// SPDX-License-Identifier: LGPL-3.0-or-later
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdint.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <stdlib.h>
#include <string.h>
static int vc_fd;
static uint32_t vc_mem_size, vc_mem_base, vc_mem_load, vc_mem_phys;
static void *vc_mem;
static uint32_t vc_syms_off;
#define VC_MEM_IOC_MAGIC 'v'
#define VC_MEM_IOC_MEM_PHYS_ADDR _IOR( VC_MEM_IOC_MAGIC, 0, unsigned long )
#define VC_MEM_IOC_MEM_SIZE _IOR( VC_MEM_IOC_MAGIC, 1, unsigned int )
#define VC_MEM_IOC_MEM_BASE _IOR( VC_MEM_IOC_MAGIC, 2, unsigned int )
#define VC_MEM_IOC_MEM_LOAD _IOR( VC_MEM_IOC_MAGIC, 3, unsigned int )
#define VC_MEM_IOC_MEM_COPY _IOWR( VC_MEM_IOC_MAGIC, 4, char *)
#define VC_DEBUG_HEADER_OFFSET 0x2800
#define VC_SYMBOL_BASE_OFFSET VC_DEBUG_HEADER_OFFSET
static void vc_read(void *buf, size_t off, size_t size) {
// if(off < vc_mem_base) {
// fprintf(stderr, "small address\n");
// abort();
// }
if(off > vc_mem_size || size > vc_mem_size - off) {
fprintf(stderr, "out of bounds read: %zx+%zx/%x\n", off, size, vc_mem_size);
abort();
}
if(size == 0) return;
size_t skip = off % 4;
volatile uint32_t *inp = (volatile uint32_t*)((char*)vc_mem + (off - skip));
char *out = buf;
if(skip) {
uint32_t v = *inp;
inp++;
size_t have = 4 - skip;
if(have >= size) {
memcpy(out, (char*)&v + skip, size);
return;
}
memcpy(out, (char*)&v + skip, have);
out += have;
size -= have;
}
while(1) {
uint32_t v = *inp;
inp++;
if(size < 4) {
memcpy(out, &v, size);
return;
}
memcpy(out, &v, 4);
out += 4;
size -= 4;
}
}
static uint32_t vc_read_u32(size_t off) {
uint32_t r = 42;
vc_read(&r, off, 4);
return r;
}
static uint16_t vc_read_u16(size_t off) {
uint16_t r = 42;
vc_read(&r, off, 2);
return r;
}
static uint8_t vc_read_u8(size_t off) {
uint8_t r = 42;
vc_read(&r, off, 1);
return r;
}
static size_t vc_read_ptr(size_t off) {
uint32_t r = vc_read_u32(off);
if(r == 0) return 0;
if(r <= 0xc0000000) {
fprintf(stderr, "invalid pointer: %x\n", r);
abort();
}
return r - 0xc0000000;
}
static char *vc_read_str(size_t off) {
size_t len = 0, alloc = 16;
char *r = malloc(alloc);
if(!r) abort();
while(1) {
size_t roff = off + len;
size_t try_read = alloc - len;
if(try_read > vc_mem_size - roff) {
try_read = vc_mem_size - roff;
}
if(try_read == 0) abort();
vc_read(r + len, roff, try_read);
size_t add = strnlen(r + len, try_read);
len += add;
if(add < try_read) {
break;
}
size_t alloc2 = alloc + (alloc << 2);
char *r2 = realloc(r, alloc2);
if(!r2) abort();
r = r2;
alloc = alloc2;
}
return r;
}
static void vc_open(void) {
int r = open("/dev/vc-mem", O_RDWR | O_SYNC | O_CLOEXEC);
if(r < 0) {
perror("open");
abort();
}
vc_fd = r;
r = ioctl(vc_fd, VC_MEM_IOC_MEM_SIZE, &vc_mem_size);
if(r < 0) {
perror("VC_MEM_IOC_MEM_SIZE");
abort();
}
r = ioctl(vc_fd, VC_MEM_IOC_MEM_BASE, &vc_mem_base);
if(r < 0) {
perror("VC_MEM_IOC_MEM_BASE");
abort();
}
r = ioctl(vc_fd, VC_MEM_IOC_MEM_LOAD, &vc_mem_load);
if(r < 0) {
perror("VC_MEM_IOC_MEM_LOAD");
abort();
}
r = ioctl(vc_fd, VC_MEM_IOC_MEM_PHYS_ADDR, &vc_mem_phys);
if(r < 0) {
perror("VC_MEM_IOC_MEM_PHYS_ADDR");
abort();
}
vc_mem = mmap(NULL, vc_mem_size, PROT_READ, MAP_SHARED, vc_fd, 0);
if(vc_mem == MAP_FAILED) {
perror("mmap");
abort();
}
uint32_t dbg_off = vc_mem_load + VC_DEBUG_HEADER_OFFSET;
uint32_t dbg_magic = vc_read_u32(dbg_off + 4);
if(dbg_magic != 0x48444356) {
fprintf(stderr, "bad debug magic: %08x, wanted 48444356\n", dbg_magic);
abort();
}
vc_syms_off = vc_read_u32(dbg_off);
}
static size_t vc_sym_find(const char *want) {
uint32_t at = vc_syms_off;
while(1) {
uint32_t label = vc_read_u32(at + 0);
uint32_t addr = vc_read_u32(at + 4);
if(label == 0) return 0;
char *name = vc_read_str(label);
int r = strcmp(name, want);
free(name);
if(!r) return addr;
at += 12;
}
}
static void vc_log_read(size_t descriptor_ptr) {
uint8_t fmt = vc_read_u8(descriptor_ptr);
size_t ptr = vc_read_ptr(descriptor_ptr + 4);
if(!ptr) {
printf("no data\n");
}
if(fmt != 1) {
printf("unsupported log format %u\n", fmt);
return;
}
uint32_t magic = vc_read_u32(ptr);
if(magic != 0x5353454d) {
printf("bad fifo log magic: %08x, wanted 5353454d", magic);
return;
}
size_t l_start = vc_read_ptr(ptr + 4);
size_t l_end = vc_read_ptr(ptr + 8);
size_t l_ptr = vc_read_ptr(ptr + 12);
size_t l_next_msg = vc_read_ptr(ptr + 16);
size_t at = l_next_msg;
do {
uint32_t time = vc_read_u32(at + 0);
uint32_t seq = vc_read_u16(at + 4);
size_t size = vc_read_u16(at + 6);
if(size < 12) {
printf("short message: %zu\n", size);
return;
}
size_t len = size - 12;
char *s = malloc(len + 1);
if(!s) abort();
vc_read(s, at + 12, len);
s[len] = 0;
printf("[%u : %u] %s\n", time, seq, s);
free(s);
at += size;
if(at == l_end) at = l_start;
} while(at != l_ptr);
}
static void vc_log_read_all(void) {
size_t log_start = vc_sym_find("__LOG_START");
if(!log_start) {
fprintf(stderr, "no __LOG_START\n");
abort();
}
log_start = vc_read_ptr(log_start);
uint32_t log_magic = vc_read_u32(log_start);
if(log_magic != 0x564c4f47) {
fprintf(stderr, "bad log header magic: %08x, wanted 564c4f47\n", log_magic);
abort();
}
vc_log_read(log_start + 40);
}
int main() {
vc_open();
vc_log_read_all();
close(vc_fd);
return 0;
}