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authorLinus Torvalds <torvalds@linux-foundation.org>2015-09-01 22:10:20 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-01 22:10:20 +0300
commitc5fc249862af862df027030188cc083e072ecd19 (patch)
tree1205eaa47b07fc06b79e8c742a15dca5bcb1066c /arch/arm/mach-ep93xx/timer-ep93xx.c
parent00e3fcc221f6fe6a890bf3e0e71c6b9944e58233 (diff)
parent97a2482d9891f0ad6a3710e0b6ae9949c140c7f1 (diff)
downloadlinux-c5fc249862af862df027030188cc083e072ecd19.tar.xz
Merge tag 'armsoc-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC cleanups from Olof Johansson: "A large cleanup branch this release, with a healthy 10k negative line delta. Most of this is removal of legacy (non-DT) support of shmobile platforms. There is also removal of two non-DT platforms on OMAP, and the plat-samsung directory is cleaned out by moving most of the previously shared-location-but-not-actually-shared files from there to the appropriate mach directories instead. There are other sets of changes in here as well: - Rob Herring removed use of set_irq_flags under all platforms and moved to genirq alternatives - a series of timer API conversions to set-state interface - ep93xx, nomadik and ux500 cleanups from Linus Walleij - __init annotation fixes from Nicolas Pitre + a bunch of other changes that all add up to a nice set of cleanups" * tag 'armsoc-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (108 commits) ARM/fb: ep93xx: switch framebuffer to use modedb only ARM: gemini: Setup timer3 as free running timer ARM: gemini: Use timer1 for clockevent ARM: gemini: Add missing register definitions for gemini timer ARM: ep93xx/timer: Migrate to new 'set-state' interface ARM: nomadik: push accelerometer down to boards ARM: nomadik: move l2x0 setup to device tree ARM: nomadik: selectively enable UART0 on boards ARM: nomadik: move hog code to use DT hogs ARM: shmobile: Fix mismerges ARM: ux500: simplify secondary CPU boot ARM: SAMSUNG: remove keypad-core header in plat-samsung ARM: SAMSUNG: local watchdog-reset header in mach-s3c64xx ARM: SAMSUNG: local onenand-core header in mach-s3c64xx ARM: SAMSUNG: local irq-uart header in mach-s3c64xx ARM: SAMSUNG: local backlight header in mach-s3c64xx ARM: SAMSUNG: local ata-core header in mach-s3c64xx ARM: SAMSUNG: local regs-usb-hsotg-phy header in mach-s3c64xx ARM: SAMSUNG: local spi-core header in mach-s3c24xx ARM: SAMSUNG: local nand-core header in mach-s3c24xx ...
Diffstat (limited to 'arch/arm/mach-ep93xx/timer-ep93xx.c')
-rw-r--r--arch/arm/mach-ep93xx/timer-ep93xx.c143
1 files changed, 143 insertions, 0 deletions
diff --git a/arch/arm/mach-ep93xx/timer-ep93xx.c b/arch/arm/mach-ep93xx/timer-ep93xx.c
new file mode 100644
index 000000000000..e5f791145bd0
--- /dev/null
+++ b/arch/arm/mach-ep93xx/timer-ep93xx.c
@@ -0,0 +1,143 @@
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/sched_clock.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <asm/mach/time.h>
+#include "soc.h"
+
+/*************************************************************************
+ * Timer handling for EP93xx
+ *************************************************************************
+ * The ep93xx has four internal timers. Timers 1, 2 (both 16 bit) and
+ * 3 (32 bit) count down at 508 kHz, are self-reloading, and can generate
+ * an interrupt on underflow. Timer 4 (40 bit) counts down at 983.04 kHz,
+ * is free-running, and can't generate interrupts.
+ *
+ * The 508 kHz timers are ideal for use for the timer interrupt, as the
+ * most common values of HZ divide 508 kHz nicely. We pick the 32 bit
+ * timer (timer 3) to get as long sleep intervals as possible when using
+ * CONFIG_NO_HZ.
+ *
+ * The higher clock rate of timer 4 makes it a better choice than the
+ * other timers for use as clock source and for sched_clock(), providing
+ * a stable 40 bit time base.
+ *************************************************************************
+ */
+#define EP93XX_TIMER_REG(x) (EP93XX_TIMER_BASE + (x))
+#define EP93XX_TIMER1_LOAD EP93XX_TIMER_REG(0x00)
+#define EP93XX_TIMER1_VALUE EP93XX_TIMER_REG(0x04)
+#define EP93XX_TIMER1_CONTROL EP93XX_TIMER_REG(0x08)
+#define EP93XX_TIMER123_CONTROL_ENABLE (1 << 7)
+#define EP93XX_TIMER123_CONTROL_MODE (1 << 6)
+#define EP93XX_TIMER123_CONTROL_CLKSEL (1 << 3)
+#define EP93XX_TIMER1_CLEAR EP93XX_TIMER_REG(0x0c)
+#define EP93XX_TIMER2_LOAD EP93XX_TIMER_REG(0x20)
+#define EP93XX_TIMER2_VALUE EP93XX_TIMER_REG(0x24)
+#define EP93XX_TIMER2_CONTROL EP93XX_TIMER_REG(0x28)
+#define EP93XX_TIMER2_CLEAR EP93XX_TIMER_REG(0x2c)
+#define EP93XX_TIMER4_VALUE_LOW EP93XX_TIMER_REG(0x60)
+#define EP93XX_TIMER4_VALUE_HIGH EP93XX_TIMER_REG(0x64)
+#define EP93XX_TIMER4_VALUE_HIGH_ENABLE (1 << 8)
+#define EP93XX_TIMER3_LOAD EP93XX_TIMER_REG(0x80)
+#define EP93XX_TIMER3_VALUE EP93XX_TIMER_REG(0x84)
+#define EP93XX_TIMER3_CONTROL EP93XX_TIMER_REG(0x88)
+#define EP93XX_TIMER3_CLEAR EP93XX_TIMER_REG(0x8c)
+
+#define EP93XX_TIMER123_RATE 508469
+#define EP93XX_TIMER4_RATE 983040
+
+static u64 notrace ep93xx_read_sched_clock(void)
+{
+ u64 ret;
+
+ ret = readl(EP93XX_TIMER4_VALUE_LOW);
+ ret |= ((u64) (readl(EP93XX_TIMER4_VALUE_HIGH) & 0xff) << 32);
+ return ret;
+}
+
+cycle_t ep93xx_clocksource_read(struct clocksource *c)
+{
+ u64 ret;
+
+ ret = readl(EP93XX_TIMER4_VALUE_LOW);
+ ret |= ((u64) (readl(EP93XX_TIMER4_VALUE_HIGH) & 0xff) << 32);
+ return (cycle_t) ret;
+}
+
+static int ep93xx_clkevt_set_next_event(unsigned long next,
+ struct clock_event_device *evt)
+{
+ /* Default mode: periodic, off, 508 kHz */
+ u32 tmode = EP93XX_TIMER123_CONTROL_MODE |
+ EP93XX_TIMER123_CONTROL_CLKSEL;
+
+ /* Clear timer */
+ writel(tmode, EP93XX_TIMER3_CONTROL);
+
+ /* Set next event */
+ writel(next, EP93XX_TIMER3_LOAD);
+ writel(tmode | EP93XX_TIMER123_CONTROL_ENABLE,
+ EP93XX_TIMER3_CONTROL);
+ return 0;
+}
+
+
+static int ep93xx_clkevt_shutdown(struct clock_event_device *evt)
+{
+ /* Disable timer */
+ writel(0, EP93XX_TIMER3_CONTROL);
+
+ return 0;
+}
+
+static struct clock_event_device ep93xx_clockevent = {
+ .name = "timer1",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .set_state_shutdown = ep93xx_clkevt_shutdown,
+ .set_state_oneshot = ep93xx_clkevt_shutdown,
+ .tick_resume = ep93xx_clkevt_shutdown,
+ .set_next_event = ep93xx_clkevt_set_next_event,
+ .rating = 300,
+};
+
+static irqreturn_t ep93xx_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ /* Writing any value clears the timer interrupt */
+ writel(1, EP93XX_TIMER3_CLEAR);
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static struct irqaction ep93xx_timer_irq = {
+ .name = "ep93xx timer",
+ .flags = IRQF_TIMER | IRQF_IRQPOLL,
+ .handler = ep93xx_timer_interrupt,
+ .dev_id = &ep93xx_clockevent,
+};
+
+void __init ep93xx_timer_init(void)
+{
+ /* Enable and register clocksource and sched_clock on timer 4 */
+ writel(EP93XX_TIMER4_VALUE_HIGH_ENABLE,
+ EP93XX_TIMER4_VALUE_HIGH);
+ clocksource_mmio_init(NULL, "timer4",
+ EP93XX_TIMER4_RATE, 200, 40,
+ ep93xx_clocksource_read);
+ sched_clock_register(ep93xx_read_sched_clock, 40,
+ EP93XX_TIMER4_RATE);
+
+ /* Set up clockevent on timer 3 */
+ setup_irq(IRQ_EP93XX_TIMER3, &ep93xx_timer_irq);
+ clockevents_config_and_register(&ep93xx_clockevent,
+ EP93XX_TIMER123_RATE,
+ 1,
+ 0xffffffffU);
+}