diff options
Diffstat (limited to 'arch/arm/boot/compressed/atags_to_fdt.c')
-rw-r--r-- | arch/arm/boot/compressed/atags_to_fdt.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/arch/arm/boot/compressed/atags_to_fdt.c b/arch/arm/boot/compressed/atags_to_fdt.c new file mode 100644 index 000000000..1feb6b0f7 --- /dev/null +++ b/arch/arm/boot/compressed/atags_to_fdt.c @@ -0,0 +1,217 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/libfdt_env.h> +#include <asm/setup.h> +#include <libfdt.h> + +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND) +#define do_extend_cmdline 1 +#else +#define do_extend_cmdline 0 +#endif + +#define NR_BANKS 16 + +static int node_offset(void *fdt, const char *node_path) +{ + int offset = fdt_path_offset(fdt, node_path); + if (offset == -FDT_ERR_NOTFOUND) + /* Add the node to root if not found, dropping the leading '/' */ + offset = fdt_add_subnode(fdt, 0, node_path + 1); + return offset; +} + +static int setprop(void *fdt, const char *node_path, const char *property, + void *val_array, int size) +{ + int offset = node_offset(fdt, node_path); + if (offset < 0) + return offset; + return fdt_setprop(fdt, offset, property, val_array, size); +} + +static int setprop_string(void *fdt, const char *node_path, + const char *property, const char *string) +{ + int offset = node_offset(fdt, node_path); + if (offset < 0) + return offset; + return fdt_setprop_string(fdt, offset, property, string); +} + +static int setprop_cell(void *fdt, const char *node_path, + const char *property, uint32_t val) +{ + int offset = node_offset(fdt, node_path); + if (offset < 0) + return offset; + return fdt_setprop_cell(fdt, offset, property, val); +} + +static const void *getprop(const void *fdt, const char *node_path, + const char *property, int *len) +{ + int offset = fdt_path_offset(fdt, node_path); + + if (offset == -FDT_ERR_NOTFOUND) + return NULL; + + return fdt_getprop(fdt, offset, property, len); +} + +static uint32_t get_cell_size(const void *fdt) +{ + int len; + uint32_t cell_size = 1; + const __be32 *size_len = getprop(fdt, "/", "#size-cells", &len); + + if (size_len) + cell_size = fdt32_to_cpu(*size_len); + return cell_size; +} + +static void merge_fdt_bootargs(void *fdt, const char *fdt_cmdline) +{ + char cmdline[COMMAND_LINE_SIZE]; + const char *fdt_bootargs; + char *ptr = cmdline; + int len = 0; + + /* copy the fdt command line into the buffer */ + fdt_bootargs = getprop(fdt, "/chosen", "bootargs", &len); + if (fdt_bootargs) + if (len < COMMAND_LINE_SIZE) { + memcpy(ptr, fdt_bootargs, len); + /* len is the length of the string + * including the NULL terminator */ + ptr += len - 1; + } + + /* and append the ATAG_CMDLINE */ + if (fdt_cmdline) { + len = strlen(fdt_cmdline); + if (ptr - cmdline + len + 2 < COMMAND_LINE_SIZE) { + *ptr++ = ' '; + memcpy(ptr, fdt_cmdline, len); + ptr += len; + } + } + *ptr = '\0'; + + setprop_string(fdt, "/chosen", "bootargs", cmdline); +} + +static void hex_str(char *out, uint32_t value) +{ + uint32_t digit; + int idx; + + for (idx = 7; idx >= 0; idx--) { + digit = value >> 28; + value <<= 4; + digit &= 0xf; + if (digit < 10) + digit += '0'; + else + digit += 'A'-10; + *out++ = digit; + } + *out = '\0'; +} + +/* + * Convert and fold provided ATAGs into the provided FDT. + * + * Return values: + * = 0 -> pretend success + * = 1 -> bad ATAG (may retry with another possible ATAG pointer) + * < 0 -> error from libfdt + */ +int atags_to_fdt(void *atag_list, void *fdt, int total_space) +{ + struct tag *atag = atag_list; + /* In the case of 64 bits memory size, need to reserve 2 cells for + * address and size for each bank */ + __be32 mem_reg_property[2 * 2 * NR_BANKS]; + int memcount = 0; + int ret, memsize; + + /* make sure we've got an aligned pointer */ + if ((u32)atag_list & 0x3) + return 1; + + /* if we get a DTB here we're done already */ + if (*(__be32 *)atag_list == cpu_to_fdt32(FDT_MAGIC)) + return 0; + + /* validate the ATAG */ + if (atag->hdr.tag != ATAG_CORE || + (atag->hdr.size != tag_size(tag_core) && + atag->hdr.size != 2)) + return 1; + + /* let's give it all the room it could need */ + ret = fdt_open_into(fdt, fdt, total_space); + if (ret < 0) + return ret; + + for_each_tag(atag, atag_list) { + if (atag->hdr.tag == ATAG_CMDLINE) { + /* Append the ATAGS command line to the device tree + * command line. + * NB: This means that if the same parameter is set in + * the device tree and in the tags, the one from the + * tags will be chosen. + */ + if (do_extend_cmdline) + merge_fdt_bootargs(fdt, + atag->u.cmdline.cmdline); + else + setprop_string(fdt, "/chosen", "bootargs", + atag->u.cmdline.cmdline); + } else if (atag->hdr.tag == ATAG_MEM) { + if (memcount >= sizeof(mem_reg_property)/4) + continue; + if (!atag->u.mem.size) + continue; + memsize = get_cell_size(fdt); + + if (memsize == 2) { + /* if memsize is 2, that means that + * each data needs 2 cells of 32 bits, + * so the data are 64 bits */ + __be64 *mem_reg_prop64 = + (__be64 *)mem_reg_property; + mem_reg_prop64[memcount++] = + cpu_to_fdt64(atag->u.mem.start); + mem_reg_prop64[memcount++] = + cpu_to_fdt64(atag->u.mem.size); + } else { + mem_reg_property[memcount++] = + cpu_to_fdt32(atag->u.mem.start); + mem_reg_property[memcount++] = + cpu_to_fdt32(atag->u.mem.size); + } + + } else if (atag->hdr.tag == ATAG_INITRD2) { + uint32_t initrd_start, initrd_size; + initrd_start = atag->u.initrd.start; + initrd_size = atag->u.initrd.size; + setprop_cell(fdt, "/chosen", "linux,initrd-start", + initrd_start); + setprop_cell(fdt, "/chosen", "linux,initrd-end", + initrd_start + initrd_size); + } else if (atag->hdr.tag == ATAG_SERIAL) { + char serno[16+2]; + hex_str(serno, atag->u.serialnr.high); + hex_str(serno+8, atag->u.serialnr.low); + setprop_string(fdt, "/", "serial-number", serno); + } + } + + if (memcount) { + setprop(fdt, "/memory", "reg", mem_reg_property, + 4 * memcount * memsize); + } + + return fdt_pack(fdt); +} |