From patchwork Mon Jan 8 06:04:50 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baolin Wang X-Patchwork-Id: 856726 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-rtc-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.b="cEawMtlJ"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3zFPs51QZDz9s9Y for ; Mon, 8 Jan 2018 17:05:45 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755641AbeAHGFo (ORCPT ); Mon, 8 Jan 2018 01:05:44 -0500 Received: from mail-pf0-f196.google.com ([209.85.192.196]:35243 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755540AbeAHGF0 (ORCPT ); Mon, 8 Jan 2018 01:05:26 -0500 Received: by mail-pf0-f196.google.com with SMTP id t12so2460954pfg.2 for ; Sun, 07 Jan 2018 22:05:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :in-reply-to:references; bh=Rzt+TIFX9pPZxeywMbYfeGddl4aUz4+E140pSFDJjbA=; b=cEawMtlJj5YcKcyCmZ0LcQk0da05HwyiJ7GZkaAVY56EgsdJmAgYYfQQMtFybTiya4 rH55LvhZbqNz5/0IF8fjku8IwuUJxv+ss8014oBzaVbC/ZOgFmK8qD3ybr+6CE/uAFef cl/hWsIUzxrToHdE1EQ+zat4RS3q95XBwrqzs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:in-reply-to:references; bh=Rzt+TIFX9pPZxeywMbYfeGddl4aUz4+E140pSFDJjbA=; b=q6zgtlUsI7fUBulzap+1rJmikqgzH2EckS59Q9/PbuDY6cK4DL406Bfq7D1coM5nYG ITuMR9/ZoQjTEG4wxfuzUyG0KlzWjh3pERNUBnIU3haYPNLcCaUwfVSBkKI6XRfORHDk rcXextm2fiFCJCvOiVXpmdn83WCwUnWUqq/xa+qWqJzNvmMQPoEODOHBrU1o//Acqgwz c7v9ky8CR0yY91NKJfXku4eOMnABsBi/xMCvnUmC0N6h2cPIt31At9ai6lUHQlzrvHqj R4wt7ihL3YCIZWXYxNNb3H8xvcHPULwGrqZuITAHZRLynpj3h3f+AGs7Jf1lY8UvhwgC +Ukw== X-Gm-Message-State: AKGB3mIy0dko9PaZdY0XqzahEHz3pk7O3nWwr3tiKyxRtX5y5rEi/IBa vcK68oQraIx5eBoIqhFzC5+D7w== X-Google-Smtp-Source: ACJfBotDMGrDV0Rfn+VmSbFwGm6KnRyjx/vwlXUOaHY1c5B24U3Lf6t1hf+5Ot+mU4A9BRPrxgOhEQ== X-Received: by 10.99.97.137 with SMTP id v131mr4259317pgb.243.1515391525472; Sun, 07 Jan 2018 22:05:25 -0800 (PST) Received: from baolinwangubtpc.spreadtrum.com ([117.18.48.82]) by smtp.gmail.com with ESMTPSA id q5sm20468615pgn.39.2018.01.07.22.05.23 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 07 Jan 2018 22:05:25 -0800 (PST) From: Baolin Wang To: a.zummo@towertech.it, alexandre.belloni@free-electrons.com Cc: arnd@arndb.de, broonie@kernel.org, linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org, baolin.wang@linaro.org Subject: [PATCH 3/3] rtc: Add one offset seconds to expand RTC range Date: Mon, 8 Jan 2018 14:04:50 +0800 Message-Id: <06dbb64a54a0f540805fe21bd791a9ae40577041.1515390560.git.baolin.wang@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: References: In-Reply-To: References: Sender: linux-rtc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rtc@vger.kernel.org From our investigation for all RTC drivers, 1 driver will be expired before year 2017, 7 drivers will be expired before year 2038, 23 drivers will be expired before year 2069, 72 drivers will be expired before 2100 and 104 drivers will be expired before 2106. Especially for these early expired drivers, we need to expand the RTC range to make the RTC can still work after the expired year. So we can expand the RTC range by adding one offset to the time when reading from hardware, and subtracting it when writing back. For example, if you have an RTC that can do 100 years, and currently is configured to be based in Jan 1 1970, so it can represents times from 1970 to 2069. Then if you change the start year from 1970 to 2000, which means it can represents times from 2000 to 2099. By adding or subtracting the offset produced by moving the wrap point, all times between 1970 and 1999 from RTC hardware could get interpreted as times from 2070 to 2099, but the interpretation of dates between 2000 and 2069 would not change. Signed-off-by: Baolin Wang --- drivers/rtc/class.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++ drivers/rtc/interface.c | 59 ++++++++++++++++++++++++++++++++++++++- include/linux/rtc.h | 3 ++ 3 files changed, 131 insertions(+), 1 deletion(-) diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index 722d683..086a42b 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -211,6 +211,73 @@ static int rtc_device_get_id(struct device *dev) return id; } +static void rtc_device_get_offset(struct rtc_device *rtc) +{ + time64_t range_secs; + u32 start_year; + int ret; + + /* + * If RTC driver did not implement the range of RTC hardware device, + * then we can not expand the RTC range by adding or subtracting one + * offset. + */ + if (rtc->range_min == rtc->range_max) + return; + + ret = device_property_read_u32(rtc->dev.parent, "start-year", + &start_year); + if (!ret) { + rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0); + rtc->set_start_time = true; + } + + /* + * If user did not implement the start time for RTC driver, then no + * need to expand the RTC range. + */ + if (!rtc->set_start_time) + return; + + range_secs = rtc->range_max - rtc->range_min + 1; + + /* + * If the start_secs is larger than the maximum seconds (rtc->range_max) + * supported by RTC hardware or the maximum seconds of new expanded + * range (start_secs + rtc->range_max - rtc->range_min) is less than + * rtc->range_min, which means the minimum seconds (rtc->range_min) of + * RTC hardware will be mapped to start_secs by adding one offset, so + * the offset seconds calculation formula should be: + * rtc->offset_secs = rtc->start_secs - rtc->range_min; + * + * If the start_secs is larger than the minimum seconds (rtc->range_min) + * supported by RTC hardware, then there is one region is overlapped + * between the original RTC hardware range and the new expanded range, + * and this overlapped region do not need to be mapped into the new + * expanded range due to it is valid for RTC device. So the minimum + * seconds of RTC hardware (rtc->range_min) should be mapped to + * rtc->range_max + 1, then the offset seconds formula should be: + * rtc->offset_secs = rtc->range_max - rtc->range_min + 1; + * + * If the start_secs is less than the minimum seconds (rtc->range_min), + * which is similar to case 2. So the start_secs should be mapped to + * start_secs + rtc->range_max - rtc->range_min + 1, then the + * offset seconds formula should be: + * rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1); + * + * Otherwise the offset seconds should be 0. + */ + if (rtc->start_secs > rtc->range_max || + rtc->start_secs + range_secs - 1 < rtc->range_min) + rtc->offset_secs = rtc->start_secs - rtc->range_min; + else if (rtc->start_secs > rtc->range_min) + rtc->offset_secs = range_secs; + else if (rtc->start_secs < rtc->range_min) + rtc->offset_secs = -range_secs; + else + rtc->offset_secs = 0; +} + /** * rtc_device_register - register w/ RTC class * @dev: the device to register @@ -247,6 +314,8 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev, dev_set_name(&rtc->dev, "rtc%d", id); + rtc_device_get_offset(rtc); + /* Check to see if there is an ALARM already set in hw */ err = __rtc_read_alarm(rtc, &alrm); @@ -435,6 +504,7 @@ int __rtc_register_device(struct module *owner, struct rtc_device *rtc) return -EINVAL; rtc->owner = owner; + rtc_device_get_offset(rtc); /* Check to see if there is an ALARM already set in hw */ err = __rtc_read_alarm(rtc, &alrm); diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index 55ada51..ce47e47 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -20,12 +20,61 @@ static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer); static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer); +static void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm) +{ + time64_t secs; + + if (!rtc->offset_secs) + return; + + secs = rtc_tm_to_time64(tm); + + /* + * Since the reading time values from RTC device are always in the RTC + * original valid range, but we need to skip the overlapped region + * between expanded range and original range, which is no need to add + * the offset. + */ + if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) || + (rtc->start_secs < rtc->range_min && + secs <= (rtc->start_secs + rtc->range_max - rtc->range_min))) + return; + + rtc_time64_to_tm(secs + rtc->offset_secs, tm); +} + +static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm) +{ + time64_t secs; + + if (!rtc->offset_secs) + return; + + secs = rtc_tm_to_time64(tm); + + /* + * If the setting time values are in the valid range of RTC hardware + * device, then no need to subtract the offset when setting time to RTC + * device. Otherwise we need to subtract the offset to make the time + * values are valid for RTC hardware device. + */ + if (secs >= rtc->range_min && secs <= rtc->range_max) + return; + + rtc_time64_to_tm(secs - rtc->offset_secs, tm); +} + static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm) { if (rtc->range_min != rtc->range_max) { time64_t time = rtc_tm_to_time64(tm); + time64_t range_min = rtc->set_start_time ? rtc->start_secs : + rtc->range_min; + time64_t range_max = rtc->set_start_time ? + (rtc->start_secs + rtc->range_max - rtc->range_min) : + rtc->range_max; - if (time < rtc->range_min || time > rtc->range_max) + if (time < range_min || time > range_max) return -ERANGE; } @@ -48,6 +97,8 @@ static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) return err; } + rtc_add_offset(rtc, tm); + err = rtc_valid_tm(tm); if (err < 0) dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n"); @@ -81,6 +132,8 @@ int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm) if (err) return err; + rtc_subtract_offset(rtc, tm); + err = mutex_lock_interruptible(&rtc->ops_lock); if (err) return err; @@ -135,6 +188,8 @@ static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *al } mutex_unlock(&rtc->ops_lock); + + rtc_add_offset(rtc, &alarm->time); return err; } @@ -345,6 +400,8 @@ static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) err = rtc_valid_tm(&alarm->time); if (err) return err; + + rtc_subtract_offset(rtc, &alarm->time); scheduled = rtc_tm_to_time64(&alarm->time); /* Make sure we're not setting alarms in the past */ diff --git a/include/linux/rtc.h b/include/linux/rtc.h index 4ac60af..c062eeb 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -154,6 +154,9 @@ struct rtc_device { time64_t range_min; time64_t range_max; + time64_t start_secs; + time64_t offset_secs; + bool set_start_time; #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL struct work_struct uie_task;