#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/mman.h>

#include "pci.h"

struct pci_access *pci;
struct pci_dev *dev;

void find_device(char *name,
                 unsigned int vendor,
                 unsigned int device)
{
    struct pci_filter filter;
    struct pci_dev *d;

    if (!pci) {
        pci = pci_alloc();
        if (!pci) {
            fprintf(stderr, "libpci alloc failed\n");
            exit(1);
        }
        pci_init(pci);
        pci_scan_bus(pci);
    }

    pci_filter_init(pci, &filter);
    filter.vendor = vendor;
    filter.device = device;

    for (d = pci->devices; d != NULL; d = d->next) {
        if (!pci_filter_match(&filter, d))
            continue;
        dev = d;
        fprintf(stderr, "%s found at %02x:%02x.%x\n",
                name, dev->bus, dev->dev, dev->func);
        return;
    }
    fprintf(stderr, "%s not found\n", name);
    exit(1);
}

void *mmap_bar(int nr)
{
    char filename[128];
    size_t size;
    int fd;
    void *bar;

    snprintf(filename, sizeof(filename),
             "/sys/bus/pci/devices/%04x:%02x:%02x.%x/resource%d",
             dev->domain, dev->bus, dev->dev, dev->func, nr);
    size = dev->size[nr];
    fd = open(filename, O_RDWR);
    if (fd < 0) {
        fprintf(stderr, "open %s: %s\n", filename, strerror(errno));
        exit(1);
    }
    bar = mmap(NULL, size, PROT_WRITE | PROT_READ, MAP_SHARED, fd, 0);
    if (bar == MAP_FAILED) {
        fprintf(stderr, "mmap %s: %s\n", filename, strerror(errno));
        exit(1);
    }
    if (size >= (1 << 20)) {
        fprintf(stderr, "bar %d mapped (%zd MB)\n", nr, size >> 20);
    } else {
        fprintf(stderr, "bar %d mapped (%zd bytes)\n", nr, size);
    }
    return bar;
}