// SPDX-License-Identifier: GPL-2.0
#include <linux/export.h>
#include <linux/types.h>
#include <linux/io.h>
#include <linux/spinlock.h>

static DEFINE_RAW_SPINLOCK(__io_lock);

/*
 * Generic atomic MMIO modify.
 *
 * Allows thread-safe access to registers shared by unrelated subsystems.
 * The access is protected by a single MMIO-wide lock.
 */
void atomic_io_modify_relaxed(void __iomem *reg, u32 mask, u32 set)
{
        unsigned long flags;
        u32 value;

        raw_spin_lock_irqsave(&__io_lock, flags);
        value = readl_relaxed(reg) & ~mask;
        value |= (set & mask);
        writel_relaxed(value, reg);
        raw_spin_unlock_irqrestore(&__io_lock, flags);
}
EXPORT_SYMBOL(atomic_io_modify_relaxed);

void atomic_io_modify(void __iomem *reg, u32 mask, u32 set)
{
        unsigned long flags;
        u32 value;

        raw_spin_lock_irqsave(&__io_lock, flags);
        value = readl_relaxed(reg) & ~mask;
        value |= (set & mask);
        writel(value, reg);
        raw_spin_unlock_irqrestore(&__io_lock, flags);
}
EXPORT_SYMBOL(atomic_io_modify);

/*
 * Copy data from IO memory space to "real" memory space.
 * This needs to be optimized.
 */
void _memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
{
        unsigned char *t = to;
        while (count) {
                count--;
                *t = readb(from);
                t++;
                from++;
        }
}
EXPORT_SYMBOL(_memcpy_fromio);

/*
 * Copy data from "real" memory space to IO memory space.
 * This needs to be optimized.
 */
void _memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
{
        const unsigned char *f = from;
        while (count) {
                count--;
                writeb(*f, to);
                f++;
                to++;
        }
}
EXPORT_SYMBOL(_memcpy_toio);

/*
 * "memset" on IO memory space.
 * This needs to be optimized.
 */
void _memset_io(volatile void __iomem *dst, int c, size_t count)
{
        while (count) {
                count--;
                writeb(c, dst);
                dst++;
        }
}
EXPORT_SYMBOL(_memset_io);