/*   SPDX-License-Identifier: BSD-3-Clause
 *   Copyright(c) 2018 Advanced Micro Devices, Inc. All rights reserved.
 */

#include <dirent.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <rte_string_fns.h>

#include "ccp_pci.h"

static const char * const uio_module_names[] = {
        "igb_uio",
        "uio_pci_generic",
        "vfio_pci"
};

int
ccp_check_pci_uio_module(void)
{
        FILE *fp;
        int i;
        char buf[BUFSIZ];

        fp = fopen(PROC_MODULES, "r");
        if (fp == NULL)
                return -1;
        i = 0;
        while (uio_module_names[i] != NULL) {
                while (fgets(buf, sizeof(buf), fp) != NULL) {
                        if (!strncmp(buf, uio_module_names[i],
                                     strlen(uio_module_names[i]))) {
                                fclose(fp);
                                return i;
                        }
                }
                i++;
                rewind(fp);
        }
        fclose(fp);
        printf("Insert igb_uio or uio_pci_generic kernel module(s)");
        return -1;/* uio not inserted */
}

/*
 * split up a pci address into its constituent parts.
 */
int
ccp_parse_pci_addr_format(const char *buf, int bufsize, uint16_t *domain,
                          uint8_t *bus, uint8_t *devid, uint8_t *function)
{
        /* first split on ':' */
        union splitaddr {
                struct {
                        char *domain;
                        char *bus;
                        char *devid;
                        char *function;
                };
                char *str[PCI_FMT_NVAL];
                /* last element-separator is "." not ":" */
        } splitaddr;

        char *buf_copy = strndup(buf, bufsize);

        if (buf_copy == NULL)
                return -1;

        if (rte_strsplit(buf_copy, bufsize, splitaddr.str, PCI_FMT_NVAL, ':')
                        != PCI_FMT_NVAL - 1)
                goto error;
        /* final split is on '.' between devid and function */
        splitaddr.function = strchr(splitaddr.devid, '.');
        if (splitaddr.function == NULL)
                goto error;
        *splitaddr.function++ = '\0';

        /* now convert to int values */
        errno = 0;
        *domain = (uint8_t)strtoul(splitaddr.domain, NULL, 16);
        *bus = (uint8_t)strtoul(splitaddr.bus, NULL, 16);
        *devid = (uint8_t)strtoul(splitaddr.devid, NULL, 16);
        *function = (uint8_t)strtoul(splitaddr.function, NULL, 10);
        if (errno != 0)
                goto error;

        free(buf_copy); /* free the copy made with strdup */
        return 0;
error:
        free(buf_copy);
        return -1;
}

int
ccp_pci_parse_sysfs_value(const char *filename, unsigned long *val)
{
        FILE *f;
        char buf[BUFSIZ];
        char *end = NULL;

        f = fopen(filename, "r");
        if (f == NULL)
                return -1;
        if (fgets(buf, sizeof(buf), f) == NULL) {
                fclose(f);
                return -1;
        }
        *val = strtoul(buf, &end, 0);
        if ((buf[0] == '\0') || (end == NULL) || (*end != '\n')) {
                fclose(f);
                return -1;
        }
        fclose(f);
        return 0;
}

/** IO resource type: */
#define IORESOURCE_IO         0x00000100
#define IORESOURCE_MEM        0x00000200

/* parse one line of the "resource" sysfs file (note that the 'line'
 * string is modified)
 */
static int
ccp_pci_parse_one_sysfs_resource(char *line, size_t len, uint64_t *phys_addr,
                                 uint64_t *end_addr, uint64_t *flags)
{
        union pci_resource_info {
                struct {
                        char *phys_addr;
                        char *end_addr;
                        char *flags;
                };
                char *ptrs[PCI_RESOURCE_FMT_NVAL];
        } res_info;

        if (rte_strsplit(line, len, res_info.ptrs, 3, ' ') != 3)
                return -1;
        errno = 0;
        *phys_addr = strtoull(res_info.phys_addr, NULL, 16);
        *end_addr = strtoull(res_info.end_addr, NULL, 16);
        *flags = strtoull(res_info.flags, NULL, 16);
        if (errno != 0)
                return -1;

        return 0;
}

/* parse the "resource" sysfs file */
int
ccp_pci_parse_sysfs_resource(const char *filename, struct rte_pci_device *dev)
{
        FILE *fp;
        char buf[BUFSIZ];
        int i;
        uint64_t phys_addr, end_addr, flags;

        fp = fopen(filename, "r");
        if (fp == NULL)
                return -1;

        for (i = 0; i < PCI_MAX_RESOURCE; i++) {
                if (fgets(buf, sizeof(buf), fp) == NULL)
                        goto error;
                if (ccp_pci_parse_one_sysfs_resource(buf, sizeof(buf),
                                &phys_addr, &end_addr, &flags) < 0)
                        goto error;

                if (flags & IORESOURCE_MEM) {
                        dev->mem_resource[i].phys_addr = phys_addr;
                        dev->mem_resource[i].len = end_addr - phys_addr + 1;
                        /* not mapped for now */
                        dev->mem_resource[i].addr = NULL;
                }
        }
        fclose(fp);
        return 0;

error:
        fclose(fp);
        return -1;
}

int
ccp_find_uio_devname(const char *dirname)
{

        DIR *dir;
        struct dirent *e;
        char dirname_uio[PATH_MAX];
        unsigned int uio_num;
        int ret = -1;

        /* depending on kernel version, uio can be located in uio/uioX
         * or uio:uioX
         */
        snprintf(dirname_uio, sizeof(dirname_uio), "%s/uio", dirname);
        dir = opendir(dirname_uio);
        if (dir == NULL) {
        /* retry with the parent directory might be different kernel version*/
                dir = opendir(dirname);
                if (dir == NULL)
                        return -1;
        }

        /* take the first file starting with "uio" */
        while ((e = readdir(dir)) != NULL) {
                /* format could be uio%d ...*/
                int shortprefix_len = sizeof("uio") - 1;
                /* ... or uio:uio%d */
                int longprefix_len = sizeof("uio:uio") - 1;
                char *endptr;

                if (strncmp(e->d_name, "uio", 3) != 0)
                        continue;

                /* first try uio%d */
                errno = 0;
                uio_num = strtoull(e->d_name + shortprefix_len, &endptr, 10);
                if (errno == 0 && endptr != (e->d_name + shortprefix_len)) {
                        ret = uio_num;
                        break;
                }

                /* then try uio:uio%d */
                errno = 0;
                uio_num = strtoull(e->d_name + longprefix_len, &endptr, 10);
                if (errno == 0 && endptr != (e->d_name + longprefix_len)) {
                        ret = uio_num;
                        break;
                }
        }
        closedir(dir);
        return ret;


}