The patch titled
PPS: low level IRQ timestamps recording
has been added to the -mm tree. Its filename is
pps-low-level-irq-timestamps-recording.patch
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------------------------------------------------------
Subject: PPS: low level IRQ timestamps recording
From: Rodolfo Giometti <giometti@xxxxxxxx>
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@xxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Dave Jones <davej@xxxxxxxxxx>
Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Cc: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Cc: Kay Sievers <kay.sievers@xxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxxxxxxx>
Cc: Roman Zippel <zippel@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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 -puN arch/x86/kernel/irq_32.c~pps-low-level-irq-timestamps-recording arch/x86/kernel/irq_32.c
--- a/arch/x86/kernel/irq_32.c~pps-low-level-irq-timestamps-recording
+++ a/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 -puN arch/x86/kernel/irq_64.c~pps-low-level-irq-timestamps-recording arch/x86/kernel/irq_64.c
--- a/arch/x86/kernel/irq_64.c~pps-low-level-irq-timestamps-recording
+++ a/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
/*
* Probabilistic stack overflow check:
@@ -49,6 +55,12 @@ asmlinkage unsigned int do_IRQ(struct pt
{
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;
@@ -61,9 +73,14 @@ asmlinkage unsigned int do_IRQ(struct pt
stack_overflow_check(regs);
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 -puN drivers/pps/Kconfig~pps-low-level-irq-timestamps-recording drivers/pps/Kconfig
--- a/drivers/pps/Kconfig~pps-low-level-irq-timestamps-recording
+++ a/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 -puN include/linux/pps.h~pps-low-level-irq-timestamps-recording include/linux/pps.h
--- a/include/linux/pps.h~pps-low-level-irq-timestamps-recording
+++ a/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 -puN include/linux/serial_core.h~pps-low-level-irq-timestamps-recording include/linux/serial_core.h
--- a/include/linux/serial_core.h~pps-low-level-irq-timestamps-recording
+++ a/include/linux/serial_core.h
@@ -174,6 +174,7 @@
#include <linux/tty.h>
#include <linux/mutex.h>
#include <linux/sysrq.h>
+#include <linux/pps.h>
struct uart_port;
struct uart_info;
@@ -501,7 +502,11 @@ uart_handle_dcd_change(struct uart_port
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
@@ -517,7 +522,7 @@ uart_handle_dcd_change(struct uart_port
}
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);
}
_
Patches currently in -mm which might be from giometti@xxxxxxxx are
linux-next.patch
linuxpps-core-support.patch
pps-userland-header-file-for-pps-api.patch
pps-documentation-programs-and-examples.patch
pps-linuxpps-clients-support.patch
ldisc-new-dcd_change-method-for-line-disciplines.patch
ldisc-n_tty-export-all-n_tty-ldisc-methods.patch
pps-serial-clients-support.patch
pps-parallel-port-clients-support.patch
pps-low-level-irq-timestamps-recording.patch
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