/* $NetBSD: fdt_memory.c,v 1.10 2024/01/14 07:53:38 mlelstv Exp $ */

/*-
* Copyright (c) 2018 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jared McNeill <[email protected]>.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include "opt_fdt.h"

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: fdt_memory.c,v 1.10 2024/01/14 07:53:38 mlelstv Exp $");

#include <sys/param.h>
#include <sys/queue.h>

#include <libfdt.h>
#include <dev/fdt/fdtvar.h>
#include <dev/fdt/fdt_memory.h>

struct fdt_memory_range {
       struct fdt_memory               mr_mem;
       bool                            mr_used;
       TAILQ_ENTRY(fdt_memory_range)   mr_list;
};

static TAILQ_HEAD(fdt_memory_rangehead, fdt_memory_range) fdt_memory_ranges =
   TAILQ_HEAD_INITIALIZER(fdt_memory_ranges);

static struct fdt_memory_range fdt_memory_range_pool[FDT_MEMORY_RANGES];

static struct fdt_memory_range *
fdt_memory_range_alloc(void)
{
       for (size_t n = 0; n < FDT_MEMORY_RANGES; n++)
               if (!fdt_memory_range_pool[n].mr_used) {
                       fdt_memory_range_pool[n].mr_used = true;
                       return &fdt_memory_range_pool[n];
               }

       printf("%s: no free memory ranges, increase FDT_MEMORY_RANGES!\n", __func__);
       return NULL;
}

static void
fdt_memory_range_free(struct fdt_memory_range *mr)
{
       mr->mr_used = false;
}

/*
* Get all of physical memory, including holes.
*/
void
fdt_memory_get(uint64_t *pstart, uint64_t *pend)
{
       const void *fdt_data = fdtbus_get_data();
       uint64_t cur_addr, cur_size;
       int index, nadd = 0, off, memory;

       off = fdt_node_offset_by_prop_value(fdt_data, -1,
           "device_type", "memory", sizeof("memory"));

       /*
        * Device Tree Specification 3.2 says that memory
        * nodes are named "memory" and have device_type
        * "memory", but if the device_type is missing, try
        * to find the (then single) node by name.
        */
       if (off == -FDT_ERR_NOTFOUND)
               off = fdt_path_offset(fdt_data, "/memory");

       while (off != -FDT_ERR_NOTFOUND) {
               memory = fdtbus_offset2phandle(off);
               for (index = 0;
                    fdtbus_get_reg64(memory, index, &cur_addr, &cur_size) == 0;
                    index++) {
                       if (cur_size == 0)
                               continue;
                       fdt_memory_add_range(cur_addr, cur_size);

                       if (nadd++ == 0) {
                               *pstart = cur_addr;
                               *pend = cur_addr + cur_size;
                               continue;
                       }
                       if (cur_addr < *pstart)
                               *pstart = cur_addr;
                       if (cur_addr + cur_size > *pend)
                               *pend = cur_addr + cur_size;
               }
               off = fdt_node_offset_by_prop_value(fdt_data, off,
                   "device_type", "memory", sizeof("memory"));
       }
       if (nadd == 0)
               panic("Cannot determine memory size");
}

/*
* Exclude memory ranges from memory config from the device tree
*/
void
fdt_memory_remove_reserved(uint64_t min_addr, uint64_t max_addr)
{
       uint64_t lstart = 0, lend = 0;
       int index, error, phandle, child;
       const void *fdt_data = fdtbus_get_data();
       const int num = fdt_num_mem_rsv(fdt_data);

       for (index = 0; index <= num; index++) {
               uint64_t addr, size;

               error = fdt_get_mem_rsv(fdt_data, index, &addr, &size);
               if (error != 0)
                       continue;

               if (lstart <= addr && addr <= lend) {
                       size -= (lend - addr);
                       addr = lend;
               }
               if (size == 0)
                       continue;
               if (addr + size <= min_addr)
                       continue;
               if (addr >= max_addr)
                       continue;
               if (addr < min_addr) {
                       size -= (min_addr - addr);
                       addr = min_addr;
               }
               if (addr + size > max_addr)
                       size = max_addr - addr;
               fdt_memory_remove_range(addr, size);
               lstart = addr;
               lend = addr + size;
       }

       /*
        * "no-map" ranges defined in the /reserved-memory node
        * must also be excluded.
        */
       phandle = OF_finddevice("/reserved-memory");
       if (phandle != -1) {
               for (child = OF_child(phandle); child; child = OF_peer(child)) {
                       bus_addr_t addr;
                       bus_size_t size;

                       if (fdtbus_get_reg(child, 0, &addr, &size) != 0)
                               continue;
                       if (size == 0)
                               continue;
                       fdt_memory_remove_range(addr, size);
               }
       }
}

void
fdt_memory_add_range(uint64_t start, uint64_t size)
{
       struct fdt_memory_range *mr, *prev, *cur, *tmp;
       bool inserted = false;

       mr = fdt_memory_range_alloc();
       if (mr == NULL)
               return;

       mr->mr_mem.start = start;
       mr->mr_mem.end = start + size;

       /*
        * Add the new range to the list of sorted ranges.
        */
       TAILQ_FOREACH(cur, &fdt_memory_ranges, mr_list)
               if (mr->mr_mem.start <= cur->mr_mem.start) {
                       TAILQ_INSERT_BEFORE(cur, mr, mr_list);
                       inserted = true;
                       break;
               }
       if (!inserted)
               TAILQ_INSERT_TAIL(&fdt_memory_ranges, mr, mr_list);

       /*
        * Remove overlaps.
        */
       TAILQ_FOREACH_SAFE(mr, &fdt_memory_ranges, mr_list, tmp) {
               prev = TAILQ_PREV(mr, fdt_memory_rangehead, mr_list);
               if (prev && prev->mr_mem.end > mr->mr_mem.start) {
                       mr->mr_mem.start = prev->mr_mem.end;
                       if (mr->mr_mem.start >= mr->mr_mem.end) {
                               TAILQ_REMOVE(&fdt_memory_ranges, mr, mr_list);
                               fdt_memory_range_free(mr);
                       }
               }
       }

       /*
        * Combine adjacent ranges.
        */
       TAILQ_FOREACH_SAFE(mr, &fdt_memory_ranges, mr_list, tmp) {
               prev = TAILQ_PREV(mr, fdt_memory_rangehead, mr_list);
               if (prev && prev->mr_mem.end == mr->mr_mem.start) {
                       prev->mr_mem.end = mr->mr_mem.end;
                       TAILQ_REMOVE(&fdt_memory_ranges, mr, mr_list);
                       fdt_memory_range_free(mr);
               }
       }
}

void
fdt_memory_remove_range(uint64_t start, uint64_t size)
{
       struct fdt_memory_range *mr, *next, *tmp;
       const uint64_t end = start + size;

       TAILQ_FOREACH_SAFE(mr, &fdt_memory_ranges, mr_list, tmp) {
               if (start <= mr->mr_mem.start && end >= mr->mr_mem.end) {
                       /*
                        * Removed range completely covers this range,
                        * just remove it.
                        */
                       TAILQ_REMOVE(&fdt_memory_ranges, mr, mr_list);
                       fdt_memory_range_free(mr);
               } else if (start > mr->mr_mem.start && end < mr->mr_mem.end) {
                       /*
                        * Removed range is completely contained by this range,
                        * split it.
                        */
                       next = fdt_memory_range_alloc();
                       if (next == NULL)
                               panic("fdt_memory_remove_range");
                       next->mr_mem.start = end;
                       next->mr_mem.end = mr->mr_mem.end;
                       mr->mr_mem.end = start;
                       TAILQ_INSERT_AFTER(&fdt_memory_ranges, mr, next, mr_list);
               } else if (start <= mr->mr_mem.start && end > mr->mr_mem.start && end < mr->mr_mem.end) {
                       /*
                        * Partial overlap at the beginning of the range.
                        */
                       mr->mr_mem.start = end;
               } else if (start > mr->mr_mem.start && start < mr->mr_mem.end && end >= mr->mr_mem.end) {
                       /*
                        * Partial overlap at the end of the range.
                        */
                       mr->mr_mem.end = start;
               }
               KASSERT(mr->mr_mem.start < mr->mr_mem.end);
       }
}

void
fdt_memory_foreach(void (*fn)(const struct fdt_memory *, void *), void *arg)
{
       struct fdt_memory_range *mr;

       TAILQ_FOREACH(mr, &fdt_memory_ranges, mr_list)
               fn(&mr->mr_mem, arg);
}

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