Messages in this thread | | | From | Jesse Barnes <> | Subject | Re: Special handling of sysfs device resource files? | Date | Wed, 12 Apr 2006 10:20:11 -0700 |
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On Tuesday, April 11, 2006 4:59 pm, Ian Romanick wrote: > I was a little mistaken about this. The BAR that causes the problem > is not I/O. It *is* memory. > > 01:00.0 VGA compatible controller: Matrox Graphics, Inc. G400/G450 > (rev 03) (prog-if 00 [VGA]) > Subsystem: Matrox Graphics, Inc. Millennium G400 16Mb SGRAM > Flags: bus master, medium devsel, latency 64, IRQ 11 > Memory at cc000000 (32-bit, prefetchable) [size=32M] > Memory at cfefc000 (32-bit, non-prefetchable) [size=16K] > Memory at cf000000 (32-bit, non-prefetchable) [size=8M] > Expansion ROM at cfee0000 [disabled] [size=64K] > > When I open and mmap resource0 (the framebuffer) I get 0x2b9aa48ea000. > When I open and mmap resource1 (the card's registers) I get > 0x2b9aa68ea000. I can access the resource0 pointer all day long > without problems. The firs access to the resource1 pointer results in > a segfault.
Just tested on my x86-64 machine with this dumb little test program. It seems to work ok, though I haven't tried writing data to the resource.
Jesse #include <errno.h> #include <fcntl.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/mman.h> #include <sys/stat.h> #include <sys/types.h>
int main(int argc, char *argv[]) { size_t len; int fd, i; void *ptr; uint32_t *val;
if (argc != 3) { fprintf(stderr, "usage: %s <file> <mapsize>\n", argv[0]); return -1; }
len = atoi(argv[2]);
fd = open(argv[1], O_RDONLY); if (fd == -1) { fprintf(stderr, "open failed: %s\n", strerror(errno)); return errno; }
ptr = mmap(NULL, len, PROT_READ, MAP_SHARED, fd, 0); if (ptr == MAP_FAILED) { fprintf(stderr, "mmap failed: %s\n", strerror(errno)); return errno; }
val = ptr; len = len / sizeof(uint32_t); for (i = 0; i < len; i += 4) { printf("%08x: 0x%08x 0x%08x 0x%08x 0x%08x\n", i * 4, val[i], val[i+1], val[i+2], val[i+3]); }
munmap(ptr, len); /* ignore any errors, we don't care */ close(fd); return 0; }
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