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[209.132.180.67]) by mx.google.com with ESMTP id c14si983370pgu.341.2018.02.26.00.34.48; Mon, 26 Feb 2018 00:34:48 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=Z6pV4qo1; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752660AbeBZIeo (ORCPT + 28 others); Mon, 26 Feb 2018 03:34:44 -0500 Received: from mail-pg0-f67.google.com ([74.125.83.67]:42467 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751999AbeBZIej (ORCPT ); Mon, 26 Feb 2018 03:34:39 -0500 Received: by mail-pg0-f67.google.com with SMTP id y8so5914226pgr.9 for ; Mon, 26 Feb 2018 00:34:38 -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=n4IjGvTYiAFzl5mzdjpCmPflLxOVDvnuwBYFmB6lcsY=; b=Z6pV4qo1a0hPSBbKjLc0FzGkOjbjexnUIbO4hTx5BqVegxxk54VZuVe3XWAJy/DC/K bjNsFqLT3xmZ4XU5y68jTs/0/AjO+hnrWzTUuCTGcpfrwVvmCdLGu2rjQIQN2YlwFRp3 t9g10i1dZbPik1TPY2v1Bfc8ZuXGT6DwCImsM= 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=n4IjGvTYiAFzl5mzdjpCmPflLxOVDvnuwBYFmB6lcsY=; b=iK+QduU9umXzUj4Y7NEz7NBv0oYWvx+Vb9Rt4S7SnWi45aqqbFyUe5opDn8J5VuDdy IfPEP1KbO2VDoMOV0Nm7hE7zT2nulOaGx/a2i8RNYp4vGJAliXgaz4dBqMjr+UlPHB/x 9AT50n3JIQPpxfLOJ5mgIvSCFsfmnUJXWgbGHJdPoQIm4/HsXzq9tXtj9m5twJ2SkXly o2XUKMvSozvG+hIuBPcYzrR7y1bL1DcfNGK+HPzpIMvaBUKfVqXrUt81LBz4Bs2Dqidi 0utj5XhiGfNgeJpjf9GKhajG3j2jNg/rm+D0gA2QCyYYcqTcMmBw2PloLI5cgiYltDXG LgWw== X-Gm-Message-State: APf1xPAxwwV5o4NG4WuYuvbQB3+zGIpf3vLHn9cJ0GsG2Bu9j7yZzvRi krBFxaq5nXziELIJV/I685wPmg== X-Received: by 10.99.122.12 with SMTP id v12mr7915120pgc.128.1519634078355; Mon, 26 Feb 2018 00:34:38 -0800 (PST) Received: from baolinwangubtpc.spreadtrum.com ([117.18.48.82]) by smtp.gmail.com with ESMTPSA id e83sm17734791pfk.148.2018.02.26.00.34.35 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 26 Feb 2018 00:34:37 -0800 (PST) From: Baolin Wang To: a.zummo@towertech.it, alexandre.belloni@bootlin.com Cc: arnd@arndb.de, broonie@kernel.org, linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org, baolin.wang@linaro.org, alexandre.belloni@free-electrons.com Subject: [RESEND PATCH 3/3] rtc: Add one offset seconds to expand RTC range Date: Mon, 26 Feb 2018 16:33:58 +0800 Message-Id: X-Mailer: git-send-email 1.7.9.5 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 | 58 ++++++++++++++++++++++++++++++++++++++- include/linux/rtc.h | 3 ++ 3 files changed, 130 insertions(+), 1 deletion(-) -- 1.7.9.5 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 25aebc5..6a0340b 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -23,12 +23,61 @@ 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; } @@ -51,6 +100,8 @@ 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"); @@ -86,6 +137,8 @@ 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; @@ -143,6 +196,7 @@ 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); trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err); return err; } @@ -355,6 +409,8 @@ 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 8560282..f63add6 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -153,6 +153,9 @@ 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;