/*	$NetBSD: intel_gt.c,v 1.3 2021/12/19 11:39:55 riastradh Exp $	*/

// SPDX-License-Identifier: MIT
/*
 * Copyright © 2019 Intel Corporation
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: intel_gt.c,v 1.3 2021/12/19 11:39:55 riastradh Exp $");

#include <linux/kernel.h>

#if IS_ENABLED(CONFIG_DEBUGFS)
#include "debugfs_gt.h"
#endif
#include "i915_drv.h"
#include "intel_context.h"
#include "intel_gt.h"
#include "intel_gt_pm.h"
#include "intel_gt_requests.h"
#include "intel_mocs.h"
#include "intel_rc6.h"
#include "intel_renderstate.h"
#include "intel_rps.h"
#include "intel_uncore.h"
#include "intel_pm.h"

void intel_gt_init_early(struct intel_gt *gt, struct drm_i915_private *i915)
{
	gt->i915 = i915;
	gt->uncore = &i915->uncore;

	spin_lock_init(&gt->irq_lock);

	INIT_LIST_HEAD(&gt->closed_vma);
	spin_lock_init(&gt->closed_lock);

	intel_gt_init_reset(gt);
	intel_gt_init_requests(gt);
	intel_gt_init_timelines(gt);
	intel_gt_pm_init_early(gt);

	intel_rps_init_early(&gt->rps);
	intel_uc_init_early(&gt->uc);
}

void intel_gt_init_hw_early(struct intel_gt *gt, struct i915_ggtt *ggtt)
{
	gt->ggtt = ggtt;
}

static void init_unused_ring(struct intel_gt *gt, u32 base)
{
	struct intel_uncore *uncore = gt->uncore;

	intel_uncore_write(uncore, RING_CTL(base), 0);
	intel_uncore_write(uncore, RING_HEAD(base), 0);
	intel_uncore_write(uncore, RING_TAIL(base), 0);
	intel_uncore_write(uncore, RING_START(base), 0);
}

static void init_unused_rings(struct intel_gt *gt)
{
	struct drm_i915_private *i915 = gt->i915;

	if (IS_I830(i915)) {
		init_unused_ring(gt, PRB1_BASE);
		init_unused_ring(gt, SRB0_BASE);
		init_unused_ring(gt, SRB1_BASE);
		init_unused_ring(gt, SRB2_BASE);
		init_unused_ring(gt, SRB3_BASE);
	} else if (IS_GEN(i915, 2)) {
		init_unused_ring(gt, SRB0_BASE);
		init_unused_ring(gt, SRB1_BASE);
	} else if (IS_GEN(i915, 3)) {
		init_unused_ring(gt, PRB1_BASE);
		init_unused_ring(gt, PRB2_BASE);
	}
}

int intel_gt_init_hw(struct intel_gt *gt)
{
	struct drm_i915_private *i915 = gt->i915;
	struct intel_uncore *uncore = gt->uncore;
	int ret;

	gt->last_init_time = ktime_get();

	/* Double layer security blanket, see i915_gem_init() */
	intel_uncore_forcewake_get(uncore, FORCEWAKE_ALL);

	if (HAS_EDRAM(i915) && INTEL_GEN(i915) < 9)
		intel_uncore_rmw(uncore, HSW_IDICR, 0, IDIHASHMSK(0xf));

	if (IS_HASWELL(i915))
		intel_uncore_write(uncore,
				   MI_PREDICATE_RESULT_2,
				   IS_HSW_GT3(i915) ?
				   LOWER_SLICE_ENABLED : LOWER_SLICE_DISABLED);

	/* Apply the GT workarounds... */
	intel_gt_apply_workarounds(gt);
	/* ...and determine whether they are sticking. */
	intel_gt_verify_workarounds(gt, "init");

	intel_gt_init_swizzling(gt);

	/*
	 * At least 830 can leave some of the unused rings
	 * "active" (ie. head != tail) after resume which
	 * will prevent c3 entry. Makes sure all unused rings
	 * are totally idle.
	 */
	init_unused_rings(gt);

	ret = i915_ppgtt_init_hw(gt);
	if (ret) {
		DRM_ERROR("Enabling PPGTT failed (%d)\n", ret);
		goto out;
	}

	/* We can't enable contexts until all firmware is loaded */
	ret = intel_uc_init_hw(&gt->uc);
	if (ret) {
		i915_probe_error(i915, "Enabling uc failed (%d)\n", ret);
		goto out;
	}

	intel_mocs_init(gt);

out:
	intel_uncore_forcewake_put(uncore, FORCEWAKE_ALL);
	return ret;
}

static void rmw_set(struct intel_uncore *uncore, i915_reg_t reg, u32 set)
{
	intel_uncore_rmw(uncore, reg, 0, set);
}

static void rmw_clear(struct intel_uncore *uncore, i915_reg_t reg, u32 clr)
{
	intel_uncore_rmw(uncore, reg, clr, 0);
}

static void clear_register(struct intel_uncore *uncore, i915_reg_t reg)
{
	intel_uncore_rmw(uncore, reg, 0, 0);
}

static void gen8_clear_engine_error_register(struct intel_engine_cs *engine)
{
	GEN6_RING_FAULT_REG_RMW(engine, RING_FAULT_VALID, 0);
	GEN6_RING_FAULT_REG_POSTING_READ(engine);
}

void
intel_gt_clear_error_registers(struct intel_gt *gt,
			       intel_engine_mask_t engine_mask)
{
	struct drm_i915_private *i915 = gt->i915;
	struct intel_uncore *uncore = gt->uncore;
	u32 eir;

	if (!IS_GEN(i915, 2))
		clear_register(uncore, PGTBL_ER);

	if (INTEL_GEN(i915) < 4)
		clear_register(uncore, IPEIR(RENDER_RING_BASE));
	else
		clear_register(uncore, IPEIR_I965);

	clear_register(uncore, EIR);
	eir = intel_uncore_read(uncore, EIR);
	if (eir) {
		/*
		 * some errors might have become stuck,
		 * mask them.
		 */
		DRM_DEBUG_DRIVER("EIR stuck: 0x%08x, masking\n", eir);
		rmw_set(uncore, EMR, eir);
		intel_uncore_write(uncore, GEN2_IIR,
				   I915_MASTER_ERROR_INTERRUPT);
	}

	if (INTEL_GEN(i915) >= 12) {
		rmw_clear(uncore, GEN12_RING_FAULT_REG, RING_FAULT_VALID);
		intel_uncore_posting_read(uncore, GEN12_RING_FAULT_REG);
	} else if (INTEL_GEN(i915) >= 8) {
		rmw_clear(uncore, GEN8_RING_FAULT_REG, RING_FAULT_VALID);
		intel_uncore_posting_read(uncore, GEN8_RING_FAULT_REG);
	} else if (INTEL_GEN(i915) >= 6) {
		struct intel_engine_cs *engine;
		enum intel_engine_id id;

		for_each_engine_masked(engine, gt, engine_mask, id)
			gen8_clear_engine_error_register(engine);
	}
}

static void gen6_check_faults(struct intel_gt *gt)
{
	struct intel_engine_cs *engine;
	enum intel_engine_id id;
	u32 fault;

	for_each_engine(engine, gt, id) {
		fault = GEN6_RING_FAULT_REG_READ(engine);
		if (fault & RING_FAULT_VALID) {
			DRM_DEBUG_DRIVER("Unexpected fault\n"
					 "\tAddr: 0x%08"PRIx32"\n"
					 "\tAddress space: %s\n"
					 "\tSource ID: %d\n"
					 "\tType: %d\n",
					 fault & PAGE_MASK,
					 fault & RING_FAULT_GTTSEL_MASK ?
					 "GGTT" : "PPGTT",
					 RING_FAULT_SRCID(fault),
					 RING_FAULT_FAULT_TYPE(fault));
		}
	}
}

static void gen8_check_faults(struct intel_gt *gt)
{
	struct intel_uncore *uncore = gt->uncore;
	i915_reg_t fault_reg, fault_data0_reg, fault_data1_reg;
	u32 fault;

	if (INTEL_GEN(gt->i915) >= 12) {
		fault_reg = GEN12_RING_FAULT_REG;
		fault_data0_reg = GEN12_FAULT_TLB_DATA0;
		fault_data1_reg = GEN12_FAULT_TLB_DATA1;
	} else {
		fault_reg = GEN8_RING_FAULT_REG;
		fault_data0_reg = GEN8_FAULT_TLB_DATA0;
		fault_data1_reg = GEN8_FAULT_TLB_DATA1;
	}

	fault = intel_uncore_read(uncore, fault_reg);
	if (fault & RING_FAULT_VALID) {
		u32 fault_data0, fault_data1;
		u64 fault_addr;

		fault_data0 = intel_uncore_read(uncore, fault_data0_reg);
		fault_data1 = intel_uncore_read(uncore, fault_data1_reg);

		fault_addr = ((u64)(fault_data1 & FAULT_VA_HIGH_BITS) << 44) |
			     ((u64)fault_data0 << 12);

		DRM_DEBUG_DRIVER("Unexpected fault\n"
				 "\tAddr: 0x%08x_%08x\n"
				 "\tAddress space: %s\n"
				 "\tEngine ID: %d\n"
				 "\tSource ID: %d\n"
				 "\tType: %d\n",
				 upper_32_bits(fault_addr),
				 lower_32_bits(fault_addr),
				 fault_data1 & FAULT_GTT_SEL ? "GGTT" : "PPGTT",
				 GEN8_RING_FAULT_ENGINE_ID(fault),
				 RING_FAULT_SRCID(fault),
				 RING_FAULT_FAULT_TYPE(fault));
	}
}

void intel_gt_check_and_clear_faults(struct intel_gt *gt)
{
	struct drm_i915_private *i915 = gt->i915;

	/* From GEN8 onwards we only have one 'All Engine Fault Register' */
	if (INTEL_GEN(i915) >= 8)
		gen8_check_faults(gt);
	else if (INTEL_GEN(i915) >= 6)
		gen6_check_faults(gt);
	else
		return;

	intel_gt_clear_error_registers(gt, ALL_ENGINES);
}

void intel_gt_flush_ggtt_writes(struct intel_gt *gt)
{
	struct intel_uncore *uncore = gt->uncore;
	intel_wakeref_t wakeref;

	/*
	 * No actual flushing is required for the GTT write domain for reads
	 * from the GTT domain. Writes to it "immediately" go to main memory
	 * as far as we know, so there's no chipset flush. It also doesn't
	 * land in the GPU render cache.
	 *
	 * However, we do have to enforce the order so that all writes through
	 * the GTT land before any writes to the device, such as updates to
	 * the GATT itself.
	 *
	 * We also have to wait a bit for the writes to land from the GTT.
	 * An uncached read (i.e. mmio) seems to be ideal for the round-trip
	 * timing. This issue has only been observed when switching quickly
	 * between GTT writes and CPU reads from inside the kernel on recent hw,
	 * and it appears to only affect discrete GTT blocks (i.e. on LLC
	 * system agents we cannot reproduce this behaviour, until Cannonlake
	 * that was!).
	 */

	wmb();

	if (INTEL_INFO(gt->i915)->has_coherent_ggtt)
		return;

	intel_gt_chipset_flush(gt);

	with_intel_runtime_pm_if_in_use(uncore->rpm, wakeref) {
		unsigned long flags;

		spin_lock_irqsave(&uncore->lock, flags);
		intel_uncore_posting_read_fw(uncore,
					     RING_HEAD(RENDER_RING_BASE));
		spin_unlock_irqrestore(&uncore->lock, flags);
	}
}

void intel_gt_chipset_flush(struct intel_gt *gt)
{
	wmb();
	if (INTEL_GEN(gt->i915) < 6)
		intel_gtt_chipset_flush();
}

void intel_gt_driver_register(struct intel_gt *gt)
{
	intel_rps_driver_register(&gt->rps);

#if IS_ENABLED(CONFIG_DEBUGFS)
	debugfs_gt_register(gt);
#endif
}

static int intel_gt_init_scratch(struct intel_gt *gt, unsigned int size)
{
	struct drm_i915_private *i915 = gt->i915;
	struct drm_i915_gem_object *obj;
	struct i915_vma *vma;
	int ret;

	obj = i915_gem_object_create_stolen(i915, size);
	if (IS_ERR(obj))
		obj = i915_gem_object_create_internal(i915, size);
	if (IS_ERR(obj)) {
		DRM_ERROR("Failed to allocate scratch page\n");
		return PTR_ERR(obj);
	}

	vma = i915_vma_instance(obj, &gt->ggtt->vm, NULL);
	if (IS_ERR(vma)) {
		ret = PTR_ERR(vma);
		goto err_unref;
	}

	ret = i915_vma_pin(vma, 0, 0, PIN_GLOBAL | PIN_HIGH);
	if (ret)
		goto err_unref;

	gt->scratch = i915_vma_make_unshrinkable(vma);

	return 0;

err_unref:
	i915_gem_object_put(obj);
	return ret;
}

static void intel_gt_fini_scratch(struct intel_gt *gt)
{
	i915_vma_unpin_and_release(&gt->scratch, 0);
}

static struct i915_address_space *kernel_vm(struct intel_gt *gt)
{
	if (INTEL_PPGTT(gt->i915) > INTEL_PPGTT_ALIASING)
		return &i915_ppgtt_create(gt)->vm;
	else
		return i915_vm_get(&gt->ggtt->vm);
}

static int __intel_context_flush_retire(struct intel_context *ce)
{
	struct intel_timeline *tl;

	tl = intel_context_timeline_lock(ce);
	if (IS_ERR(tl))
		return PTR_ERR(tl);

	intel_context_timeline_unlock(tl);
	return 0;
}

static int __engines_record_defaults(struct intel_gt *gt)
{
	struct i915_request *requests[I915_NUM_ENGINES] = {};
	struct intel_engine_cs *engine;
	enum intel_engine_id id;
	int err = 0;

	/*
	 * As we reset the gpu during very early sanitisation, the current
	 * register state on the GPU should reflect its defaults values.
	 * We load a context onto the hw (with restore-inhibit), then switch
	 * over to a second context to save that default register state. We
	 * can then prime every new context with that state so they all start
	 * from the same default HW values.
	 */

	for_each_engine(engine, gt, id) {
		struct intel_renderstate so;
		struct intel_context *ce;
		struct i915_request *rq;

		/* We must be able to switch to something! */
		GEM_BUG_ON(!engine->kernel_context);

		err = intel_renderstate_init(&so, engine);
		if (err)
			goto out;

		ce = intel_context_create(engine);
		if (IS_ERR(ce)) {
			err = PTR_ERR(ce);
			goto out;
		}

		rq = intel_context_create_request(ce);
		if (IS_ERR(rq)) {
			err = PTR_ERR(rq);
			intel_context_put(ce);
			goto out;
		}

		err = intel_engine_emit_ctx_wa(rq);
		if (err)
			goto err_rq;

		err = intel_renderstate_emit(&so, rq);
		if (err)
			goto err_rq;

err_rq:
		requests[id] = i915_request_get(rq);
		i915_request_add(rq);
		intel_renderstate_fini(&so);
		if (err)
			goto out;
	}

	/* Flush the default context image to memory, and enable powersaving. */
	if (intel_gt_wait_for_idle(gt, I915_GEM_IDLE_TIMEOUT) == -ETIME) {
		err = -EIO;
		goto out;
	}

	for (id = 0; id < ARRAY_SIZE(requests); id++) {
		struct i915_request *rq;
		struct i915_vma *state;
		void *vaddr;

		rq = requests[id];
		if (!rq)
			continue;

		GEM_BUG_ON(!test_bit(CONTEXT_ALLOC_BIT, &rq->context->flags));
		state = rq->context->state;
		if (!state)
			continue;

		/* Serialise with retirement on another CPU */
		GEM_BUG_ON(!i915_request_completed(rq));
		err = __intel_context_flush_retire(rq->context);
		if (err)
			goto out;

		/* We want to be able to unbind the state from the GGTT */
		GEM_BUG_ON(intel_context_is_pinned(rq->context));

		/*
		 * As we will hold a reference to the logical state, it will
		 * not be torn down with the context, and importantly the
		 * object will hold onto its vma (making it possible for a
		 * stray GTT write to corrupt our defaults). Unmap the vma
		 * from the GTT to prevent such accidents and reclaim the
		 * space.
		 */
		err = i915_vma_unbind(state);
		if (err)
			goto out;

		i915_gem_object_lock(state->obj);
		err = i915_gem_object_set_to_cpu_domain(state->obj, false);
		i915_gem_object_unlock(state->obj);
		if (err)
			goto out;

		i915_gem_object_set_cache_coherency(state->obj, I915_CACHE_LLC);

		/* Check we can acquire the image of the context state */
		vaddr = i915_gem_object_pin_map(state->obj, I915_MAP_FORCE_WB);
		if (IS_ERR(vaddr)) {
			err = PTR_ERR(vaddr);
			goto out;
		}

		rq->engine->default_state = i915_gem_object_get(state->obj);
		i915_gem_object_unpin_map(state->obj);
	}

out:
	/*
	 * If we have to abandon now, we expect the engines to be idle
	 * and ready to be torn-down. The quickest way we can accomplish
	 * this is by declaring ourselves wedged.
	 */
	if (err)
		intel_gt_set_wedged(gt);

	for (id = 0; id < ARRAY_SIZE(requests); id++) {
		struct intel_context *ce;
		struct i915_request *rq;

		rq = requests[id];
		if (!rq)
			continue;

		ce = rq->context;
		i915_request_put(rq);
		intel_context_put(ce);
	}
	return err;
}

static int __engines_verify_workarounds(struct intel_gt *gt)
{
	struct intel_engine_cs *engine;
	enum intel_engine_id id;
	int err = 0;

	if (!IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
		return 0;

	for_each_engine(engine, gt, id) {
		if (intel_engine_verify_workarounds(engine, "load"))
			err = -EIO;
	}

	return err;
}

static void __intel_gt_disable(struct intel_gt *gt)
{
	intel_gt_set_wedged_on_init(gt);

	intel_gt_suspend_prepare(gt);
	intel_gt_suspend_late(gt);

	GEM_BUG_ON(intel_gt_pm_is_awake(gt));
}

int intel_gt_init(struct intel_gt *gt)
{
	int err;

	err = i915_inject_probe_error(gt->i915, -ENODEV);
	if (err)
		return err;

	/*
	 * This is just a security blanket to placate dragons.
	 * On some systems, we very sporadically observe that the first TLBs
	 * used by the CS may be stale, despite us poking the TLB reset. If
	 * we hold the forcewake during initialisation these problems
	 * just magically go away.
	 */
	intel_uncore_forcewake_get(gt->uncore, FORCEWAKE_ALL);

	err = intel_gt_init_scratch(gt, IS_GEN(gt->i915, 2) ? SZ_256K : SZ_4K);
	if (err)
		goto out_fw;

	intel_gt_pm_init(gt);

	gt->vm = kernel_vm(gt);
	if (!gt->vm) {
		err = -ENOMEM;
		goto err_pm;
	}

	err = intel_engines_init(gt);
	if (err)
		goto err_engines;

	intel_uc_init(&gt->uc);

	err = intel_gt_resume(gt);
	if (err)
		goto err_uc_init;

	err = __engines_record_defaults(gt);
	if (err)
		goto err_gt;

	err = __engines_verify_workarounds(gt);
	if (err)
		goto err_gt;

	err = i915_inject_probe_error(gt->i915, -EIO);
	if (err)
		goto err_gt;

	goto out_fw;
err_gt:
	__intel_gt_disable(gt);
	intel_uc_fini_hw(&gt->uc);
err_uc_init:
	intel_uc_fini(&gt->uc);
err_engines:
	intel_engines_release(gt);
	i915_vm_put(fetch_and_zero(&gt->vm));
err_pm:
	intel_gt_pm_fini(gt);
	intel_gt_fini_scratch(gt);
out_fw:
	if (err)
		intel_gt_set_wedged_on_init(gt);
	intel_uncore_forcewake_put(gt->uncore, FORCEWAKE_ALL);
	return err;
}

void intel_gt_driver_remove(struct intel_gt *gt)
{
	__intel_gt_disable(gt);

	intel_uc_fini_hw(&gt->uc);
	intel_uc_fini(&gt->uc);

	intel_engines_release(gt);
}

void intel_gt_driver_unregister(struct intel_gt *gt)
{
	intel_rps_driver_unregister(&gt->rps);
}

void intel_gt_driver_release(struct intel_gt *gt)
{
	struct i915_address_space *vm;

	vm = fetch_and_zero(&gt->vm);
	if (vm) /* FIXME being called twice on error paths :( */
		i915_vm_put(vm);

	intel_gt_pm_fini(gt);
	intel_gt_fini_scratch(gt);
}

void intel_gt_driver_late_release(struct intel_gt *gt)
{
	intel_uc_driver_late_release(&gt->uc);
	intel_gt_fini_requests(gt);
	intel_gt_fini_reset(gt);
	intel_gt_fini_timelines(gt);
	intel_engines_free(gt);
}