diff options
Diffstat (limited to 'common/dtb_patch.c')
| -rw-r--r-- | common/dtb_patch.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/common/dtb_patch.c b/common/dtb_patch.c index 34d1a6c..cd9a1f3 100644 --- a/common/dtb_patch.c +++ b/common/dtb_patch.c @@ -32,6 +32,15 @@ static uint32_t be32(const void *p) ((uint32_t)b[2] << 8) | (uint32_t)b[3]; } +static void put_be32(void *p, uint32_t v) +{ + uint8_t *b = p; + b[0] = (uint8_t)(v >> 24); + b[1] = (uint8_t)(v >> 16); + b[2] = (uint8_t)(v >> 8); + b[3] = (uint8_t)v; +} + static void put_be64(void *p, uint64_t v) { uint8_t *b = p; @@ -57,6 +66,76 @@ static int name_eq(const char *node, const char *want) } /* + * rewrite /memory reg with the RAM the bootloader actually sees. + * the value is two u32 cells, base and size, addresses above 4GB + * need the parent #address-cells respected, virt is below 4GB and + * 2 cells for size. returns 0 on success. + */ +int tb_dtb_patch_memory(uintptr_t dtb, uint64_t base, uint64_t size) +{ + uint8_t *basep = (uint8_t *)dtb; + uint32_t off_struct = be32(basep + 8); + uint32_t off_strings = be32(basep + 12); + uint8_t *p = basep + off_struct; + uint8_t *strings = basep + off_strings; + const char *cur_node = NULL; + int depth = 0; + + if (be32(basep) != 0xd00dfeed) + return -1; + + while (p < basep + be32(basep + 4)) { + uint32_t token = be32(p); + + switch (token) { + case FDT_BEGIN_NODE: { + char *name = (char *)(p + 4); + size_t len = strlen(name) + 1; + + p += 4 + ((len + 3) & ~3); + depth++; + cur_node = name; + break; + } + case FDT_END_NODE: + depth--; + p += 4; + break; + case FDT_PROP: { + uint32_t plen = be32(p + 4); + const char *pname = (char *)strings + be32(p + 8); + uint8_t *val = p + 12; + + p += 12 + ((plen + 3) & ~3); + + if (depth == 2 && name_eq(cur_node, "memory") && + strcmp(pname, "reg") == 0 && plen >= 16) { + /* + * #address-cells 2, #size-cells 2, the + * reg is four cells, base hi lo and + * size hi lo, below 4GB the hi cells + * are zero. + */ + put_be32(val, (uint32_t)(base >> 32)); + put_be32(val + 4, (uint32_t)base); + put_be32(val + 8, (uint32_t)(size >> 32)); + put_be32(val + 12, (uint32_t)size); + return 0; + } + break; + } + case FDT_NOP: + p += 4; + break; + case FDT_END: + return -2; + } + } + + return -3; +} + +/* * walk and rewrite. returns the number of cpu-release-addr values * written, negative on a malformed blob. */ @@ -140,3 +219,70 @@ int tb_dtb_patch_spin_table(uintptr_t dtb, uintptr_t *gates, int ngates) return written; } + +/* + * tell the kernel where the initrd landed. /chosen is created by + * the machine firmware, the two cells exist when an initrd was + * already staged, we overwrite them in place. depth 2 under the + * root, node name "chosen". + */ +int tb_dtb_patch_initrd(uintptr_t dtb, uint64_t start, uint64_t end) +{ + uint8_t *basep = (uint8_t *)dtb; + uint32_t off_struct = be32(basep + 8); + uint32_t off_strings = be32(basep + 12); + uint8_t *p = basep + off_struct; + uint8_t *strings = basep + off_strings; + const char *cur_node = NULL; + int depth = 0; + + if (be32(basep) != 0xd00dfeed) + return -1; + + while (p < basep + be32(basep + 4)) { + uint32_t token = be32(p); + + switch (token) { + case FDT_BEGIN_NODE: { + char *name = (char *)(p + 4); + size_t len = strlen(name) + 1; + + p += 4 + ((len + 3) & ~3); + depth++; + cur_node = name; + break; + } + case FDT_END_NODE: + depth--; + p += 4; + break; + case FDT_PROP: { + uint32_t plen = be32(p + 4); + const char *pname = (char *)strings + be32(p + 8); + uint8_t *val = p + 12; + + p += 12 + ((plen + 3) & ~3); + + if (depth == 2 && name_eq(cur_node, "chosen") && + strcmp(pname, "linux,initrd-start") == 0 && + plen >= 8) { + put_be64(val, start); + } + if (depth == 2 && name_eq(cur_node, "chosen") && + strcmp(pname, "linux,initrd-end") == 0 && + plen >= 8) { + put_be64(val, end); + return 0; + } + break; + } + case FDT_NOP: + p += 4; + break; + case FDT_END: + return -2; + } + } + + return -2; +} |