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1// SPDX-License-Identifier: MIT
2/*
3 * Copyright © 2019 Intel Corporation
4 *
5 */
6
7#include "gem/i915_gem_internal.h"
8
9#include "i915_drv.h"
10#include "i915_reg.h"
11#include "intel_de.h"
12#include "intel_display_types.h"
13#include "intel_dsb.h"
14
15struct i915_vma;
16
17enum dsb_id {
18 INVALID_DSB = -1,
19 DSB1,
20 DSB2,
21 DSB3,
22 MAX_DSB_PER_PIPE
23};
24
25struct intel_dsb {
26 enum dsb_id id;
27 u32 *cmd_buf;
28 struct i915_vma *vma;
29
30 /*
31 * free_pos will point the first free entry position
32 * and help in calculating tail of command buffer.
33 */
34 int free_pos;
35
36 /*
37 * ins_start_offset will help to store start address of the dsb
38 * instuction and help in identifying the batch of auto-increment
39 * register.
40 */
41 u32 ins_start_offset;
42};
43
44#define DSB_BUF_SIZE (2 * PAGE_SIZE)
45
46/**
47 * DOC: DSB
48 *
49 * A DSB (Display State Buffer) is a queue of MMIO instructions in the memory
50 * which can be offloaded to DSB HW in Display Controller. DSB HW is a DMA
51 * engine that can be programmed to download the DSB from memory.
52 * It allows driver to batch submit display HW programming. This helps to
53 * reduce loading time and CPU activity, thereby making the context switch
54 * faster. DSB Support added from Gen12 Intel graphics based platform.
55 *
56 * DSB's can access only the pipe, plane, and transcoder Data Island Packet
57 * registers.
58 *
59 * DSB HW can support only register writes (both indexed and direct MMIO
60 * writes). There are no registers reads possible with DSB HW engine.
61 */
62
63/* DSB opcodes. */
64#define DSB_OPCODE_SHIFT 24
65#define DSB_OPCODE_MMIO_WRITE 0x1
66#define DSB_OPCODE_INDEXED_WRITE 0x9
67#define DSB_BYTE_EN 0xF
68#define DSB_BYTE_EN_SHIFT 20
69#define DSB_REG_VALUE_MASK 0xfffff
70
71static bool is_dsb_busy(struct drm_i915_private *i915, enum pipe pipe,
72 enum dsb_id id)
73{
74 return DSB_STATUS & intel_de_read(i915, DSB_CTRL(pipe, id));
75}
76
77static bool intel_dsb_enable_engine(struct drm_i915_private *i915,
78 enum pipe pipe, enum dsb_id id)
79{
80 u32 dsb_ctrl;
81
82 dsb_ctrl = intel_de_read(i915, DSB_CTRL(pipe, id));
83 if (DSB_STATUS & dsb_ctrl) {
84 drm_dbg_kms(&i915->drm, "DSB engine is busy.\n");
85 return false;
86 }
87
88 dsb_ctrl |= DSB_ENABLE;
89 intel_de_write(i915, DSB_CTRL(pipe, id), dsb_ctrl);
90
91 intel_de_posting_read(i915, DSB_CTRL(pipe, id));
92 return true;
93}
94
95static bool intel_dsb_disable_engine(struct drm_i915_private *i915,
96 enum pipe pipe, enum dsb_id id)
97{
98 u32 dsb_ctrl;
99
100 dsb_ctrl = intel_de_read(i915, DSB_CTRL(pipe, id));
101 if (DSB_STATUS & dsb_ctrl) {
102 drm_dbg_kms(&i915->drm, "DSB engine is busy.\n");
103 return false;
104 }
105
106 dsb_ctrl &= ~DSB_ENABLE;
107 intel_de_write(i915, DSB_CTRL(pipe, id), dsb_ctrl);
108
109 intel_de_posting_read(i915, DSB_CTRL(pipe, id));
110 return true;
111}
112
113/**
114 * intel_dsb_indexed_reg_write() -Write to the DSB context for auto
115 * increment register.
116 * @crtc_state: intel_crtc_state structure
117 * @reg: register address.
118 * @val: value.
119 *
120 * This function is used for writing register-value pair in command
121 * buffer of DSB for auto-increment register. During command buffer overflow,
122 * a warning is thrown and rest all erroneous condition register programming
123 * is done through mmio write.
124 */
125
126void intel_dsb_indexed_reg_write(const struct intel_crtc_state *crtc_state,
127 i915_reg_t reg, u32 val)
128{
129 struct intel_dsb *dsb = crtc_state->dsb;
130 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
131 struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
132 u32 *buf;
133 u32 reg_val;
134
135 if (!dsb) {
136 intel_de_write_fw(dev_priv, reg, val);
137 return;
138 }
139 buf = dsb->cmd_buf;
140 if (drm_WARN_ON(&dev_priv->drm, dsb->free_pos >= DSB_BUF_SIZE)) {
141 drm_dbg_kms(&dev_priv->drm, "DSB buffer overflow\n");
142 return;
143 }
144
145 /*
146 * For example the buffer will look like below for 3 dwords for auto
147 * increment register:
148 * +--------------------------------------------------------+
149 * | size = 3 | offset &| value1 | value2 | value3 | zero |
150 * | | opcode | | | | |
151 * +--------------------------------------------------------+
152 * + + + + + + +
153 * 0 4 8 12 16 20 24
154 * Byte
155 *
156 * As every instruction is 8 byte aligned the index of dsb instruction
157 * will start always from even number while dealing with u32 array. If
158 * we are writing odd no of dwords, Zeros will be added in the end for
159 * padding.
160 */
161 reg_val = buf[dsb->ins_start_offset + 1] & DSB_REG_VALUE_MASK;
162 if (reg_val != i915_mmio_reg_offset(reg)) {
163 /* Every instruction should be 8 byte aligned. */
164 dsb->free_pos = ALIGN(dsb->free_pos, 2);
165
166 dsb->ins_start_offset = dsb->free_pos;
167
168 /* Update the size. */
169 buf[dsb->free_pos++] = 1;
170
171 /* Update the opcode and reg. */
172 buf[dsb->free_pos++] = (DSB_OPCODE_INDEXED_WRITE <<
173 DSB_OPCODE_SHIFT) |
174 i915_mmio_reg_offset(reg);
175
176 /* Update the value. */
177 buf[dsb->free_pos++] = val;
178 } else {
179 /* Update the new value. */
180 buf[dsb->free_pos++] = val;
181
182 /* Update the size. */
183 buf[dsb->ins_start_offset]++;
184 }
185
186 /* if number of data words is odd, then the last dword should be 0.*/
187 if (dsb->free_pos & 0x1)
188 buf[dsb->free_pos] = 0;
189}
190
191/**
192 * intel_dsb_reg_write() -Write to the DSB context for normal
193 * register.
194 * @crtc_state: intel_crtc_state structure
195 * @reg: register address.
196 * @val: value.
197 *
198 * This function is used for writing register-value pair in command
199 * buffer of DSB. During command buffer overflow, a warning is thrown
200 * and rest all erroneous condition register programming is done
201 * through mmio write.
202 */
203void intel_dsb_reg_write(const struct intel_crtc_state *crtc_state,
204 i915_reg_t reg, u32 val)
205{
206 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
207 struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
208 struct intel_dsb *dsb;
209 u32 *buf;
210
211 dsb = crtc_state->dsb;
212 if (!dsb) {
213 intel_de_write_fw(dev_priv, reg, val);
214 return;
215 }
216
217 buf = dsb->cmd_buf;
218 if (drm_WARN_ON(&dev_priv->drm, dsb->free_pos >= DSB_BUF_SIZE)) {
219 drm_dbg_kms(&dev_priv->drm, "DSB buffer overflow\n");
220 return;
221 }
222
223 dsb->ins_start_offset = dsb->free_pos;
224 buf[dsb->free_pos++] = val;
225 buf[dsb->free_pos++] = (DSB_OPCODE_MMIO_WRITE << DSB_OPCODE_SHIFT) |
226 (DSB_BYTE_EN << DSB_BYTE_EN_SHIFT) |
227 i915_mmio_reg_offset(reg);
228}
229
230/**
231 * intel_dsb_commit() - Trigger workload execution of DSB.
232 * @crtc_state: intel_crtc_state structure
233 *
234 * This function is used to do actual write to hardware using DSB.
235 * On errors, fall back to MMIO. Also this function help to reset the context.
236 */
237void intel_dsb_commit(const struct intel_crtc_state *crtc_state)
238{
239 struct intel_dsb *dsb = crtc_state->dsb;
240 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
241 struct drm_device *dev = crtc->base.dev;
242 struct drm_i915_private *dev_priv = to_i915(dev);
243 enum pipe pipe = crtc->pipe;
244 u32 tail;
245
246 if (!(dsb && dsb->free_pos))
247 return;
248
249 if (!intel_dsb_enable_engine(dev_priv, pipe, dsb->id))
250 goto reset;
251
252 if (is_dsb_busy(dev_priv, pipe, dsb->id)) {
253 drm_err(&dev_priv->drm,
254 "HEAD_PTR write failed - dsb engine is busy.\n");
255 goto reset;
256 }
257 intel_de_write(dev_priv, DSB_HEAD(pipe, dsb->id),
258 i915_ggtt_offset(dsb->vma));
259
260 tail = ALIGN(dsb->free_pos * 4, CACHELINE_BYTES);
261 if (tail > dsb->free_pos * 4)
262 memset(&dsb->cmd_buf[dsb->free_pos], 0,
263 (tail - dsb->free_pos * 4));
264
265 if (is_dsb_busy(dev_priv, pipe, dsb->id)) {
266 drm_err(&dev_priv->drm,
267 "TAIL_PTR write failed - dsb engine is busy.\n");
268 goto reset;
269 }
270 drm_dbg_kms(&dev_priv->drm,
271 "DSB execution started - head 0x%x, tail 0x%x\n",
272 i915_ggtt_offset(dsb->vma), tail);
273 intel_de_write(dev_priv, DSB_TAIL(pipe, dsb->id),
274 i915_ggtt_offset(dsb->vma) + tail);
275 if (wait_for(!is_dsb_busy(dev_priv, pipe, dsb->id), 1)) {
276 drm_err(&dev_priv->drm,
277 "Timed out waiting for DSB workload completion.\n");
278 goto reset;
279 }
280
281reset:
282 dsb->free_pos = 0;
283 dsb->ins_start_offset = 0;
284 intel_dsb_disable_engine(dev_priv, pipe, dsb->id);
285}
286
287/**
288 * intel_dsb_prepare() - Allocate, pin and map the DSB command buffer.
289 * @crtc_state: intel_crtc_state structure to prepare associated dsb instance.
290 *
291 * This function prepare the command buffer which is used to store dsb
292 * instructions with data.
293 */
294void intel_dsb_prepare(struct intel_crtc_state *crtc_state)
295{
296 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
297 struct drm_i915_private *i915 = to_i915(crtc->base.dev);
298 struct intel_dsb *dsb;
299 struct drm_i915_gem_object *obj;
300 struct i915_vma *vma;
301 u32 *buf;
302 intel_wakeref_t wakeref;
303
304 if (!HAS_DSB(i915))
305 return;
306
307 dsb = kmalloc(sizeof(*dsb), GFP_KERNEL);
308 if (!dsb) {
309 drm_err(&i915->drm, "DSB object creation failed\n");
310 return;
311 }
312
313 wakeref = intel_runtime_pm_get(&i915->runtime_pm);
314
315 obj = i915_gem_object_create_internal(i915, DSB_BUF_SIZE);
316 if (IS_ERR(obj)) {
317 kfree(dsb);
318 goto out;
319 }
320
321 vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, 0);
322 if (IS_ERR(vma)) {
323 i915_gem_object_put(obj);
324 kfree(dsb);
325 goto out;
326 }
327
328 buf = i915_gem_object_pin_map_unlocked(vma->obj, I915_MAP_WC);
329 if (IS_ERR(buf)) {
330 i915_vma_unpin_and_release(&vma, I915_VMA_RELEASE_MAP);
331 kfree(dsb);
332 goto out;
333 }
334
335 dsb->id = DSB1;
336 dsb->vma = vma;
337 dsb->cmd_buf = buf;
338 dsb->free_pos = 0;
339 dsb->ins_start_offset = 0;
340 crtc_state->dsb = dsb;
341out:
342 if (!crtc_state->dsb)
343 drm_info(&i915->drm,
344 "DSB queue setup failed, will fallback to MMIO for display HW programming\n");
345
346 intel_runtime_pm_put(&i915->runtime_pm, wakeref);
347}
348
349/**
350 * intel_dsb_cleanup() - To cleanup DSB context.
351 * @crtc_state: intel_crtc_state structure to cleanup associated dsb instance.
352 *
353 * This function cleanup the DSB context by unpinning and releasing
354 * the VMA object associated with it.
355 */
356void intel_dsb_cleanup(struct intel_crtc_state *crtc_state)
357{
358 if (!crtc_state->dsb)
359 return;
360
361 i915_vma_unpin_and_release(&crtc_state->dsb->vma, I915_VMA_RELEASE_MAP);
362 kfree(crtc_state->dsb);
363 crtc_state->dsb = NULL;
364}