diff options
Diffstat (limited to 'roms/skiboot/external/opal-prd/i2c.c')
| -rw-r--r-- | roms/skiboot/external/opal-prd/i2c.c | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/roms/skiboot/external/opal-prd/i2c.c b/roms/skiboot/external/opal-prd/i2c.c new file mode 100644 index 000000000..f4c7f27a4 --- /dev/null +++ b/roms/skiboot/external/opal-prd/i2c.c @@ -0,0 +1,257 @@ +// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later +/* + * I2C operations for opal-prd + * + * Copyright 2013-2018 IBM Corp. + */ + +#define _GNU_SOURCE /* for aspritnf */ +#include <errno.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <fcntl.h> +#include <stdlib.h> +#include <stdio.h> +#include <unistd.h> +#include <stdbool.h> +#include <stdint.h> +#include <dirent.h> +#include <sys/param.h> +#include <string.h> +#include <sys/ioctl.h> +#include <linux/i2c.h> +#include <linux/i2c-dev.h> +#include <ccan/list/list.h> + +#include "opal-prd.h" +#include "module.h" +#include "i2c.h" + +struct i2c_bus { + uint32_t chip_id; + uint8_t engine; + uint8_t port; + const char *devpath; + int fd; + struct list_node link; +}; + +static struct list_head bus_list = LIST_HEAD_INIT(bus_list); + +static int i2c_get_dev(uint32_t chip, uint8_t eng, uint8_t port, uint16_t dev) +{ + struct i2c_bus *b, *bus = NULL; + + list_for_each(&bus_list, b, link) { + if (b->chip_id == chip && b->engine == eng && b->port == port) { + bus = b; + break; + } + } + if (!bus) { + pr_log(LOG_WARNING, "I2C: Bus %08x/%d/%d not found", + chip, eng, port); + return -1; + } + if (bus->fd < 0) { + bus->fd = open(bus->devpath, O_RDWR); + if (bus->fd < 0) { + pr_log(LOG_ERR, "I2C: Failed to open %s: %m", + bus->devpath); + return -1; + } + } + + /* XXX We could use the I2C_SLAVE ioctl to check if the device + * is currently in use by a kernel driver... + */ + + return bus->fd; +} + +int i2c_read(uint32_t chip_id, uint8_t engine, uint8_t port, + uint16_t device, uint32_t offset_size, uint32_t offset, + uint32_t length, void* data) +{ + struct i2c_rdwr_ioctl_data ioargs; + struct i2c_msg msgs[2]; + uint8_t obuf[4]; + int fd, i, midx = 0; + + if (offset_size > 4) { + pr_log(LOG_ERR, "I2C: Invalid write offset_size %d", + offset_size); + return -1; + } + fd = i2c_get_dev(chip_id, engine, port, device); + if (fd == -1) + return -1; + + /* If we have an offset, build a message for it */ + if (offset_size) { + /* The offset has a variable size so let's handle this properly + * as it has to be laid out in memory MSB first + */ + for (i = 0; i < offset_size; i++) + obuf[i] = offset >> (8 * (offset_size - i - 1)); + msgs[0].addr = device; + msgs[0].flags = 0; + msgs[0].buf = obuf; + msgs[0].len = offset_size; + midx = 1; + } + + /* Build the message for the data portion */ + msgs[midx].addr = device; + msgs[midx].flags = I2C_M_RD; + msgs[midx].buf = data; + msgs[midx].len = length; + midx++; + + ioargs.msgs = msgs; + ioargs.nmsgs = midx; + if (ioctl(fd, I2C_RDWR, &ioargs) < 0) { + pr_log(LOG_ERR, "I2C: Read error: %m"); + return -1; + } + pr_debug("I2C: Read from %08x:%d:%d@%02x+0x%x %d bytes ok", + chip_id, engine, port, device, offset_size ? offset : 0, length); + + return 0; +} + +int i2c_write(uint32_t chip_id, uint8_t engine, uint8_t port, + uint16_t device, uint32_t offset_size, uint32_t offset, + uint32_t length, void* data) +{ + struct i2c_rdwr_ioctl_data ioargs; + struct i2c_msg msg; + int fd, size, i, rc; + uint8_t *buf; + + if (offset_size > 4) { + pr_log(LOG_ERR, "I2C: Invalid write offset_size %d", + offset_size); + return -1; + } + fd = i2c_get_dev(chip_id, engine, port, device); + if (fd == -1) + return -1; + + /* Not all kernel driver versions support breaking up a write into + * two components (offset, data), so we coalesce them first and + * issue a single write. The offset is laid out in BE format. + */ + size = offset_size + length; + buf = malloc(size); + if (!buf) { + pr_log(LOG_ERR, "I2C: Out of memory"); + return -1; + } + + /* The offset has a variable size so let's handle this properly + * as it has to be laid out in memory MSB first + */ + for (i = 0; i < offset_size; i++) + buf[i] = offset >> (8 * (offset_size - i - 1)); + + /* Copy the remaining data */ + memcpy(buf + offset_size, data, length); + + /* Build the message */ + msg.addr = device; + msg.flags = 0; + msg.buf = buf; + msg.len = size; + ioargs.msgs = &msg; + ioargs.nmsgs = 1; + rc = ioctl(fd, I2C_RDWR, &ioargs); + free(buf); + if (rc < 0) { + pr_log(LOG_ERR, "I2C: Write error: %m"); + return -1; + } + + return 0; +} + +static void i2c_add_bus(uint32_t chip, uint32_t engine, uint32_t port, + const char *devname) +{ + struct i2c_bus *b = malloc(sizeof(struct i2c_bus)); + char *dn; + + if (asprintf(&dn, "/dev/%s", devname) < 0) { + pr_log(LOG_ERR, "I2C: Error creating devpath for %s: %m", + devname); + free(b); + return; + } + + memset(b, 0, sizeof(*b)); + b->chip_id = chip; + b->engine = engine; + b->port = port; + b->devpath = dn; + b->fd = -1; + list_add(&bus_list, &b->link); +} + +void i2c_init(void) +{ +#define SYSFS "/sys" /* XXX Find it ? */ + DIR *devsdir; + struct dirent *devent; + char dpath[PATH_MAX]; + char busname[256]; + char *s; + FILE *f; + unsigned int chip, engine, port; + + /* Ensure i2c-dev is loaded */ + insert_module("i2c-dev"); + + /* Get directory of i2c char devs in sysfs */ + devsdir = opendir(SYSFS "/class/i2c-dev"); + if (!devsdir) { + pr_log(LOG_ERR, "I2C: Error opening " + SYSFS "/class/i2c-dev: %m"); + return; + } + while ((devent = readdir(devsdir)) != NULL) { + if (!strcmp(devent->d_name, ".")) + continue; + if (!strcmp(devent->d_name, "..")) + continue; + + /* Get bus name */ + sprintf(dpath, SYSFS "/class/i2c-dev/%s/name", devent->d_name); + f = fopen(dpath, "r"); + if (!f) { + pr_log(LOG_NOTICE, "I2C: Can't open %s: %m, skipping.", + dpath); + continue; + } + s = fgets(busname, sizeof(busname), f); + fclose(f); + if (!s) { + pr_log(LOG_NOTICE, "Failed to read %s, skipping.", + dpath); + continue; + } + + /* Is this a P8 or Centaur i2c bus ? No -> move on */ + if (strncmp(s, "p8_", 3) == 0) + sscanf(s, "p8_%x_e%dp%d", &chip, &engine, &port); + else if (strncmp(s, "cen_", 4) == 0) + sscanf(s, "cen_%x_e%dp%d", &chip, &engine, &port); + else + continue; + + pr_log(LOG_INFO, "I2C: Found Chip: %08x engine %d port %d", + chip, engine, port); + i2c_add_bus(chip, engine, port, devent->d_name); + } + closedir(devsdir); +} + |