diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/dt.c | 95 |
1 files changed, 67 insertions, 28 deletions
@@ -29,13 +29,12 @@ struct fdt_header { /* * Find the device tree property by "name" starting at the given index "idx". - * This function assumes that the property is exactly 8 bytes long (hey, it's - * not so general purpose after all :D). + * The size of the property is to be provided by `prop_size`. * * Returns -1 if the given property could not be found. */ __kernel int64_t find_dt_property_from(uint32_t *dtb, struct fdt_header *header, uint32_t idx, - const char *const name) + const char *const name, size_t prop_size) { char *base_dt_string = ((char *)dtb) + header->off_dt_string; uint32_t len, nameoff; @@ -45,7 +44,10 @@ __kernel int64_t find_dt_property_from(uint32_t *dtb, struct fdt_header *header, len = __bswap_constant_32(dtb[idx + 1]); nameoff = __bswap_constant_32(dtb[idx + 2]); - if (len == 8 && strcmp(&base_dt_string[nameoff], name) == 0) { + if (len == prop_size && strcmp(&base_dt_string[nameoff], name) == 0) { + if (len == sizeof(uint32_t)) { + return (int64_t)__bswap_constant_32(dtb[idx + 3]); + } ret = (int64_t)__bswap_constant_32(dtb[idx + 3]) << 32; ret += (int64_t)__bswap_constant_32(dtb[idx + 4]); return ret; @@ -57,27 +59,30 @@ __kernel int64_t find_dt_property_from(uint32_t *dtb, struct fdt_header *header, return -1; } -// Find the "initrd" values from the given DTB blob. Returns an empty -// `initrd_addr` if these values could not be found. -__kernel struct initrd_addr __find_dt_initrd_addr(uint32_t *dtb, struct fdt_header *header) +/* + * Returns the index of the node identified by 'name' into the 'dtb' blob. This + * index will already account for the padding. + * + * Returns -1 if the node could not be found. + */ +__kernel int32_t find_dt_node(uint32_t *dtb, struct fdt_header *header, const char *const name) { uint32_t idx; - struct initrd_addr ret = { - .start = 0, - .end = 0, - }; // Try to find out the 32-bit offset of the "chosen" property inside of the // FDT structure block. for (idx = header->off_dt_struct; idx < header->size_dt_struct; idx++) { /* - * We only care about beginning of nodes, and then that the block is - * literally named "chosen". After that, our offset will be that + 3 - * (skipping FDT_BEGIN_NODE + 2 that takes "chosen" with padding for - * alignment). + * We only care about beginning of nodes, and then that the block has + * the interesting 'name'. After that, our offset will be that + 3 + * (skipping FDT_BEGIN_NODE + 2 that takes "chosen/cpus" with padding + * for alignment). + * + * NOTE: for future extension, the +2 stems from "chosen/cpus". If there + * is another node name to be found, we are cooked. */ if (dtb[idx] == FDT_BEGIN_NODE_LE) { - if (strcmp((char *)&dtb[idx + 1], "chosen") == 0) { + if (strcmp((char *)&dtb[idx + 1], name) == 0) { idx += 3; break; } @@ -86,7 +91,32 @@ __kernel struct initrd_addr __find_dt_initrd_addr(uint32_t *dtb, struct fdt_head // "chosen" property could not be found. Leave early with an empty result. if (idx == header->size_dt_struct || dtb[idx] != FDT_PROP_LE) { - return ret; + return -1; + } + return (int32_t)idx; +} + +// Set the 'cpu_freq' field of 'info' if available on the 'dtb' blob. +__kernel void set_cpu_freq(uint32_t *dtb, struct dt_info *info, struct fdt_header *header) +{ + int32_t idx = find_dt_node(dtb, header, "cpus"); + if (idx < 0) { + return; + } + + int64_t i = + find_dt_property_from(dtb, header, (uint32_t)idx, "timebase-frequency", sizeof(uint32_t)); + if (i > 0) { + info->cpu_freq = (uint64_t)i; + } +} + +// Set the "initrd" values from the given 'dtb' blob into 'info'. +__kernel void set_initrd_addr(uint32_t *dtb, struct dt_info *info, struct fdt_header *header) +{ + int32_t idx = find_dt_node(dtb, header, "chosen"); + if (idx < 0) { + return; } /* @@ -94,23 +124,22 @@ __kernel struct initrd_addr __find_dt_initrd_addr(uint32_t *dtb, struct fdt_head * values and return that. */ - int64_t i = find_dt_property_from(dtb, header, idx, "linux,initrd-start"); + int64_t i = + find_dt_property_from(dtb, header, (uint32_t)idx, "linux,initrd-start", sizeof(uint64_t)); if (i < 0) { - return ret; + return; } - ret.start = (uintptr_t)i; + info->initrd_start = (uintptr_t)i; - i = find_dt_property_from(dtb, header, idx, "linux,initrd-end"); + i = find_dt_property_from(dtb, header, (uint32_t)idx, "linux,initrd-end", sizeof(uint64_t)); if (i < 0) { - ret.start = 0; - return ret; + info->initrd_start = 0; + return; } - ret.end = (uintptr_t)i; - - return ret; + info->initrd_end = (uintptr_t)i; } -__kernel struct initrd_addr find_dt_initrd_addr(uint32_t *dtb) +__kernel void get_dt_info(uint32_t *dtb, struct dt_info *info) { if (dtb[0] != FDT_MAGIC_LE) { die("FDT structure does not have a valid magic identifier\n"); @@ -122,5 +151,15 @@ __kernel struct initrd_addr find_dt_initrd_addr(uint32_t *dtb) .size_dt_struct = __bswap_constant_32(dtb[9]) / sizeof(uint32_t), }; - return __find_dt_initrd_addr(dtb, &header); + set_initrd_addr(dtb, info, &header); + if (!info->initrd_start || !info->initrd_end) { + die("Could not fetch the addresses for the initramfs\n"); + } + + set_cpu_freq(dtb, info, &header); + if (!info->cpu_freq) { + printk("WARNING: could not figure out the CPU frequency. " + "Defaulting to 10000000 even if this might be bad\n"); + info->cpu_freq = DEFAULT_CPU_FREQ; + } } |