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![Clément Léger](/assets/img/avatar_default.png)
This drivers allows to communicate with a RTC PTA handled by OP-TEE [1]. This PTA allows to query RTC information, set/get time and set/get offset depending on the supported features. [1] https://github.com/OP-TEE/optee_os/pull/5179 Signed-off-by: Clément Léger <clement.leger@bootlin.com> Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20220308133505.471601-1-clement.leger@bootlin.com
362 lines
8.7 KiB
C
362 lines
8.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2022 Microchip.
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*/
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/rtc.h>
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#include <linux/tee_drv.h>
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#define RTC_INFO_VERSION 0x1
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#define TA_CMD_RTC_GET_INFO 0x0
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#define TA_CMD_RTC_GET_TIME 0x1
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#define TA_CMD_RTC_SET_TIME 0x2
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#define TA_CMD_RTC_GET_OFFSET 0x3
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#define TA_CMD_RTC_SET_OFFSET 0x4
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#define TA_RTC_FEATURE_CORRECTION BIT(0)
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struct optee_rtc_time {
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u32 tm_sec;
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u32 tm_min;
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u32 tm_hour;
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u32 tm_mday;
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u32 tm_mon;
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u32 tm_year;
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u32 tm_wday;
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};
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struct optee_rtc_info {
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u64 version;
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u64 features;
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struct optee_rtc_time range_min;
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struct optee_rtc_time range_max;
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};
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/**
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* struct optee_rtc - OP-TEE RTC private data
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* @dev: OP-TEE based RTC device.
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* @ctx: OP-TEE context handler.
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* @session_id: RTC TA session identifier.
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* @shm: Memory pool shared with RTC device.
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* @features: Bitfield of RTC features
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*/
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struct optee_rtc {
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struct device *dev;
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struct tee_context *ctx;
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u32 session_id;
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struct tee_shm *shm;
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u64 features;
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};
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static int optee_rtc_readtime(struct device *dev, struct rtc_time *tm)
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{
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struct optee_rtc *priv = dev_get_drvdata(dev);
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struct tee_ioctl_invoke_arg inv_arg = {0};
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struct optee_rtc_time *optee_tm;
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struct tee_param param[4] = {0};
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int ret;
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inv_arg.func = TA_CMD_RTC_GET_TIME;
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inv_arg.session = priv->session_id;
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inv_arg.num_params = 4;
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/* Fill invoke cmd params */
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param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
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param[0].u.memref.shm = priv->shm;
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param[0].u.memref.size = sizeof(struct optee_rtc_time);
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ret = tee_client_invoke_func(priv->ctx, &inv_arg, param);
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if (ret < 0 || inv_arg.ret != 0)
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return ret ? ret : -EPROTO;
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optee_tm = tee_shm_get_va(priv->shm, 0);
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if (IS_ERR(optee_tm))
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return PTR_ERR(optee_tm);
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if (param[0].u.memref.size != sizeof(*optee_tm))
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return -EPROTO;
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tm->tm_sec = optee_tm->tm_sec;
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tm->tm_min = optee_tm->tm_min;
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tm->tm_hour = optee_tm->tm_hour;
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tm->tm_mday = optee_tm->tm_mday;
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tm->tm_mon = optee_tm->tm_mon;
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tm->tm_year = optee_tm->tm_year - 1900;
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tm->tm_wday = optee_tm->tm_wday;
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tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
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return 0;
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}
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static int optee_rtc_settime(struct device *dev, struct rtc_time *tm)
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{
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struct optee_rtc *priv = dev_get_drvdata(dev);
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struct tee_ioctl_invoke_arg inv_arg = {0};
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struct tee_param param[4] = {0};
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struct optee_rtc_time optee_tm;
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void *rtc_data;
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int ret;
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optee_tm.tm_sec = tm->tm_sec;
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optee_tm.tm_min = tm->tm_min;
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optee_tm.tm_hour = tm->tm_hour;
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optee_tm.tm_mday = tm->tm_mday;
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optee_tm.tm_mon = tm->tm_mon;
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optee_tm.tm_year = tm->tm_year + 1900;
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optee_tm.tm_wday = tm->tm_wday;
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inv_arg.func = TA_CMD_RTC_SET_TIME;
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inv_arg.session = priv->session_id;
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inv_arg.num_params = 4;
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param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
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param[0].u.memref.shm = priv->shm;
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param[0].u.memref.size = sizeof(struct optee_rtc_time);
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rtc_data = tee_shm_get_va(priv->shm, 0);
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if (IS_ERR(rtc_data))
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return PTR_ERR(rtc_data);
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memcpy(rtc_data, &optee_tm, sizeof(struct optee_rtc_time));
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ret = tee_client_invoke_func(priv->ctx, &inv_arg, param);
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if (ret < 0 || inv_arg.ret != 0)
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return ret ? ret : -EPROTO;
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return 0;
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}
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static int optee_rtc_readoffset(struct device *dev, long *offset)
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{
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struct optee_rtc *priv = dev_get_drvdata(dev);
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struct tee_ioctl_invoke_arg inv_arg = {0};
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struct tee_param param[4] = {0};
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int ret;
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if (!(priv->features & TA_RTC_FEATURE_CORRECTION))
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return -EOPNOTSUPP;
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inv_arg.func = TA_CMD_RTC_GET_OFFSET;
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inv_arg.session = priv->session_id;
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inv_arg.num_params = 4;
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param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
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ret = tee_client_invoke_func(priv->ctx, &inv_arg, param);
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if (ret < 0 || inv_arg.ret != 0)
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return ret ? ret : -EPROTO;
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*offset = param[0].u.value.a;
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return 0;
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}
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static int optee_rtc_setoffset(struct device *dev, long offset)
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{
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struct optee_rtc *priv = dev_get_drvdata(dev);
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struct tee_ioctl_invoke_arg inv_arg = {0};
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struct tee_param param[4] = {0};
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int ret;
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if (!(priv->features & TA_RTC_FEATURE_CORRECTION))
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return -EOPNOTSUPP;
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inv_arg.func = TA_CMD_RTC_SET_OFFSET;
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inv_arg.session = priv->session_id;
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inv_arg.num_params = 4;
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param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
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param[0].u.value.a = offset;
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ret = tee_client_invoke_func(priv->ctx, &inv_arg, param);
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if (ret < 0 || inv_arg.ret != 0)
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return ret ? ret : -EPROTO;
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return 0;
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}
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static const struct rtc_class_ops optee_rtc_ops = {
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.read_time = optee_rtc_readtime,
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.set_time = optee_rtc_settime,
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.set_offset = optee_rtc_setoffset,
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.read_offset = optee_rtc_readoffset,
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};
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static int optee_rtc_read_info(struct device *dev, struct rtc_device *rtc,
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u64 *features)
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{
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struct optee_rtc *priv = dev_get_drvdata(dev);
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struct tee_ioctl_invoke_arg inv_arg = {0};
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struct tee_param param[4] = {0};
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struct optee_rtc_info *info;
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struct optee_rtc_time *tm;
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int ret;
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inv_arg.func = TA_CMD_RTC_GET_INFO;
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inv_arg.session = priv->session_id;
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inv_arg.num_params = 4;
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param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
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param[0].u.memref.shm = priv->shm;
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param[0].u.memref.size = sizeof(*info);
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ret = tee_client_invoke_func(priv->ctx, &inv_arg, param);
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if (ret < 0 || inv_arg.ret != 0)
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return ret ? ret : -EPROTO;
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info = tee_shm_get_va(priv->shm, 0);
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if (IS_ERR(info))
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return PTR_ERR(info);
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if (param[0].u.memref.size != sizeof(*info))
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return -EPROTO;
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if (info->version != RTC_INFO_VERSION)
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return -EPROTO;
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*features = info->features;
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tm = &info->range_min;
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rtc->range_min = mktime64(tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min,
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tm->tm_sec);
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tm = &info->range_max;
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rtc->range_max = mktime64(tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min,
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tm->tm_sec);
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return 0;
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}
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static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
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{
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if (ver->impl_id == TEE_IMPL_ID_OPTEE)
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return 1;
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else
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return 0;
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}
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static int optee_rtc_probe(struct device *dev)
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{
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struct tee_client_device *rtc_device = to_tee_client_device(dev);
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struct tee_ioctl_open_session_arg sess_arg;
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struct optee_rtc *priv;
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struct rtc_device *rtc;
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struct tee_shm *shm;
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int ret, err;
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memset(&sess_arg, 0, sizeof(sess_arg));
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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rtc = devm_rtc_allocate_device(dev);
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if (IS_ERR(rtc))
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return PTR_ERR(rtc);
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/* Open context with TEE driver */
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priv->ctx = tee_client_open_context(NULL, optee_ctx_match, NULL, NULL);
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if (IS_ERR(priv->ctx))
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return -ENODEV;
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/* Open session with rtc Trusted App */
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export_uuid(sess_arg.uuid, &rtc_device->id.uuid);
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sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
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ret = tee_client_open_session(priv->ctx, &sess_arg, NULL);
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if (ret < 0 || sess_arg.ret != 0) {
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dev_err(dev, "tee_client_open_session failed, err: %x\n", sess_arg.ret);
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err = -EINVAL;
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goto out_ctx;
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}
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priv->session_id = sess_arg.session;
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shm = tee_shm_alloc_kernel_buf(priv->ctx, sizeof(struct optee_rtc_info));
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if (IS_ERR(shm)) {
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dev_err(priv->dev, "tee_shm_alloc_kernel_buf failed\n");
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err = PTR_ERR(shm);
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goto out_sess;
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}
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priv->shm = shm;
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priv->dev = dev;
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dev_set_drvdata(dev, priv);
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rtc->ops = &optee_rtc_ops;
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err = optee_rtc_read_info(dev, rtc, &priv->features);
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if (err) {
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dev_err(dev, "Failed to get RTC features from OP-TEE\n");
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goto out_shm;
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}
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err = devm_rtc_register_device(rtc);
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if (err)
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goto out_shm;
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/*
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* We must clear this bit after registering because rtc_register_device
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* will set it if it sees that .set_offset is provided.
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*/
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if (!(priv->features & TA_RTC_FEATURE_CORRECTION))
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clear_bit(RTC_FEATURE_CORRECTION, rtc->features);
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return 0;
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out_shm:
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tee_shm_free(priv->shm);
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out_sess:
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tee_client_close_session(priv->ctx, priv->session_id);
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out_ctx:
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tee_client_close_context(priv->ctx);
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return err;
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}
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static int optee_rtc_remove(struct device *dev)
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{
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struct optee_rtc *priv = dev_get_drvdata(dev);
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tee_client_close_session(priv->ctx, priv->session_id);
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tee_client_close_context(priv->ctx);
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return 0;
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}
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static const struct tee_client_device_id optee_rtc_id_table[] = {
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{UUID_INIT(0xf389f8c8, 0x845f, 0x496c,
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0x8b, 0xbe, 0xd6, 0x4b, 0xd2, 0x4c, 0x92, 0xfd)},
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{}
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};
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MODULE_DEVICE_TABLE(tee, optee_rtc_id_table);
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static struct tee_client_driver optee_rtc_driver = {
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.id_table = optee_rtc_id_table,
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.driver = {
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.name = "optee_rtc",
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.bus = &tee_bus_type,
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.probe = optee_rtc_probe,
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.remove = optee_rtc_remove,
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},
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};
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static int __init optee_rtc_mod_init(void)
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{
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return driver_register(&optee_rtc_driver.driver);
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}
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static void __exit optee_rtc_mod_exit(void)
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{
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driver_unregister(&optee_rtc_driver.driver);
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}
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module_init(optee_rtc_mod_init);
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module_exit(optee_rtc_mod_exit);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Clément Léger <clement.leger@bootlin.com>");
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MODULE_DESCRIPTION("OP-TEE based RTC driver");
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