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| -rw-r--r-- | sdram-malloc.c | 89 | ||||
| -rw-r--r-- | sdram-malloc.h | 36 |
2 files changed, 125 insertions, 0 deletions
diff --git a/sdram-malloc.c b/sdram-malloc.c new file mode 100644 index 0000000..0c5813a --- /dev/null +++ b/sdram-malloc.c @@ -0,0 +1,89 @@ +/* + * sdram_malloc.c + * -------------- + * Use SDRAM for a very limited sort of heap. + * + * Copyright (c) 2016, NORDUnet A/S All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * - Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * - 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. + * + * - Neither the name of the NORDUnet nor the names of its contributors may + * be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT + * HOLDER 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. + */ + +/* Allocate memory from SDRAM1. This is not a general allocator, and + * should only be used with the greatest of caution and care. + * + * This is intended for allocating memory that will never be freed + * (e.g. thread stack buffers), or for memory that will be freed as soon + * as the requesting function is done with it (e.g. file upload + * buffers). + * + * Memory should be freed in reverse order of allocation (most + * recent first). + * + * There are no memory block control fields, so no protection to ensure + * that memory that is freed is actually the memory that was allocated. + */ + +#include <stddef.h> +#include <stdint.h> + +/* end of variables declared with __attribute__((section(".sdram1"))) */ +extern uint8_t _esdram1 __asm ("_esdram1"); +static uint8_t * const sdram_heap_base = &_esdram1; + +/* end of sdram1 section */ +extern uint8_t __end_sdram1 __asm ("__end_sdram1"); +static uint8_t * const sdram_heap_end = &__end_sdram1; + +/* current heap top */ +static uint8_t *sdram_heap = &_esdram1; + +/* Allocate some memory. Allocations are not padded, because kermit will + * call repeatedly to write blocks of data to a "file". OTOH, it's a good + * idea to allocate padding after the last write, so the next allocation + * will be aligned. + */ +uint8_t *sdram_malloc(size_t size) +{ + uint8_t *p = sdram_heap; + + if (p + size > sdram_heap_end) + return NULL; + + sdram_heap += size; + return p; +} + +/* Free some memory allocated from sdram. This does only the most basic of + * sanity checks. + */ +void sdram_free(uint8_t *s) +{ + if (s < sdram_heap_base || s >= sdram_heap_end) + return; + if (s < sdram_heap) + sdram_heap = s; +} diff --git a/sdram-malloc.h b/sdram-malloc.h new file mode 100644 index 0000000..5fc80fc --- /dev/null +++ b/sdram-malloc.h @@ -0,0 +1,36 @@ +/* + * sdram_malloc.h + * -------------- + * Use SDRAM for a very limited sort of heap. + * + * Copyright (c) 2016, NORDUnet A/S All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * - Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * - 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. + * + * - Neither the name of the NORDUnet nor the names of its contributors may + * be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT + * HOLDER 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. + */ + +extern uint8_t *sdram_malloc(size_t size); +extern void sdram_free(uint8_t *s); |