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author | vetch <vetch97@gmail.com> | 2020-01-02 17:54:31 +0100 |
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committer | vetch <vetch97@gmail.com> | 2020-01-02 17:54:31 +0100 |
commit | ab7b754bb32022336527c1a2d5d710b95a589d0e (patch) | |
tree | 19f508f06c72efcbdd2cfad46949ed6f1ae45a3c /atags.c | |
parent | 5e1e6796109c892c4300c3da17c35e7874a40107 (diff) | |
parent | 6bf5a3b8c6e8a5d1cb3fb4880a5d9688ab094c62 (diff) | |
download | rpi-MMU-example-ab7b754bb32022336527c1a2d5d710b95a589d0e.tar.gz rpi-MMU-example-ab7b754bb32022336527c1a2d5d710b95a589d0e.zip |
Merge branch 'bob' of https://repo.or.cz/RPi-MMU-example into alice
# Conflicts:
# .gitignore
# PL0_test.ld
# demo_functionality.c
# interrupt_vector.S
# interrupts.c
# kernel.c
# memory.h
Diffstat (limited to 'atags.c')
-rw-r--r-- | atags.c | 103 |
1 files changed, 103 insertions, 0 deletions
@@ -0,0 +1,103 @@ +#include "atags.h" +#include "io.h" + +static inline struct atag_header *next_tag(struct atag_header *tag) +{ + return (struct atag_header*) (((uint32_t*) tag) + tag->size); +} + +#define TAG_CONTENTS_FUN(tagname) \ + static inline struct atag_##tagname *tagname##_tag_contents \ + (struct atag_header *tag) \ + { \ + return (struct atag_##tagname*) (tag + 1); \ + } + +TAG_CONTENTS_FUN(header) +TAG_CONTENTS_FUN(core) +TAG_CONTENTS_FUN(mem) +TAG_CONTENTS_FUN(videotext) +TAG_CONTENTS_FUN(ramdisk) +TAG_CONTENTS_FUN(initrd2) +TAG_CONTENTS_FUN(serialnr) +TAG_CONTENTS_FUN(revision) +TAG_CONTENTS_FUN(videolfb) +TAG_CONTENTS_FUN(cmdline) + +uint32_t find_memory_size(struct atag_header *atags) +{ + // we silently assume there will only be one mem atag + while (atags->tag != ATAG_MEM && atags->tag != ATAG_NONE) + atags = next_tag(atags); + + if (atags->tag == ATAG_NONE) + return 0; + + struct atag_mem *mem_tag = mem_tag_contents(atags); + + // our design assumes address 0x0 is available, so we reject mem + // atag saying otherwise + if (mem_tag->start != 0) + { + puts("ignoring information about memory, " + "that doesn't start at 0x0"); + return 0; + } + + return mem_tag->size; +} + +void print_tag(struct atag_header *tag) +{ +#define TAG_CASE(tagname_upcase, tagname_locase, instructions) \ + case ATAG_##tagname_upcase: \ + puts("ATAG_" #tagname_upcase ":"); \ + { \ + struct atag_##tagname_locase *contents = \ + tagname_locase##_tag_contents(tag); \ + instructions; \ + } \ + break + + switch (tag->tag) + { + TAG_CASE(CORE, core, + prints(" flags: 0x"); + printhex(contents->flags); puts(""); + prints(" page size: "); + printdec(contents->pagesize); puts(""); + prints(" root device: "); + printdec(contents->rootdev); puts("");); + TAG_CASE(MEM, mem, + prints(" memory size: 0x"); + printhex(contents->size); puts(""); + prints(" memory start: 0x"); + printhex(contents->start); puts("");); + // the rest are unimportant for now, + // as they're not passed by qemu + TAG_CASE(VIDEOTEXT, videotext, (void) contents;); + TAG_CASE(RAMDISK, ramdisk, (void) contents;); + TAG_CASE(INITRD2, initrd2, (void) contents;); + TAG_CASE(SERIAL, serialnr, (void) contents;); + TAG_CASE(REVISION, revision, (void) contents;); + TAG_CASE(VIDEOLFB, videolfb, (void) contents;); + TAG_CASE(CMDLINE, cmdline, (void) contents;); + + case ATAG_NONE: + puts("ATAG_NONE"); + break; + default: + prints("!! unknown tag: 0x"); printhex(tag->tag); puts(" !!"); + } +} + +void print_atags(struct atag_header *atags) +{ + while (atags->tag != ATAG_NONE) + { + print_tag(atags); + atags = next_tag(atags); + } + + print_tag(atags); // also print ATAG_NONE +} |