#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <inttypes.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <dirent.h>

#include <sys/stat.h>
#include <sys/mman.h>

/* ------------------------------------------------------------- */

#define BASEPATH "/sys/bus/pci/devices"

void *mapbar(char *dev, int bar, uint32_t offset)
{
    char filename[128];
    struct stat st;
    uint8_t *map;
    int fd;

    snprintf(filename, sizeof(filename),
             "%s/%s/resource%d", BASEPATH, dev, bar);
    fd = open(filename, O_RDONLY);
    if (-1 == fd) {
        fprintf(stderr, "open %s: %s", filename, strerror(errno));
        return NULL;
    }
    fstat(fd, &st);

    map = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
    if (MAP_FAILED == map) {
        fprintf(stderr, "mmap %s: %s", filename, strerror(errno));
        return NULL;
    }

    close(fd);
    return map + offset;
}

uint32_t readsys(char *dev, char *file)
{
    char filename[128], content[128];
    FILE *fp;

    snprintf(filename, sizeof(filename),
             "%s/%s/%s", BASEPATH, dev, file);
    fp = fopen(filename, "r");
    if (NULL == fp)
        return 0;
    fgets(content, sizeof(content), fp);
    fclose(fp);
    return strtol(content, NULL, 0);
}

/* ------------------------------------------------------------- */

static const char *xhci_capname[] = {
    [   0         ] = "Reserved",
    [   1         ] = "USB Legacy Support",
    [   2         ] = "Supported Protocol",
    [   3         ] = "Extended Power Management",
    [   4         ] = "I/O Virtualization",
    [   5         ] = "Message Interrupt",
    [   6         ] = "Local Memory",
    [   7 ...   9 ] = "Reserved",
    [  10         ] = "USB Debug Capability",
    [  11 ...  16 ] = "Reserved",
    [  17         ] = "Extended Message Interrupt",
    [  18 ... 191 ] = "Reserved",
    [ 192 ... 255 ] = "Vendor Defined",
};

void xhcidump(char *dev, uint32_t offset)
{
    uint32_t *map, val;
    int i, n, ext = 0, off, cid;

    map = mapbar(dev, 0, offset);
    if (!map)
        return;

    n = map[0] & 0xff;
    if (n > 0x20)
        n = 0x20;
    printf("  xhci base caps\n");
    for (i = 0; i * 4 < n; i++) {
        val = map[i];
        printf("    0x%04x: 0x%08x", i * 4, val);
        switch (i * 4) {
        case 0x00:
            printf(" - version %x.%02x, caplength 0x%x",
                   (val >> 24) & 0xff, (val >> 16) & 0xff, val & 0xff);
            break;
        case 0x04:
            printf(" - ports %d, intrs %d, slots %d",
                   (val >> 24) & 0xff, (val >> 8) & 0x3ff, val & 0xff);
            break;
        case 0x08:
            printf(" - erst max 0x%x, ist 0x%x",
                   (val >> 4) & 0x0f, val & 0x0f);
            break;
        case 0x0c:
            printf(" - u2 lat 0x%x, u1 lat 0x%x",
                   (val >> 16) & 0xffff, val & 0xff);
            break;
        case 0x10:
            ext = (val >> 16) & 0xffff;
            printf(" - extptr 0x%x, maxpsasize 0x%x%s%s%s%s%s%s%s%s",
                   ext, (val >> 12) & 0xf,
                   (val & 0x80) ? ", nss"  : "",
                   (val & 0x40) ? ", ltc"  : "",
                   (val & 0x20) ? ", lhrc" : "",
                   (val & 0x10) ? ", pind" : "",
                   (val & 0x08) ? ", ppc"  : "",
                   (val & 0x04) ? ", csz"  : "",
                   (val & 0x02) ? ", bnc"  : "",
                   (val & 0x01) ? ", ac64" : "");
            break;
        case 0x14:
            printf(" - doorbell offset 0x%x", val);
            break;
        case 0x18:
            printf(" - runtime offset 0x%x", val);
            break;
        default:
            break;
        }
        printf("\n");
    }

    while (ext) {
        printf("  xhci ext cap @ 0x%x\n", ext*4);
        val = map[ext];
        off = val >> 8 & 0xff;
        cid = val & 0xff;
        printf("    0x%04x: 0x%08x - next 0x%x, cap 0x%x [ %s ]\n",
               ext*4, val, off, cid, xhci_capname[cid]);
        switch (cid) {
        case 2:
            printf("                       - version %x.%02x\n",
                   (val >> 24) & 0xff, (val >> 16) & 0xff);
            val = map[ext+1];
            printf("    0x%04x: 0x%08x - name %c%c%c%c\n",
                   ext*4+4, val, val & 0xff, (val >> 8) & 0xff,
                   (val >> 16) & 0xff, (val >> 24) & 0xff);
            val = map[ext+2];
            printf("    0x%04x: 0x%08x - psic 0x%x, port count %d, port offset %d\n",
                   ext*4+8, val, (val >> 28) & 0xf, (val >> 8) & 0xff, val & 0xff);
            break;
        }
        if (off) {
            ext += off;
        } else {
            ext = 0;
        }
    }
    return;
}

/* ------------------------------------------------------------- */

void ehcidump(char *dev, uint32_t offset)
{
    uint32_t *map, val;
    int i, n;

    map = mapbar(dev, 0, offset);
    if (!map)
        return;

    n = map[0] & 0xff;
    if (n > 0x10)
        n = 0x10;
    printf("  ehci caps\n");
    for (i = 0; i * 4 < n; i++) {
        val = map[i];
        printf("    0x%04x: 0x%08x", i * 4, val);
        switch (i * 4) {
        case 0x00:
            printf(" - version %x.%02x, caplength 0x%x",
                   (val >> 24) & 0xff, (val >> 16) & 0xff, val & 0xff);
            break;
        case 0x04:
            printf(" - dbg port %d%s, companion %d ctl %d prt%s, ports %d",
                   (val >> 20) & 0x0f,
                   (val >> 16) & 0x01 ? ", pi" : "",
                   (val >> 12) & 0x0f,
                   (val >>  8) & 0x0f,
                   (val >>  4) & 0x01 ? ", ppc" : "",
                   (val >>  0) & 0x07);
            break;
        case 0x08:
            printf(" - extptr 0x%x, iso thresh %d%s%s%s",
                   (val >> 8) & 0xff,
                   (val >> 4) & 0x0f,
                   (val >> 2) & 0x01 ? ", aspc" : "",
                   (val >> 1) & 0x01 ? ", pflf" : "",
                   (val >> 0) & 0x01 ? ", 64ac" : "");
            break;
        default:
            break;
        }
        printf("\n");
    }

    return;
}

/* ------------------------------------------------------------- */

void ahcidump(char *dev)
{
    uint32_t *map, val;
    int ports,i;

    map = mapbar(dev, 5, 0);
    if (!map)
        return;

    printf("  ahci caps\n");

    val = map[0];
    ports = (val >> 0) & 0x1f;
    printf("    0x%04x: 0x%08x", 0, val);
    printf(" - maxports: %d\n",
           ports);

    val = map[3];
    printf("    0x%04x: 0x%08x", 3*4, val);
    printf(" - port map:");
    for (i = 0; i < ports+1; i++) {
        if (val & (1 << i)) {
            printf(" %d", i);
        } else {
            printf(" -");
        }
    }
    printf("\n");

    val = map[4];
    printf("    0x%04x: 0x%08x", 4*4, val);
    printf(" - ahci ver: %x.%x%x\n",
           (val >> 16) & 0xffff,
           (val >>  8) & 0xff,
           (val >>  0) & 0xff);

    return;
}

/* ------------------------------------------------------------- */

int main(int argc, char *argv[])
{
    unsigned long addr0;
    struct dirent *entry;
    uint32_t class, vendor, device;
    DIR *dir;

    dir = opendir(BASEPATH);
    while ((entry = readdir(dir)) != NULL) {
        if (entry->d_name[0] == '.')
            continue;
        if (argc > 1 && !strstr(entry->d_name, argv[1]))
            continue;
        class  = readsys(entry->d_name, "class");
        vendor = readsys(entry->d_name, "vendor");
        device = readsys(entry->d_name, "device");
        addr0  = readsys(entry->d_name, "resource");
        switch (class) {
        case 0x0c0300:
            printf("uhci @ %s %04x:%04x\n", entry->d_name, vendor, device);
            break;
        case 0x0c0310:
            printf("ohci @ %s %04x:%04x\n", entry->d_name, vendor, device);
            break;
        case 0x0c0320:
            printf("ehci @ %s %04x:%04x\n", entry->d_name, vendor, device);
            printf("  bar0 @ 0x%lx\n", addr0);
            ehcidump(entry->d_name, addr0 & 0xfff);
            break;
        case 0x0c0330:
            printf("xhci @ %s %04x:%04x\n", entry->d_name, vendor, device);
            printf("  bar0 @ 0x%lx\n", addr0);
            xhcidump(entry->d_name, addr0 & 0xfff);
            break;
        case 0x010601:
            printf("ahci @ %s %04x:%04x\n", entry->d_name, vendor, device);
            if (1) {
                ahcidump(entry->d_name);
            }
            break;
        }
    }
    return 0;
}