for IPS enable\n");
51 	}
52 }
53 
54 bool hsw_ips_disable(const struct intel_crtc_state *crtc_state)
55 {
56 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
57 	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
58 	bool need_vblank_wait = false;
59 
60 	if (!crtc_state->ips_enabled)
61 		return need_vblank_wait;
62 
63 	if (IS_BROADWELL(i915)) {
64 		drm_WARN_ON(&i915->drm,
65 			    snb_pcode_write(&i915->uncore, DISPLAY_IPS_CONTROL, 0));
66 		/*
67 		 * Wait for PCODE to finish disabling IPS. The BSpec specified
68 		 * 42ms timeout value leads to occasional timeouts so use 100ms
69 		 * instead.
70 		 */
71 		if (intel_de_wait_for_clear(i915, IPS_CTL, IPS_ENABLE, 100))
72 			drm_err(&i915->drm,
73 				"Timed out waiting for IPS disable\n");
74 	} else {
75 		intel_de_write(i915, IPS_CTL, 0);
76 		intel_de_posting_read(i915, IPS_CTL);
77 	}
78 
79 	/* We need to wait for a vblank before we can disable the plane. */
80 	need_vblank_wait = true;
81 
82 	return need_vblank_wait;
83 }
84 
85 static bool hsw_ips_need_disable(struct intel_atomic_state *state,
86 				 struct intel_crtc *crtc)
87 {
88 	struct drm_i915_private *i915 = to_i915(state->base.dev);
89 	const struct intel_crtc_state *old_crtc_state =
90 		intel_atomic_get_old_crtc_state(state, crtc);
91 	const struct intel_crtc_state *new_crtc_state =
92 		intel_atomic_get_new_crtc_state(state, crtc);
93 
94 	if (!old_crtc_state->ips_enabled)
95 		return false;
96 
97 	if (intel_crtc_needs_modeset(new_crtc_state))
98 		return true;
99 
100 	/*
101 	 * Workaround : Do not read or write the pipe palette/gamma data while
102 	 * GAMMA_MODE is configured for split gamma and IPS_CTL has IPS enabled.
103 	 *
104 	 * Disable IPS before we program the LUT.
105 	 */
106 	if (IS_HASWELL(i915) &&
107 	    (new_crtc_state->uapi.color_mgmt_changed ||
108 	     new_crtc_state->update_pipe) &&
109 	    new_crtc_state->gamma_mode == GAMMA_MODE_MODE_SPLIT)
110 		return true;
111 
112 	return !new_crtc_state->ips_enabled;
113 }
114 
115 bool hsw_ips_pre_update(struct intel_atomic_state *state,
116 			struct intel_crtc *crtc)
117 {
118 	const struct intel_crtc_state *old_crtc_state =
119 		intel_atomic_get_old_crtc_state(state, crtc);
120 
121 	if (!hsw_ips_need_disable(state, crtc))
122 		return false;
123 
124 	return hsw_ips_disable(old_crtc_state);
125 }
126 
127 static bool hsw_ips_need_enable(struct intel_atomic_state *state,
128 				struct intel_crtc *crtc)
129 {
130 	struct drm_i915_private *i915 = to_i915(state->base.dev);
131 	const struct intel_crtc_state *old_crtc_state =
132 		intel_atomic_get_old_crtc_state(state, crtc);
133 	const struct intel_crtc_state *new_crtc_state =
134 		intel_atomic_get_new_crtc_state(state, crtc);
135 
136 	if (!new_crtc_state->ips_enabled)
137 		return false;
138 
139 	if (intel_crtc_needs_modeset(new_crtc_state))
140 		return true;
141 
142 	/*
143 	 * Workaround : Do not read or write the pipe palette/gamma data while
144 	 * GAMMA_MODE is configured for split gamma and IPS_CTL has IPS enabled.
145 	 *
146 	 * Re-enable IPS after the LUT has been programmed.
147 	 */
148 	if (IS_HASWELL(i915) &&
149 	    (new_crtc_state->uapi.color_mgmt_changed ||
150 	     new_crtc_state->update_pipe) &&
151 	    new_crtc_state->gamma_mode == GAMMA_MODE_MODE_SPLIT)
152 		return true;
153 
154 	/*
155 	 * We can't read out IPS on broadwell, assume the worst and
156 	 * forcibly enable IPS on the first fastset.
157 	 */
158 	if (new_crtc_state->update_pipe && old_crtc_state->inherited)
159 		return true;
160 
161 	return !old_crtc_state->ips_enabled;
162 }
163 
164 void hsw_ips_post_update(struct intel_atomic_state *state,
165 			 struct intel_crtc *crtc)
166 {
167 	const struct intel_crtc_state *new_crtc_state =
168 		intel_atomic_get_new_crtc_state(state, crtc);
169 
170 	if (!hsw_ips_need_enable(state, crtc))
171 		return;
172 
173 	hsw_ips_enable(new_crtc_state);
174 }
175 
176 /* IPS only exists on ULT machines and is tied to pipe A. */
177 bool hsw_crtc_supports_ips(struct intel_crtc *crtc)
178 {
179 	return HAS_IPS(to_i915(crtc->base.dev)) && crtc->pipe == PIPE_A;
180 }
181 
182 bool hsw_crtc_state_ips_capable(const struct intel_crtc_state *crtc_state)
183 {
184 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
185 	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
186 
187 	/* IPS only exists on ULT machines and is tied to pipe A. */
188 	if (!hsw_crtc_supports_ips(crtc))
189 		return false;
190 
191 	if (!i915->params.enable_ips)
192 		return false;
193 
194 	if (crtc_state->pipe_bpp > 24)
195 		return false;
196 
197 	/*
198 	 * We compare against max which means we must take
199 	 * the increased cdclk requirement into account when
200 	 * calculating the new cdclk.
201 	 *
202 	 * Should measure whether using a lower cdclk w/o IPS
203 	 */
204 	if (IS_BROADWELL(i915) &&
205 	    crtc_state->pixel_rate > i915->max_cdclk_freq * 95 / 100)
206 		return false;
207 
208 	return true;
209 }
210 
211 int hsw_ips_compute_config(struct intel_atomic_state *state,
212 			   struct intel_crtc *crtc)
213 {
214 	struct drm_i915_private *i915 = to_i915(state->base.dev);
215 	struct intel_crtc_state *crtc_state =
216 		intel_atomic_get_new_crtc_state(state, crtc);
217 
218 	crtc_state->ips_enabled = false;
219 
220 	if (!hsw_crtc_state_ips_capable(crtc_state))
221 		return 0;
222 
223 	/*
224 	 * When IPS gets enabled, the pipe CRC changes. Since IPS gets
225 	 * enabled and disabled dynamically based on package C states,
226 	 * user space can't make reliable use of the CRCs, so let's just
227 	 * completely disable it.
228 	 */
229 	if (crtc_state->crc_enabled)
230 		return 0;
231 
232 	/* IPS should be fine as long as at least one plane is enabled. */
233 	if (!(crtc_state->active_planes & ~BIT(PLANE_CURSOR)))
234 		return 0;
235 
236 	if (IS_BROADWELL(i915)) {
237 		const struct intel_cdclk_state *cdclk_state;
238 
239 		cdclk_state = intel_atomic_get_cdclk_state(state);
240 		if (IS_ERR(cdclk_state))
241 			return PTR_ERR(cdclk_state);
242 
243 		/* pixel rate mustn't exceed 95% of cdclk with IPS on BDW */
244 		if (crtc_state->pixel_rate > cdclk_state->logical.cdclk * 95 / 100)
245 			return 0;
246 	}
247 
248 	crtc_state->ips_enabled = true;
249 
250 	return 0;
251 }
252 
253 void hsw_ips_get_config(struct intel_crtc_state *crtc_state)
254 {
255 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
256 	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
257 
258 	if (!hsw_crtc_supports_ips(crtc))
259 		return;
260 
261 	if (IS_HASWELL(i915)) {
262 		crtc_state->ips_enabled = intel_de_read(i915, IPS_CTL) & IPS_ENABLE;
263 	} else {
264 		/*
265 		 * We cannot readout IPS state on broadwell, set to
266 		 * true so we can set it to a defined state on first
267 		 * commit.
268 		 */
269 		crtc_state->ips_enabled = true;
270 	}
271 }
272