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Date: Wed, 2 Dec 2009 18:18:47 +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>,
Michael Kerrisk <mtk.manpages@...il.com>,
Christoph Hellwig <hch@...radead.org>,
Rodolfo Giometti <giometti@...ux.it>
Subject: [PATCH 09/11] 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 | 2 +
arch/x86/kernel/irq_64.c | 2 +
drivers/pps/Kconfig | 12 +++++++++++
include/linux/irqnr.h | 4 +++
include/linux/serial_core.h | 5 ++++
kernel/irq/handle.c | 46 +++++++++++++++++++++++++++++++++++++++++++
6 files changed, 71 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 7d35d0f..0e34854 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -199,6 +199,8 @@ bool handle_irq(unsigned irq, struct pt_regs *regs)
overflow = check_stack_overflow();
+ irq_save_ts(irq);
+
desc = irq_to_desc(irq);
if (unlikely(!desc))
return false;
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 977d8b4..afbdba0 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -54,6 +54,8 @@ bool handle_irq(unsigned irq, struct pt_regs *regs)
stack_overflow_check(regs);
+ irq_save_ts(irq);
+
desc = irq_to_desc(irq);
if (unlikely(!desc))
return false;
diff --git a/drivers/pps/Kconfig b/drivers/pps/Kconfig
index 1afe4e0..6e8a2aa 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 no
+ 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 may not be supported by some
+ PPS clients!
+
config PPS_DEBUG
bool "PPS debugging messages"
depends on PPS
diff --git a/include/linux/irqnr.h b/include/linux/irqnr.h
index 7bf89bc..4a7f4e8 100644
--- a/include/linux/irqnr.h
+++ b/include/linux/irqnr.h
@@ -25,6 +25,7 @@
extern int nr_irqs;
extern struct irq_desc *irq_to_desc(unsigned int irq);
+extern struct timespec *irq_to_ts(unsigned int irq);
# define for_each_irq_desc(irq, desc) \
for (irq = 0, desc = irq_to_desc(irq); irq < nr_irqs; \
@@ -49,6 +50,9 @@ extern struct irq_desc *irq_to_desc(unsigned int irq);
#endif /* CONFIG_GENERIC_HARDIRQS */
+extern struct timespec *irq_to_ts(unsigned int irq);
+extern void irq_save_ts(unsigned int irq);
+
#define for_each_irq_nr(irq) \
for (irq = 0; irq < nr_irqs; irq++)
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 4bfb046..5ffd720 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -189,6 +189,7 @@
#include <linux/tty.h>
#include <linux/mutex.h>
#include <linux/sysrq.h>
+#include <linux/irqnr.h>
struct uart_port;
struct serial_struct;
@@ -492,7 +493,11 @@ uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
struct timespec ts;
if (ld && ld->ops->dcd_change)
+#ifdef CONFIG_PPS_IRQ_EVENTS
+ ts = *(irq_to_ts(uport->irq));
+#else
getnstimeofday(&ts);
+#endif
uport->icount.dcd++;
#ifdef CONFIG_HARD_PPS
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 17c71bb..5c6d71b 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -133,6 +133,7 @@ static void init_one_irq_desc(int irq, struct irq_desc *desc, int node)
DEFINE_SPINLOCK(sparse_irq_lock);
struct irq_desc **irq_desc_ptrs __read_mostly;
+struct timespec *irq_ts __read_mostly;
static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
[0 ... NR_IRQS_LEGACY-1] = {
@@ -167,6 +168,9 @@ int __init early_irq_init(void)
/* allocate irq_desc_ptrs array based on nr_irqs */
irq_desc_ptrs = kcalloc(nr_irqs, sizeof(void *), GFP_NOWAIT);
+ /* allocate irq_ts array based on nr_irqs */
+ irq_ts = kcalloc(nr_irqs, sizeof(struct timespec), GFP_NOWAIT);
+
/* allocate based on nr_cpu_ids */
kstat_irqs_legacy = kzalloc_node(NR_IRQS_LEGACY * nr_cpu_ids *
sizeof(int), GFP_NOWAIT, node);
@@ -197,6 +201,26 @@ struct irq_desc *irq_to_desc(unsigned int irq)
return NULL;
}
+void irq_save_ts(unsigned int irq)
+{
+#ifdef CONFIG_PPS_IRQ_EVENTS
+ if (irq_desc_ptrs && irq < nr_irqs)
+ getnstimeofday(&irq_ts[irq]);
+#endif
+}
+
+struct timespec *irq_to_ts(unsigned int irq)
+{
+ if (irq >= nr_irqs) {
+ WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_ts\n",
+ irq, nr_irqs);
+ return NULL;
+ }
+
+ return &irq_ts[irq];
+}
+EXPORT_SYMBOL(irq_to_ts);
+
struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
{
struct irq_desc *desc;
@@ -251,6 +275,8 @@ struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
}
};
+struct timespec irq_ts[NR_IRQS] __cacheline_aligned_in_smp;
+
static unsigned int kstat_irqs_all[NR_IRQS][NR_CPUS];
int __init early_irq_init(void)
{
@@ -279,6 +305,26 @@ struct irq_desc *irq_to_desc(unsigned int irq)
return (irq < NR_IRQS) ? irq_desc + irq : NULL;
}
+void irq_save_ts(unsigned int irq)
+{
+#ifdef CONFIG_PPS_IRQ_EVENTS
+ if (irq < NR_IRQS)
+ getnstimeofday(&irq_ts[irq]);
+#endif
+}
+
+struct timespec *irq_to_ts(unsigned int irq)
+{
+ if (irq >= NR_IRQS) {
+ WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_ts\n",
+ irq, nr_irqs);
+ return NULL;
+ }
+
+ return &irq_ts[irq];
+}
+EXPORT_SYMBOL(irq_to_ts);
+
struct irq_desc *irq_to_desc_alloc_node(unsigned int irq, int node)
{
return irq_to_desc(irq);
--
1.6.3.3
--
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