openwrtv4/target/linux/ramips/patches-3.9/0142-clocksource-MIPS-ralink-add-support-for-systick-time.patch

From bc350a91da176ae8573c0755c66f5ee1911495bc Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Tue, 30 Apr 2013 12:35:50 +0200
Subject: [PATCH 142/164] clocksource: MIPS: ralink: add support for systick
 timer found on newer ralink SoC

Signed-off-by: John Crispin <blogic@openwrt.org>
---
 arch/mips/ralink/Kconfig          |    2 +
 arch/mips/ralink/clk.c            |    1 +
 drivers/clocksource/Kconfig       |    6 ++
 drivers/clocksource/Makefile      |    1 +
 drivers/clocksource/cevt-rt3352.c |  162 +++++++++++++++++++++++++++++++++++++
 include/linux/clocksource.h       |    1 +
 6 files changed, 173 insertions(+)
 create mode 100644 drivers/clocksource/cevt-rt3352.c

--- a/arch/mips/ralink/Kconfig
+++ b/arch/mips/ralink/Kconfig
@@ -14,6 +14,7 @@ choice
 		select USB_ARCH_HAS_HCD
 		select USB_ARCH_HAS_OHCI
 		select USB_ARCH_HAS_EHCI
+		select CLKEVT_RT3352
 
 	config SOC_RT3883
 		bool "RT3883"
@@ -22,6 +23,7 @@ choice
 
 	config SOC_MT7620
 		bool "MT7620"
+		select CLKEVT_RT3352
 
 endchoice
 
--- a/arch/mips/ralink/clk.c
+++ b/arch/mips/ralink/clk.c
@@ -69,4 +69,5 @@ void __init plat_time_init(void)
 	pr_info("CPU Clock: %ldMHz\n", clk_get_rate(clk) / 1000000);
 	mips_hpt_frequency = clk_get_rate(clk) / 2;
 	clk_put(clk);
+	clocksource_of_init();
 }
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -7,6 +7,12 @@ config CLKSRC_I8253
 config CLKEVT_I8253
 	bool
 
+config CLKEVT_RT3352
+	bool
+	depends on MIPS && RALINK
+	select CLKSRC_OF
+	select CLKSRC_MMIO
+
 config I8253_LOCK
 	bool
 
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_SH_TIMER_TMU)	+= sh_tmu.o
 obj-$(CONFIG_EM_TIMER_STI)	+= em_sti.o
 obj-$(CONFIG_CLKBLD_I8253)	+= i8253.o
 obj-$(CONFIG_CLKSRC_MMIO)	+= mmio.o
+obj-$(CONFIG_CLKEVT_RT3352)	+= cevt-rt3352.o
 obj-$(CONFIG_DW_APB_TIMER)	+= dw_apb_timer.o
 obj-$(CONFIG_DW_APB_TIMER_OF)	+= dw_apb_timer_of.o
 obj-$(CONFIG_CLKSRC_NOMADIK_MTU)	+= nomadik-mtu.o
--- /dev/null
+++ b/drivers/clocksource/cevt-rt3352.c
@@ -0,0 +1,162 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2013 by John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+#include <linux/reset.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+
+#include <asm/mach-ralink/ralink_regs.h>
+#include <asm/time.h>
+
+#define SYSTICK_FREQ	(50 * 1000)
+
+#define SYSTICK_CONFIG	0x00
+#define SYSTICK_COMPARE	0x04
+#define SYSTICK_COUNT	0x08
+
+/* route systick irq to mips irq 7 instead of the r4k-timer */
+#define CFG_EXT_STK_EN	0x2
+/* enable the counter */
+#define CFG_CNT_EN	0x1
+
+struct systick_device {
+	void __iomem *membase;
+	struct clock_event_device dev;
+	int irq_requested;
+	int freq_scale;
+};
+
+static void systick_set_clock_mode(enum clock_event_mode mode,
+				struct clock_event_device *evt);
+
+static int systick_next_event(unsigned long delta,
+				struct clock_event_device *evt)
+{
+	struct systick_device *sdev = container_of(evt, struct systick_device, dev);
+	u32 count;
+
+	count = ioread32(sdev->membase + SYSTICK_COUNT);
+	count = (count + delta) % SYSTICK_FREQ;
+	iowrite32(count + delta, sdev->membase + SYSTICK_COMPARE);
+
+	return 0;
+}
+
+static void systick_event_handler(struct clock_event_device *dev)
+{
+	/* noting to do here */
+}
+
+static irqreturn_t systick_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *dev = (struct clock_event_device *) dev_id;
+
+	dev->event_handler(dev);
+
+	return IRQ_HANDLED;
+}
+
+static struct systick_device systick = {
+	.dev = {
+		/* cevt-r4k uses 300, make sure systick gets used if available */
+		.rating		= 310,
+		.features	= CLOCK_EVT_FEAT_ONESHOT,
+		.set_next_event	= systick_next_event,
+		.set_mode	= systick_set_clock_mode,
+		.event_handler	= systick_event_handler,
+	},
+};
+
+static struct irqaction systick_irqaction = {
+	.handler = systick_interrupt,
+	.flags = IRQF_PERCPU | IRQF_TIMER,
+	.dev_id = &systick.dev,
+};
+
+/* ugly hack */
+#ifdef CONFIG_SOC_MT7620
+
+#define CLK_LUT_CFG	0x40
+#define SLEEP_EN	BIT(31)
+
+static inline void mt7620_freq_scaling(struct systick_device *sdev, int status)
+{
+	if (sdev->freq_scale == status)
+		return;
+
+	sdev->freq_scale = status;
+
+	pr_info("%s: %s autosleep mode\n", systick.dev.name, (status) ? ("enable") : ("disable"));
+	if (status)
+		rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) | SLEEP_EN, CLK_LUT_CFG);
+	else
+		rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) & ~SLEEP_EN, CLK_LUT_CFG);
+}
+#else
+static inline void mt7620_freq_scaling(struct systick_device *sdev, int status) {}
+#endif
+
+static void systick_set_clock_mode(enum clock_event_mode mode,
+				struct clock_event_device *evt)
+{
+	struct systick_device *sdev = container_of(evt, struct systick_device, dev);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_ONESHOT:
+		if (!sdev->irq_requested)
+			setup_irq(systick.dev.irq, &systick_irqaction);
+		mt7620_freq_scaling(sdev, 1);
+		sdev->irq_requested = 1;
+		iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN, systick.membase + SYSTICK_CONFIG);
+		break;
+
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		if (sdev->irq_requested)
+			free_irq(systick.dev.irq, &systick_irqaction);
+		mt7620_freq_scaling(sdev, 0);
+		sdev->irq_requested = 0;
+		iowrite32(0, systick.membase + SYSTICK_CONFIG);
+		break;
+
+	default:
+		pr_err("%s: Unhandeled mips clock_mode\n", systick.dev.name);
+		break;
+	}
+}
+
+static void __init ralink_systick_init(struct device_node *np)
+{
+	systick.membase = of_iomap(np, 0);
+	if (!systick.membase) {
+		pr_err("%s: of_iomap failed", np->name);
+		return;
+	}
+
+	clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,
+			SYSTICK_FREQ, 301, 16, clocksource_mmio_readl_up);
+
+	systick_irqaction.name = np->name;
+	systick.dev.name = np->name;
+	clockevent_set_clock(&systick.dev, SYSTICK_FREQ);
+	systick.dev.max_delta_ns = clockevent_delta2ns(0x7fff, &systick.dev);
+	systick.dev.min_delta_ns = clockevent_delta2ns(0x3, &systick.dev);
+	systick.dev.irq = irq_of_parse_and_map(np, 0);
+	if (!systick.dev.irq)
+		panic("%s: request_irq failed", np->name);
+
+	clockevents_register_device(&systick.dev);
+
+	pr_info("%s: runing - mult: %d, shift: %d\n", np->name, systick.dev.mult, systick.dev.shift);
+}
+
+CLOCKSOURCE_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init);
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -340,6 +340,7 @@ extern void clocksource_of_init(void);
 		__used __section(__clksrc_of_table)			\
 		 = { .compatible = compat, .data = fn };
 #else
+static inline void clocksource_of_init(void) {}
 #define CLOCKSOURCE_OF_DECLARE(name, compat, fn)
 #endif