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author | fishsoupisgood <github@madingley.org> | 2019-04-29 01:17:54 +0100 |
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committer | fishsoupisgood <github@madingley.org> | 2019-05-27 03:43:43 +0100 |
commit | 3f2546b2ef55b661fd8dd69682b38992225e86f6 (patch) | |
tree | 65ca85f13617aee1dce474596800950f266a456c /roms/u-boot/common/memsize.c | |
download | qemu-master.tar.gz qemu-master.tar.bz2 qemu-master.zip |
Diffstat (limited to 'roms/u-boot/common/memsize.c')
-rw-r--r-- | roms/u-boot/common/memsize.c | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/roms/u-boot/common/memsize.c b/roms/u-boot/common/memsize.c new file mode 100644 index 00000000..589400d3 --- /dev/null +++ b/roms/u-boot/common/memsize.c @@ -0,0 +1,92 @@ +/* + * (C) Copyright 2004 + * Wolfgang Denk, DENX Software Engineering, wd@denx.de. + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <common.h> + +DECLARE_GLOBAL_DATA_PTR; + +#ifdef __PPC__ +/* + * At least on G2 PowerPC cores, sequential accesses to non-existent + * memory must be synchronized. + */ +# include <asm/io.h> /* for sync() */ +#else +# define sync() /* nothing */ +#endif + +/* + * Check memory range for valid RAM. A simple memory test determines + * the actually available RAM size between addresses `base' and + * `base + maxsize'. + */ +long get_ram_size(long *base, long maxsize) +{ + volatile long *addr; + long save[32]; + long cnt; + long val; + long size; + int i = 0; + + for (cnt = (maxsize / sizeof (long)) >> 1; cnt > 0; cnt >>= 1) { + addr = base + cnt; /* pointer arith! */ + sync (); + save[i++] = *addr; + sync (); + *addr = ~cnt; + } + + addr = base; + sync (); + save[i] = *addr; + sync (); + *addr = 0; + + sync (); + if ((val = *addr) != 0) { + /* Restore the original data before leaving the function. + */ + sync (); + *addr = save[i]; + for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) { + addr = base + cnt; + sync (); + *addr = save[--i]; + } + return (0); + } + + for (cnt = 1; cnt < maxsize / sizeof (long); cnt <<= 1) { + addr = base + cnt; /* pointer arith! */ + val = *addr; + *addr = save[--i]; + if (val != ~cnt) { + size = cnt * sizeof (long); + /* Restore the original data before leaving the function. + */ + for (cnt <<= 1; cnt < maxsize / sizeof (long); cnt <<= 1) { + addr = base + cnt; + *addr = save[--i]; + } + return (size); + } + } + + return (maxsize); +} + +phys_size_t __weak get_effective_memsize(void) +{ +#ifndef CONFIG_VERY_BIG_RAM + return gd->ram_size; +#else + /* limit stack to what we can reasonable map */ + return ((gd->ram_size > CONFIG_MAX_MEM_MAPPED) ? + CONFIG_MAX_MEM_MAPPED : gd->ram_size); +#endif +} |