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Message-Id: <1227542451-31969-10-git-send-email-giometti@linux.it>
Date: Mon, 24 Nov 2008 17:00:51 +0100
From: Rodolfo Giometti <giometti@...ux.it>
To: linux-kernel@...r.kernel.org
Cc: Andrew Morton <akpm@...ux-foundation.org>,
David Woodhouse <dwmw2@...radead.org>,
Dave Jones <davej@...hat.com>, Sam Ravnborg <sam@...nborg.org>,
Greg KH <greg@...ah.com>,
Randy Dunlap <randy.dunlap@...cle.com>,
Kay Sievers <kay.sievers@...y.org>,
Alan Cox <alan@...rguk.ukuu.org.uk>,
"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>,
Rodolfo Giometti <giometti@...ux.it>
Subject: [PATCH 9/9] PPS: low level IRQ timestamps recording.
Add low level IRQ timestamps recording for x86 (32 and 64 bits)
platforms and enable UART clients in order to use it.
This improves PPS precision. :)
Signed-off-by: Rodolfo Giometti <giometti@...ux.it>
---
arch/x86/kernel/irq_32.c | 16 ++++++++++++++++
arch/x86/kernel/irq_64.c | 21 +++++++++++++++++++--
drivers/pps/Kconfig | 12 ++++++++++++
include/linux/pps.h | 1 +
include/linux/serial_core.h | 7 ++++++-
5 files changed, 54 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index a513826..7fce1e2 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -15,6 +15,7 @@
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/delay.h>
+#include <linux/pps.h>
#include <asm/apic.h>
#include <asm/uaccess.h>
@@ -25,6 +26,11 @@ EXPORT_PER_CPU_SYMBOL(irq_stat);
DEFINE_PER_CPU(struct pt_regs *, irq_regs);
EXPORT_PER_CPU_SYMBOL(irq_regs);
+#ifdef CONFIG_PPS_IRQ_EVENTS
+struct timespec pps_irq_ts[NR_IRQS];
+EXPORT_SYMBOL(pps_irq_ts);
+#endif
+
#ifdef CONFIG_DEBUG_STACKOVERFLOW
/* Debugging check for stack overflow: is there less than 1KB free? */
static int check_stack_overflow(void)
@@ -204,7 +210,12 @@ unsigned int do_IRQ(struct pt_regs *regs)
unsigned vector = ~regs->orig_ax;
struct irq_desc *desc;
unsigned irq;
+#ifdef CONFIG_PPS_IRQ_EVENTS
+ struct timespec ts;
+ /* Get IRQ timestamps as soon as possible for the PPS layer */
+ getnstimeofday(&ts);
+#endif
old_regs = set_irq_regs(regs);
irq_enter();
@@ -219,6 +230,11 @@ unsigned int do_IRQ(struct pt_regs *regs)
BUG();
}
+#ifdef CONFIG_PPS_IRQ_EVENTS
+ /* Then, after sanity check, store the IRQ timestamp */
+ pps_irq_ts[irq] = ts;
+#endif
+
if (!execute_on_irq_stack(overflow, desc, irq)) {
if (unlikely(overflow))
print_stack_overflow();
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 60eb84e..a1457a0 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -17,6 +17,12 @@
#include <asm/io_apic.h>
#include <asm/idle.h>
#include <asm/smp.h>
+#include <linux/pps.h>
+
+#ifdef CONFIG_PPS_IRQ_EVENTS
+struct timespec pps_irq_ts[NR_IRQS];
+EXPORT_SYMBOL(pps_irq_ts);
+#endif
#ifdef CONFIG_DEBUG_STACKOVERFLOW
/*
@@ -51,6 +57,12 @@ asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
struct irq_desc *desc;
+#ifdef CONFIG_PPS_IRQ_EVENTS
+ struct timespec ts;
+
+ /* Get IRQ timestamps as soon as possible for the PPS layer */
+ getnstimeofday(&ts);
+#endif
/* high bit used in ret_from_ code */
unsigned vector = ~regs->orig_ax;
@@ -65,9 +77,14 @@ asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
#endif
desc = irq_to_desc(irq);
- if (likely(desc))
+ if (likely(desc)) {
+#ifdef CONFIG_PPS_IRQ_EVENTS
+ /* Then, after sanity check, store the IRQ timestamp */
+ pps_irq_ts[irq] = ts;
+#endif
+
generic_handle_irq_desc(irq, desc);
- else {
+ } else {
if (!disable_apic)
ack_APIC_irq();
diff --git a/drivers/pps/Kconfig b/drivers/pps/Kconfig
index 1afe4e0..7c0b094 100644
--- a/drivers/pps/Kconfig
+++ b/drivers/pps/Kconfig
@@ -22,6 +22,18 @@ config PPS
To compile this driver as a module, choose M here: the module
will be called pps_core.ko.
+config PPS_IRQ_EVENTS
+ bool "Use low level IRQ timestamps"
+ depends on PPS && (X86_32 || X86_64)
+ default yes
+ help
+ Say Y here if you wish using low level IRQ timestamps to register
+ PPS events.
+
+ This should improve PPS resolution but it delays echo functions
+ call. Note also that this function is not implemented on all
+ platforms and PPS clients!
+
config PPS_DEBUG
bool "PPS debugging messages"
depends on PPS
diff --git a/include/linux/pps.h b/include/linux/pps.h
index b5c3cf9..191190e 100644
--- a/include/linux/pps.h
+++ b/include/linux/pps.h
@@ -181,6 +181,7 @@ struct pps_device {
extern spinlock_t pps_idr_lock;
extern struct idr pps_idr;
+extern struct timespec pps_irq_ts[];
extern struct device_attribute pps_attrs[];
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index be8e653..d168c04 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -165,6 +165,7 @@
#include <linux/tty.h>
#include <linux/mutex.h>
#include <linux/sysrq.h>
+#include <linux/pps.h>
struct uart_port;
struct uart_info;
@@ -492,7 +493,11 @@ uart_handle_dcd_change(struct uart_port *port, unsigned int status)
struct timespec ts;
if (ld && ld->ops->dcd_change)
+#ifdef CONFIG_PPS_IRQ_EVENTS
+ ts = pps_irq_ts[port->irq];
+#else
getnstimeofday(&ts);
+#endif
port->icount.dcd++;
#ifdef CONFIG_HARD_PPS
@@ -508,7 +513,7 @@ uart_handle_dcd_change(struct uart_port *port, unsigned int status)
}
if (ld && ld->ops->dcd_change)
- ld->ops->dcd_change(port, status, &ts);
+ ld->ops->dcd_change(info->port.tty, status, &ts);
if (ld)
tty_ldisc_deref(ld);
}
--
1.5.4.3
--
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