[PATCH 05/22] clocksource: Add driver for the Cortina Gemini
Linus Walleij
linus.walleij at linaro.org
Sun Jan 22 04:17:17 PST 2017
This is a rewrite of the Gemini timer
driver in arch/arm/mach-gemini/timer.c trying to do everything
the device tree way:
- Make every IO-access relative to a base address and dynamic
so we can do a dynamic ioremap and get going.
- Do not poke around directly in the global syscon registers,
access them using the syscon regmap style design pattern for
the one register we need to check.
- Find register range and interrupt from the device tree.
Cc: Janos Laube <janos.dev at gmail.com>
Cc: Paulius Zaleckas <paulius.zaleckas at gmail.com>
Cc: Hans Ulli Kroll <ulli.kroll at googlemail.com>
Cc: Florian Fainelli <f.fainelli at gmail.com>
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
clocksource maintainers: please just apply this when you feel
pleased with it. These portions are functionally orthogonal to
the series, it is just in a series for context.
---
drivers/clocksource/Kconfig | 10 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/timer-gemini.c | 277 +++++++++++++++++++++++++++++++++++++
3 files changed, 288 insertions(+)
create mode 100644 drivers/clocksource/timer-gemini.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 4866f7aa32e6..60989d5b5135 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -60,6 +60,16 @@ config DW_APB_TIMER_OF
select DW_APB_TIMER
select CLKSRC_OF
+config GEMINI_TIMER
+ bool "Cortina Gemini timer driver" if COMPILE_TEST
+ depends on GENERIC_CLOCKEVENTS
+ depends on HAS_IOMEM
+ select CLKSRC_MMIO
+ select CLKSRC_OF
+ select MFD_SYSCON
+ help
+ Enables support for the Gemini timer
+
config ROCKCHIP_TIMER
bool "Rockchip timer driver" if COMPILE_TEST
depends on ARM || ARM64
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index a14111e1f087..a6dc6466bfa7 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_CLKSRC_MMIO) += mmio.o
obj-$(CONFIG_DIGICOLOR_TIMER) += timer-digicolor.o
obj-$(CONFIG_DW_APB_TIMER) += dw_apb_timer.o
obj-$(CONFIG_DW_APB_TIMER_OF) += dw_apb_timer_of.o
+obj-$(CONFIG_GEMINI_TIMER) += timer-gemini.o
obj-$(CONFIG_ROCKCHIP_TIMER) += rockchip_timer.o
obj-$(CONFIG_CLKSRC_NOMADIK_MTU) += nomadik-mtu.o
obj-$(CONFIG_CLKSRC_DBX500_PRCMU) += clksrc-dbx500-prcmu.o
diff --git a/drivers/clocksource/timer-gemini.c b/drivers/clocksource/timer-gemini.c
new file mode 100644
index 000000000000..dda27b7bf1a1
--- /dev/null
+++ b/drivers/clocksource/timer-gemini.c
@@ -0,0 +1,277 @@
+/*
+ * Gemini timer driver
+ * Copyright (C) 2017 Linus Walleij <linus.walleij at linaro.org>
+ *
+ * Based on a rewrite of arch/arm/mach-gemini/timer.c:
+ * Copyright (C) 2001-2006 Storlink, Corp.
+ * Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas at teltonika.lt>
+ */
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
+
+/*
+ * Relevant registers in the global syscon
+ */
+#define GLOBAL_STATUS 0x04
+#define CPU_AHB_RATIO_MASK (0x3 << 18)
+#define CPU_AHB_1_1 (0x0 << 18)
+#define CPU_AHB_3_2 (0x1 << 18)
+#define CPU_AHB_24_13 (0x2 << 18)
+#define CPU_AHB_2_1 (0x3 << 18)
+#define REG_TO_AHB_SPEED(reg) ((((reg) >> 15) & 0x7) * 10 + 130)
+
+/*
+ * Register definitions for the timers
+ */
+#define TIMER1_COUNT (0x00)
+#define TIMER1_LOAD (0x04)
+#define TIMER1_MATCH1 (0x08)
+#define TIMER1_MATCH2 (0x0c)
+#define TIMER2_COUNT (0x10)
+#define TIMER2_LOAD (0x14)
+#define TIMER2_MATCH1 (0x18)
+#define TIMER2_MATCH2 (0x1c)
+#define TIMER3_COUNT (0x20)
+#define TIMER3_LOAD (0x24)
+#define TIMER3_MATCH1 (0x28)
+#define TIMER3_MATCH2 (0x2c)
+#define TIMER_CR (0x30)
+#define TIMER_INTR_STATE (0x34)
+#define TIMER_INTR_MASK (0x38)
+
+#define TIMER_1_CR_ENABLE (1 << 0)
+#define TIMER_1_CR_CLOCK (1 << 1)
+#define TIMER_1_CR_INT (1 << 2)
+#define TIMER_2_CR_ENABLE (1 << 3)
+#define TIMER_2_CR_CLOCK (1 << 4)
+#define TIMER_2_CR_INT (1 << 5)
+#define TIMER_3_CR_ENABLE (1 << 6)
+#define TIMER_3_CR_CLOCK (1 << 7)
+#define TIMER_3_CR_INT (1 << 8)
+#define TIMER_1_CR_UPDOWN (1 << 9)
+#define TIMER_2_CR_UPDOWN (1 << 10)
+#define TIMER_3_CR_UPDOWN (1 << 11)
+#define TIMER_DEFAULT_FLAGS (TIMER_1_CR_UPDOWN | \
+ TIMER_3_CR_ENABLE | \
+ TIMER_3_CR_UPDOWN)
+
+#define TIMER_1_INT_MATCH1 (1 << 0)
+#define TIMER_1_INT_MATCH2 (1 << 1)
+#define TIMER_1_INT_OVERFLOW (1 << 2)
+#define TIMER_2_INT_MATCH1 (1 << 3)
+#define TIMER_2_INT_MATCH2 (1 << 4)
+#define TIMER_2_INT_OVERFLOW (1 << 5)
+#define TIMER_3_INT_MATCH1 (1 << 6)
+#define TIMER_3_INT_MATCH2 (1 << 7)
+#define TIMER_3_INT_OVERFLOW (1 << 8)
+#define TIMER_INT_ALL_MASK 0x1ff
+
+static unsigned int tick_rate;
+static void __iomem *base;
+
+static u64 notrace gemini_read_sched_clock(void)
+{
+ return readl(base + TIMER3_COUNT);
+}
+
+static int gemini_timer_set_next_event(unsigned long cycles,
+ struct clock_event_device *evt)
+{
+ u32 cr;
+
+ /* Setup the match register */
+ cr = readl(base + TIMER1_COUNT);
+ writel(cr + cycles, base + TIMER1_MATCH1);
+ if (readl(base + TIMER1_COUNT) - cr > cycles)
+ return -ETIME;
+
+ return 0;
+}
+
+static int gemini_timer_shutdown(struct clock_event_device *evt)
+{
+ u32 cr;
+
+ /*
+ * Disable also for oneshot: the set_next() call will arm the timer
+ * instead.
+ */
+ /* Stop timer and interrupt. */
+ cr = readl(base + TIMER_CR);
+ cr &= ~(TIMER_1_CR_ENABLE | TIMER_1_CR_INT);
+ writel(cr, base + TIMER_CR);
+
+ /* Setup counter start from 0 */
+ writel(0, base + TIMER1_COUNT);
+ writel(0, base + TIMER1_LOAD);
+
+ /* enable interrupt */
+ cr = readl(base + TIMER_INTR_MASK);
+ cr &= ~(TIMER_1_INT_OVERFLOW | TIMER_1_INT_MATCH2);
+ cr |= TIMER_1_INT_MATCH1;
+ writel(cr, base + TIMER_INTR_MASK);
+
+ /* start the timer */
+ cr = readl(base + TIMER_CR);
+ cr |= TIMER_1_CR_ENABLE;
+ writel(cr, base + TIMER_CR);
+
+ return 0;
+}
+
+static int gemini_timer_set_periodic(struct clock_event_device *evt)
+{
+ u32 period = DIV_ROUND_CLOSEST(tick_rate, HZ);
+ u32 cr;
+
+ /* Stop timer and interrupt */
+ cr = readl(base + TIMER_CR);
+ cr &= ~(TIMER_1_CR_ENABLE | TIMER_1_CR_INT);
+ writel(cr, base + TIMER_CR);
+
+ /* Setup timer to fire at 1/HT intervals. */
+ cr = 0xffffffff - (period - 1);
+ writel(cr, base + TIMER1_COUNT);
+ writel(cr, base + TIMER1_LOAD);
+
+ /* enable interrupt on overflow */
+ cr = readl(base + TIMER_INTR_MASK);
+ cr &= ~(TIMER_1_INT_MATCH1 | TIMER_1_INT_MATCH2);
+ cr |= TIMER_1_INT_OVERFLOW;
+ writel(cr, base + TIMER_INTR_MASK);
+
+ /* Start the timer */
+ cr = readl(base + TIMER_CR);
+ cr |= TIMER_1_CR_ENABLE;
+ cr |= TIMER_1_CR_INT;
+ writel(cr, base + TIMER_CR);
+
+ return 0;
+}
+
+/* Use TIMER1 as clock event */
+static struct clock_event_device gemini_clockevent = {
+ .name = "TIMER1",
+ /* Reasonably fast and accurate clock event */
+ .rating = 300,
+ .shift = 32,
+ .features = CLOCK_EVT_FEAT_PERIODIC |
+ CLOCK_EVT_FEAT_ONESHOT,
+ .set_next_event = gemini_timer_set_next_event,
+ .set_state_shutdown = gemini_timer_shutdown,
+ .set_state_periodic = gemini_timer_set_periodic,
+ .set_state_oneshot = gemini_timer_shutdown,
+ .tick_resume = gemini_timer_shutdown,
+};
+
+/*
+ * IRQ handler for the timer
+ */
+static irqreturn_t gemini_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = &gemini_clockevent;
+
+ evt->event_handler(evt);
+ return IRQ_HANDLED;
+}
+
+static struct irqaction gemini_timer_irq = {
+ .name = "Gemini Timer Tick",
+ .flags = IRQF_TIMER,
+ .handler = gemini_timer_interrupt,
+};
+
+static int __init gemini_timer_of_init(struct device_node *np)
+{
+ static struct regmap *map;
+ int irq;
+ int ret;
+ u32 val;
+
+ map = syscon_regmap_lookup_by_phandle(np, "syscon");
+ if (IS_ERR(map)) {
+ pr_err("Can't get regmap for syscon handle");
+ return -ENODEV;
+ }
+ ret = regmap_read(map, GLOBAL_STATUS, &val);
+ if (ret) {
+ pr_err("Can't read syscon status register");
+ return -ENXIO;
+ }
+
+ base = of_iomap(np, 0);
+ if (!base) {
+ pr_err("Can't remap registers");
+ return -ENXIO;
+ }
+ /* IRQ for timer 1 */
+ irq = irq_of_parse_and_map(np, 0);
+ if (irq <= 0) {
+ pr_err("Can't parse IRQ");
+ return -EINVAL;
+ }
+
+ tick_rate = REG_TO_AHB_SPEED(val) * 1000000;
+ printk(KERN_INFO "Bus: %dMHz", tick_rate / 1000000);
+
+ tick_rate /= 6; /* APB bus run AHB*(1/6) */
+
+ switch (val & CPU_AHB_RATIO_MASK) {
+ case CPU_AHB_1_1:
+ printk(KERN_CONT "(1/1)\n");
+ break;
+ case CPU_AHB_3_2:
+ printk(KERN_CONT "(3/2)\n");
+ break;
+ case CPU_AHB_24_13:
+ printk(KERN_CONT "(24/13)\n");
+ break;
+ case CPU_AHB_2_1:
+ printk(KERN_CONT "(2/1)\n");
+ break;
+ }
+
+ /*
+ * Reset the interrupt mask and status
+ */
+ writel(TIMER_INT_ALL_MASK, base + TIMER_INTR_MASK);
+ writel(0, base + TIMER_INTR_STATE);
+ writel(TIMER_DEFAULT_FLAGS, base + TIMER_CR);
+
+ /*
+ * Setup free-running clocksource timer (interrupts
+ * disabled.)
+ */
+ writel(0, base + TIMER3_COUNT);
+ writel(0, base + TIMER3_LOAD);
+ writel(0, base + TIMER3_MATCH1);
+ writel(0, base + TIMER3_MATCH2);
+ clocksource_mmio_init(base + TIMER3_COUNT,
+ "gemini_clocksource", tick_rate,
+ 300, 32, clocksource_mmio_readl_up);
+ sched_clock_register(gemini_read_sched_clock, 32, tick_rate);
+
+ /*
+ * Setup clockevent timer (interrupt-driven.)
+ */
+ writel(0, base + TIMER1_COUNT);
+ writel(0, base + TIMER1_LOAD);
+ writel(0, base + TIMER1_MATCH1);
+ writel(0, base + TIMER1_MATCH2);
+ setup_irq(irq, &gemini_timer_irq);
+ gemini_clockevent.cpumask = cpumask_of(0);
+ clockevents_config_and_register(&gemini_clockevent, tick_rate,
+ 1, 0xffffffff);
+
+ return 0;
+}
+CLOCKSOURCE_OF_DECLARE(nomadik_mtu, "cortina,gemini-timer",
+ gemini_timer_of_init);
--
2.9.3
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