esp-idf/components/heap/heap_caps.c

// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <stdbool.h>
#include <string.h>
#include <assert.h>
#include <stdio.h>
#include <sys/param.h>
#include "esp_attr.h"
#include "esp_heap_caps.h"
#include "multi_heap.h"
#include "esp_log.h"
#include "heap_private.h"

/*
This file, combined with a region allocator that supports multiple heaps, solves the problem that the ESP32 has RAM
that's slightly heterogeneous. Some RAM can be byte-accessed, some allows only 32-bit accesses, some can execute memory,
some can be remapped by the MMU to only be accessed by a certain PID etc. In order to allow the most flexible memory
allocation possible, this code makes it possible to request memory that has certain capabilities. The code will then use
its knowledge of how the memory is configured along with a priority scheme to allocate that memory in the most sane way
possible. This should optimize the amount of RAM accessible to the code without hardwiring addresses.
*/

/*
  This takes a memory chunk in a region that can be addressed as both DRAM as well as IRAM. It will convert it to
  IRAM in such a way that it can be later freed. It assumes both the address as wel as the length to be word-aligned.
  It returns a region that's 1 word smaller than the region given because it stores the original Dram address there.

  In theory, we can also make this work by prepending a struct that looks similar to the block link struct used by the
  heap allocator itself, which will allow inspection tools relying on any block returned from any sort of malloc to
  have such a block in front of it, work. We may do this later, if/when there is demand for it. For now, a simple
  pointer is used.
*/
IRAM_ATTR static void *dram_alloc_to_iram_addr(void *addr, size_t len)
{
    uint32_t dstart = (int)addr; //First word
    uint32_t dend = ((int)addr) + len - 4; //Last word
    assert(dstart >= SOC_DIRAM_DRAM_LOW);
    assert(dend <= SOC_DIRAM_DRAM_HIGH);
    assert((dstart & 3) == 0);
    assert((dend & 3) == 0);
    uint32_t istart = SOC_DIRAM_IRAM_LOW + (SOC_DIRAM_DRAM_HIGH - dend);
    uint32_t *iptr = (uint32_t *)istart;
    *iptr = dstart;
    return (void *)(iptr + 1);
}

/* return all possible capabilities (across all priorities) for a given heap */
inline static uint32_t get_all_caps(const heap_t *heap)
{
    if (heap->heap == NULL) {
        return 0;
    }
    uint32_t all_caps = 0;
    for (int prio = 0; prio < SOC_MEMORY_TYPE_NO_PRIOS; prio++) {
        all_caps |= heap->caps[prio];
    }
    return all_caps;
}

bool heap_caps_match(const heap_t *heap, uint32_t caps)
{
    return heap->heap != NULL && ((get_all_caps(heap) & caps) == caps);
}

/*
Routine to allocate a bit of memory with certain capabilities. caps is a bitfield of MALLOC_CAP_* bits.
*/
IRAM_ATTR void *heap_caps_malloc( size_t size, uint32_t caps )
{
    void *ret = NULL;
    uint32_t remCaps;

    if (caps & MALLOC_CAP_EXEC) {
        //MALLOC_CAP_EXEC forces an alloc from IRAM. There is a region which has both this as well as the following
        //caps, but the following caps are not possible for IRAM.  Thus, the combination is impossible and we return
        //NULL directly, even although our heap capabilities (based on soc_memory_tags & soc_memory_regions) would
        //indicate there is a tag for this.
        if ((caps & MALLOC_CAP_8BIT) || (caps & MALLOC_CAP_DMA)) {
            return NULL;
        }
        //If any, EXEC memory should be 32-bit aligned, so round up to the next multiple of 4.
        size = (size + 3) & (~3);
    }
    for (int prio = 0; prio < SOC_MEMORY_TYPE_NO_PRIOS; prio++) {
        //Iterate over heaps and check capabilities at this priority
        for (int heap_idx = 0; heap_idx < num_registered_heaps; heap_idx++) {
            heap_t *heap = &registered_heaps[heap_idx];
            if (heap->heap == NULL) {
                continue;
            }
            if ((heap->caps[prio] & caps) != 0) {
                //Heap has at least one of the caps requested. If caps has other bits set that this prio
                //doesn't cover, see if they're available in other prios.
                remCaps = caps & (~heap->caps[prio]); //Remaining caps to be fulfilled
                int j = prio + 1;
                while (remCaps != 0 && j < SOC_MEMORY_TYPE_NO_PRIOS) {
                    remCaps = remCaps & (~heap->caps[j]);
                    j++;
                }
                if (remCaps == 0) {
                    //This heap can satisfy all the requested capabilities. See if we can grab some memory using it.
                    if ((caps & MALLOC_CAP_EXEC) && heap->start >= SOC_DIRAM_DRAM_LOW && heap->start < SOC_DIRAM_DRAM_HIGH) {
                        //This is special, insofar that what we're going to get back is a DRAM address. If so,
                        //we need to 'invert' it (lowest address in DRAM == highest address in IRAM and vice-versa) and
                        //add a pointer to the DRAM equivalent before the address we're going to return.
                        ret = multi_heap_malloc(heap->heap, size + 4);
                        if (ret != NULL) {
                            return dram_alloc_to_iram_addr(ret, size + 4);
                        }
                    } else {
                        //Just try to alloc, nothing special.
                        ret = multi_heap_malloc(heap->heap, size);
                        if (ret != NULL) {
                            return ret;
                        }
                    }
                }
            }
        }
    }
    //Nothing usable found.
    return NULL;
}

/* Find the heap which belongs to ptr, or return NULL if it's
   not in any heap.

   (This confirms if ptr is inside the heap's region, doesn't confirm if 'ptr'
   is an allocated block or is some other random address inside the heap.)
*/
IRAM_ATTR static heap_t *find_containing_heap(void *ptr )
{
    intptr_t p = (intptr_t)ptr;
    for (size_t i = 0; i < num_registered_heaps; i++) {
        heap_t *heap = &registered_heaps[i];
        if (heap->heap != NULL && p >= heap->start && p < heap->end) {
            return heap;
        }
    }
    return NULL;
}

IRAM_ATTR void heap_caps_free( void *ptr)
{
    intptr_t p = (intptr_t)ptr;

    if (ptr == NULL) {
        return;
    }

    if ((p >= SOC_DIRAM_IRAM_LOW) && (p <= SOC_DIRAM_IRAM_HIGH)) {
        //Memory allocated here is actually allocated in the DRAM alias region and
        //cannot be de-allocated as usual. dram_alloc_to_iram_addr stores a pointer to
        //the equivalent DRAM address, though; free that.
        uint32_t *dramAddrPtr = (uint32_t *)ptr;
        ptr = (void *)dramAddrPtr[-1];
    }

    heap_t *heap = find_containing_heap(ptr);
    assert(heap != NULL && "free() target pointer is outside heap areas");
    multi_heap_free(heap->heap, ptr);
}

IRAM_ATTR void *heap_caps_realloc( void *ptr, size_t size, int caps)
{
    if (ptr == NULL) {
        return heap_caps_malloc(size, caps);
    }

    if (size == 0) {
        heap_caps_free(ptr);
        return NULL;
    }

    heap_t *heap = find_containing_heap(ptr);

    assert(heap != NULL && "realloc() pointer is outside heap areas");

    // are the existing heap's capabilities compatible with the
    // requested ones?
    bool compatible_caps = (caps & get_all_caps(heap)) == caps;

    if (compatible_caps) {
        // try to reallocate this memory within the same heap
        // (which will resize the block if it can)
        void *r = multi_heap_realloc(heap->heap, ptr, size);
        if (r != NULL) {
            return r;
        }
    }

    // if we couldn't do that, try to see if we can reallocate
    // in a different heap with requested capabilities.
    void *new_p = heap_caps_malloc(size, caps);
    if (new_p != NULL) {
        size_t old_size = multi_heap_get_allocated_size(heap->heap, ptr);
        assert(old_size > 0);
        memcpy(new_p, ptr, old_size);
        heap_caps_free(ptr);
        return new_p;
    }
    return NULL;
}

size_t heap_caps_get_free_size( uint32_t caps )
{
    size_t ret = 0;
    for (int i = 0; i < num_registered_heaps; i++) {
        heap_t *heap = &registered_heaps[i];
        if (heap_caps_match(heap, caps)) {
            ret += multi_heap_free_size(heap->heap);
        }
    }
    return ret;
}

size_t heap_caps_get_minimum_free_size( uint32_t caps )
{
    size_t ret = 0;
    for (int i = 0; i < num_registered_heaps; i++) {
        heap_t *heap = &registered_heaps[i];
        if (heap_caps_match(heap, caps)) {
            ret += multi_heap_minimum_free_size(heap->heap);
        }
    }
    return ret;
}

size_t heap_caps_get_largest_free_block( uint32_t caps )
{
    multi_heap_info_t info;
    heap_caps_get_info(&info, caps);
    return info.largest_free_block;
}

void heap_caps_get_info( multi_heap_info_t *info, uint32_t caps )
{
    bzero(info, sizeof(multi_heap_info_t));

    for (int i = 0; i < num_registered_heaps; i++) {
        heap_t *heap = &registered_heaps[i];
        if (heap_caps_match(heap, caps)) {
            multi_heap_info_t hinfo;
            multi_heap_get_info(heap->heap, &hinfo);

            info->total_free_bytes += hinfo.total_free_bytes;
            info->total_allocated_bytes += hinfo.total_allocated_bytes;
            info->largest_free_block = MAX(info->largest_free_block,
                                           hinfo.largest_free_block);
            info->minimum_free_bytes += hinfo.minimum_free_bytes;
            info->allocated_blocks += hinfo.allocated_blocks;
            info->free_blocks += hinfo.free_blocks;
            info->total_blocks += hinfo.total_blocks;
        }
    }
}

void heap_caps_print_heap_info( uint32_t caps )
{
    multi_heap_info_t info;
    printf("Heap summary for capabilities 0x%08X:\n", caps);
    for (int i = 0; i < num_registered_heaps; i++) {
        heap_t *heap = &registered_heaps[i];
        if (heap_caps_match(heap, caps)) {
            multi_heap_get_info(heap->heap, &info);

            printf("  At 0x%08x len %d free %d allocated %d min_free %d\n",
                   heap->start, heap->end - heap->start, info.total_free_bytes, info.total_allocated_bytes, info.minimum_free_bytes);
            printf("    largest_free_block %d alloc_blocks %d free_blocks %d total_blocks %d\n",
                   info.largest_free_block, info.allocated_blocks,
                   info.free_blocks, info.total_blocks);
        }
    }
    printf("  Totals:\n");
    heap_caps_get_info(&info, caps);

    printf("    free %d allocated %d min_free %d largest_free_block %d\n", info.total_free_bytes, info.total_allocated_bytes, info.minimum_free_bytes, info.largest_free_block);
}