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1// SPDX-License-Identifier: MIT
2/*
3 * Copyright © 2019 Intel Corporation
4 *
5 */
6
7#include "i915_drv.h"
8#include "intel_display_types.h"
9
10#define DSB_BUF_SIZE (2 * PAGE_SIZE)
11
12/**
13 * DOC: DSB
14 *
15 * A DSB (Display State Buffer) is a queue of MMIO instructions in the memory
16 * which can be offloaded to DSB HW in Display Controller. DSB HW is a DMA
17 * engine that can be programmed to download the DSB from memory.
18 * It allows driver to batch submit display HW programming. This helps to
19 * reduce loading time and CPU activity, thereby making the context switch
20 * faster. DSB Support added from Gen12 Intel graphics based platform.
21 *
22 * DSB's can access only the pipe, plane, and transcoder Data Island Packet
23 * registers.
24 *
25 * DSB HW can support only register writes (both indexed and direct MMIO
26 * writes). There are no registers reads possible with DSB HW engine.
27 */
28
29/* DSB opcodes. */
30#define DSB_OPCODE_SHIFT 24
31#define DSB_OPCODE_MMIO_WRITE 0x1
32#define DSB_OPCODE_INDEXED_WRITE 0x9
33#define DSB_BYTE_EN 0xF
34#define DSB_BYTE_EN_SHIFT 20
35#define DSB_REG_VALUE_MASK 0xfffff
36
37static bool is_dsb_busy(struct drm_i915_private *i915, enum pipe pipe,
38 enum dsb_id id)
39{
40 return DSB_STATUS & intel_de_read(i915, DSB_CTRL(pipe, id));
41}
42
43static bool intel_dsb_enable_engine(struct drm_i915_private *i915,
44 enum pipe pipe, enum dsb_id id)
45{
46 u32 dsb_ctrl;
47
48 dsb_ctrl = intel_de_read(i915, DSB_CTRL(pipe, id));
49 if (DSB_STATUS & dsb_ctrl) {
50 drm_dbg_kms(&i915->drm, "DSB engine is busy.\n");
51 return false;
52 }
53
54 dsb_ctrl |= DSB_ENABLE;
55 intel_de_write(i915, DSB_CTRL(pipe, id), dsb_ctrl);
56
57 intel_de_posting_read(i915, DSB_CTRL(pipe, id));
58 return true;
59}
60
61static bool intel_dsb_disable_engine(struct drm_i915_private *i915,
62 enum pipe pipe, enum dsb_id id)
63{
64 u32 dsb_ctrl;
65
66 dsb_ctrl = intel_de_read(i915, DSB_CTRL(pipe, id));
67 if (DSB_STATUS & dsb_ctrl) {
68 drm_dbg_kms(&i915->drm, "DSB engine is busy.\n");
69 return false;
70 }
71
72 dsb_ctrl &= ~DSB_ENABLE;
73 intel_de_write(i915, DSB_CTRL(pipe, id), dsb_ctrl);
74
75 intel_de_posting_read(i915, DSB_CTRL(pipe, id));
76 return true;
77}
78
79/**
80 * intel_dsb_indexed_reg_write() -Write to the DSB context for auto
81 * increment register.
82 * @crtc_state: intel_crtc_state structure
83 * @reg: register address.
84 * @val: value.
85 *
86 * This function is used for writing register-value pair in command
87 * buffer of DSB for auto-increment register. During command buffer overflow,
88 * a warning is thrown and rest all erroneous condition register programming
89 * is done through mmio write.
90 */
91
92void intel_dsb_indexed_reg_write(const struct intel_crtc_state *crtc_state,
93 i915_reg_t reg, u32 val)
94{
95 struct intel_dsb *dsb = crtc_state->dsb;
96 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
97 struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
98 u32 *buf;
99 u32 reg_val;
100
101 if (!dsb) {
102 intel_de_write(dev_priv, reg, val);
103 return;
104 }
105 buf = dsb->cmd_buf;
106 if (drm_WARN_ON(&dev_priv->drm, dsb->free_pos >= DSB_BUF_SIZE)) {
107 drm_dbg_kms(&dev_priv->drm, "DSB buffer overflow\n");
108 return;
109 }
110
111 /*
112 * For example the buffer will look like below for 3 dwords for auto
113 * increment register:
114 * +--------------------------------------------------------+
115 * | size = 3 | offset &| value1 | value2 | value3 | zero |
116 * | | opcode | | | | |
117 * +--------------------------------------------------------+
118 * + + + + + + +
119 * 0 4 8 12 16 20 24
120 * Byte
121 *
122 * As every instruction is 8 byte aligned the index of dsb instruction
123 * will start always from even number while dealing with u32 array. If
124 * we are writing odd no of dwords, Zeros will be added in the end for
125 * padding.
126 */
127 reg_val = buf[dsb->ins_start_offset + 1] & DSB_REG_VALUE_MASK;
128 if (reg_val != i915_mmio_reg_offset(reg)) {
129 /* Every instruction should be 8 byte aligned. */
130 dsb->free_pos = ALIGN(dsb->free_pos, 2);
131
132 dsb->ins_start_offset = dsb->free_pos;
133
134 /* Update the size. */
135 buf[dsb->free_pos++] = 1;
136
137 /* Update the opcode and reg. */
138 buf[dsb->free_pos++] = (DSB_OPCODE_INDEXED_WRITE <<
139 DSB_OPCODE_SHIFT) |
140 i915_mmio_reg_offset(reg);
141
142 /* Update the value. */
143 buf[dsb->free_pos++] = val;
144 } else {
145 /* Update the new value. */
146 buf[dsb->free_pos++] = val;
147
148 /* Update the size. */
149 buf[dsb->ins_start_offset]++;
150 }
151
152 /* if number of data words is odd, then the last dword should be 0.*/
153 if (dsb->free_pos & 0x1)
154 buf[dsb->free_pos] = 0;
155}
156
157/**
158 * intel_dsb_reg_write() -Write to the DSB context for normal
159 * register.
160 * @crtc_state: intel_crtc_state structure
161 * @reg: register address.
162 * @val: value.
163 *
164 * This function is used for writing register-value pair in command
165 * buffer of DSB. During command buffer overflow, a warning is thrown
166 * and rest all erroneous condition register programming is done
167 * through mmio write.
168 */
169void intel_dsb_reg_write(const struct intel_crtc_state *crtc_state,
170 i915_reg_t reg, u32 val)
171{
172 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
173 struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
174 struct intel_dsb *dsb;
175 u32 *buf;
176
177 dsb = crtc_state->dsb;
178 if (!dsb) {
179 intel_de_write(dev_priv, reg, val);
180 return;
181 }
182
183 buf = dsb->cmd_buf;
184 if (drm_WARN_ON(&dev_priv->drm, dsb->free_pos >= DSB_BUF_SIZE)) {
185 drm_dbg_kms(&dev_priv->drm, "DSB buffer overflow\n");
186 return;
187 }
188
189 dsb->ins_start_offset = dsb->free_pos;
190 buf[dsb->free_pos++] = val;
191 buf[dsb->free_pos++] = (DSB_OPCODE_MMIO_WRITE << DSB_OPCODE_SHIFT) |
192 (DSB_BYTE_EN << DSB_BYTE_EN_SHIFT) |
193 i915_mmio_reg_offset(reg);
194}
195
196/**
197 * intel_dsb_commit() - Trigger workload execution of DSB.
198 * @crtc_state: intel_crtc_state structure
199 *
200 * This function is used to do actual write to hardware using DSB.
201 * On errors, fall back to MMIO. Also this function help to reset the context.
202 */
203void intel_dsb_commit(const struct intel_crtc_state *crtc_state)
204{
205 struct intel_dsb *dsb = crtc_state->dsb;
206 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
207 struct drm_device *dev = crtc->base.dev;
208 struct drm_i915_private *dev_priv = to_i915(dev);
209 enum pipe pipe = crtc->pipe;
210 u32 tail;
211
212 if (!(dsb && dsb->free_pos))
213 return;
214
215 if (!intel_dsb_enable_engine(dev_priv, pipe, dsb->id))
216 goto reset;
217
218 if (is_dsb_busy(dev_priv, pipe, dsb->id)) {
219 drm_err(&dev_priv->drm,
220 "HEAD_PTR write failed - dsb engine is busy.\n");
221 goto reset;
222 }
223 intel_de_write(dev_priv, DSB_HEAD(pipe, dsb->id),
224 i915_ggtt_offset(dsb->vma));
225
226 tail = ALIGN(dsb->free_pos * 4, CACHELINE_BYTES);
227 if (tail > dsb->free_pos * 4)
228 memset(&dsb->cmd_buf[dsb->free_pos], 0,
229 (tail - dsb->free_pos * 4));
230
231 if (is_dsb_busy(dev_priv, pipe, dsb->id)) {
232 drm_err(&dev_priv->drm,
233 "TAIL_PTR write failed - dsb engine is busy.\n");
234 goto reset;
235 }
236 drm_dbg_kms(&dev_priv->drm,
237 "DSB execution started - head 0x%x, tail 0x%x\n",
238 i915_ggtt_offset(dsb->vma), tail);
239 intel_de_write(dev_priv, DSB_TAIL(pipe, dsb->id),
240 i915_ggtt_offset(dsb->vma) + tail);
241 if (wait_for(!is_dsb_busy(dev_priv, pipe, dsb->id), 1)) {
242 drm_err(&dev_priv->drm,
243 "Timed out waiting for DSB workload completion.\n");
244 goto reset;
245 }
246
247reset:
248 dsb->free_pos = 0;
249 dsb->ins_start_offset = 0;
250 intel_dsb_disable_engine(dev_priv, pipe, dsb->id);
251}
252
253/**
254 * intel_dsb_prepare() - Allocate, pin and map the DSB command buffer.
255 * @crtc_state: intel_crtc_state structure to prepare associated dsb instance.
256 *
257 * This function prepare the command buffer which is used to store dsb
258 * instructions with data.
259 */
260void intel_dsb_prepare(struct intel_crtc_state *crtc_state)
261{
262 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
263 struct drm_i915_private *i915 = to_i915(crtc->base.dev);
264 struct intel_dsb *dsb;
265 struct drm_i915_gem_object *obj;
266 struct i915_vma *vma;
267 u32 *buf;
268 intel_wakeref_t wakeref;
269
270 if (!HAS_DSB(i915))
271 return;
272
273 dsb = kmalloc(sizeof(*dsb), GFP_KERNEL);
274 if (!dsb) {
275 drm_err(&i915->drm, "DSB object creation failed\n");
276 return;
277 }
278
279 wakeref = intel_runtime_pm_get(&i915->runtime_pm);
280
281 obj = i915_gem_object_create_internal(i915, DSB_BUF_SIZE);
282 if (IS_ERR(obj)) {
283 drm_err(&i915->drm, "Gem object creation failed\n");
284 kfree(dsb);
285 goto out;
286 }
287
288 vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, 0);
289 if (IS_ERR(vma)) {
290 drm_err(&i915->drm, "Vma creation failed\n");
291 i915_gem_object_put(obj);
292 kfree(dsb);
293 goto out;
294 }
295
296 buf = i915_gem_object_pin_map(vma->obj, I915_MAP_WC);
297 if (IS_ERR(buf)) {
298 drm_err(&i915->drm, "Command buffer creation failed\n");
299 i915_vma_unpin_and_release(&vma, I915_VMA_RELEASE_MAP);
300 kfree(dsb);
301 goto out;
302 }
303
304 dsb->id = DSB1;
305 dsb->vma = vma;
306 dsb->cmd_buf = buf;
307 dsb->free_pos = 0;
308 dsb->ins_start_offset = 0;
309 crtc_state->dsb = dsb;
310out:
311 intel_runtime_pm_put(&i915->runtime_pm, wakeref);
312}
313
314/**
315 * intel_dsb_cleanup() - To cleanup DSB context.
316 * @crtc_state: intel_crtc_state structure to cleanup associated dsb instance.
317 *
318 * This function cleanup the DSB context by unpinning and releasing
319 * the VMA object associated with it.
320 */
321void intel_dsb_cleanup(struct intel_crtc_state *crtc_state)
322{
323 if (!crtc_state->dsb)
324 return;
325
326 i915_vma_unpin_and_release(&crtc_state->dsb->vma, I915_VMA_RELEASE_MAP);
327 kfree(crtc_state->dsb);
328 crtc_state->dsb = NULL;
329}