From: Alexander Holler <holler@ahsoftware.de>
To: linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
John Stultz <john.stultz@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Alessandro Zummo <a.zummo@towertech.it>,
rtc-linux@googlegroups.com,
Alexander Holler <holler@ahsoftware.de>
Subject: [PATCH 2/3 v2] RFC: timekeeping: rtc: Introduce new kernel parameter hctosys
Date: Thu, 6 Jun 2013 12:51:49 +0200 [thread overview]
Message-ID: <1370515910-2883-3-git-send-email-holler@ahsoftware.de> (raw)
In-Reply-To: <1370515910-2883-1-git-send-email-holler@ahsoftware.de>
hctosys= specifies the driver (RTC) name which sets the system clock at
boot, if and only if userspace hasn't set the time before the driver will
be loaded.
If hctosys will not be specified, the first available hardware clock
with a valid time will be used (again, if and only if ...).
If you don't want that the system clock will be set by any hardware clock,
just specify a non-existent RTC driver name, e.g. with hctosys=none.
Currently there exist a special name "persistent" for the persistent clock
found on some systems (e.g. the CMOS clock on x86 platforms which might be
handled by the driver named rtc_cmos too).
This will replace the existent driver/mechanism hctosys and the kernel
config options CONFIG_RTC_HCTOSYS and CONFIG_RTC_HCTOSYS_DEVICE (done
with one of the following patches)
Signed-off-by: Alexander Holler <holler@ahsoftware.de>
---
Documentation/kernel-parameters.txt | 12 +++++++++
drivers/rtc/class.c | 39 +++++++++++++++++++++++++++++
include/linux/time.h | 6 +++++
kernel/time/timekeeping.c | 49 +++++++++++++++++++++++++++++--------
4 files changed, 96 insertions(+), 10 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 6e3b18a..a8b7a9c 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -983,6 +983,18 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
hcl= [IA-64] SGI's Hardware Graph compatibility layer
+ hctosys= [KNL] Specifies the driver (RTC) name which sets the
+ time at boot, if and only if userspace hasn't set the
+ time before the driver will be loaded. If hctosys will
+ not be specified, the first available hardware clock
+ with a valid time will be used.
+ Use a non-existent name (e.g. hctosys=none) if you want
+ to avoid that a hardware clock will set the time.
+ Currently there exist a special name "persistent" for
+ the persistent clock found on some systems (e.g. the
+ CMOS clock on x86 platforms which might be handled
+ by the driver named rtc_cmos too).
+
hd= [EIDE] (E)IDE hard drive subsystem geometry
Format: <cyl>,<head>,<sect>
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 6638540..a159d1f 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -141,6 +141,40 @@ static int rtc_resume(struct device *dev)
#endif
+static void hctosys(struct rtc_device *rtc)
+{
+ struct rtc_time now;
+ struct timespec tv = {
+ .tv_nsec = NSEC_PER_SEC >> 1,
+ };
+ int rc;
+
+ rc = rtc_read_time(rtc, &now);
+ if (rc) {
+ dev_err(rtc->dev.parent, "rtc core: error reading time from RTC: %d\n", rc);
+ return;
+ }
+ rc = rtc_valid_tm(&now);
+ if (rc) {
+ dev_err(rtc->dev.parent, "rtc core: date/time from RTC is invalid\n");
+ return;
+ }
+ rtc_tm_to_time(&now, &tv.tv_sec);
+ if (systime_was_set)
+ return;
+ rc = do_settimeofday(&tv);
+ if (rc) {
+ dev_err(rtc->dev.parent, "rtc core: error setting system clock: %d\n", rc);
+ return;
+ } else if (systime_was_set)
+ dev_info(rtc->dev.parent,
+ "setting system clock to "
+ "%d-%02d-%02d %02d:%02d:%02d UTC (%u)\n",
+ now.tm_year + 1900, now.tm_mon + 1, now.tm_mday,
+ now.tm_hour, now.tm_min, now.tm_sec,
+ (unsigned int) tv.tv_sec);
+}
+
/**
* rtc_device_register - register w/ RTC class
* @dev: the device to register
@@ -157,6 +191,7 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev,
struct rtc_device *rtc;
struct rtc_wkalrm alrm;
int id, err;
+ const char *hctosys_name = get_hctosys_name();
id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
if (id < 0) {
@@ -196,6 +231,10 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev,
rtc->pie_timer.function = rtc_pie_update_irq;
rtc->pie_enabled = 0;
+ if (!systime_was_set &&
+ (!hctosys_name[0] || !strcasecmp(name, hctosys_name)))
+ hctosys(rtc);
+
/* Check to see if there is an ALARM already set in hw */
err = __rtc_read_alarm(rtc, &alrm);
diff --git a/include/linux/time.h b/include/linux/time.h
index 888280f..e5f644c 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -135,6 +135,12 @@ extern int timekeeping_suspended;
*/
extern bool systime_was_set;
+/*
+ * Returns a pointer to the string specified with
+ * hctosys= at the kernel command line.
+ */
+const char *get_hctosys_name(void);
+
unsigned long get_seconds(void);
struct timespec current_kernel_time(void);
struct timespec __current_kernel_time(void); /* does not take xtime_lock */
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 07f151f..fdbe3ab 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -22,6 +22,7 @@
#include <linux/tick.h>
#include <linux/stop_machine.h>
#include <linux/pvclock_gtod.h>
+#include <linux/rtc.h>
#include "tick-internal.h"
#include "ntp_internal.h"
@@ -40,6 +41,22 @@ bool __read_mostly persistent_clock_exist = false;
/* Flag for if the system time was set at least once */
bool __read_mostly systime_was_set;
+static char hctosys_name[RTC_DEVICE_NAME_SIZE];
+
+static int __init hctosys_setup(char *line)
+{
+ strlcpy(hctosys_name, line, sizeof(hctosys_name));
+ return 1;
+}
+
+__setup("hctosys=", hctosys_setup);
+
+const char *get_hctosys_name(void)
+{
+ return hctosys_name;
+}
+EXPORT_SYMBOL_GPL(get_hctosys_name);
+
static inline void tk_normalize_xtime(struct timekeeper *tk)
{
while (tk->xtime_nsec >= ((u64)NSEC_PER_SEC << tk->shift)) {
@@ -780,16 +797,17 @@ void __init timekeeping_init(void)
unsigned long flags;
struct timespec now, boot, tmp;
- read_persistent_clock(&now);
-
- if (!timespec_valid_strict(&now)) {
- pr_warn("WARNING: Persistent clock returned invalid value!\n"
- " Check your CMOS/BIOS settings.\n");
- now.tv_sec = 0;
- now.tv_nsec = 0;
- } else if (now.tv_sec || now.tv_nsec) {
- persistent_clock_exist = true;
- systime_was_set = true;
+ if (!hctosys_name[0] || !strcasecmp(hctosys_name, "persistent")) {
+ read_persistent_clock(&now);
+ if (!timespec_valid_strict(&now)) {
+ pr_warn("WARNING: Persistent clock returned invalid value!\n"
+ " Check your CMOS/BIOS settings.\n");
+ now.tv_sec = 0;
+ now.tv_nsec = 0;
+ } else if (now.tv_sec || now.tv_nsec) {
+ persistent_clock_exist = true;
+ systime_was_set = true;
+ }
}
read_boot_clock(&boot);
@@ -826,6 +844,17 @@ void __init timekeeping_init(void)
write_seqcount_end(&timekeeper_seq);
raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+ if (systime_was_set) {
+ /* print a msg like if the time was set by a RTC */
+ struct tm now_tm;
+ time_to_tm(now.tv_sec, 0, &now_tm);
+ pr_info("persistent clock: setting system clock to "
+ "%d-%02d-%02d %02d:%02d:%02d UTC (%u)\n",
+ (int)now_tm.tm_year + 1900, now_tm.tm_mon + 1,
+ now_tm.tm_mday, now_tm.tm_hour, now_tm.tm_min,
+ now_tm.tm_sec, (unsigned int) now.tv_sec);
+ }
}
/* time in seconds when suspend began */
--
1.8.1.5
next prev parent reply other threads:[~2013-06-06 10:53 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-19 15:14 [PATCH 0/3] rtc: rtc-hid-sensor-time Alexander Holler
2013-04-19 15:14 ` [PATCH 1/3 RESEND] rtc: rtc-hid-sensor-time: allow full years (16bit) in HID reports Alexander Holler
2013-04-19 15:14 ` [PATCH 2/3] rtc: rtc-hid-sensor-time: allow 16 and 32 bit values for all attributes Alexander Holler
2013-04-19 15:14 ` [PATCH 3/3] rtc: rtc-hid-sensor-time; add option hctosys to set time at boot Alexander Holler
2013-04-22 23:38 ` Andrew Morton
2013-04-23 8:51 ` Alexander Holler
2013-04-23 10:08 ` Alexander Holler
2013-04-23 10:13 ` Alexander Holler
2013-04-23 10:17 ` Alexander Holler
2013-04-23 15:47 ` Alexander Holler
2013-04-24 21:14 ` Andrew Morton
2013-04-25 6:55 ` Alexander Holler
2013-05-05 11:21 ` [PATCH 0/4] rtc: rtc-hid-sensor-time: some changes Alexander Holler
2013-05-05 11:21 ` [PATCH 1/4] rtc: rtc-hid-sensor-time: allow full years (16bit) in HID reports Alexander Holler
2013-05-05 11:21 ` [PATCH 2/4] rtc: rtc-hid-sensor-time: allow 16 and 32 bit values for all attributes Alexander Holler
2013-05-05 11:21 ` [PATCH 3/4] rtc: rtc-hid-sensor-time: add option hctosys to set time at boot Alexander Holler
2013-05-21 21:42 ` Andrew Morton
2013-05-21 22:02 ` John Stultz
2013-05-21 23:15 ` Alexander Holler
2013-05-28 19:37 ` John Stultz
2013-05-29 4:42 ` Alexander Holler
2013-06-04 13:41 ` Alexander Holler
2013-06-05 17:15 ` [PATCH 0/3] RFC: timekeeping: rtc: change hctosys mechanism Alexander Holler
2013-06-05 17:15 ` [PATCH 1/3] RFC: timekeeping: introduce flag systime_was_set Alexander Holler
2013-06-05 17:15 ` [PATCH 2/3] RFC: timekeeping: rtc: Introduce new kernel parameter hctosys Alexander Holler
2013-06-05 17:15 ` [PATCH 3/3] RFC: timekeeping: rtc: remove CONFIG_RTC_HCTOSYS and RTC_HCTOSYS_DEVICE Alexander Holler
2013-06-06 10:51 ` [PATCH 0/3 v2] RFC: timekeeping: rtc: change hctosys mechanism Alexander Holler
2013-06-06 10:51 ` [PATCH 1/3 RESEND] RFC: timekeeping: introduce flag systime_was_set Alexander Holler
2013-06-06 10:51 ` Alexander Holler [this message]
2013-06-13 19:39 ` [PATCH 2/3 v2] RFC: timekeeping: rtc: Introduce new kernel parameter hctosys Alexander Holler
2013-06-14 16:52 ` [PATCH 0/9 v3] RFC: timekeeping: rtc: change hctosys mechanism Alexander Holler
2013-06-14 16:52 ` [PATCH 1/9 RESEND] rtc: rtc-hid-sensor-time: allow full years (16bit) in HID reports Alexander Holler
2013-06-14 16:52 ` [PATCH 2/9 RESEND] rtc: rtc-hid-sensor-time: allow 16 and 32 bit values for all attributes Alexander Holler
2013-06-14 16:52 ` [PATCH 3/9] rtc: rtc-hid-sensor-time: delay registering as rtc into a work Alexander Holler
2013-06-20 10:39 ` [PATCH 3/9 v2] " Alexander Holler
2013-06-26 19:55 ` Andrew Morton
2013-06-26 21:34 ` [rtc-linux] " Alexander Holler
2013-06-26 22:07 ` Greg KH
2013-06-26 23:51 ` Alexander Holler
2013-07-06 8:55 ` Alexander Holler
2013-07-06 18:21 ` Jiri Kosina
2013-07-07 7:35 ` Alexander Holler
2013-07-08 9:12 ` [PATCH 0/2] rtc: rtc-hid-sensor-time: enable HID input processing early Alexander Holler
2013-07-08 9:12 ` [PATCH 1/2] rtc: rtc-hid-sensor-time: improve error handling when rtc register fails Alexander Holler
2013-07-08 9:12 ` [PATCH 2/2] rtc: rtc-hid-sensor-time: enable HID input processing early Alexander Holler
2013-06-28 1:29 ` [rtc-linux] Re: [PATCH 3/9 v2] rtc: rtc-hid-sensor-time: delay registering as rtc into a work Alexander Holler
2013-06-14 16:52 ` [PATCH 4/9 RESEND] RFC: timekeeping: introduce flag systime_was_set Alexander Holler
2013-06-14 17:41 ` John Stultz
2013-06-14 18:05 ` [rtc-linux] " Alexander Holler
2013-06-14 18:28 ` John Stultz
2013-06-15 6:01 ` Alexander Holler
2013-06-17 18:10 ` John Stultz
2013-06-20 10:15 ` Alexander Holler
2013-06-20 17:27 ` John Stultz
2013-06-20 18:45 ` Alexander Holler
2013-06-20 19:28 ` John Stultz
2013-06-20 23:10 ` Alexander Holler
2013-06-14 16:52 ` [PATCH 5/9 v3] RFC: timekeeping: rtc: Introduce new kernel parameter hctosys Alexander Holler
2013-06-14 19:24 ` John Stultz
2013-06-14 16:52 ` [PATCH 6/9 v3] RFC: timekeeping: rtc: remove CONFIG_RTC_HCTOSYS and RTC_HCTOSYS_DEVICE Alexander Holler
2013-06-14 19:11 ` John Stultz
2013-06-22 8:00 ` Alexander Holler
2013-06-14 16:52 ` [PATCH 7/9] RFC: rtc: implement rtc_read_timeval() Alexander Holler
2013-06-14 17:23 ` John Stultz
2013-06-14 17:43 ` Alexander Holler
2013-06-14 19:18 ` John Stultz
2013-06-14 17:28 ` John Stultz
2013-06-14 16:52 ` [PATCH 8/9] RFC: rtc: hctosys: support rtc_read_timeval() for high precision clocks Alexander Holler
2013-06-14 19:20 ` John Stultz
2013-06-14 16:52 ` [PATCH 9/9] RFC: rtc: rtc-hid-sensor-time: add support for rtc_read_timeval() Alexander Holler
2013-06-14 17:27 ` [PATCH 0/9 v3] RFC: timekeeping: rtc: change hctosys mechanism John Stultz
2013-06-06 10:51 ` [PATCH 3/3 v2] RFC: timekeeping: rtc: remove CONFIG_RTC_HCTOSYS and RTC_HCTOSYS_DEVICE Alexander Holler
2013-06-04 9:38 ` [PATCH] rtc: rtc-hid-sensor-time: fix possible bug on driver_remove Alexander Holler
2013-06-08 8:56 ` Alexander Holler
2013-05-05 11:21 ` [PATCH 4/4] rtc: rtc-hid-sensor-time: add support for milliseconds Alexander Holler
2013-04-20 23:46 ` [PATCH 0/3] rtc: rtc-hid-sensor-time Jiri Kosina
2013-04-21 6:38 ` Alexander Holler
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