avr32: Generic clockevents support

This combines three patches from David Brownell:
  * avr32: tclib support
  * avr32: simplify clocksources
  * avr32: Turn count/compare into a oneshot clockevent device

Register both TC blocks (instead of just the first one) so that
the AT32/AT91 tclib code will pick them up (instead of just the
avr32-only PIT-style clocksource).

Rename the first one and its resources appropriately.

More cleanups to the cycle counter clocksource code

 - Disable all the weak symbol magic; remove the AVR32-only TCB-based
   clocksource code (source and header).

 - Mark the __init code properly.

 - Don't forget to report IRQF_TIMER.

 - Make the system work properly with this clocksource, by preventing
   use of the CPU "idle" sleep state in the idle loop when it's used.

Package the avr32 count/compare timekeeping support as a oneshot
clockevent device, so it supports NO_HZ and high res timers.
This means it also supports plugging in other clockevent devices
and clocksources.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

3 files changed, 24 insertions, 228 deletions

diff --git a/arch/avr32/mach-at32ap/Makefile b/arch/avr32/mach-at32ap/Makefile
index 83cab2a..e890094 100644
--- a/arch/avr32/mach-at32ap/Makefile
+++ b/arch/avr32/mach-at32ap/Makefile
@@ -1,4 +1,3 @@
 obj-y				+= at32ap.o clock.o intc.o extint.o pio.o hsmc.o
 obj-$(CONFIG_CPU_AT32AP700X)	+= at32ap700x.o pm-at32ap700x.o
-obj-$(CONFIG_CPU_AT32AP700X)	+= time-tc.o
 obj-$(CONFIG_CPU_FREQ_AT32AP)	+= cpufreq.o
diff --git a/arch/avr32/mach-at32ap/at32ap700x.c b/arch/avr32/mach-at32ap/at32ap700x.c
index 6302bfd..22c302a 100644
--- a/arch/avr32/mach-at32ap/at32ap700x.c
+++ b/arch/avr32/mach-at32ap/at32ap700x.c
@@ -606,19 +606,32 @@ static inline void set_ebi_sfr_bits(u32 mask)
 }
 
 /* --------------------------------------------------------------------
- *  System Timer/Counter (TC)
+ *  Timer/Counter (TC)
  * -------------------------------------------------------------------- */
-static struct resource at32_systc0_resource[] = {
+
+static struct resource at32_tcb0_resource[] = {
 	PBMEM(0xfff00c00),
 	IRQ(22),
 };
-struct platform_device at32_systc0_device = {
-	.name		= "systc",
+static struct platform_device at32_tcb0_device = {
+	.name		= "atmel_tcb",
 	.id		= 0,
-	.resource	= at32_systc0_resource,
-	.num_resources	= ARRAY_SIZE(at32_systc0_resource),
+	.resource	= at32_tcb0_resource,
+	.num_resources	= ARRAY_SIZE(at32_tcb0_resource),
+};
+DEV_CLK(t0_clk, at32_tcb0, pbb, 3);
+
+static struct resource at32_tcb1_resource[] = {
+	PBMEM(0xfff01000),
+	IRQ(23),
+};
+static struct platform_device at32_tcb1_device = {
+	.name		= "atmel_tcb",
+	.id		= 1,
+	.resource	= at32_tcb1_resource,
+	.num_resources	= ARRAY_SIZE(at32_tcb1_resource),
 };
-DEV_CLK(pclk, at32_systc0, pbb, 3);
+DEV_CLK(t0_clk, at32_tcb1, pbb, 4);
 
 /* --------------------------------------------------------------------
  *  PIO
@@ -670,7 +683,8 @@ void __init at32_add_system_devices(void)
 	platform_device_register(&pdc_device);
 	platform_device_register(&dmaca0_device);
 
-	platform_device_register(&at32_systc0_device);
+	platform_device_register(&at32_tcb0_device);
+	platform_device_register(&at32_tcb1_device);
 
 	platform_device_register(&pio0_device);
 	platform_device_register(&pio1_device);
@@ -1737,7 +1751,8 @@ struct clk *at32_clock_list[] = {
 	&pio2_mck,
 	&pio3_mck,
 	&pio4_mck,
-	&at32_systc0_pclk,
+	&at32_tcb0_t0_clk,
+	&at32_tcb1_t0_clk,
 	&atmel_usart0_usart,
 	&atmel_usart1_usart,
 	&atmel_usart2_usart,
diff --git a/arch/avr32/mach-at32ap/time-tc.c b/arch/avr32/mach-at32ap/time-tc.c
deleted file mode 100644
index 1026586..0000000
--- a/arch/avr32/mach-at32ap/time-tc.c
+++ /dev/null
@@ -1,218 +0,0 @@
-/*
- * Copyright (C) 2004-2007 Atmel Corporation
- *
- * Based on MIPS implementation arch/mips/kernel/time.c
- *   Copyright 2001 MontaVista Software Inc.
- *
- * 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.
- */
-
-#include <linux/clk.h>
-#include <linux/clocksource.h>
-#include <linux/time.h>
-#include <linux/module.h>
-#include <linux/interrupt.h>
-#include <linux/irq.h>
-#include <linux/kernel_stat.h>
-#include <linux/errno.h>
-#include <linux/init.h>
-#include <linux/profile.h>
-#include <linux/sysdev.h>
-#include <linux/err.h>
-
-#include <asm/div64.h>
-#include <asm/sysreg.h>
-#include <asm/io.h>
-#include <asm/sections.h>
-
-#include <asm/arch/time.h>
-
-/* how many counter cycles in a jiffy? */
-static u32 cycles_per_jiffy;
-
-/* the count value for the next timer interrupt */
-static u32 expirelo;
-
-/* the I/O registers of the TC module */
-static void __iomem *ioregs;
-
-cycle_t read_cycle_count(void)
-{
-	return (cycle_t)timer_read(ioregs, 0, CV);
-}
-
-struct clocksource clocksource_avr32 = {
-	.name		= "avr32",
-	.rating		= 342,
-	.read		= read_cycle_count,
-	.mask		= CLOCKSOURCE_MASK(16),
-	.shift		= 16,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
-};
-
-static void avr32_timer_ack(void)
-{
-	u16 count = expirelo;
-
-	/* Ack this timer interrupt and set the next one, use a u16
-	 * variable so it will wrap around correctly */
-	count += cycles_per_jiffy;
-	expirelo = count;
-	timer_write(ioregs, 0, RC, expirelo);
-
-	/* Check to see if we have missed any timer interrupts */
-	count = timer_read(ioregs, 0, CV);
-	if ((count - expirelo) < 0x7fff) {
-		expirelo = count + cycles_per_jiffy;
-		timer_write(ioregs, 0, RC, expirelo);
-	}
-}
-
-u32 avr32_hpt_read(void)
-{
-	return timer_read(ioregs, 0, CV);
-}
-
-static int avr32_timer_calc_div_and_set_jiffies(struct clk *pclk)
-{
-	unsigned int cycles_max = (clocksource_avr32.mask + 1) / 2;
-	unsigned int divs[] = { 4, 8, 16, 32 };
-	int divs_size = ARRAY_SIZE(divs);
-	int i = 0;
-	unsigned long count_hz;
-	unsigned long shift;
-	unsigned long mult;
-	int clock_div = -1;
-	u64 tmp;
-
-	shift = clocksource_avr32.shift;
-
-	do {
-		count_hz = clk_get_rate(pclk) / divs[i];
-		mult = clocksource_hz2mult(count_hz, shift);
-		clocksource_avr32.mult = mult;
-
-		tmp = TICK_NSEC;
-		tmp <<= shift;
-		tmp += mult / 2;
-		do_div(tmp, mult);
-
-		cycles_per_jiffy = tmp;
-	} while (cycles_per_jiffy > cycles_max && ++i < divs_size);
-
-	clock_div = i + 1;
-
-	if (clock_div > divs_size) {
-		pr_debug("timer: could not calculate clock divider\n");
-		return -EFAULT;
-	}
-
-	/* Set the clock divider */
-	timer_write(ioregs, 0, CMR, TIMER_BF(CMR_TCCLKS, clock_div));
-
-	return 0;
-}
-
-int avr32_hpt_init(unsigned int count)
-{
-	struct resource *regs;
-	struct clk *pclk;
-	int irq = -1;
-	int ret = 0;
-
-	ret = -ENXIO;
-
-	irq = platform_get_irq(&at32_systc0_device, 0);
-	if (irq < 0) {
-		pr_debug("timer: could not get irq\n");
-		goto out_error;
-	}
-
-	pclk = clk_get(&at32_systc0_device.dev, "pclk");
-	if (IS_ERR(pclk)) {
-		pr_debug("timer: could not get clk: %ld\n", PTR_ERR(pclk));
-		goto out_error;
-	}
-	clk_enable(pclk);
-
-	regs = platform_get_resource(&at32_systc0_device, IORESOURCE_MEM, 0);
-	if (!regs) {
-		pr_debug("timer: could not get resource\n");
-		goto out_error_clk;
-	}
-
-	ioregs = ioremap(regs->start, regs->end - regs->start + 1);
-	if (!ioregs) {
-		pr_debug("timer: could not get ioregs\n");
-		goto out_error_clk;
-	}
-
-	ret = avr32_timer_calc_div_and_set_jiffies(pclk);
-	if (ret)
-		goto out_error_io;
-
-	ret = setup_irq(irq, &timer_irqaction);
-	if (ret) {
-		pr_debug("timer: could not request irq %d: %d\n",
-				irq, ret);
-		goto out_error_io;
-	}
-
-	expirelo = (timer_read(ioregs, 0, CV) / cycles_per_jiffy + 1)
-		* cycles_per_jiffy;
-
-	/* Enable clock and interrupts on RC compare */
-	timer_write(ioregs, 0, CCR, TIMER_BIT(CCR_CLKEN));
-	timer_write(ioregs, 0, IER, TIMER_BIT(IER_CPCS));
-	/* Set cycles to first interrupt */
-	timer_write(ioregs, 0,  RC, expirelo);
-
-	printk(KERN_INFO "timer: AT32AP system timer/counter at 0x%p irq %d\n",
-			ioregs, irq);
-
-	return 0;
-
-out_error_io:
-	iounmap(ioregs);
-out_error_clk:
-	clk_put(pclk);
-out_error:
-	return ret;
-}
-
-int avr32_hpt_start(void)
-{
-	timer_write(ioregs, 0, CCR, TIMER_BIT(CCR_SWTRG));
-	return 0;
-}
-
-irqreturn_t timer_interrupt(int irq, void *dev_id)
-{
-	unsigned int sr = timer_read(ioregs, 0, SR);
-
-	if (sr & TIMER_BIT(SR_CPCS)) {
-		/* ack timer interrupt and try to set next interrupt */
-		avr32_timer_ack();
-
-		/*
-		 * Call the generic timer interrupt handler
-		 */
-		write_seqlock(&xtime_lock);
-		do_timer(1);
-		write_sequnlock(&xtime_lock);
-
-		/*
-		 * In UP mode, we call local_timer_interrupt() to do profiling
-		 * and process accounting.
-		 *
-		 * SMP is not supported yet.
-		 */
-		local_timer_interrupt(irq, dev_id);
-
-		return IRQ_HANDLED;
-	}
-
-	return IRQ_NONE;
-}