// SPDX-License-Identifier: GPL-2.0
/*
**  linux/amiga/chipram.c
**
**      Modified 03-May-94 by Geert Uytterhoeven <geert@linux-m68k.org>
**          - 64-bit aligned allocations for full AGA compatibility
**
**      Rewritten 15/9/2000 by Geert to use resource management
*/

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/module.h>

#include <asm/atomic.h>
#include <asm/page.h>
#include <asm/amigahw.h>

unsigned long amiga_chip_size;
EXPORT_SYMBOL(amiga_chip_size);

static struct resource chipram_res = {
        .name = "Chip RAM", .start = CHIP_PHYSADDR
};
static atomic_t chipavail;


void __init amiga_chip_init(void)
{
        if (!AMIGAHW_PRESENT(CHIP_RAM))
                return;

        chipram_res.end = CHIP_PHYSADDR + amiga_chip_size - 1;
        request_resource(&iomem_resource, &chipram_res);

        atomic_set(&chipavail, amiga_chip_size);
}


void *amiga_chip_alloc(unsigned long size, const char *name)
{
        struct resource *res;
        void *p;

        res = kzalloc_obj(struct resource);
        if (!res)
                return NULL;

        res->name = name;
        p = amiga_chip_alloc_res(size, res);
        if (!p) {
                kfree(res);
                return NULL;
        }

        return p;
}
EXPORT_SYMBOL(amiga_chip_alloc);


        /*
         *  Warning:
         *  amiga_chip_alloc_res is meant only for drivers that need to
         *  allocate Chip RAM before kmalloc() is functional. As a consequence,
         *  those drivers must not free that Chip RAM afterwards.
         */

void *amiga_chip_alloc_res(unsigned long size, struct resource *res)
{
        int error;

        /* round up */
        size = PAGE_ALIGN(size);

        pr_debug("amiga_chip_alloc_res: allocate %lu bytes\n", size);
        error = allocate_resource(&chipram_res, res, size, 0, UINT_MAX,
                                  PAGE_SIZE, NULL, NULL);
        if (error < 0) {
                pr_err("amiga_chip_alloc_res: allocate_resource() failed %d!\n",
                       error);
                return NULL;
        }

        atomic_sub(size, &chipavail);
        pr_debug("amiga_chip_alloc_res: returning %pR\n", res);
        return ZTWO_VADDR(res->start);
}

void amiga_chip_free(void *ptr)
{
        unsigned long start = ZTWO_PADDR(ptr);
        struct resource *res;
        unsigned long size;

        res = lookup_resource(&chipram_res, start);
        if (!res) {
                pr_err("amiga_chip_free: trying to free nonexistent region at "
                       "%p\n", ptr);
                return;
        }

        size = resource_size(res);
        pr_debug("amiga_chip_free: free %lu bytes at %p\n", size, ptr);
        atomic_add(size, &chipavail);
        release_resource(res);
        kfree(res);
}
EXPORT_SYMBOL(amiga_chip_free);


unsigned long amiga_chip_avail(void)
{
        unsigned long n = atomic_read(&chipavail);

        pr_debug("amiga_chip_avail : %lu bytes\n", n);
        return n;
}
EXPORT_SYMBOL(amiga_chip_avail);