// SPDX-License-Identifier: GPL-2.0 or MIT
/* Copyright 2018 Marty E. Plummer <hanetzer@startmail.com> */
/* Copyright 2019 Linaro, Ltd, Rob Herring <robh@kernel.org> */
/* Copyright 2023 Collabora ltd. */

#include <linux/clk.h>
#include <linux/mm.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
#include <linux/reset.h>

#include <drm/drm_drv.h>
#include <drm/drm_managed.h>
#include <drm/drm_print.h>

#include "panthor_devfreq.h"
#include "panthor_device.h"
#include "panthor_fw.h"
#include "panthor_gem.h"
#include "panthor_gpu.h"
#include "panthor_hw.h"
#include "panthor_mmu.h"
#include "panthor_pwr.h"
#include "panthor_regs.h"
#include "panthor_sched.h"

static int panthor_gpu_coherency_init(struct panthor_device *ptdev)
{
        BUILD_BUG_ON(GPU_COHERENCY_NONE != DRM_PANTHOR_GPU_COHERENCY_NONE);
        BUILD_BUG_ON(GPU_COHERENCY_ACE_LITE != DRM_PANTHOR_GPU_COHERENCY_ACE_LITE);
        BUILD_BUG_ON(GPU_COHERENCY_ACE != DRM_PANTHOR_GPU_COHERENCY_ACE);

        /* Start with no coherency, and update it if the device is flagged coherent. */
        ptdev->gpu_info.selected_coherency = GPU_COHERENCY_NONE;
        ptdev->coherent = device_get_dma_attr(ptdev->base.dev) == DEV_DMA_COHERENT;

        if (!ptdev->coherent)
                return 0;

        /* Check if the ACE-Lite coherency protocol is actually supported by the GPU.
         * ACE protocol has never been supported for command stream frontend GPUs.
         */
        if ((gpu_read(ptdev, GPU_COHERENCY_FEATURES) &
                      GPU_COHERENCY_PROT_BIT(ACE_LITE))) {
                ptdev->gpu_info.selected_coherency = GPU_COHERENCY_ACE_LITE;
                return 0;
        }

        drm_err(&ptdev->base, "Coherency not supported by the device");
        return -ENOTSUPP;
}

static int panthor_clk_init(struct panthor_device *ptdev)
{
        ptdev->clks.core = devm_clk_get(ptdev->base.dev, NULL);
        if (IS_ERR(ptdev->clks.core))
                return dev_err_probe(ptdev->base.dev,
                                     PTR_ERR(ptdev->clks.core),
                                     "get 'core' clock failed");

        ptdev->clks.stacks = devm_clk_get_optional(ptdev->base.dev, "stacks");
        if (IS_ERR(ptdev->clks.stacks))
                return dev_err_probe(ptdev->base.dev,
                                     PTR_ERR(ptdev->clks.stacks),
                                     "get 'stacks' clock failed");

        ptdev->clks.coregroup = devm_clk_get_optional(ptdev->base.dev, "coregroup");
        if (IS_ERR(ptdev->clks.coregroup))
                return dev_err_probe(ptdev->base.dev,
                                     PTR_ERR(ptdev->clks.coregroup),
                                     "get 'coregroup' clock failed");

        drm_info(&ptdev->base, "clock rate = %lu\n", clk_get_rate(ptdev->clks.core));
        return 0;
}

static int panthor_init_power(struct device *dev)
{
        struct dev_pm_domain_list  *pd_list = NULL;

        if (dev->pm_domain)
                return 0;

        return devm_pm_domain_attach_list(dev, NULL, &pd_list);
}

void panthor_device_unplug(struct panthor_device *ptdev)
{
        /* This function can be called from two different path: the reset work
         * and the platform device remove callback. drm_dev_unplug() doesn't
         * deal with concurrent callers, so we have to protect drm_dev_unplug()
         * calls with our own lock, and bail out if the device is already
         * unplugged.
         */
        mutex_lock(&ptdev->unplug.lock);
        if (drm_dev_is_unplugged(&ptdev->base)) {
                /* Someone beat us, release the lock and wait for the unplug
                 * operation to be reported as done.
                 **/
                mutex_unlock(&ptdev->unplug.lock);
                wait_for_completion(&ptdev->unplug.done);
                return;
        }

        drm_WARN_ON(&ptdev->base, pm_runtime_get_sync(ptdev->base.dev) < 0);

        /* Call drm_dev_unplug() so any access to HW blocks happening after
         * that point get rejected.
         */
        drm_dev_unplug(&ptdev->base);

        /* We do the rest of the unplug with the unplug lock released,
         * future callers will wait on ptdev->unplug.done anyway.
         */
        mutex_unlock(&ptdev->unplug.lock);

        /* Now, try to cleanly shutdown the GPU before the device resources
         * get reclaimed.
         */
        panthor_sched_unplug(ptdev);
        panthor_fw_unplug(ptdev);
        panthor_mmu_unplug(ptdev);
        panthor_gpu_unplug(ptdev);
        panthor_pwr_unplug(ptdev);

        pm_runtime_dont_use_autosuspend(ptdev->base.dev);
        pm_runtime_put_sync_suspend(ptdev->base.dev);

        /* If PM is disabled, we need to call the suspend handler manually. */
        if (!IS_ENABLED(CONFIG_PM))
                panthor_device_suspend(ptdev->base.dev);

        /* Report the unplug operation as done to unblock concurrent
         * panthor_device_unplug() callers.
         */
        complete_all(&ptdev->unplug.done);
}

static void panthor_device_reset_cleanup(struct drm_device *ddev, void *data)
{
        struct panthor_device *ptdev = container_of(ddev, struct panthor_device, base);

        disable_work_sync(&ptdev->reset.work);
        destroy_workqueue(ptdev->reset.wq);
}

static void panthor_device_reset_work(struct work_struct *work)
{
        struct panthor_device *ptdev = container_of(work, struct panthor_device, reset.work);
        int ret = 0, cookie;

        /* If the device is entering suspend, we don't reset. A slow reset will
         * be forced at resume time instead.
         */
        if (atomic_read(&ptdev->pm.state) != PANTHOR_DEVICE_PM_STATE_ACTIVE)
                return;

        if (!drm_dev_enter(&ptdev->base, &cookie))
                return;

        panthor_sched_pre_reset(ptdev);
        panthor_fw_pre_reset(ptdev, true);
        panthor_mmu_pre_reset(ptdev);
        panthor_hw_soft_reset(ptdev);
        panthor_hw_l2_power_on(ptdev);
        panthor_mmu_post_reset(ptdev);
        ret = panthor_fw_post_reset(ptdev);
        atomic_set(&ptdev->reset.pending, 0);
        panthor_sched_post_reset(ptdev, ret != 0);
        drm_dev_exit(cookie);

        if (ret) {
                panthor_device_unplug(ptdev);
                drm_err(&ptdev->base, "Failed to boot MCU after reset, making device unusable.");
        }
}

static bool panthor_device_is_initialized(struct panthor_device *ptdev)
{
        return !!ptdev->scheduler;
}

static void panthor_device_free_page(struct drm_device *ddev, void *data)
{
        __free_page(data);
}

int panthor_device_init(struct panthor_device *ptdev)
{
        u32 *dummy_page_virt;
        struct resource *res;
        struct page *p;
        int ret;

        ptdev->soc_data = of_device_get_match_data(ptdev->base.dev);

        init_completion(&ptdev->unplug.done);
        ret = drmm_mutex_init(&ptdev->base, &ptdev->unplug.lock);
        if (ret)
                return ret;

        ret = drmm_mutex_init(&ptdev->base, &ptdev->pm.mmio_lock);
        if (ret)
                return ret;

#ifdef CONFIG_DEBUG_FS
        drmm_mutex_init(&ptdev->base, &ptdev->gems.lock);
        INIT_LIST_HEAD(&ptdev->gems.node);
#endif

        atomic_set(&ptdev->pm.state, PANTHOR_DEVICE_PM_STATE_SUSPENDED);
        p = alloc_page(GFP_KERNEL | __GFP_ZERO);
        if (!p)
                return -ENOMEM;

        ptdev->pm.dummy_latest_flush = p;
        dummy_page_virt = page_address(p);
        ret = drmm_add_action_or_reset(&ptdev->base, panthor_device_free_page,
                                       ptdev->pm.dummy_latest_flush);
        if (ret)
                return ret;

        /*
         * Set the dummy page holding the latest flush to 1. This will cause the
         * flush to avoided as we know it isn't necessary if the submission
         * happens while the dummy page is mapped. Zero cannot be used because
         * that means 'always flush'.
         */
        *dummy_page_virt = 1;

        INIT_WORK(&ptdev->reset.work, panthor_device_reset_work);
        ptdev->reset.wq = alloc_ordered_workqueue("panthor-reset-wq", 0);
        if (!ptdev->reset.wq)
                return -ENOMEM;

        ret = drmm_add_action_or_reset(&ptdev->base, panthor_device_reset_cleanup, NULL);
        if (ret)
                return ret;

        ret = panthor_clk_init(ptdev);
        if (ret)
                return ret;

        ret = panthor_init_power(ptdev->base.dev);
        if (ret < 0) {
                drm_err(&ptdev->base, "init power domains failed, ret=%d", ret);
                return ret;
        }

        ret = panthor_devfreq_init(ptdev);
        if (ret)
                return ret;

        ptdev->iomem = devm_platform_get_and_ioremap_resource(to_platform_device(ptdev->base.dev),
                                                              0, &res);
        if (IS_ERR(ptdev->iomem))
                return PTR_ERR(ptdev->iomem);

        ptdev->phys_addr = res->start;

        ret = devm_pm_runtime_enable(ptdev->base.dev);
        if (ret)
                return ret;

        ret = pm_runtime_resume_and_get(ptdev->base.dev);
        if (ret)
                return ret;

        /* If PM is disabled, we need to call panthor_device_resume() manually. */
        if (!IS_ENABLED(CONFIG_PM)) {
                ret = panthor_device_resume(ptdev->base.dev);
                if (ret)
                        return ret;
        }

        ret = panthor_hw_init(ptdev);
        if (ret)
                goto err_rpm_put;

        ret = panthor_pwr_init(ptdev);
        if (ret)
                goto err_rpm_put;

        ret = panthor_gpu_init(ptdev);
        if (ret)
                goto err_unplug_pwr;

        ret = panthor_gpu_coherency_init(ptdev);
        if (ret)
                goto err_unplug_gpu;

        ret = panthor_mmu_init(ptdev);
        if (ret)
                goto err_unplug_gpu;

        ret = panthor_fw_init(ptdev);
        if (ret)
                goto err_unplug_mmu;

        ret = panthor_sched_init(ptdev);
        if (ret)
                goto err_unplug_fw;

        panthor_gem_init(ptdev);

        /* ~3 frames */
        pm_runtime_set_autosuspend_delay(ptdev->base.dev, 50);
        pm_runtime_use_autosuspend(ptdev->base.dev);

        ret = drm_dev_register(&ptdev->base, 0);
        if (ret)
                goto err_disable_autosuspend;

        pm_runtime_put_autosuspend(ptdev->base.dev);
        return 0;

err_disable_autosuspend:
        pm_runtime_dont_use_autosuspend(ptdev->base.dev);
        panthor_sched_unplug(ptdev);

err_unplug_fw:
        panthor_fw_unplug(ptdev);

err_unplug_mmu:
        panthor_mmu_unplug(ptdev);

err_unplug_gpu:
        panthor_gpu_unplug(ptdev);

err_unplug_pwr:
        panthor_pwr_unplug(ptdev);

err_rpm_put:
        pm_runtime_put_sync_suspend(ptdev->base.dev);
        return ret;
}

#define PANTHOR_EXCEPTION(id) \
        [DRM_PANTHOR_EXCEPTION_ ## id] = { \
                .name = #id, \
        }

struct panthor_exception_info {
        const char *name;
};

static const struct panthor_exception_info panthor_exception_infos[] = {
        PANTHOR_EXCEPTION(OK),
        PANTHOR_EXCEPTION(TERMINATED),
        PANTHOR_EXCEPTION(KABOOM),
        PANTHOR_EXCEPTION(EUREKA),
        PANTHOR_EXCEPTION(ACTIVE),
        PANTHOR_EXCEPTION(CS_RES_TERM),
        PANTHOR_EXCEPTION(CS_CONFIG_FAULT),
        PANTHOR_EXCEPTION(CS_UNRECOVERABLE),
        PANTHOR_EXCEPTION(CS_ENDPOINT_FAULT),
        PANTHOR_EXCEPTION(CS_BUS_FAULT),
        PANTHOR_EXCEPTION(CS_INSTR_INVALID),
        PANTHOR_EXCEPTION(CS_CALL_STACK_OVERFLOW),
        PANTHOR_EXCEPTION(CS_INHERIT_FAULT),
        PANTHOR_EXCEPTION(INSTR_INVALID_PC),
        PANTHOR_EXCEPTION(INSTR_INVALID_ENC),
        PANTHOR_EXCEPTION(INSTR_BARRIER_FAULT),
        PANTHOR_EXCEPTION(DATA_INVALID_FAULT),
        PANTHOR_EXCEPTION(TILE_RANGE_FAULT),
        PANTHOR_EXCEPTION(ADDR_RANGE_FAULT),
        PANTHOR_EXCEPTION(IMPRECISE_FAULT),
        PANTHOR_EXCEPTION(OOM),
        PANTHOR_EXCEPTION(CSF_FW_INTERNAL_ERROR),
        PANTHOR_EXCEPTION(CSF_RES_EVICTION_TIMEOUT),
        PANTHOR_EXCEPTION(GPU_BUS_FAULT),
        PANTHOR_EXCEPTION(GPU_SHAREABILITY_FAULT),
        PANTHOR_EXCEPTION(SYS_SHAREABILITY_FAULT),
        PANTHOR_EXCEPTION(GPU_CACHEABILITY_FAULT),
        PANTHOR_EXCEPTION(TRANSLATION_FAULT_0),
        PANTHOR_EXCEPTION(TRANSLATION_FAULT_1),
        PANTHOR_EXCEPTION(TRANSLATION_FAULT_2),
        PANTHOR_EXCEPTION(TRANSLATION_FAULT_3),
        PANTHOR_EXCEPTION(TRANSLATION_FAULT_4),
        PANTHOR_EXCEPTION(PERM_FAULT_0),
        PANTHOR_EXCEPTION(PERM_FAULT_1),
        PANTHOR_EXCEPTION(PERM_FAULT_2),
        PANTHOR_EXCEPTION(PERM_FAULT_3),
        PANTHOR_EXCEPTION(ACCESS_FLAG_1),
        PANTHOR_EXCEPTION(ACCESS_FLAG_2),
        PANTHOR_EXCEPTION(ACCESS_FLAG_3),
        PANTHOR_EXCEPTION(ADDR_SIZE_FAULT_IN),
        PANTHOR_EXCEPTION(ADDR_SIZE_FAULT_OUT0),
        PANTHOR_EXCEPTION(ADDR_SIZE_FAULT_OUT1),
        PANTHOR_EXCEPTION(ADDR_SIZE_FAULT_OUT2),
        PANTHOR_EXCEPTION(ADDR_SIZE_FAULT_OUT3),
        PANTHOR_EXCEPTION(MEM_ATTR_FAULT_0),
        PANTHOR_EXCEPTION(MEM_ATTR_FAULT_1),
        PANTHOR_EXCEPTION(MEM_ATTR_FAULT_2),
        PANTHOR_EXCEPTION(MEM_ATTR_FAULT_3),
};

const char *panthor_exception_name(struct panthor_device *ptdev, u32 exception_code)
{
        if (exception_code >= ARRAY_SIZE(panthor_exception_infos) ||
            !panthor_exception_infos[exception_code].name)
                return "Unknown exception type";

        return panthor_exception_infos[exception_code].name;
}

static vm_fault_t panthor_mmio_vm_fault(struct vm_fault *vmf)
{
        struct vm_area_struct *vma = vmf->vma;
        struct panthor_device *ptdev = vma->vm_private_data;
        u64 offset = (u64)vma->vm_pgoff << PAGE_SHIFT;
        unsigned long pfn;
        pgprot_t pgprot;
        vm_fault_t ret;
        bool active;
        int cookie;

        if (!drm_dev_enter(&ptdev->base, &cookie))
                return VM_FAULT_SIGBUS;

        mutex_lock(&ptdev->pm.mmio_lock);
        active = atomic_read(&ptdev->pm.state) == PANTHOR_DEVICE_PM_STATE_ACTIVE;

        switch (offset) {
        case DRM_PANTHOR_USER_FLUSH_ID_MMIO_OFFSET:
                if (active)
                        pfn = __phys_to_pfn(ptdev->phys_addr + CSF_GPU_LATEST_FLUSH_ID);
                else
                        pfn = page_to_pfn(ptdev->pm.dummy_latest_flush);
                break;

        default:
                ret = VM_FAULT_SIGBUS;
                goto out_unlock;
        }

        pgprot = vma->vm_page_prot;
        if (active)
                pgprot = pgprot_noncached(pgprot);

        ret = vmf_insert_pfn_prot(vma, vmf->address, pfn, pgprot);

out_unlock:
        mutex_unlock(&ptdev->pm.mmio_lock);
        drm_dev_exit(cookie);
        return ret;
}

static const struct vm_operations_struct panthor_mmio_vm_ops = {
        .fault = panthor_mmio_vm_fault,
};

int panthor_device_mmap_io(struct panthor_device *ptdev, struct vm_area_struct *vma)
{
        u64 offset = (u64)vma->vm_pgoff << PAGE_SHIFT;

        if ((vma->vm_flags & VM_SHARED) == 0)
                return -EINVAL;

        switch (offset) {
        case DRM_PANTHOR_USER_FLUSH_ID_MMIO_OFFSET:
                if (vma->vm_end - vma->vm_start != PAGE_SIZE ||
                    (vma->vm_flags & (VM_WRITE | VM_EXEC)))
                        return -EINVAL;
                vm_flags_clear(vma, VM_MAYWRITE);

                break;

        default:
                return -EINVAL;
        }

        /* Defer actual mapping to the fault handler. */
        vma->vm_private_data = ptdev;
        vma->vm_ops = &panthor_mmio_vm_ops;
        vm_flags_set(vma,
                     VM_IO | VM_DONTCOPY | VM_DONTEXPAND |
                     VM_NORESERVE | VM_DONTDUMP | VM_PFNMAP);
        return 0;
}

static int panthor_device_resume_hw_components(struct panthor_device *ptdev)
{
        int ret;

        panthor_pwr_resume(ptdev);
        panthor_gpu_resume(ptdev);
        panthor_mmu_resume(ptdev);

        ret = panthor_fw_resume(ptdev);
        if (!ret)
                return 0;

        panthor_mmu_suspend(ptdev);
        panthor_gpu_suspend(ptdev);
        panthor_pwr_suspend(ptdev);
        return ret;
}

int panthor_device_resume(struct device *dev)
{
        struct panthor_device *ptdev = dev_get_drvdata(dev);
        int ret, cookie;

        if (atomic_read(&ptdev->pm.state) != PANTHOR_DEVICE_PM_STATE_SUSPENDED)
                return -EINVAL;

        atomic_set(&ptdev->pm.state, PANTHOR_DEVICE_PM_STATE_RESUMING);

        ret = clk_prepare_enable(ptdev->clks.core);
        if (ret)
                goto err_set_suspended;

        ret = clk_prepare_enable(ptdev->clks.stacks);
        if (ret)
                goto err_disable_core_clk;

        ret = clk_prepare_enable(ptdev->clks.coregroup);
        if (ret)
                goto err_disable_stacks_clk;

        panthor_devfreq_resume(ptdev);

        if (panthor_device_is_initialized(ptdev) &&
            drm_dev_enter(&ptdev->base, &cookie)) {
                /* If there was a reset pending at the time we suspended the
                 * device, we force a slow reset.
                 */
                if (atomic_read(&ptdev->reset.pending)) {
                        ptdev->reset.fast = false;
                        atomic_set(&ptdev->reset.pending, 0);
                }

                ret = panthor_device_resume_hw_components(ptdev);
                if (ret && ptdev->reset.fast) {
                        drm_err(&ptdev->base, "Fast reset failed, trying a slow reset");
                        ptdev->reset.fast = false;
                        ret = panthor_device_resume_hw_components(ptdev);
                }

                if (!ret)
                        panthor_sched_resume(ptdev);

                drm_dev_exit(cookie);

                if (ret)
                        goto err_suspend_devfreq;
        }

        /* Clear all IOMEM mappings pointing to this device after we've
         * resumed. This way the fake mappings pointing to the dummy pages
         * are removed and the real iomem mapping will be restored on next
         * access.
         */
        mutex_lock(&ptdev->pm.mmio_lock);
        unmap_mapping_range(ptdev->base.anon_inode->i_mapping,
                            DRM_PANTHOR_USER_MMIO_OFFSET, 0, 1);
        atomic_set(&ptdev->pm.state, PANTHOR_DEVICE_PM_STATE_ACTIVE);
        mutex_unlock(&ptdev->pm.mmio_lock);
        return 0;

err_suspend_devfreq:
        panthor_devfreq_suspend(ptdev);
        clk_disable_unprepare(ptdev->clks.coregroup);

err_disable_stacks_clk:
        clk_disable_unprepare(ptdev->clks.stacks);

err_disable_core_clk:
        clk_disable_unprepare(ptdev->clks.core);

err_set_suspended:
        atomic_set(&ptdev->pm.state, PANTHOR_DEVICE_PM_STATE_SUSPENDED);
        atomic_set(&ptdev->pm.recovery_needed, 1);
        return ret;
}

int panthor_device_suspend(struct device *dev)
{
        struct panthor_device *ptdev = dev_get_drvdata(dev);
        int cookie;

        if (atomic_read(&ptdev->pm.state) != PANTHOR_DEVICE_PM_STATE_ACTIVE)
                return -EINVAL;

        /* Clear all IOMEM mappings pointing to this device before we
         * shutdown the power-domain and clocks. Failing to do that results
         * in external aborts when the process accesses the iomem region.
         * We change the state and call unmap_mapping_range() with the
         * mmio_lock held to make sure the vm_fault handler won't set up
         * invalid mappings.
         */
        mutex_lock(&ptdev->pm.mmio_lock);
        atomic_set(&ptdev->pm.state, PANTHOR_DEVICE_PM_STATE_SUSPENDING);
        unmap_mapping_range(ptdev->base.anon_inode->i_mapping,
                            DRM_PANTHOR_USER_MMIO_OFFSET, 0, 1);
        mutex_unlock(&ptdev->pm.mmio_lock);

        if (panthor_device_is_initialized(ptdev) &&
            drm_dev_enter(&ptdev->base, &cookie)) {
                cancel_work_sync(&ptdev->reset.work);

                /* We prepare everything as if we were resetting the GPU.
                 * The end of the reset will happen in the resume path though.
                 */
                panthor_sched_suspend(ptdev);
                panthor_fw_suspend(ptdev);
                panthor_mmu_suspend(ptdev);
                panthor_gpu_suspend(ptdev);
                panthor_pwr_suspend(ptdev);
                drm_dev_exit(cookie);
        }

        panthor_devfreq_suspend(ptdev);

        clk_disable_unprepare(ptdev->clks.coregroup);
        clk_disable_unprepare(ptdev->clks.stacks);
        clk_disable_unprepare(ptdev->clks.core);
        atomic_set(&ptdev->pm.state, PANTHOR_DEVICE_PM_STATE_SUSPENDED);
        return 0;
}