From 6778948f9de86c3cfaf36725a7c87dcff9ba247f Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Mon, 11 Dec 2023 08:20:59 +0000
Subject: [PATCH] kernel_5.10 no rt
---
kernel/arch/arm/mach-rpc/time.c | 51 ++++++++++++++++++++++++++++-----------------------
1 files changed, 28 insertions(+), 23 deletions(-)
diff --git a/kernel/arch/arm/mach-rpc/time.c b/kernel/arch/arm/mach-rpc/time.c
index 2689771..da85cac 100644
--- a/kernel/arch/arm/mach-rpc/time.c
+++ b/kernel/arch/arm/mach-rpc/time.c
@@ -1,11 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/arch/arm/common/time-acorn.c
*
* Copyright (c) 1996-2000 Russell King.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
*
* Changelog:
* 24-Sep-1996 RMK Created
@@ -13,7 +10,7 @@
* 04-Dec-1997 RMK Updated for new arch/arm/time.c
* 13=Jun-2004 DS Moved to arch/arm/common b/c shared w/CLPS7500
*/
-#include <linux/timex.h>
+#include <linux/clocksource.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
@@ -27,11 +24,15 @@
#define RPC_CLOCK_FREQ 2000000
#define RPC_LATCH DIV_ROUND_CLOSEST(RPC_CLOCK_FREQ, HZ)
-static u32 ioc_timer_gettimeoffset(void)
+static u32 ioc_time;
+
+static u64 ioc_timer_read(struct clocksource *cs)
{
unsigned int count1, count2, status;
- long offset;
+ unsigned long flags;
+ u32 ticks;
+ local_irq_save(flags);
ioc_writeb (0, IOC_T0LATCH);
barrier ();
count1 = ioc_readb(IOC_T0CNTL) | (ioc_readb(IOC_T0CNTH) << 8);
@@ -41,26 +42,33 @@
ioc_writeb (0, IOC_T0LATCH);
barrier ();
count2 = ioc_readb(IOC_T0CNTL) | (ioc_readb(IOC_T0CNTH) << 8);
+ ticks = ioc_time + RPC_LATCH - count2;
+ local_irq_restore(flags);
- offset = count2;
if (count2 < count1) {
/*
- * We have not had an interrupt between reading count1
- * and count2.
+ * The timer has not reloaded between reading count1 and
+ * count2, check whether an interrupt was actually pending.
*/
if (status & (1 << 5))
- offset -= RPC_LATCH;
+ ticks += RPC_LATCH;
} else if (count2 > count1) {
/*
- * We have just had another interrupt between reading
- * count1 and count2.
+ * The timer has reloaded, so count2 indicates the new
+ * count since the wrap. The interrupt would not have
+ * been processed, so add the missed ticks.
*/
- offset -= RPC_LATCH;
+ ticks += RPC_LATCH;
}
- offset = (RPC_LATCH - offset) * (tick_nsec / 1000);
- return DIV_ROUND_CLOSEST(offset, RPC_LATCH) * 1000;
+ return ticks;
}
+
+static struct clocksource ioctime_clocksource = {
+ .read = ioc_timer_read,
+ .mask = CLOCKSOURCE_MASK(32),
+ .rating = 100,
+};
void __init ioctime_init(void)
{
@@ -72,21 +80,18 @@
static irqreturn_t
ioc_timer_interrupt(int irq, void *dev_id)
{
+ ioc_time += RPC_LATCH;
timer_tick();
return IRQ_HANDLED;
}
-
-static struct irqaction ioc_timer_irq = {
- .name = "timer",
- .handler = ioc_timer_interrupt
-};
/*
* Set up timer interrupt.
*/
void __init ioc_timer_init(void)
{
- arch_gettimeoffset = ioc_timer_gettimeoffset;
+ WARN_ON(clocksource_register_hz(&ioctime_clocksource, RPC_CLOCK_FREQ));
ioctime_init();
- setup_irq(IRQ_TIMER0, &ioc_timer_irq);
+ if (request_irq(IRQ_TIMER0, ioc_timer_interrupt, 0, "timer", NULL))
+ pr_err("Failed to request irq %d (timer)\n", IRQ_TIMER0);
}
--
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