xref: /linux/drivers/gpu/drm/i915/gt/intel_gt_mcr.c (revision 6c7353836a91b1479e6b81791cdc163fb04b4834)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2022 Intel Corporation
4  */
5 
6 #include "i915_drv.h"
7 #include "intel_gt.h"
8 #include "intel_gt_mcr.h"
9 #include "intel_gt_print.h"
10 #include "intel_gt_regs.h"
11 
12 /**
13  * DOC: GT Multicast/Replicated (MCR) Register Support
14  *
15  * Some GT registers are designed as "multicast" or "replicated" registers:
16  * multiple instances of the same register share a single MMIO offset.  MCR
17  * registers are generally used when the hardware needs to potentially track
18  * independent values of a register per hardware unit (e.g., per-subslice,
19  * per-L3bank, etc.).  The specific types of replication that exist vary
20  * per-platform.
21  *
22  * MMIO accesses to MCR registers are controlled according to the settings
23  * programmed in the platform's MCR_SELECTOR register(s).  MMIO writes to MCR
24  * registers can be done in either a (i.e., a single write updates all
25  * instances of the register to the same value) or unicast (a write updates only
26  * one specific instance).  Reads of MCR registers always operate in a unicast
27  * manner regardless of how the multicast/unicast bit is set in MCR_SELECTOR.
28  * Selection of a specific MCR instance for unicast operations is referred to
29  * as "steering."
30  *
31  * If MCR register operations are steered toward a hardware unit that is
32  * fused off or currently powered down due to power gating, the MMIO operation
33  * is "terminated" by the hardware.  Terminated read operations will return a
34  * value of zero and terminated unicast write operations will be silently
35  * ignored.
36  */
37 
38 #define HAS_MSLICE_STEERING(i915)	(INTEL_INFO(i915)->has_mslice_steering)
39 
40 static const char * const intel_steering_types[] = {
41 	"L3BANK",
42 	"MSLICE",
43 	"LNCF",
44 	"GAM",
45 	"DSS",
46 	"OADDRM",
47 	"INSTANCE 0",
48 };
49 
50 static const struct intel_mmio_range icl_l3bank_steering_table[] = {
51 	{ 0x00B100, 0x00B3FF },
52 	{},
53 };
54 
55 /*
56  * Although the bspec lists more "MSLICE" ranges than shown here, some of those
57  * are of a "GAM" subclass that has special rules.  Thus we use a separate
58  * GAM table farther down for those.
59  */
60 static const struct intel_mmio_range xehpsdv_mslice_steering_table[] = {
61 	{ 0x00DD00, 0x00DDFF },
62 	{ 0x00E900, 0x00FFFF }, /* 0xEA00 - OxEFFF is unused */
63 	{},
64 };
65 
66 static const struct intel_mmio_range xehpsdv_gam_steering_table[] = {
67 	{ 0x004000, 0x004AFF },
68 	{ 0x00C800, 0x00CFFF },
69 	{},
70 };
71 
72 static const struct intel_mmio_range xehpsdv_lncf_steering_table[] = {
73 	{ 0x00B000, 0x00B0FF },
74 	{ 0x00D800, 0x00D8FF },
75 	{},
76 };
77 
78 static const struct intel_mmio_range dg2_lncf_steering_table[] = {
79 	{ 0x00B000, 0x00B0FF },
80 	{ 0x00D880, 0x00D8FF },
81 	{},
82 };
83 
84 /*
85  * We have several types of MCR registers on PVC where steering to (0,0)
86  * will always provide us with a non-terminated value.  We'll stick them
87  * all in the same table for simplicity.
88  */
89 static const struct intel_mmio_range pvc_instance0_steering_table[] = {
90 	{ 0x004000, 0x004AFF },		/* HALF-BSLICE */
91 	{ 0x008800, 0x00887F },		/* CC */
92 	{ 0x008A80, 0x008AFF },		/* TILEPSMI */
93 	{ 0x00B000, 0x00B0FF },		/* HALF-BSLICE */
94 	{ 0x00B100, 0x00B3FF },		/* L3BANK */
95 	{ 0x00C800, 0x00CFFF },		/* HALF-BSLICE */
96 	{ 0x00D800, 0x00D8FF },		/* HALF-BSLICE */
97 	{ 0x00DD00, 0x00DDFF },		/* BSLICE */
98 	{ 0x00E900, 0x00E9FF },		/* HALF-BSLICE */
99 	{ 0x00EC00, 0x00EEFF },		/* HALF-BSLICE */
100 	{ 0x00F000, 0x00FFFF },		/* HALF-BSLICE */
101 	{ 0x024180, 0x0241FF },		/* HALF-BSLICE */
102 	{},
103 };
104 
105 static const struct intel_mmio_range xelpg_instance0_steering_table[] = {
106 	{ 0x000B00, 0x000BFF },         /* SQIDI */
107 	{ 0x001000, 0x001FFF },         /* SQIDI */
108 	{ 0x004000, 0x0048FF },         /* GAM */
109 	{ 0x008700, 0x0087FF },         /* SQIDI */
110 	{ 0x00B000, 0x00B0FF },         /* NODE */
111 	{ 0x00C800, 0x00CFFF },         /* GAM */
112 	{ 0x00D880, 0x00D8FF },         /* NODE */
113 	{ 0x00DD00, 0x00DDFF },         /* OAAL2 */
114 	{},
115 };
116 
117 static const struct intel_mmio_range xelpg_l3bank_steering_table[] = {
118 	{ 0x00B100, 0x00B3FF },
119 	{},
120 };
121 
122 /* DSS steering is used for SLICE ranges as well */
123 static const struct intel_mmio_range xelpg_dss_steering_table[] = {
124 	{ 0x005200, 0x0052FF },		/* SLICE */
125 	{ 0x005500, 0x007FFF },		/* SLICE */
126 	{ 0x008140, 0x00815F },		/* SLICE (0x8140-0x814F), DSS (0x8150-0x815F) */
127 	{ 0x0094D0, 0x00955F },		/* SLICE (0x94D0-0x951F), DSS (0x9520-0x955F) */
128 	{ 0x009680, 0x0096FF },		/* DSS */
129 	{ 0x00D800, 0x00D87F },		/* SLICE */
130 	{ 0x00DC00, 0x00DCFF },		/* SLICE */
131 	{ 0x00DE80, 0x00E8FF },		/* DSS (0xE000-0xE0FF reserved) */
132 	{},
133 };
134 
135 static const struct intel_mmio_range xelpmp_oaddrm_steering_table[] = {
136 	{ 0x393200, 0x39323F },
137 	{ 0x393400, 0x3934FF },
138 	{},
139 };
140 
141 void intel_gt_mcr_init(struct intel_gt *gt)
142 {
143 	struct drm_i915_private *i915 = gt->i915;
144 	unsigned long fuse;
145 	int i;
146 
147 	spin_lock_init(&gt->mcr_lock);
148 
149 	/*
150 	 * An mslice is unavailable only if both the meml3 for the slice is
151 	 * disabled *and* all of the DSS in the slice (quadrant) are disabled.
152 	 */
153 	if (HAS_MSLICE_STEERING(i915)) {
154 		gt->info.mslice_mask =
155 			intel_slicemask_from_xehp_dssmask(gt->info.sseu.subslice_mask,
156 							  GEN_DSS_PER_MSLICE);
157 		gt->info.mslice_mask |=
158 			(intel_uncore_read(gt->uncore, GEN10_MIRROR_FUSE3) &
159 			 GEN12_MEML3_EN_MASK);
160 
161 		if (!gt->info.mslice_mask) /* should be impossible! */
162 			gt_warn(gt, "mslice mask all zero!\n");
163 	}
164 
165 	if (MEDIA_VER(i915) >= 13 && gt->type == GT_MEDIA) {
166 		gt->steering_table[OADDRM] = xelpmp_oaddrm_steering_table;
167 	} else if (GRAPHICS_VER_FULL(i915) >= IP_VER(12, 70)) {
168 		/* Wa_14016747170 */
169 		if (IS_GFX_GT_IP_STEP(gt, IP_VER(12, 70), STEP_A0, STEP_B0) ||
170 		    IS_GFX_GT_IP_STEP(gt, IP_VER(12, 71), STEP_A0, STEP_B0))
171 			fuse = REG_FIELD_GET(MTL_GT_L3_EXC_MASK,
172 					     intel_uncore_read(gt->uncore,
173 							       MTL_GT_ACTIVITY_FACTOR));
174 		else
175 			fuse = REG_FIELD_GET(GT_L3_EXC_MASK,
176 					     intel_uncore_read(gt->uncore, XEHP_FUSE4));
177 
178 		/*
179 		 * Despite the register field being named "exclude mask" the
180 		 * bits actually represent enabled banks (two banks per bit).
181 		 */
182 		for_each_set_bit(i, &fuse, 3)
183 			gt->info.l3bank_mask |= 0x3 << 2 * i;
184 
185 		gt->steering_table[INSTANCE0] = xelpg_instance0_steering_table;
186 		gt->steering_table[L3BANK] = xelpg_l3bank_steering_table;
187 		gt->steering_table[DSS] = xelpg_dss_steering_table;
188 	} else if (IS_PONTEVECCHIO(i915)) {
189 		gt->steering_table[INSTANCE0] = pvc_instance0_steering_table;
190 	} else if (IS_DG2(i915)) {
191 		gt->steering_table[MSLICE] = xehpsdv_mslice_steering_table;
192 		gt->steering_table[LNCF] = dg2_lncf_steering_table;
193 		/*
194 		 * No need to hook up the GAM table since it has a dedicated
195 		 * steering control register on DG2 and can use implicit
196 		 * steering.
197 		 */
198 	} else if (IS_XEHPSDV(i915)) {
199 		gt->steering_table[MSLICE] = xehpsdv_mslice_steering_table;
200 		gt->steering_table[LNCF] = xehpsdv_lncf_steering_table;
201 		gt->steering_table[GAM] = xehpsdv_gam_steering_table;
202 	} else if (GRAPHICS_VER(i915) >= 11 &&
203 		   GRAPHICS_VER_FULL(i915) < IP_VER(12, 50)) {
204 		gt->steering_table[L3BANK] = icl_l3bank_steering_table;
205 		gt->info.l3bank_mask =
206 			~intel_uncore_read(gt->uncore, GEN10_MIRROR_FUSE3) &
207 			GEN10_L3BANK_MASK;
208 		if (!gt->info.l3bank_mask) /* should be impossible! */
209 			gt_warn(gt, "L3 bank mask is all zero!\n");
210 	} else if (GRAPHICS_VER(i915) >= 11) {
211 		/*
212 		 * We expect all modern platforms to have at least some
213 		 * type of steering that needs to be initialized.
214 		 */
215 		MISSING_CASE(INTEL_INFO(i915)->platform);
216 	}
217 }
218 
219 /*
220  * Although the rest of the driver should use MCR-specific functions to
221  * read/write MCR registers, we still use the regular intel_uncore_* functions
222  * internally to implement those, so we need a way for the functions in this
223  * file to "cast" an i915_mcr_reg_t into an i915_reg_t.
224  */
225 static i915_reg_t mcr_reg_cast(const i915_mcr_reg_t mcr)
226 {
227 	i915_reg_t r = { .reg = mcr.reg };
228 
229 	return r;
230 }
231 
232 /*
233  * rw_with_mcr_steering_fw - Access a register with specific MCR steering
234  * @gt: GT to read register from
235  * @reg: register being accessed
236  * @rw_flag: FW_REG_READ for read access or FW_REG_WRITE for write access
237  * @group: group number (documented as "sliceid" on older platforms)
238  * @instance: instance number (documented as "subsliceid" on older platforms)
239  * @value: register value to be written (ignored for read)
240  *
241  * Context: The caller must hold the MCR lock
242  * Return: 0 for write access. register value for read access.
243  *
244  * Caller needs to make sure the relevant forcewake wells are up.
245  */
246 static u32 rw_with_mcr_steering_fw(struct intel_gt *gt,
247 				   i915_mcr_reg_t reg, u8 rw_flag,
248 				   int group, int instance, u32 value)
249 {
250 	struct intel_uncore *uncore = gt->uncore;
251 	u32 mcr_mask, mcr_ss, mcr, old_mcr, val = 0;
252 
253 	lockdep_assert_held(&gt->mcr_lock);
254 
255 	if (GRAPHICS_VER_FULL(uncore->i915) >= IP_VER(12, 70)) {
256 		/*
257 		 * Always leave the hardware in multicast mode when doing reads
258 		 * (see comment about Wa_22013088509 below) and only change it
259 		 * to unicast mode when doing writes of a specific instance.
260 		 *
261 		 * No need to save old steering reg value.
262 		 */
263 		intel_uncore_write_fw(uncore, MTL_MCR_SELECTOR,
264 				      REG_FIELD_PREP(MTL_MCR_GROUPID, group) |
265 				      REG_FIELD_PREP(MTL_MCR_INSTANCEID, instance) |
266 				      (rw_flag == FW_REG_READ ? GEN11_MCR_MULTICAST : 0));
267 	} else if (GRAPHICS_VER(uncore->i915) >= 11) {
268 		mcr_mask = GEN11_MCR_SLICE_MASK | GEN11_MCR_SUBSLICE_MASK;
269 		mcr_ss = GEN11_MCR_SLICE(group) | GEN11_MCR_SUBSLICE(instance);
270 
271 		/*
272 		 * Wa_22013088509
273 		 *
274 		 * The setting of the multicast/unicast bit usually wouldn't
275 		 * matter for read operations (which always return the value
276 		 * from a single register instance regardless of how that bit
277 		 * is set), but some platforms have a workaround requiring us
278 		 * to remain in multicast mode for reads.  There's no real
279 		 * downside to this, so we'll just go ahead and do so on all
280 		 * platforms; we'll only clear the multicast bit from the mask
281 		 * when exlicitly doing a write operation.
282 		 */
283 		if (rw_flag == FW_REG_WRITE)
284 			mcr_mask |= GEN11_MCR_MULTICAST;
285 
286 		mcr = intel_uncore_read_fw(uncore, GEN8_MCR_SELECTOR);
287 		old_mcr = mcr;
288 
289 		mcr &= ~mcr_mask;
290 		mcr |= mcr_ss;
291 		intel_uncore_write_fw(uncore, GEN8_MCR_SELECTOR, mcr);
292 	} else {
293 		mcr_mask = GEN8_MCR_SLICE_MASK | GEN8_MCR_SUBSLICE_MASK;
294 		mcr_ss = GEN8_MCR_SLICE(group) | GEN8_MCR_SUBSLICE(instance);
295 
296 		mcr = intel_uncore_read_fw(uncore, GEN8_MCR_SELECTOR);
297 		old_mcr = mcr;
298 
299 		mcr &= ~mcr_mask;
300 		mcr |= mcr_ss;
301 		intel_uncore_write_fw(uncore, GEN8_MCR_SELECTOR, mcr);
302 	}
303 
304 	if (rw_flag == FW_REG_READ)
305 		val = intel_uncore_read_fw(uncore, mcr_reg_cast(reg));
306 	else
307 		intel_uncore_write_fw(uncore, mcr_reg_cast(reg), value);
308 
309 	/*
310 	 * For pre-MTL platforms, we need to restore the old value of the
311 	 * steering control register to ensure that implicit steering continues
312 	 * to behave as expected.  For MTL and beyond, we need only reinstate
313 	 * the 'multicast' bit (and only if we did a write that cleared it).
314 	 */
315 	if (GRAPHICS_VER_FULL(uncore->i915) >= IP_VER(12, 70) && rw_flag == FW_REG_WRITE)
316 		intel_uncore_write_fw(uncore, MTL_MCR_SELECTOR, GEN11_MCR_MULTICAST);
317 	else if (GRAPHICS_VER_FULL(uncore->i915) < IP_VER(12, 70))
318 		intel_uncore_write_fw(uncore, GEN8_MCR_SELECTOR, old_mcr);
319 
320 	return val;
321 }
322 
323 static u32 rw_with_mcr_steering(struct intel_gt *gt,
324 				i915_mcr_reg_t reg, u8 rw_flag,
325 				int group, int instance,
326 				u32 value)
327 {
328 	struct intel_uncore *uncore = gt->uncore;
329 	enum forcewake_domains fw_domains;
330 	unsigned long flags;
331 	u32 val;
332 
333 	fw_domains = intel_uncore_forcewake_for_reg(uncore, mcr_reg_cast(reg),
334 						    rw_flag);
335 	fw_domains |= intel_uncore_forcewake_for_reg(uncore,
336 						     GEN8_MCR_SELECTOR,
337 						     FW_REG_READ | FW_REG_WRITE);
338 
339 	intel_gt_mcr_lock(gt, &flags);
340 	spin_lock(&uncore->lock);
341 	intel_uncore_forcewake_get__locked(uncore, fw_domains);
342 
343 	val = rw_with_mcr_steering_fw(gt, reg, rw_flag, group, instance, value);
344 
345 	intel_uncore_forcewake_put__locked(uncore, fw_domains);
346 	spin_unlock(&uncore->lock);
347 	intel_gt_mcr_unlock(gt, flags);
348 
349 	return val;
350 }
351 
352 /**
353  * intel_gt_mcr_lock - Acquire MCR steering lock
354  * @gt: GT structure
355  * @flags: storage to save IRQ flags to
356  *
357  * Performs locking to protect the steering for the duration of an MCR
358  * operation.  On MTL and beyond, a hardware lock will also be taken to
359  * serialize access not only for the driver, but also for external hardware and
360  * firmware agents.
361  *
362  * Context: Takes gt->mcr_lock.  uncore->lock should *not* be held when this
363  *          function is called, although it may be acquired after this
364  *          function call.
365  */
366 void intel_gt_mcr_lock(struct intel_gt *gt, unsigned long *flags)
367 	__acquires(&gt->mcr_lock)
368 {
369 	unsigned long __flags;
370 	int err = 0;
371 
372 	lockdep_assert_not_held(&gt->uncore->lock);
373 
374 	/*
375 	 * Starting with MTL, we need to coordinate not only with other
376 	 * driver threads, but also with hardware/firmware agents.  A dedicated
377 	 * locking register is used.
378 	 */
379 	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70)) {
380 		/*
381 		 * The steering control and semaphore registers are inside an
382 		 * "always on" power domain with respect to RC6.  However there
383 		 * are some issues if higher-level platform sleep states are
384 		 * entering/exiting at the same time these registers are
385 		 * accessed.  Grabbing GT forcewake and holding it over the
386 		 * entire lock/steer/unlock cycle ensures that those sleep
387 		 * states have been fully exited before we access these
388 		 * registers.  This wakeref will be released in the unlock
389 		 * routine.
390 		 *
391 		 * Wa_22018931422
392 		 */
393 		intel_uncore_forcewake_get(gt->uncore, FORCEWAKE_GT);
394 
395 		err = wait_for(intel_uncore_read_fw(gt->uncore,
396 						    MTL_STEER_SEMAPHORE) == 0x1, 100);
397 	}
398 
399 	/*
400 	 * Even on platforms with a hardware lock, we'll continue to grab
401 	 * a software spinlock too for lockdep purposes.  If the hardware lock
402 	 * was already acquired, there should never be contention on the
403 	 * software lock.
404 	 */
405 	spin_lock_irqsave(&gt->mcr_lock, __flags);
406 
407 	*flags = __flags;
408 
409 	/*
410 	 * In theory we should never fail to acquire the HW semaphore; this
411 	 * would indicate some hardware/firmware is misbehaving and not
412 	 * releasing it properly.
413 	 */
414 	if (err == -ETIMEDOUT) {
415 		gt_err_ratelimited(gt, "hardware MCR steering semaphore timed out");
416 		add_taint_for_CI(gt->i915, TAINT_WARN);  /* CI is now unreliable */
417 	}
418 }
419 
420 /**
421  * intel_gt_mcr_unlock - Release MCR steering lock
422  * @gt: GT structure
423  * @flags: IRQ flags to restore
424  *
425  * Releases the lock acquired by intel_gt_mcr_lock().
426  *
427  * Context: Releases gt->mcr_lock
428  */
429 void intel_gt_mcr_unlock(struct intel_gt *gt, unsigned long flags)
430 	__releases(&gt->mcr_lock)
431 {
432 	spin_unlock_irqrestore(&gt->mcr_lock, flags);
433 
434 	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70)) {
435 		intel_uncore_write_fw(gt->uncore, MTL_STEER_SEMAPHORE, 0x1);
436 
437 		intel_uncore_forcewake_put(gt->uncore, FORCEWAKE_GT);
438 	}
439 }
440 
441 /**
442  * intel_gt_mcr_lock_sanitize - Sanitize MCR steering lock
443  * @gt: GT structure
444  *
445  * This will be used to sanitize the initial status of the hardware lock
446  * during driver load and resume since there won't be any concurrent access
447  * from other agents at those times, but it's possible that boot firmware
448  * may have left the lock in a bad state.
449  *
450  */
451 void intel_gt_mcr_lock_sanitize(struct intel_gt *gt)
452 {
453 	/*
454 	 * This gets called at load/resume time, so we shouldn't be
455 	 * racing with other driver threads grabbing the mcr lock.
456 	 */
457 	lockdep_assert_not_held(&gt->mcr_lock);
458 
459 	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70))
460 		intel_uncore_write_fw(gt->uncore, MTL_STEER_SEMAPHORE, 0x1);
461 }
462 
463 /**
464  * intel_gt_mcr_read - read a specific instance of an MCR register
465  * @gt: GT structure
466  * @reg: the MCR register to read
467  * @group: the MCR group
468  * @instance: the MCR instance
469  *
470  * Context: Takes and releases gt->mcr_lock
471  *
472  * Returns the value read from an MCR register after steering toward a specific
473  * group/instance.
474  */
475 u32 intel_gt_mcr_read(struct intel_gt *gt,
476 		      i915_mcr_reg_t reg,
477 		      int group, int instance)
478 {
479 	return rw_with_mcr_steering(gt, reg, FW_REG_READ, group, instance, 0);
480 }
481 
482 /**
483  * intel_gt_mcr_unicast_write - write a specific instance of an MCR register
484  * @gt: GT structure
485  * @reg: the MCR register to write
486  * @value: value to write
487  * @group: the MCR group
488  * @instance: the MCR instance
489  *
490  * Write an MCR register in unicast mode after steering toward a specific
491  * group/instance.
492  *
493  * Context: Calls a function that takes and releases gt->mcr_lock
494  */
495 void intel_gt_mcr_unicast_write(struct intel_gt *gt, i915_mcr_reg_t reg, u32 value,
496 				int group, int instance)
497 {
498 	rw_with_mcr_steering(gt, reg, FW_REG_WRITE, group, instance, value);
499 }
500 
501 /**
502  * intel_gt_mcr_multicast_write - write a value to all instances of an MCR register
503  * @gt: GT structure
504  * @reg: the MCR register to write
505  * @value: value to write
506  *
507  * Write an MCR register in multicast mode to update all instances.
508  *
509  * Context: Takes and releases gt->mcr_lock
510  */
511 void intel_gt_mcr_multicast_write(struct intel_gt *gt,
512 				  i915_mcr_reg_t reg, u32 value)
513 {
514 	unsigned long flags;
515 
516 	intel_gt_mcr_lock(gt, &flags);
517 
518 	/*
519 	 * Ensure we have multicast behavior, just in case some non-i915 agent
520 	 * left the hardware in unicast mode.
521 	 */
522 	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70))
523 		intel_uncore_write_fw(gt->uncore, MTL_MCR_SELECTOR, GEN11_MCR_MULTICAST);
524 
525 	intel_uncore_write(gt->uncore, mcr_reg_cast(reg), value);
526 
527 	intel_gt_mcr_unlock(gt, flags);
528 }
529 
530 /**
531  * intel_gt_mcr_multicast_write_fw - write a value to all instances of an MCR register
532  * @gt: GT structure
533  * @reg: the MCR register to write
534  * @value: value to write
535  *
536  * Write an MCR register in multicast mode to update all instances.  This
537  * function assumes the caller is already holding any necessary forcewake
538  * domains; use intel_gt_mcr_multicast_write() in cases where forcewake should
539  * be obtained automatically.
540  *
541  * Context: The caller must hold gt->mcr_lock.
542  */
543 void intel_gt_mcr_multicast_write_fw(struct intel_gt *gt, i915_mcr_reg_t reg, u32 value)
544 {
545 	lockdep_assert_held(&gt->mcr_lock);
546 
547 	/*
548 	 * Ensure we have multicast behavior, just in case some non-i915 agent
549 	 * left the hardware in unicast mode.
550 	 */
551 	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70))
552 		intel_uncore_write_fw(gt->uncore, MTL_MCR_SELECTOR, GEN11_MCR_MULTICAST);
553 
554 	intel_uncore_write_fw(gt->uncore, mcr_reg_cast(reg), value);
555 }
556 
557 /**
558  * intel_gt_mcr_multicast_rmw - Performs a multicast RMW operations
559  * @gt: GT structure
560  * @reg: the MCR register to read and write
561  * @clear: bits to clear during RMW
562  * @set: bits to set during RMW
563  *
564  * Performs a read-modify-write on an MCR register in a multicast manner.
565  * This operation only makes sense on MCR registers where all instances are
566  * expected to have the same value.  The read will target any non-terminated
567  * instance and the write will be applied to all instances.
568  *
569  * This function assumes the caller is already holding any necessary forcewake
570  * domains; use intel_gt_mcr_multicast_rmw() in cases where forcewake should
571  * be obtained automatically.
572  *
573  * Context: Calls functions that take and release gt->mcr_lock
574  *
575  * Returns the old (unmodified) value read.
576  */
577 u32 intel_gt_mcr_multicast_rmw(struct intel_gt *gt, i915_mcr_reg_t reg,
578 			       u32 clear, u32 set)
579 {
580 	u32 val = intel_gt_mcr_read_any(gt, reg);
581 
582 	intel_gt_mcr_multicast_write(gt, reg, (val & ~clear) | set);
583 
584 	return val;
585 }
586 
587 /*
588  * reg_needs_read_steering - determine whether a register read requires
589  *     explicit steering
590  * @gt: GT structure
591  * @reg: the register to check steering requirements for
592  * @type: type of multicast steering to check
593  *
594  * Determines whether @reg needs explicit steering of a specific type for
595  * reads.
596  *
597  * Returns false if @reg does not belong to a register range of the given
598  * steering type, or if the default (subslice-based) steering IDs are suitable
599  * for @type steering too.
600  */
601 static bool reg_needs_read_steering(struct intel_gt *gt,
602 				    i915_mcr_reg_t reg,
603 				    enum intel_steering_type type)
604 {
605 	u32 offset = i915_mmio_reg_offset(reg);
606 	const struct intel_mmio_range *entry;
607 
608 	if (likely(!gt->steering_table[type]))
609 		return false;
610 
611 	if (IS_GSI_REG(offset))
612 		offset += gt->uncore->gsi_offset;
613 
614 	for (entry = gt->steering_table[type]; entry->end; entry++) {
615 		if (offset >= entry->start && offset <= entry->end)
616 			return true;
617 	}
618 
619 	return false;
620 }
621 
622 /*
623  * get_nonterminated_steering - determines valid IDs for a class of MCR steering
624  * @gt: GT structure
625  * @type: multicast register type
626  * @group: Group ID returned
627  * @instance: Instance ID returned
628  *
629  * Determines group and instance values that will steer reads of the specified
630  * MCR class to a non-terminated instance.
631  */
632 static void get_nonterminated_steering(struct intel_gt *gt,
633 				       enum intel_steering_type type,
634 				       u8 *group, u8 *instance)
635 {
636 	u32 dss;
637 
638 	switch (type) {
639 	case L3BANK:
640 		*group = 0;		/* unused */
641 		*instance = __ffs(gt->info.l3bank_mask);
642 		break;
643 	case MSLICE:
644 		GEM_WARN_ON(!HAS_MSLICE_STEERING(gt->i915));
645 		*group = __ffs(gt->info.mslice_mask);
646 		*instance = 0;	/* unused */
647 		break;
648 	case LNCF:
649 		/*
650 		 * An LNCF is always present if its mslice is present, so we
651 		 * can safely just steer to LNCF 0 in all cases.
652 		 */
653 		GEM_WARN_ON(!HAS_MSLICE_STEERING(gt->i915));
654 		*group = __ffs(gt->info.mslice_mask) << 1;
655 		*instance = 0;	/* unused */
656 		break;
657 	case GAM:
658 		*group = IS_DG2(gt->i915) ? 1 : 0;
659 		*instance = 0;
660 		break;
661 	case DSS:
662 		dss = intel_sseu_find_first_xehp_dss(&gt->info.sseu, 0, 0);
663 		*group = dss / GEN_DSS_PER_GSLICE;
664 		*instance = dss % GEN_DSS_PER_GSLICE;
665 		break;
666 	case INSTANCE0:
667 		/*
668 		 * There are a lot of MCR types for which instance (0, 0)
669 		 * will always provide a non-terminated value.
670 		 */
671 		*group = 0;
672 		*instance = 0;
673 		break;
674 	case OADDRM:
675 		if ((VDBOX_MASK(gt) | VEBOX_MASK(gt) | gt->info.sfc_mask) & BIT(0))
676 			*group = 0;
677 		else
678 			*group = 1;
679 		*instance = 0;
680 		break;
681 	default:
682 		MISSING_CASE(type);
683 		*group = 0;
684 		*instance = 0;
685 	}
686 }
687 
688 /**
689  * intel_gt_mcr_get_nonterminated_steering - find group/instance values that
690  *    will steer a register to a non-terminated instance
691  * @gt: GT structure
692  * @reg: register for which the steering is required
693  * @group: return variable for group steering
694  * @instance: return variable for instance steering
695  *
696  * This function returns a group/instance pair that is guaranteed to work for
697  * read steering of the given register. Note that a value will be returned even
698  * if the register is not replicated and therefore does not actually require
699  * steering.
700  */
701 void intel_gt_mcr_get_nonterminated_steering(struct intel_gt *gt,
702 					     i915_mcr_reg_t reg,
703 					     u8 *group, u8 *instance)
704 {
705 	int type;
706 
707 	for (type = 0; type < NUM_STEERING_TYPES; type++) {
708 		if (reg_needs_read_steering(gt, reg, type)) {
709 			get_nonterminated_steering(gt, type, group, instance);
710 			return;
711 		}
712 	}
713 
714 	*group = gt->default_steering.groupid;
715 	*instance = gt->default_steering.instanceid;
716 }
717 
718 /**
719  * intel_gt_mcr_read_any_fw - reads one instance of an MCR register
720  * @gt: GT structure
721  * @reg: register to read
722  *
723  * Reads a GT MCR register.  The read will be steered to a non-terminated
724  * instance (i.e., one that isn't fused off or powered down by power gating).
725  * This function assumes the caller is already holding any necessary forcewake
726  * domains; use intel_gt_mcr_read_any() in cases where forcewake should be
727  * obtained automatically.
728  *
729  * Context: The caller must hold gt->mcr_lock.
730  *
731  * Returns the value from a non-terminated instance of @reg.
732  */
733 u32 intel_gt_mcr_read_any_fw(struct intel_gt *gt, i915_mcr_reg_t reg)
734 {
735 	int type;
736 	u8 group, instance;
737 
738 	lockdep_assert_held(&gt->mcr_lock);
739 
740 	for (type = 0; type < NUM_STEERING_TYPES; type++) {
741 		if (reg_needs_read_steering(gt, reg, type)) {
742 			get_nonterminated_steering(gt, type, &group, &instance);
743 			return rw_with_mcr_steering_fw(gt, reg,
744 						       FW_REG_READ,
745 						       group, instance, 0);
746 		}
747 	}
748 
749 	return intel_uncore_read_fw(gt->uncore, mcr_reg_cast(reg));
750 }
751 
752 /**
753  * intel_gt_mcr_read_any - reads one instance of an MCR register
754  * @gt: GT structure
755  * @reg: register to read
756  *
757  * Reads a GT MCR register.  The read will be steered to a non-terminated
758  * instance (i.e., one that isn't fused off or powered down by power gating).
759  *
760  * Context: Calls a function that takes and releases gt->mcr_lock.
761  *
762  * Returns the value from a non-terminated instance of @reg.
763  */
764 u32 intel_gt_mcr_read_any(struct intel_gt *gt, i915_mcr_reg_t reg)
765 {
766 	int type;
767 	u8 group, instance;
768 
769 	for (type = 0; type < NUM_STEERING_TYPES; type++) {
770 		if (reg_needs_read_steering(gt, reg, type)) {
771 			get_nonterminated_steering(gt, type, &group, &instance);
772 			return rw_with_mcr_steering(gt, reg,
773 						    FW_REG_READ,
774 						    group, instance, 0);
775 		}
776 	}
777 
778 	return intel_uncore_read(gt->uncore, mcr_reg_cast(reg));
779 }
780 
781 static void report_steering_type(struct drm_printer *p,
782 				 struct intel_gt *gt,
783 				 enum intel_steering_type type,
784 				 bool dump_table)
785 {
786 	const struct intel_mmio_range *entry;
787 	u8 group, instance;
788 
789 	BUILD_BUG_ON(ARRAY_SIZE(intel_steering_types) != NUM_STEERING_TYPES);
790 
791 	if (!gt->steering_table[type]) {
792 		drm_printf(p, "%s steering: uses default steering\n",
793 			   intel_steering_types[type]);
794 		return;
795 	}
796 
797 	get_nonterminated_steering(gt, type, &group, &instance);
798 	drm_printf(p, "%s steering: group=0x%x, instance=0x%x\n",
799 		   intel_steering_types[type], group, instance);
800 
801 	if (!dump_table)
802 		return;
803 
804 	for (entry = gt->steering_table[type]; entry->end; entry++)
805 		drm_printf(p, "\t0x%06x - 0x%06x\n", entry->start, entry->end);
806 }
807 
808 void intel_gt_mcr_report_steering(struct drm_printer *p, struct intel_gt *gt,
809 				  bool dump_table)
810 {
811 	/*
812 	 * Starting with MTL we no longer have default steering;
813 	 * all ranges are explicitly steered.
814 	 */
815 	if (GRAPHICS_VER_FULL(gt->i915) < IP_VER(12, 70))
816 		drm_printf(p, "Default steering: group=0x%x, instance=0x%x\n",
817 			   gt->default_steering.groupid,
818 			   gt->default_steering.instanceid);
819 
820 	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70)) {
821 		for (int i = 0; i < NUM_STEERING_TYPES; i++)
822 			if (gt->steering_table[i])
823 				report_steering_type(p, gt, i, dump_table);
824 	} else if (IS_PONTEVECCHIO(gt->i915)) {
825 		report_steering_type(p, gt, INSTANCE0, dump_table);
826 	} else if (HAS_MSLICE_STEERING(gt->i915)) {
827 		report_steering_type(p, gt, MSLICE, dump_table);
828 		report_steering_type(p, gt, LNCF, dump_table);
829 	}
830 }
831 
832 /**
833  * intel_gt_mcr_get_ss_steering - returns the group/instance steering for a SS
834  * @gt: GT structure
835  * @dss: DSS ID to obtain steering for
836  * @group: pointer to storage for steering group ID
837  * @instance: pointer to storage for steering instance ID
838  *
839  * Returns the steering IDs (via the @group and @instance parameters) that
840  * correspond to a specific subslice/DSS ID.
841  */
842 void intel_gt_mcr_get_ss_steering(struct intel_gt *gt, unsigned int dss,
843 				   unsigned int *group, unsigned int *instance)
844 {
845 	if (IS_PONTEVECCHIO(gt->i915)) {
846 		*group = dss / GEN_DSS_PER_CSLICE;
847 		*instance = dss % GEN_DSS_PER_CSLICE;
848 	} else if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 50)) {
849 		*group = dss / GEN_DSS_PER_GSLICE;
850 		*instance = dss % GEN_DSS_PER_GSLICE;
851 	} else {
852 		*group = dss / GEN_MAX_SS_PER_HSW_SLICE;
853 		*instance = dss % GEN_MAX_SS_PER_HSW_SLICE;
854 		return;
855 	}
856 }
857 
858 /**
859  * intel_gt_mcr_wait_for_reg - wait until MCR register matches expected state
860  * @gt: GT structure
861  * @reg: the register to read
862  * @mask: mask to apply to register value
863  * @value: value to wait for
864  * @fast_timeout_us: fast timeout in microsecond for atomic/tight wait
865  * @slow_timeout_ms: slow timeout in millisecond
866  *
867  * This routine waits until the target register @reg contains the expected
868  * @value after applying the @mask, i.e. it waits until ::
869  *
870  *     (intel_gt_mcr_read_any_fw(gt, reg) & mask) == value
871  *
872  * Otherwise, the wait will timeout after @slow_timeout_ms milliseconds.
873  * For atomic context @slow_timeout_ms must be zero and @fast_timeout_us
874  * must be not larger than 20,0000 microseconds.
875  *
876  * This function is basically an MCR-friendly version of
877  * __intel_wait_for_register_fw().  Generally this function will only be used
878  * on GAM registers which are a bit special --- although they're MCR registers,
879  * reads (e.g., waiting for status updates) are always directed to the primary
880  * instance.
881  *
882  * Note that this routine assumes the caller holds forcewake asserted, it is
883  * not suitable for very long waits.
884  *
885  * Context: Calls a function that takes and releases gt->mcr_lock
886  * Return: 0 if the register matches the desired condition, or -ETIMEDOUT.
887  */
888 int intel_gt_mcr_wait_for_reg(struct intel_gt *gt,
889 			      i915_mcr_reg_t reg,
890 			      u32 mask,
891 			      u32 value,
892 			      unsigned int fast_timeout_us,
893 			      unsigned int slow_timeout_ms)
894 {
895 	int ret;
896 
897 	lockdep_assert_not_held(&gt->mcr_lock);
898 
899 #define done ((intel_gt_mcr_read_any(gt, reg) & mask) == value)
900 
901 	/* Catch any overuse of this function */
902 	might_sleep_if(slow_timeout_ms);
903 	GEM_BUG_ON(fast_timeout_us > 20000);
904 	GEM_BUG_ON(!fast_timeout_us && !slow_timeout_ms);
905 
906 	ret = -ETIMEDOUT;
907 	if (fast_timeout_us && fast_timeout_us <= 20000)
908 		ret = _wait_for_atomic(done, fast_timeout_us, 0);
909 	if (ret && slow_timeout_ms)
910 		ret = wait_for(done, slow_timeout_ms);
911 
912 	return ret;
913 #undef done
914 }
915