aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/clocksource/tegra20_timer.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2013-02-21 14:58:40 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-21 14:58:40 -0800
commitb274776c54c320763bc12eb035c0e244f76ccb43 (patch)
treec75b70d0824a7ae029229b19d61884039abf2127 /drivers/clocksource/tegra20_timer.c
parentMerge tag 'fixes-non-critical' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc (diff)
parentMerge tag 'cleanup_for_v3.9_round3' of git://git.infradead.org/users/jcooper/linux into next/cleanup (diff)
downloadlinux-dev-b274776c54c320763bc12eb035c0e244f76ccb43.tar.xz
linux-dev-b274776c54c320763bc12eb035c0e244f76ccb43.zip
Merge tag 'cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC cleanups from Arnd Bergmann: "A large number of cleanups, all over the platforms. This is dominated largely by the Samsung platforms (s3c, s5p, exynos) and a few of the others moving code out of arch/arm into more appropriate subsystems. The clocksource and irqchip drivers are now abstracted to the point where platforms that are already cleaned up do not need to even specify the driver they use, it can all get configured from the device tree as we do for normal device drivers. The clocksource changes basically touch every single platform in the process. We further clean up the use of platform specific header files here, with the goal of turning more of the platforms over to being "multiplatform" enabled, which implies that they cannot expose their headers to architecture independent code any more. It is expected that no functional changes are part of the cleanup. The overall reduction in total code lines is mostly the result of removing broken and obsolete code." * tag 'cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (133 commits) ARM: mvebu: correct gated clock documentation ARM: kirkwood: add missing include for nsa310 ARM: exynos: move exynos4210-combiner to drivers/irqchip mfd: db8500-prcmu: update resource passing drivers/db8500-cpufreq: delete dangling include ARM: at91: remove NEOCORE 926 board sunxi: Cleanup the reset code and add meaningful registers defines ARM: S3C24XX: header mach/regs-mem.h local ARM: S3C24XX: header mach/regs-power.h local ARM: S3C24XX: header mach/regs-s3c2412-mem.h local ARM: S3C24XX: Remove plat-s3c24xx directory in arch/arm/ ARM: S3C24XX: transform s3c2443 subirqs into new structure ARM: S3C24XX: modify s3c2443 irq init to initialize all irqs ARM: S3C24XX: move s3c2443 irq code to irq.c ARM: S3C24XX: transform s3c2416 irqs into new structure ARM: S3C24XX: modify s3c2416 irq init to initialize all irqs ARM: S3C24XX: move s3c2416 irq init to common irq code ARM: S3C24XX: Modify s3c_irq_wake to use the hwirq property ARM: S3C24XX: Move irq syscore-ops to irq-pm clocksource: always define CLOCKSOURCE_OF_DECLARE ...
Diffstat (limited to 'drivers/clocksource/tegra20_timer.c')
-rw-r--r--drivers/clocksource/tegra20_timer.c281
1 files changed, 281 insertions, 0 deletions
diff --git a/drivers/clocksource/tegra20_timer.c b/drivers/clocksource/tegra20_timer.c
new file mode 100644
index 000000000000..0bde03feb095
--- /dev/null
+++ b/drivers/clocksource/tegra20_timer.c
@@ -0,0 +1,281 @@
+/*
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * Author:
+ * Colin Cross <ccross@google.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/time.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include <asm/mach/time.h>
+#include <asm/smp_twd.h>
+#include <asm/sched_clock.h>
+
+#define RTC_SECONDS 0x08
+#define RTC_SHADOW_SECONDS 0x0c
+#define RTC_MILLISECONDS 0x10
+
+#define TIMERUS_CNTR_1US 0x10
+#define TIMERUS_USEC_CFG 0x14
+#define TIMERUS_CNTR_FREEZE 0x4c
+
+#define TIMER1_BASE 0x0
+#define TIMER2_BASE 0x8
+#define TIMER3_BASE 0x50
+#define TIMER4_BASE 0x58
+
+#define TIMER_PTV 0x0
+#define TIMER_PCR 0x4
+
+static void __iomem *timer_reg_base;
+static void __iomem *rtc_base;
+
+static struct timespec persistent_ts;
+static u64 persistent_ms, last_persistent_ms;
+
+#define timer_writel(value, reg) \
+ __raw_writel(value, timer_reg_base + (reg))
+#define timer_readl(reg) \
+ __raw_readl(timer_reg_base + (reg))
+
+static int tegra_timer_set_next_event(unsigned long cycles,
+ struct clock_event_device *evt)
+{
+ u32 reg;
+
+ reg = 0x80000000 | ((cycles > 1) ? (cycles-1) : 0);
+ timer_writel(reg, TIMER3_BASE + TIMER_PTV);
+
+ return 0;
+}
+
+static void tegra_timer_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ u32 reg;
+
+ timer_writel(0, TIMER3_BASE + TIMER_PTV);
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ reg = 0xC0000000 | ((1000000/HZ)-1);
+ timer_writel(reg, TIMER3_BASE + TIMER_PTV);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ break;
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_RESUME:
+ break;
+ }
+}
+
+static struct clock_event_device tegra_clockevent = {
+ .name = "timer0",
+ .rating = 300,
+ .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
+ .set_next_event = tegra_timer_set_next_event,
+ .set_mode = tegra_timer_set_mode,
+};
+
+static u32 notrace tegra_read_sched_clock(void)
+{
+ return timer_readl(TIMERUS_CNTR_1US);
+}
+
+/*
+ * tegra_rtc_read - Reads the Tegra RTC registers
+ * Care must be taken that this funciton is not called while the
+ * tegra_rtc driver could be executing to avoid race conditions
+ * on the RTC shadow register
+ */
+static u64 tegra_rtc_read_ms(void)
+{
+ u32 ms = readl(rtc_base + RTC_MILLISECONDS);
+ u32 s = readl(rtc_base + RTC_SHADOW_SECONDS);
+ return (u64)s * MSEC_PER_SEC + ms;
+}
+
+/*
+ * tegra_read_persistent_clock - Return time from a persistent clock.
+ *
+ * Reads the time from a source which isn't disabled during PM, the
+ * 32k sync timer. Convert the cycles elapsed since last read into
+ * nsecs and adds to a monotonically increasing timespec.
+ * Care must be taken that this funciton is not called while the
+ * tegra_rtc driver could be executing to avoid race conditions
+ * on the RTC shadow register
+ */
+static void tegra_read_persistent_clock(struct timespec *ts)
+{
+ u64 delta;
+ struct timespec *tsp = &persistent_ts;
+
+ last_persistent_ms = persistent_ms;
+ persistent_ms = tegra_rtc_read_ms();
+ delta = persistent_ms - last_persistent_ms;
+
+ timespec_add_ns(tsp, delta * NSEC_PER_MSEC);
+ *ts = *tsp;
+}
+
+static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = (struct clock_event_device *)dev_id;
+ timer_writel(1<<30, TIMER3_BASE + TIMER_PCR);
+ evt->event_handler(evt);
+ return IRQ_HANDLED;
+}
+
+static struct irqaction tegra_timer_irq = {
+ .name = "timer0",
+ .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_HIGH,
+ .handler = tegra_timer_interrupt,
+ .dev_id = &tegra_clockevent,
+};
+
+static const struct of_device_id timer_match[] __initconst = {
+ { .compatible = "nvidia,tegra20-timer" },
+ {}
+};
+
+static const struct of_device_id rtc_match[] __initconst = {
+ { .compatible = "nvidia,tegra20-rtc" },
+ {}
+};
+
+static void __init tegra20_init_timer(void)
+{
+ struct device_node *np;
+ struct clk *clk;
+ unsigned long rate;
+ int ret;
+
+ np = of_find_matching_node(NULL, timer_match);
+ if (!np) {
+ pr_err("Failed to find timer DT node\n");
+ BUG();
+ }
+
+ timer_reg_base = of_iomap(np, 0);
+ if (!timer_reg_base) {
+ pr_err("Can't map timer registers\n");
+ BUG();
+ }
+
+ tegra_timer_irq.irq = irq_of_parse_and_map(np, 2);
+ if (tegra_timer_irq.irq <= 0) {
+ pr_err("Failed to map timer IRQ\n");
+ BUG();
+ }
+
+ clk = clk_get_sys("timer", NULL);
+ if (IS_ERR(clk)) {
+ pr_warn("Unable to get timer clock. Assuming 12Mhz input clock.\n");
+ rate = 12000000;
+ } else {
+ clk_prepare_enable(clk);
+ rate = clk_get_rate(clk);
+ }
+
+ of_node_put(np);
+
+ np = of_find_matching_node(NULL, rtc_match);
+ if (!np) {
+ pr_err("Failed to find RTC DT node\n");
+ BUG();
+ }
+
+ rtc_base = of_iomap(np, 0);
+ if (!rtc_base) {
+ pr_err("Can't map RTC registers");
+ BUG();
+ }
+
+ /*
+ * rtc registers are used by read_persistent_clock, keep the rtc clock
+ * enabled
+ */
+ clk = clk_get_sys("rtc-tegra", NULL);
+ if (IS_ERR(clk))
+ pr_warn("Unable to get rtc-tegra clock\n");
+ else
+ clk_prepare_enable(clk);
+
+ of_node_put(np);
+
+ switch (rate) {
+ case 12000000:
+ timer_writel(0x000b, TIMERUS_USEC_CFG);
+ break;
+ case 13000000:
+ timer_writel(0x000c, TIMERUS_USEC_CFG);
+ break;
+ case 19200000:
+ timer_writel(0x045f, TIMERUS_USEC_CFG);
+ break;
+ case 26000000:
+ timer_writel(0x0019, TIMERUS_USEC_CFG);
+ break;
+ default:
+ WARN(1, "Unknown clock rate");
+ }
+
+ setup_sched_clock(tegra_read_sched_clock, 32, 1000000);
+
+ if (clocksource_mmio_init(timer_reg_base + TIMERUS_CNTR_1US,
+ "timer_us", 1000000, 300, 32, clocksource_mmio_readl_up)) {
+ pr_err("Failed to register clocksource\n");
+ BUG();
+ }
+
+ ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq);
+ if (ret) {
+ pr_err("Failed to register timer IRQ: %d\n", ret);
+ BUG();
+ }
+
+ tegra_clockevent.cpumask = cpu_all_mask;
+ tegra_clockevent.irq = tegra_timer_irq.irq;
+ clockevents_config_and_register(&tegra_clockevent, 1000000,
+ 0x1, 0x1fffffff);
+#ifdef CONFIG_HAVE_ARM_TWD
+ twd_local_timer_of_register();
+#endif
+ register_persistent_clock(NULL, tegra_read_persistent_clock);
+}
+CLOCKSOURCE_OF_DECLARE(tegra20, "nvidia,tegra20-timer", tegra20_init_timer);
+
+#ifdef CONFIG_PM
+static u32 usec_config;
+
+void tegra_timer_suspend(void)
+{
+ usec_config = timer_readl(TIMERUS_USEC_CFG);
+}
+
+void tegra_timer_resume(void)
+{
+ timer_writel(usec_config, TIMERUS_USEC_CFG);
+}
+#endif