// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2017 HiSilicon Limited, All Rights Reserved.
 * Author: Gabriele Paoloni <gabriele.paoloni@huawei.com>
 * Author: Zhichang Yuan <yuanzhichang@hisilicon.com>
 * Author: John Garry <john.garry@huawei.com>
 */

#define pr_fmt(fmt)     "LOGIC PIO: " fmt

#include <linux/of.h>
#include <linux/io.h>
#include <linux/logic_pio.h>
#include <linux/mm.h>
#include <linux/rculist.h>
#include <linux/sizes.h>
#include <linux/slab.h>

/* The unique hardware address list */
static LIST_HEAD(io_range_list);
static DEFINE_MUTEX(io_range_mutex);

/**
 * logic_pio_register_range - register logical PIO range for a host
 * @new_range: pointer to the IO range to be registered.
 *
 * Returns 0 on success, the error code in case of failure.
 * If the range already exists, -EEXIST will be returned, which should be
 * considered a success.
 *
 * Register a new IO range node in the IO range list.
 */
int logic_pio_register_range(struct logic_pio_hwaddr *new_range)
{
        struct logic_pio_hwaddr *range;
        resource_size_t start;
        resource_size_t end;
        resource_size_t mmio_end = 0;
        resource_size_t iio_sz = MMIO_UPPER_LIMIT;
        int ret = 0;

        if (!new_range || !new_range->fwnode || !new_range->size ||
            (new_range->flags == LOGIC_PIO_INDIRECT && !new_range->ops))
                return -EINVAL;

        start = new_range->hw_start;
        end = new_range->hw_start + new_range->size;

        mutex_lock(&io_range_mutex);
        list_for_each_entry(range, &io_range_list, list) {
                if (range->fwnode == new_range->fwnode) {
                        /* range already there */
                        ret = -EEXIST;
                        goto end_register;
                }
                if (range->flags == LOGIC_PIO_CPU_MMIO &&
                    new_range->flags == LOGIC_PIO_CPU_MMIO) {
                        /* for MMIO ranges we need to check for overlap */
                        if (start >= range->hw_start + range->size ||
                            end < range->hw_start) {
                                mmio_end = range->io_start + range->size;
                        } else {
                                ret = -EFAULT;
                                goto end_register;
                        }
                } else if (range->flags == LOGIC_PIO_INDIRECT &&
                           new_range->flags == LOGIC_PIO_INDIRECT) {
                        iio_sz += range->size;
                }
        }

        /* range not registered yet, check for available space */
        if (new_range->flags == LOGIC_PIO_CPU_MMIO) {
                if (mmio_end + new_range->size - 1 > MMIO_UPPER_LIMIT) {
                        /* if it's too big check if 64K space can be reserved */
                        if (mmio_end + SZ_64K - 1 > MMIO_UPPER_LIMIT) {
                                ret = -E2BIG;
                                goto end_register;
                        }
                        new_range->size = SZ_64K;
                        pr_warn("Requested IO range too big, new size set to 64K\n");
                }
                new_range->io_start = mmio_end;
        } else if (new_range->flags == LOGIC_PIO_INDIRECT) {
                if (iio_sz + new_range->size - 1 > IO_SPACE_LIMIT) {
                        ret = -E2BIG;
                        goto end_register;
                }
                new_range->io_start = iio_sz;
        } else {
                /* invalid flag */
                ret = -EINVAL;
                goto end_register;
        }

        list_add_tail_rcu(&new_range->list, &io_range_list);

end_register:
        mutex_unlock(&io_range_mutex);
        return ret;
}

/**
 * logic_pio_unregister_range - unregister a logical PIO range for a host
 * @range: pointer to the IO range which has been already registered.
 *
 * Unregister a previously-registered IO range node.
 */
void logic_pio_unregister_range(struct logic_pio_hwaddr *range)
{
        mutex_lock(&io_range_mutex);
        list_del_rcu(&range->list);
        mutex_unlock(&io_range_mutex);
        synchronize_rcu();
}

/**
 * find_io_range_by_fwnode - find logical PIO range for given FW node
 * @fwnode: FW node handle associated with logical PIO range
 *
 * Returns pointer to node on success, NULL otherwise.
 *
 * Traverse the io_range_list to find the registered node for @fwnode.
 */
struct logic_pio_hwaddr *find_io_range_by_fwnode(const struct fwnode_handle *fwnode)
{
        struct logic_pio_hwaddr *range, *found_range = NULL;

        rcu_read_lock();
        list_for_each_entry_rcu(range, &io_range_list, list) {
                if (range->fwnode == fwnode) {
                        found_range = range;
                        break;
                }
        }
        rcu_read_unlock();

        return found_range;
}

/* Return a registered range given an input PIO token */
static struct logic_pio_hwaddr *find_io_range(unsigned long pio)
{
        struct logic_pio_hwaddr *range, *found_range = NULL;

        rcu_read_lock();
        list_for_each_entry_rcu(range, &io_range_list, list) {
                if (in_range(pio, range->io_start, range->size)) {
                        found_range = range;
                        break;
                }
        }
        rcu_read_unlock();

        if (!found_range)
                pr_err("PIO entry token 0x%lx invalid\n", pio);

        return found_range;
}

/**
 * logic_pio_to_hwaddr - translate logical PIO to HW address
 * @pio: logical PIO value
 *
 * Returns HW address if valid, ~0 otherwise.
 *
 * Translate the input logical PIO to the corresponding hardware address.
 * The input PIO should be unique in the whole logical PIO space.
 */
resource_size_t logic_pio_to_hwaddr(unsigned long pio)
{
        struct logic_pio_hwaddr *range;

        range = find_io_range(pio);
        if (range)
                return range->hw_start + pio - range->io_start;

        return (resource_size_t)~0;
}

/**
 * logic_pio_trans_hwaddr - translate HW address to logical PIO
 * @fwnode: FW node reference for the host
 * @addr: Host-relative HW address
 * @size: size to translate
 *
 * Returns Logical PIO value if successful, ~0UL otherwise
 */
unsigned long logic_pio_trans_hwaddr(const struct fwnode_handle *fwnode,
                                     resource_size_t addr, resource_size_t size)
{
        struct logic_pio_hwaddr *range;

        range = find_io_range_by_fwnode(fwnode);
        if (!range || range->flags == LOGIC_PIO_CPU_MMIO) {
                pr_err("IO range not found or invalid\n");
                return ~0UL;
        }
        if (range->size < size) {
                pr_err("resource size %pa cannot fit in IO range size %pa\n",
                       &size, &range->size);
                return ~0UL;
        }
        return addr - range->hw_start + range->io_start;
}

unsigned long logic_pio_trans_cpuaddr(resource_size_t addr)
{
        struct logic_pio_hwaddr *range;

        rcu_read_lock();
        list_for_each_entry_rcu(range, &io_range_list, list) {
                if (range->flags != LOGIC_PIO_CPU_MMIO)
                        continue;
                if (in_range(addr, range->hw_start, range->size)) {
                        unsigned long cpuaddr;

                        cpuaddr = addr - range->hw_start + range->io_start;

                        rcu_read_unlock();
                        return cpuaddr;
                }
        }
        rcu_read_unlock();

        pr_err("addr %pa not registered in io_range_list\n", &addr);

        return ~0UL;
}

#if defined(CONFIG_INDIRECT_PIO) && defined(PCI_IOBASE)
#define BUILD_LOGIC_IO(bwl, type)                                       \
type logic_in##bwl(unsigned long addr)                                  \
{                                                                       \
        type ret = (type)~0;                                            \
                                                                        \
        if (addr < MMIO_UPPER_LIMIT) {                                  \
                ret = _in##bwl(addr);                                   \
        } else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) { \
                struct logic_pio_hwaddr *entry = find_io_range(addr);   \
                                                                        \
                if (entry)                                              \
                        ret = entry->ops->in(entry->hostdata,           \
                                        addr, sizeof(type));            \
                else                                                    \
                        WARN_ON_ONCE(1);                                \
        }                                                               \
        return ret;                                                     \
}                                                                       \
                                                                        \
void logic_out##bwl(type value, unsigned long addr)                     \
{                                                                       \
        if (addr < MMIO_UPPER_LIMIT) {                                  \
                _out##bwl(value, addr);                         \
        } else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) { \
                struct logic_pio_hwaddr *entry = find_io_range(addr);   \
                                                                        \
                if (entry)                                              \
                        entry->ops->out(entry->hostdata,                \
                                        addr, value, sizeof(type));     \
                else                                                    \
                        WARN_ON_ONCE(1);                                \
        }                                                               \
}                                                                       \
                                                                        \
void logic_ins##bwl(unsigned long addr, void *buffer,                   \
                    unsigned int count)                                 \
{                                                                       \
        if (addr < MMIO_UPPER_LIMIT) {                                  \
                reads##bwl(PCI_IOBASE + addr, buffer, count);           \
        } else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) { \
                struct logic_pio_hwaddr *entry = find_io_range(addr);   \
                                                                        \
                if (entry)                                              \
                        entry->ops->ins(entry->hostdata,                \
                                addr, buffer, sizeof(type), count);     \
                else                                                    \
                        WARN_ON_ONCE(1);                                \
        }                                                               \
                                                                        \
}                                                                       \
                                                                        \
void logic_outs##bwl(unsigned long addr, const void *buffer,            \
                     unsigned int count)                                \
{                                                                       \
        if (addr < MMIO_UPPER_LIMIT) {                                  \
                writes##bwl(PCI_IOBASE + addr, buffer, count);          \
        } else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) { \
                struct logic_pio_hwaddr *entry = find_io_range(addr);   \
                                                                        \
                if (entry)                                              \
                        entry->ops->outs(entry->hostdata,               \
                                addr, buffer, sizeof(type), count);     \
                else                                                    \
                        WARN_ON_ONCE(1);                                \
        }                                                               \
}

BUILD_LOGIC_IO(b, u8)
EXPORT_SYMBOL(logic_inb);
EXPORT_SYMBOL(logic_insb);
EXPORT_SYMBOL(logic_outb);
EXPORT_SYMBOL(logic_outsb);

BUILD_LOGIC_IO(w, u16)
EXPORT_SYMBOL(logic_inw);
EXPORT_SYMBOL(logic_insw);
EXPORT_SYMBOL(logic_outw);
EXPORT_SYMBOL(logic_outsw);

BUILD_LOGIC_IO(l, u32)
EXPORT_SYMBOL(logic_inl);
EXPORT_SYMBOL(logic_insl);
EXPORT_SYMBOL(logic_outl);
EXPORT_SYMBOL(logic_outsl);

#endif /* CONFIG_INDIRECT_PIO && PCI_IOBASE */