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@linux.it>
---
arch/x86/kernel/irq_32.c | 17 +++++++++++++++++
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, 55 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 1cf8c1f..85c3182 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
+
/*
* 'what should we do if we get a hw irq event on an illegal vector'.
* each architecture has to answer this themselves.
@@ -225,6 +231,12 @@ unsigned int do_IRQ(struct pt_regs *regs)
/* high bit used in ret_from_ code */
int overflow, irq = ~regs->orig_ax;
struct irq_desc *desc = irq_desc + irq;
+#ifdef CONFIG_PPS_IRQ_EVENTS
+ struct timespec ts;
+
+ /* Get IRQ timestamps as soon as possible for the PPS layer */
+ getnstimeofday(&ts);
+#endif
if (unlikely((unsigned)irq >= NR_IRQS)) {
printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
@@ -232,6 +244,11 @@ 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
+
old_regs = set_irq_regs(regs);
irq_enter();
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 1f78b23..e9184ce 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -17,9 +17,15 @@
#include <asm/io_apic.h>
#include <asm/idle.h>
#include <asm/smp.h>
+#include <linux/pps.h>
atomic_t irq_err_count;
+#ifdef CONFIG_PPS_IRQ_EVENTS
+struct timespec pps_irq_ts[NR_IRQS];
+EXPORT_SYMBOL(pps_irq_ts);
+#endif
+
/*
* 'what should we do if we get a hw irq event on an illegal vector'.
* each architecture has to answer this themselves.
@@ -188,6 +194,12 @@ u64 arch_irq_stat(void)
asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
+#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;
@@ -201,9 +213,14 @@ asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
stack_overflow_check(regs);
#endif
- if (likely(irq < NR_IRQS))
+ if (likely(irq < NR_IRQS)) {
+#ifdef CONFIG_PPS_IRQ_EVENTS
+ /* Then, after sanity check, store the IRQ timestamp */
+ pps_irq_ts[irq] = ts;
+#endif
+
generic_handle_irq(irq);
- 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 6695f7c..9a74d06 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 1aa894c..f4cfc66 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->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->ops->dcd_change)
- ld->ops->dcd_change(port, status, &ts);
+ ld->ops->dcd_change(info->port.tty, status, &ts);
tty_ldisc_deref(ld);
}
--
1.5.4.3
--
