/*
 * Copyright 2014 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)
{
        return roundup(kfd->device_info->doorbell_size *
                        KFD_MAX_NUM_OF_QUEUES_PER_PROCESS,
                        PAGE_SIZE);
}

/* Doorbell calculations for device init. */
int kfd_doorbell_init(struct kfd_dev *kfd)
{
        size_t doorbell_start_offset;
        size_t doorbell_aperture_size;
        size_t doorbell_process_limit;

        /*
         * We start with calculations in bytes because the input data might
         * only be byte-aligned.
         * Only after we have done the rounding can we assume any alignment.
         */

        doorbell_start_offset =
                        roundup(kfd->shared_resources.doorbell_start_offset,
                                        kfd_doorbell_process_slice(kfd));

        doorbell_aperture_size =
                        rounddown(kfd->shared_resources.doorbell_aperture_size,
                                        kfd_doorbell_process_slice(kfd));

        if (doorbell_aperture_size > doorbell_start_offset)
                doorbell_process_limit =
                        (doorbell_aperture_size - doorbell_start_offset) /
                                                kfd_doorbell_process_slice(kfd);
        else
                return -ENOSPC;

        if (!kfd->max_doorbell_slices ||
            doorbell_process_limit < kfd->max_doorbell_slices)
                kfd->max_doorbell_slices = doorbell_process_limit;

        kfd->doorbell_base = kfd->shared_resources.doorbell_physical_address +
                                doorbell_start_offset;

        kfd->doorbell_base_dw_offset = doorbell_start_offset / sizeof(u32);

        kfd->doorbell_kernel_ptr = ioremap(kfd->doorbell_base,
                                           kfd_doorbell_process_slice(kfd));

        if (!kfd->doorbell_kernel_ptr)
                return -ENOMEM;

        pr_debug("Doorbell initialization:\n");
        pr_debug("doorbell base           == 0x%08lX\n",
                        (uintptr_t)kfd->doorbell_base);

        pr_debug("doorbell_base_dw_offset      == 0x%08lX\n",
                        kfd->doorbell_base_dw_offset);

        pr_debug("doorbell_process_limit  == 0x%08lX\n",
                        doorbell_process_limit);

        pr_debug("doorbell_kernel_offset  == 0x%08lX\n",
                        (uintptr_t)kfd->doorbell_base);

        pr_debug("doorbell aperture size  == 0x%08lX\n",
                        kfd->shared_resources.doorbell_aperture_size);

        pr_debug("doorbell kernel address == %p\n", kfd->doorbell_kernel_ptr);

        return 0;
}

void kfd_doorbell_fini(struct kfd_dev *kfd)
{
        if (kfd->doorbell_kernel_ptr)
                iounmap(kfd->doorbell_kernel_ptr);
}

int kfd_doorbell_mmap(struct kfd_dev *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))
                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);
        vma->vm_flags |= 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));


        return io_remap_pfn_range(vma,
                                vma->vm_start,
                                address >> PAGE_SHIFT,
                                kfd_doorbell_process_slice(dev),
                                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_available_index,
                                        KFD_MAX_NUM_OF_QUEUES_PER_PROCESS);

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

        if (inx >= KFD_MAX_NUM_OF_QUEUES_PER_PROCESS)
                return NULL;

        inx *= kfd->device_info->doorbell_size / sizeof(u32);

        /*
         * Calculating the kernel doorbell offset using the first
         * doorbell page.
         */
        *doorbell_off = kfd->doorbell_base_dw_offset + inx;

        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)
                * sizeof(u32) / kfd->device_info->doorbell_size;

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

unsigned int kfd_get_doorbell_dw_offset_in_bar(struct kfd_dev *kfd,
                                        struct kfd_process_device *pdd,
                                        unsigned int doorbell_id)
{
        /*
         * doorbell_base_dw_offset accounts for doorbells taken by KGD.
         * index * kfd_doorbell_process_slice/sizeof(u32) adjusts to
         * the process's doorbells. The offset returned is in dword
         * units regardless of the ASIC-dependent doorbell size.
         */
        return kfd->doorbell_base_dw_offset +
                pdd->doorbell_index
                * kfd_doorbell_process_slice(kfd) / sizeof(u32) +
                doorbell_id * kfd->device_info->doorbell_size / sizeof(u32);
}

uint64_t kfd_get_number_elems(struct kfd_dev *kfd)
{
        uint64_t num_of_elems = (kfd->shared_resources.doorbell_aperture_size -
                                kfd->shared_resources.doorbell_start_offset) /
                                        kfd_doorbell_process_slice(kfd) + 1;

        return num_of_elems;

}

phys_addr_t kfd_get_process_doorbells(struct kfd_process_device *pdd)
{
        return pdd->dev->doorbell_base +
                pdd->doorbell_index * kfd_doorbell_process_slice(pdd->dev);
}

int kfd_alloc_process_doorbells(struct kfd_dev *kfd, unsigned int *doorbell_index)
{
        int r = ida_simple_get(&kfd->doorbell_ida, 1, kfd->max_doorbell_slices,
                                GFP_KERNEL);
        if (r > 0)
                *doorbell_index = r;

        return r;
}

void kfd_free_process_doorbells(struct kfd_dev *kfd, unsigned int doorbell_index)
{
        if (doorbell_index)
                ida_simple_remove(&kfd->doorbell_ida, doorbell_index);
}