diff options
Diffstat (limited to 'roms/skiboot/external/xscom-utils/xscom.c')
| -rw-r--r-- | roms/skiboot/external/xscom-utils/xscom.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/roms/skiboot/external/xscom-utils/xscom.c b/roms/skiboot/external/xscom-utils/xscom.c new file mode 100644 index 000000000..031f9e193 --- /dev/null +++ b/roms/skiboot/external/xscom-utils/xscom.c @@ -0,0 +1,206 @@ +// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later +/* + * Do XSCOMs through linux debugfs interface + * + * Copyright 2014-2017 IBM Corp. + */ + +#define _LARGEFILE64_SOURCE +#include <sys/mman.h> +#include <string.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <errno.h> +#include <stdlib.h> +#include <stdio.h> +#include <unistd.h> +#include <stdint.h> +#include <stdbool.h> +#include <dirent.h> +#include <assert.h> +#include <ctype.h> + +#include "xscom.h" + +#define XSCOM_BASE_PATH "/sys/kernel/debug/powerpc/scom" + +struct xscom_chip { + struct xscom_chip *next; + uint32_t chip_id; + int fd; +}; +static struct xscom_chip *xscom_chips; + +void xscom_for_each_chip(void (*cb)(uint32_t chip_id)) +{ + struct xscom_chip *c; + + for (c = xscom_chips; c; c = c->next) + cb(c->chip_id); +} + +static uint32_t xscom_add_chip(const char *base_path, const char *dname) +{ + char nbuf[strlen(base_path) + strlen(dname) + 16]; + struct xscom_chip *chip; + int fd; + + snprintf(nbuf, sizeof(nbuf), "%s/%s/access", base_path, dname); + fd = open(nbuf, O_RDWR); + if (fd < 0) { + perror("Failed to open SCOM access file"); + exit(1); + } + + chip = malloc(sizeof(*chip)); + assert(chip); + memset(chip, 0, sizeof(*chip)); + chip->fd = fd; + chip->chip_id = strtoul(dname, NULL, 16); + chip->next = xscom_chips; + xscom_chips = chip; + + return chip->chip_id; +} + +static bool xscom_check_dirname(const char *n) +{ + while(*n) { + char c = toupper(*(n++)); + + if ((c < 'A' || c > 'Z') && + (c < '0' || c > '9')) + return false; + } + return true; +} + +static uint32_t xscom_scan_chips(const char *base_path) +{ + int i, nfiles; + struct dirent **filelist; + uint32_t lower = 0xffffffff; + + nfiles = scandir(base_path, &filelist, NULL, alphasort); + if (nfiles < 0) { + perror("Error accessing sysfs scom directory"); + exit(1); + } + if (nfiles == 0) { + fprintf(stderr, "No SCOM dir found in sysfs\n"); + exit(1); + } + + for (i = 0; i < nfiles; i++) { + struct dirent *d = filelist[i]; + uint32_t id; + + if (d->d_type != DT_DIR) + continue; + if (!xscom_check_dirname(d->d_name)) + continue; + id = xscom_add_chip(base_path, d->d_name); + if (id < lower) + lower = id; + free(d); + } + + free(filelist); + return lower; +} + +static struct xscom_chip *xscom_find_chip(uint32_t chip_id) +{ + struct xscom_chip *c; + + for (c = xscom_chips; c; c = c->next) + if (c->chip_id == chip_id) + return c; + return NULL; +} + +static uint64_t xscom_mangle_addr(uint64_t addr) +{ + uint64_t tmp; + + /* + * Shift the top 4 bits (indirect mode) down by 4 bits so we + * don't lose going through the debugfs interfaces. + */ + tmp = (addr & 0xf000000000000000) >> 4; + addr &= 0x00ffffffffffffff; + addr |= tmp; + + /* Shift up by 3 for debugfs */ + return addr << 3; +} + +int xscom_read(uint32_t chip_id, uint64_t addr, uint64_t *val) +{ + struct xscom_chip *c = xscom_find_chip(chip_id); + int rc; + + if (!c) + return -ENODEV; + addr = xscom_mangle_addr(addr); + lseek64(c->fd, addr, SEEK_SET); + rc = read(c->fd, val, 8); + if (rc < 0) + return -errno; + if (rc != 8) + return -EIO; + return 0; +} + +int xscom_write(uint32_t chip_id, uint64_t addr, uint64_t val) +{ + struct xscom_chip *c = xscom_find_chip(chip_id); + int rc; + + if (!c) + return -ENODEV; + addr = xscom_mangle_addr(addr); + lseek64(c->fd, addr, SEEK_SET); + rc = write(c->fd, &val, 8); + if (rc < 0) + return -errno; + if (rc != 8) + return -EIO; + return 0; +} + +int xscom_read_ex(uint32_t ex_target_id, uint64_t addr, uint64_t *val) +{ + uint32_t chip_id = ex_target_id >> 4;; + + addr |= (ex_target_id & 0xf) << 24; + + /* XXX TODO: Special wakeup ? */ + + return xscom_read(chip_id, addr, val); +} + +int xscom_write_ex(uint32_t ex_target_id, uint64_t addr, uint64_t val) +{ + uint32_t chip_id = ex_target_id >> 4;; + + addr |= (ex_target_id & 0xf) << 24; + + /* XXX TODO: Special wakeup ? */ + + return xscom_write(chip_id, addr, val); +} + +bool xscom_readable(uint64_t addr) +{ + /* Top nibble 9 indicates form 1 indirect, which is write only */ + if (((addr >> 60) & 0xf) == 9) + return false; + return true; +} + +uint32_t xscom_init(void) +{ + return xscom_scan_chips(XSCOM_BASE_PATH); +} |