Initial commit: Schunix as it stands before the SchOS rename
An x86-64 operating system built from xv6, now largely rewritten: SMP, a copy-on-write root filesystem (SchFS), PCI/USB/virtio drivers, a TTF rasteriser, and a Linux-numbered syscall ABI. No history before this point -- the tree was never under version control. This commit exists so the rename that follows has something to undo to.
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Nexoniarz
commit
d0f7acf9eb
275 changed files with 51417 additions and 0 deletions
219
cmd/fbinfo/main.c
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219
cmd/fbinfo/main.c
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// fbinfo -- ask /dev/fb0 what it is, and optionally draw on it.
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//
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// This exists because the framebuffer is the one device whose correctness you
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// cannot check by reading kernel source: the numbers have to come back from
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// the hardware the bootloader actually programmed. Three places in the kernel
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// used to assume the framebuffer lived at 0xfd000000 and was 800x600x32; they
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// agreed with QEMU's stdvga by luck, and nothing would have told us when the
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// luck ran out. Now `fbinfo` would.
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//
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// fbinfo print the geometry
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// fbinfo fill draw a gradient over the whole screen through mmap
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// fbinfo bars draw colour bars through write(), no mmap involved
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//
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// The two drawing modes take different paths on purpose. If `fill` works and
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// `bars` does not, the mapping is right and the device's read/write is wrong;
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// if it is the other way round, the reverse. Having both makes a failure say
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// which half broke.
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#include "types.h"
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#include "user.h"
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#include "fcntl.h"
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#include "fb.h"
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#define PROT_READ 0x1
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#define PROT_WRITE 0x2
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#define MAP_SHARED 0x01
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static void
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puts(const char *s)
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{
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int n = 0;
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while (s[n]) n++;
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write(1, (void*)s, n);
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}
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// Unsigned decimal. No printf in lib/, and pulling one in for six numbers
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// would be a worse trade than fourteen lines.
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static void
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putu(unsigned long v)
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{
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char buf[24];
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int i = 0;
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if (v == 0) {
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write(1, "0", 1);
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return;
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}
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while (v > 0 && i < (int)sizeof(buf)) {
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buf[i++] = (char)('0' + (v % 10));
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v /= 10;
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}
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while (i > 0) {
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i--;
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write(1, &buf[i], 1);
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}
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}
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static void
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puthex(unsigned long v)
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{
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static const char d[] = "0123456789abcdef";
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char buf[16];
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int i = 0;
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write(1, "0x", 2);
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if (v == 0) {
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write(1, "0", 1);
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return;
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}
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while (v > 0 && i < (int)sizeof(buf)) {
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buf[i++] = d[v & 0xf];
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v >>= 4;
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}
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while (i > 0) {
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i--;
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write(1, &buf[i], 1);
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}
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}
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// Name, then spaces out to a fixed column. Padding inside each string
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// literal is what produced "bits_per_pixel32": the longest name happened to
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// be exactly as wide as the column, so it got no separator at all and the
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// value ran straight into it.
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static void
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label(const char *name)
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{
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int n = 0;
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while (name[n]) n++;
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write(1, (void*)name, n);
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while (n < 16) { write(1, " ", 1); n++; }
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}
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static void
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field(const char *name, unsigned long v)
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{
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label(name);
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putu(v);
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puts("\n");
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}
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static void
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chanline(const char *name, struct fb_bitfield *b)
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{
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label(name);
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puts("offset ");
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putu(b->offset);
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puts(", length ");
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putu(b->length);
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if (b->length == 0)
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puts(" (absent)");
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puts("\n");
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}
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int
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main(int argc, char *argv[])
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{
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struct fb_var_screeninfo var;
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struct fb_fix_screeninfo fix;
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int fd;
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fd = open("/dev/fb0", O_RDWR);
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if (fd < 0) {
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puts("fbinfo: cannot open /dev/fb0\n");
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return 1;
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}
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if (ioctl(fd, FBIOGET_VSCREENINFO, &var) < 0) {
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puts("fbinfo: FBIOGET_VSCREENINFO failed\n");
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return 1;
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}
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if (ioctl(fd, FBIOGET_FSCREENINFO, &fix) < 0) {
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puts("fbinfo: FBIOGET_FSCREENINFO failed\n");
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return 1;
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}
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if (argc < 2) {
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label("id");
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puts(fix.id);
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puts("\n");
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field("xres", var.xres);
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field("yres", var.yres);
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field("bits_per_pixel", var.bits_per_pixel);
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label("smem_start");
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puthex(fix.smem_start);
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puts("\n");
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field("smem_len", fix.smem_len);
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field("line_length", fix.line_length);
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// The stride is the number worth staring at. A card is free to pad
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// each row, and a program that computes row starts as
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// y * xres * bytes_per_pixel instead of y * line_length draws a
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// picture that shears progressively down the screen.
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if (fix.line_length != var.xres * (var.bits_per_pixel / 8)) {
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label("note");
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puts("stride is padded; rows are not xres*bpp/8 apart\n");
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}
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chanline("red", &var.red);
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chanline("green", &var.green);
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chanline("blue", &var.blue);
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chanline("transp", &var.transp);
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return 0;
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}
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if (argv[1][0] == 'f') { // fill
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unsigned char *fb = mmap(0, fix.smem_len,
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PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
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if (fb == 0 || (long)fb < 0) {
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puts("fbinfo: mmap failed\n");
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return 1;
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}
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unsigned bpp = var.bits_per_pixel / 8;
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for (unsigned y = 0; y < var.yres; y++) {
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unsigned char *row = fb + (unsigned long)y * fix.line_length;
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for (unsigned x = 0; x < var.xres; x++) {
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unsigned r = (x * 255) / (var.xres ? var.xres : 1);
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unsigned g = (y * 255) / (var.yres ? var.yres : 1);
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unsigned long px = ((unsigned long)r << var.red.offset) |
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((unsigned long)g << var.green.offset) |
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((unsigned long)0x80 << var.blue.offset);
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unsigned char *p = row + (unsigned long)x * bpp;
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for (unsigned b = 0; b < bpp; b++)
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p[b] = (unsigned char)(px >> (b * 8));
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}
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}
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puts("fbinfo: gradient drawn through mmap\n");
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return 0;
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}
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if (argv[1][0] == 'b') { // bars
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// One scanline at a time through write(). No mapping: this is the
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// path that used to be devsw's nullwrite, i.e. a silent no-op.
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static unsigned char row[8192];
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unsigned bpp = var.bits_per_pixel / 8;
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unsigned len = fix.line_length;
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if (len > sizeof(row))
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len = sizeof(row);
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for (unsigned y = 0; y < var.yres; y++) {
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unsigned band = (y * 8) / (var.yres ? var.yres : 1);
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unsigned long px =
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((unsigned long)((band & 1) ? 255 : 0) << var.red.offset) |
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((unsigned long)((band & 2) ? 255 : 0) << var.green.offset) |
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((unsigned long)((band & 4) ? 255 : 0) << var.blue.offset);
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for (unsigned x = 0; x * bpp + bpp <= len; x++)
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for (unsigned b = 0; b < bpp; b++)
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row[x * bpp + b] = (unsigned char)(px >> (b * 8));
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if (write(fd, row, len) != (int)len) {
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puts("fbinfo: short write to /dev/fb0\n");
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return 1;
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}
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}
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puts("fbinfo: colour bars drawn through write()\n");
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return 0;
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}
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puts("usage: fbinfo [fill|bars]\n");
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return 1;
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}
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