// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
 * Copyright 2014-2022 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */
#include "kfd_priv.h"
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/idr.h>

/*
 * This extension supports a kernel level doorbells management for the
 * kernel queues using the first doorbell page reserved for the kernel.
 */

/*
 * Each device exposes a doorbell aperture, a PCI MMIO aperture that
 * receives 32-bit writes that are passed to queues as wptr values.
 * The doorbells are intended to be written by applications as part
 * of queueing work on user-mode queues.
 * We assign doorbells to applications in PAGE_SIZE-sized and aligned chunks.
 * We map the doorbell address space into user-mode when a process creates
 * its first queue on each device.
 * Although the mapping is done by KFD, it is equivalent to an mmap of
 * the /dev/kfd with the particular device encoded in the mmap offset.
 * There will be other uses for mmap of /dev/kfd, so only a range of
 * offsets (KFD_MMAP_DOORBELL_START-END) is used for doorbells.
 */

/* # of doorbell bytes allocated for each process. */
size_t kfd_doorbell_process_slice(struct kfd_dev *kfd)
{
        if (!kfd->shared_resources.enable_mes)
                return roundup(kfd->device_info.doorbell_size *
                                KFD_MAX_NUM_OF_QUEUES_PER_PROCESS,
                                PAGE_SIZE);
        else
                return amdgpu_mes_doorbell_process_slice(
                                        (struct amdgpu_device *)kfd->adev);
}

/* Doorbell calculations for device init. */
int kfd_doorbell_init(struct kfd_dev *kfd)
{
        int size = PAGE_SIZE;
        int r;

        /*
         * Todo: KFD kernel level operations need only one doorbell for
         * ring test/HWS. So instead of reserving a whole page here for
         * kernel, reserve and consume a doorbell from existing KGD kernel
         * doorbell page.
         */

        /* Bitmap to dynamically allocate doorbells from kernel page */
        kfd->doorbell_bitmap = bitmap_zalloc(size / sizeof(u32), GFP_KERNEL);
        if (!kfd->doorbell_bitmap) {
                DRM_ERROR("Failed to allocate kernel doorbell bitmap\n");
                return -ENOMEM;
        }

        /* Alloc a doorbell page for KFD kernel usages */
        r = amdgpu_bo_create_kernel(kfd->adev,
                                    size,
                                    PAGE_SIZE,
                                    AMDGPU_GEM_DOMAIN_DOORBELL,
                                    &kfd->doorbells,
                                    NULL,
                                    (void **)&kfd->doorbell_kernel_ptr);
        if (r) {
                pr_err("failed to allocate kernel doorbells\n");
                bitmap_free(kfd->doorbell_bitmap);
                return r;
        }

        pr_debug("Doorbell kernel address == %p\n", kfd->doorbell_kernel_ptr);
        return 0;
}

void kfd_doorbell_fini(struct kfd_dev *kfd)
{
        bitmap_free(kfd->doorbell_bitmap);
        amdgpu_bo_free_kernel(&kfd->doorbells, NULL,
                             (void **)&kfd->doorbell_kernel_ptr);
}

int kfd_doorbell_mmap(struct kfd_node *dev, struct kfd_process *process,
                      struct vm_area_struct *vma)
{
        phys_addr_t address;
        struct kfd_process_device *pdd;

        /*
         * For simplicitly we only allow mapping of the entire doorbell
         * allocation of a single device & process.
         */
        if (vma->vm_end - vma->vm_start != kfd_doorbell_process_slice(dev->kfd))
                return -EINVAL;

        pdd = kfd_get_process_device_data(dev, process);
        if (!pdd)
                return -EINVAL;

        /* Calculate physical address of doorbell */
        address = kfd_get_process_doorbells(pdd);
        if (!address)
                return -ENOMEM;
        vm_flags_set(vma, VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_NORESERVE |
                                VM_DONTDUMP | VM_PFNMAP);

        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

        pr_debug("Mapping doorbell page\n"
                 "     target user address == 0x%08llX\n"
                 "     physical address    == 0x%08llX\n"
                 "     vm_flags            == 0x%04lX\n"
                 "     size                == 0x%04lX\n",
                 (unsigned long long) vma->vm_start, address, vma->vm_flags,
                 kfd_doorbell_process_slice(dev->kfd));


        return io_remap_pfn_range(vma,
                                vma->vm_start,
                                address >> PAGE_SHIFT,
                                kfd_doorbell_process_slice(dev->kfd),
                                vma->vm_page_prot);
}


/* get kernel iomem pointer for a doorbell */
void __iomem *kfd_get_kernel_doorbell(struct kfd_dev *kfd,
                                        unsigned int *doorbell_off)
{
        u32 inx;

        mutex_lock(&kfd->doorbell_mutex);
        inx = find_first_zero_bit(kfd->doorbell_bitmap, PAGE_SIZE / sizeof(u32));

        __set_bit(inx, kfd->doorbell_bitmap);
        mutex_unlock(&kfd->doorbell_mutex);

        if (inx >= KFD_MAX_NUM_OF_QUEUES_PER_PROCESS)
                return NULL;

        *doorbell_off = amdgpu_doorbell_index_on_bar(kfd->adev,
                                                     kfd->doorbells,
                                                     inx,
                                                     kfd->device_info.doorbell_size);
        inx *= 2;

        pr_debug("Get kernel queue doorbell\n"
                        "     doorbell offset   == 0x%08X\n"
                        "     doorbell index    == 0x%x\n",
                *doorbell_off, inx);

        return kfd->doorbell_kernel_ptr + inx;
}

void kfd_release_kernel_doorbell(struct kfd_dev *kfd, u32 __iomem *db_addr)
{
        unsigned int inx;

        inx = (unsigned int)(db_addr - kfd->doorbell_kernel_ptr);
        inx /= 2;

        mutex_lock(&kfd->doorbell_mutex);
        __clear_bit(inx, kfd->doorbell_bitmap);
        mutex_unlock(&kfd->doorbell_mutex);
}

void write_kernel_doorbell(void __iomem *db, u32 value)
{
        if (db) {
                writel(value, db);
                pr_debug("Writing %d to doorbell address %p\n", value, db);
        }
}

void write_kernel_doorbell64(void __iomem *db, u64 value)
{
        if (db) {
                WARN(((unsigned long)db & 7) != 0,
                     "Unaligned 64-bit doorbell");
                writeq(value, (u64 __iomem *)db);
                pr_debug("writing %llu to doorbell address %p\n", value, db);
        }
}

static int init_doorbell_bitmap(struct qcm_process_device *qpd,
                                struct kfd_dev *dev)
{
        unsigned int i;
        int range_start = dev->shared_resources.non_cp_doorbells_start;
        int range_end = dev->shared_resources.non_cp_doorbells_end;

        if (!KFD_IS_SOC15(dev))
                return 0;

        /* Mask out doorbells reserved for SDMA, IH, and VCN on SOC15. */
        pr_debug("reserved doorbell 0x%03x - 0x%03x\n", range_start, range_end);
        pr_debug("reserved doorbell 0x%03x - 0x%03x\n",
                        range_start + KFD_QUEUE_DOORBELL_MIRROR_OFFSET,
                        range_end + KFD_QUEUE_DOORBELL_MIRROR_OFFSET);

        for (i = 0; i < KFD_MAX_NUM_OF_QUEUES_PER_PROCESS / 2; i++) {
                if (i >= range_start && i <= range_end) {
                        __set_bit(i, qpd->doorbell_bitmap);
                        __set_bit(i + KFD_QUEUE_DOORBELL_MIRROR_OFFSET,
                                  qpd->doorbell_bitmap);
                }
        }

        return 0;
}

phys_addr_t kfd_get_process_doorbells(struct kfd_process_device *pdd)
{
        struct amdgpu_device *adev = pdd->dev->adev;
        uint32_t first_db_index;

        if (!pdd->qpd.proc_doorbells) {
                if (kfd_alloc_process_doorbells(pdd->dev->kfd, pdd))
                        /* phys_addr_t 0 is error */
                        return 0;
        }

        first_db_index = amdgpu_doorbell_index_on_bar(adev,
                                                      pdd->qpd.proc_doorbells,
                                                      0,
                                                      pdd->dev->kfd->device_info.doorbell_size);
        return adev->doorbell.base + first_db_index * sizeof(uint32_t);
}

int kfd_alloc_process_doorbells(struct kfd_dev *kfd, struct kfd_process_device *pdd)
{
        int r;
        struct qcm_process_device *qpd = &pdd->qpd;

        /* Allocate bitmap for dynamic doorbell allocation */
        qpd->doorbell_bitmap = bitmap_zalloc(KFD_MAX_NUM_OF_QUEUES_PER_PROCESS,
                                             GFP_KERNEL);
        if (!qpd->doorbell_bitmap) {
                DRM_ERROR("Failed to allocate process doorbell bitmap\n");
                return -ENOMEM;
        }

        r = init_doorbell_bitmap(&pdd->qpd, kfd);
        if (r) {
                DRM_ERROR("Failed to initialize process doorbells\n");
                r = -ENOMEM;
                goto err;
        }

        /* Allocate doorbells for this process */
        r = amdgpu_bo_create_kernel(kfd->adev,
                                    kfd_doorbell_process_slice(kfd),
                                    PAGE_SIZE,
                                    AMDGPU_GEM_DOMAIN_DOORBELL,
                                    &qpd->proc_doorbells,
                                    NULL,
                                    NULL);
        if (r) {
                DRM_ERROR("Failed to allocate process doorbells\n");
                goto err;
        }
        return 0;

err:
        bitmap_free(qpd->doorbell_bitmap);
        qpd->doorbell_bitmap = NULL;
        return r;
}

void kfd_free_process_doorbells(struct kfd_dev *kfd, struct kfd_process_device *pdd)
{
        struct qcm_process_device *qpd = &pdd->qpd;

        if (qpd->doorbell_bitmap) {
                bitmap_free(qpd->doorbell_bitmap);
                qpd->doorbell_bitmap = NULL;
        }

        amdgpu_bo_free_kernel(&qpd->proc_doorbells, NULL, NULL);
}