diff options
Diffstat (limited to 'drivers/rtc/rtc-optee.c')
| -rw-r--r-- | drivers/rtc/rtc-optee.c | 362 |
1 files changed, 362 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-optee.c b/drivers/rtc/rtc-optee.c new file mode 100644 index 000000000000..9f8b5d4a8f6b --- /dev/null +++ b/drivers/rtc/rtc-optee.c @@ -0,0 +1,362 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2022 Microchip. + */ + +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/rtc.h> +#include <linux/tee_drv.h> + +#define RTC_INFO_VERSION 0x1 + +#define TA_CMD_RTC_GET_INFO 0x0 +#define TA_CMD_RTC_GET_TIME 0x1 +#define TA_CMD_RTC_SET_TIME 0x2 +#define TA_CMD_RTC_GET_OFFSET 0x3 +#define TA_CMD_RTC_SET_OFFSET 0x4 + +#define TA_RTC_FEATURE_CORRECTION BIT(0) + +struct optee_rtc_time { + u32 tm_sec; + u32 tm_min; + u32 tm_hour; + u32 tm_mday; + u32 tm_mon; + u32 tm_year; + u32 tm_wday; +}; + +struct optee_rtc_info { + u64 version; + u64 features; + struct optee_rtc_time range_min; + struct optee_rtc_time range_max; +}; + +/** + * struct optee_rtc - OP-TEE RTC private data + * @dev: OP-TEE based RTC device. + * @ctx: OP-TEE context handler. + * @session_id: RTC TA session identifier. + * @shm: Memory pool shared with RTC device. + * @features: Bitfield of RTC features + */ +struct optee_rtc { + struct device *dev; + struct tee_context *ctx; + u32 session_id; + struct tee_shm *shm; + u64 features; +}; + +static int optee_rtc_readtime(struct device *dev, struct rtc_time *tm) +{ + struct optee_rtc *priv = dev_get_drvdata(dev); + struct tee_ioctl_invoke_arg inv_arg = {0}; + struct optee_rtc_time *optee_tm; + struct tee_param param[4] = {0}; + int ret; + + inv_arg.func = TA_CMD_RTC_GET_TIME; + inv_arg.session = priv->session_id; + inv_arg.num_params = 4; + + /* Fill invoke cmd params */ + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT; + param[0].u.memref.shm = priv->shm; + param[0].u.memref.size = sizeof(struct optee_rtc_time); + + ret = tee_client_invoke_func(priv->ctx, &inv_arg, param); + if (ret < 0 || inv_arg.ret != 0) + return ret ? ret : -EPROTO; + + optee_tm = tee_shm_get_va(priv->shm, 0); + if (IS_ERR(optee_tm)) + return PTR_ERR(optee_tm); + + if (param[0].u.memref.size != sizeof(*optee_tm)) + return -EPROTO; + + tm->tm_sec = optee_tm->tm_sec; + tm->tm_min = optee_tm->tm_min; + tm->tm_hour = optee_tm->tm_hour; + tm->tm_mday = optee_tm->tm_mday; + tm->tm_mon = optee_tm->tm_mon; + tm->tm_year = optee_tm->tm_year - 1900; + tm->tm_wday = optee_tm->tm_wday; + tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); + + return 0; +} + +static int optee_rtc_settime(struct device *dev, struct rtc_time *tm) +{ + struct optee_rtc *priv = dev_get_drvdata(dev); + struct tee_ioctl_invoke_arg inv_arg = {0}; + struct tee_param param[4] = {0}; + struct optee_rtc_time optee_tm; + void *rtc_data; + int ret; + + optee_tm.tm_sec = tm->tm_sec; + optee_tm.tm_min = tm->tm_min; + optee_tm.tm_hour = tm->tm_hour; + optee_tm.tm_mday = tm->tm_mday; + optee_tm.tm_mon = tm->tm_mon; + optee_tm.tm_year = tm->tm_year + 1900; + optee_tm.tm_wday = tm->tm_wday; + + inv_arg.func = TA_CMD_RTC_SET_TIME; + inv_arg.session = priv->session_id; + inv_arg.num_params = 4; + + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT; + param[0].u.memref.shm = priv->shm; + param[0].u.memref.size = sizeof(struct optee_rtc_time); + + rtc_data = tee_shm_get_va(priv->shm, 0); + if (IS_ERR(rtc_data)) + return PTR_ERR(rtc_data); + + memcpy(rtc_data, &optee_tm, sizeof(struct optee_rtc_time)); + + ret = tee_client_invoke_func(priv->ctx, &inv_arg, param); + if (ret < 0 || inv_arg.ret != 0) + return ret ? ret : -EPROTO; + + return 0; +} + +static int optee_rtc_readoffset(struct device *dev, long *offset) +{ + struct optee_rtc *priv = dev_get_drvdata(dev); + struct tee_ioctl_invoke_arg inv_arg = {0}; + struct tee_param param[4] = {0}; + int ret; + + if (!(priv->features & TA_RTC_FEATURE_CORRECTION)) + return -EOPNOTSUPP; + + inv_arg.func = TA_CMD_RTC_GET_OFFSET; + inv_arg.session = priv->session_id; + inv_arg.num_params = 4; + + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT; + + ret = tee_client_invoke_func(priv->ctx, &inv_arg, param); + if (ret < 0 || inv_arg.ret != 0) + return ret ? ret : -EPROTO; + + *offset = param[0].u.value.a; + + return 0; +} + +static int optee_rtc_setoffset(struct device *dev, long offset) +{ + struct optee_rtc *priv = dev_get_drvdata(dev); + struct tee_ioctl_invoke_arg inv_arg = {0}; + struct tee_param param[4] = {0}; + int ret; + + if (!(priv->features & TA_RTC_FEATURE_CORRECTION)) + return -EOPNOTSUPP; + + inv_arg.func = TA_CMD_RTC_SET_OFFSET; + inv_arg.session = priv->session_id; + inv_arg.num_params = 4; + + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT; + param[0].u.value.a = offset; + + ret = tee_client_invoke_func(priv->ctx, &inv_arg, param); + if (ret < 0 || inv_arg.ret != 0) + return ret ? ret : -EPROTO; + + return 0; +} + +static const struct rtc_class_ops optee_rtc_ops = { + .read_time = optee_rtc_readtime, + .set_time = optee_rtc_settime, + .set_offset = optee_rtc_setoffset, + .read_offset = optee_rtc_readoffset, +}; + +static int optee_rtc_read_info(struct device *dev, struct rtc_device *rtc, + u64 *features) +{ + struct optee_rtc *priv = dev_get_drvdata(dev); + struct tee_ioctl_invoke_arg inv_arg = {0}; + struct tee_param param[4] = {0}; + struct optee_rtc_info *info; + struct optee_rtc_time *tm; + int ret; + + inv_arg.func = TA_CMD_RTC_GET_INFO; + inv_arg.session = priv->session_id; + inv_arg.num_params = 4; + + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT; + param[0].u.memref.shm = priv->shm; + param[0].u.memref.size = sizeof(*info); + + ret = tee_client_invoke_func(priv->ctx, &inv_arg, param); + if (ret < 0 || inv_arg.ret != 0) + return ret ? ret : -EPROTO; + + info = tee_shm_get_va(priv->shm, 0); + if (IS_ERR(info)) + return PTR_ERR(info); + + if (param[0].u.memref.size != sizeof(*info)) + return -EPROTO; + + if (info->version != RTC_INFO_VERSION) + return -EPROTO; + + *features = info->features; + + tm = &info->range_min; + rtc->range_min = mktime64(tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, + tm->tm_sec); + tm = &info->range_max; + rtc->range_max = mktime64(tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, + tm->tm_sec); + + return 0; +} + +static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data) +{ + if (ver->impl_id == TEE_IMPL_ID_OPTEE) + return 1; + else + return 0; +} + +static int optee_rtc_probe(struct device *dev) +{ + struct tee_client_device *rtc_device = to_tee_client_device(dev); + struct tee_ioctl_open_session_arg sess_arg; + struct optee_rtc *priv; + struct rtc_device *rtc; + struct tee_shm *shm; + int ret, err; + + memset(&sess_arg, 0, sizeof(sess_arg)); + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + rtc = devm_rtc_allocate_device(dev); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + /* Open context with TEE driver */ + priv->ctx = tee_client_open_context(NULL, optee_ctx_match, NULL, NULL); + if (IS_ERR(priv->ctx)) + return -ENODEV; + + /* Open session with rtc Trusted App */ + export_uuid(sess_arg.uuid, &rtc_device->id.uuid); + sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL; + + ret = tee_client_open_session(priv->ctx, &sess_arg, NULL); + if (ret < 0 || sess_arg.ret != 0) { + dev_err(dev, "tee_client_open_session failed, err: %x\n", sess_arg.ret); + err = -EINVAL; + goto out_ctx; + } + priv->session_id = sess_arg.session; + + shm = tee_shm_alloc_kernel_buf(priv->ctx, sizeof(struct optee_rtc_info)); + if (IS_ERR(shm)) { + dev_err(priv->dev, "tee_shm_alloc_kernel_buf failed\n"); + err = PTR_ERR(shm); + goto out_sess; + } + + priv->shm = shm; + priv->dev = dev; + dev_set_drvdata(dev, priv); + + rtc->ops = &optee_rtc_ops; + + err = optee_rtc_read_info(dev, rtc, &priv->features); + if (err) { + dev_err(dev, "Failed to get RTC features from OP-TEE\n"); + goto out_shm; + } + + err = devm_rtc_register_device(rtc); + if (err) + goto out_shm; + + /* + * We must clear this bit after registering because rtc_register_device + * will set it if it sees that .set_offset is provided. + */ + if (!(priv->features & TA_RTC_FEATURE_CORRECTION)) + clear_bit(RTC_FEATURE_CORRECTION, rtc->features); + + return 0; + +out_shm: + tee_shm_free(priv->shm); +out_sess: + tee_client_close_session(priv->ctx, priv->session_id); +out_ctx: + tee_client_close_context(priv->ctx); + + return err; +} + +static int optee_rtc_remove(struct device *dev) +{ + struct optee_rtc *priv = dev_get_drvdata(dev); + + tee_client_close_session(priv->ctx, priv->session_id); + tee_client_close_context(priv->ctx); + + return 0; +} + +static const struct tee_client_device_id optee_rtc_id_table[] = { + {UUID_INIT(0xf389f8c8, 0x845f, 0x496c, + 0x8b, 0xbe, 0xd6, 0x4b, 0xd2, 0x4c, 0x92, 0xfd)}, + {} +}; + +MODULE_DEVICE_TABLE(tee, optee_rtc_id_table); + +static struct tee_client_driver optee_rtc_driver = { + .id_table = optee_rtc_id_table, + .driver = { + .name = "optee_rtc", + .bus = &tee_bus_type, + .probe = optee_rtc_probe, + .remove = optee_rtc_remove, + }, +}; + +static int __init optee_rtc_mod_init(void) +{ + return driver_register(&optee_rtc_driver.driver); +} + +static void __exit optee_rtc_mod_exit(void) +{ + driver_unregister(&optee_rtc_driver.driver); +} + +module_init(optee_rtc_mod_init); +module_exit(optee_rtc_mod_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Clément Léger <clement.leger@bootlin.com>"); +MODULE_DESCRIPTION("OP-TEE based RTC driver"); |