[PATCH v1 1/2] clocksource: npcm: add NPCM7xx timer driver

Tomer Maimon
2017-10-01T10:11:34Z

Add Nuvoton BMC NPCM7xx timer driver.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
---
drivers/clocksource/Kconfig | 9 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/npcm7xx_timer.c | 205 ++++++++++++++++++++++++++++++++++++
3 files changed, 215 insertions(+)
create mode 100644 drivers/clocksource/npcm7xx_timer.c

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index cc6062049170..e26a203ce4ab 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -140,6 +140,15 @@ config VT8500_TIMER
help
Enables support for the VT8500 driver.

+config NPCM7XX_TIMER
+ bool "NPCM7xx timer driver" if (COMPILE_TEST || ARCH_NPCM7XX)
+ depends on GENERIC_CLOCKEVENTS
+ depends on HAS_IOMEM
+ select CLKSRC_MMIO
+ help
+ Enable 24-bit TIMER0 and TIMER1 counters in the NPCM7xx arcithcture,
+ While TIMER0 serves as clockevent and TIMER1 serves as clocksource.
+
config CADENCE_TTC_TIMER
bool "Cadence TTC timer driver" if COMPILE_TEST
depends on COMMON_CLK
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index dbc1ad14515e..fd3a1c33364b 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_CLKSRC_TI_32K) += timer-ti-32k.o
obj-$(CONFIG_CLKSRC_NPS) += timer-nps.o
obj-$(CONFIG_OXNAS_RPS_TIMER) += timer-oxnas-rps.o
obj-$(CONFIG_OWL_TIMER) += owl-timer.o
+obj-$(CONFIG_NPCM7XX_TIMER) += npcm7xx_timer.o

obj-$(CONFIG_ARC_TIMERS) += arc_timer.o
obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o
diff --git a/drivers/clocksource/npcm7xx_timer.c b/drivers/clocksource/npcm7xx_timer.c
new file mode 100644
index 000000000000..6da77202a22d
--- /dev/null
+++ b/drivers/clocksource/npcm7xx_timer.c
@@ -0,0 +1,205 @@
+/*
+ * Copyright (c) 2017 Nuvoton Technology corporation.
+ * Copyright 2017 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation;version 2 of the License.
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/clockchips.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+
+struct npcm7xx_clockevent_data {
+ struct clock_event_device cvd;
+ void __iomem *timer_base;
+ unsigned int rate;
+};
+
+/* Timers registers */
+#define REG_TCSR0 0x0 /* Timer 0 Control and Status Register */
+#define REG_TICR0 0x8 /* Timer 0 Initial Count Register */
+#define REG_TCSR1 0x4 /* Timer 1 Control and Status Register */
+#define REG_TICR1 0xc /* Timer 1 Initial Count Register */
+#define REG_TDR1 0x14 /* Timer 1 Data Register */
+#define REG_TISR 0x18 /* Timer Interrupt Status Register */
+
+#define RESETINT 0x1f
+#define PERIOD BIT(27)
+#define INTEN BIT(29)
+#define COUNTEN BIT(30)
+#define ONESHOT 0x0
+#define TIMER_OPER GENMASK(3, 27)
+#define MIN_PRESCALE 0x1 /* minimal timer prescale */
+#define TDR_MASK_BITS 24
+#define MAX_TIMER_CNT 0xFFFFFF
+#define CLR_TIMER0_INT 0x1
+#define CLR_TIMER_CSR 0x0
+
+
+static int npcm7xx_timer_oneshot(struct clock_event_device *evt)
+{
+ u32 val;
+ struct npcm7xx_clockevent_data *cevtd =
+ container_of(evt, struct npcm7xx_clockevent_data, cvd);
+
+ val = readl(cevtd->timer_base + REG_TCSR0);
+ val &= ~TIMER_OPER;
+
+ val = readl(cevtd->timer_base + REG_TCSR0);
+ val |= (ONESHOT | COUNTEN | INTEN | MIN_PRESCALE);
+ writel(val, cevtd->timer_base + REG_TCSR0);
+
+ return 0;
+}
+
+static int npcm7xx_timer_periodic(struct clock_event_device *evt)
+{
+ struct npcm7xx_clockevent_data *cevtd =
+ container_of(evt, struct npcm7xx_clockevent_data, cvd);
+ u32 val;
+
+ val = readl(cevtd->timer_base + REG_TCSR0);
+ val &= ~TIMER_OPER;
+
+ writel((cevtd->rate / HZ), cevtd->timer_base + REG_TICR0);
+ val |= (PERIOD | COUNTEN | INTEN | MIN_PRESCALE);
+
+ writel(val, cevtd->timer_base + REG_TCSR0);
+
+ return 0;
+}
+
+static int npcm7xx_clockevent_setnextevent(unsigned long evt,
+ struct clock_event_device *clk)
+{
+ struct npcm7xx_clockevent_data *cevtd =
+ container_of(clk, struct npcm7xx_clockevent_data, cvd);
+ u32 val;
+
+ writel(evt, cevtd->timer_base + REG_TICR0);
+ val = readl(cevtd->timer_base + REG_TCSR0);
+ val |= (COUNTEN | INTEN | MIN_PRESCALE);
+ writel(val, cevtd->timer_base + REG_TCSR0);
+
+ return 0;
+}
+
+static struct npcm7xx_clockevent_data npcm7xx_clockevent_data = {
+ .cvd = {
+ .name = "npcm7xx-timer0",
+ .features = CLOCK_EVT_FEAT_PERIODIC |
+ CLOCK_EVT_FEAT_ONESHOT,
+ .set_next_event = npcm7xx_clockevent_setnextevent,
+ .set_state_shutdown = npcm7xx_timer_oneshot,
+ .set_state_periodic = npcm7xx_timer_periodic,
+ .set_state_oneshot = npcm7xx_timer_oneshot,
+ .tick_resume = npcm7xx_timer_oneshot,
+ .rating = 300
+ },
+};
+
+static irqreturn_t npcm7xx_timer0_interrupt(int irq, void *dev_id)
+{
+ struct npcm7xx_clockevent_data *cevtd = dev_id;
+ struct clock_event_device *evt = &cevtd->cvd;
+
+ writel(CLR_TIMER0_INT, cevtd->timer_base + REG_TISR);
+
+ if (evt->event_handler)
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static struct irqaction npcm7xx_timer0_irq = {
+ .name = "npcm7xx-timer0",
+ .flags = IRQF_TIMER | IRQF_IRQPOLL,
+ .handler = npcm7xx_timer0_interrupt,
+ .dev_id = &npcm7xx_clockevent_data,
+};
+
+static void __init npcm7xx_clockevents_init(int irq, u32 rate)
+{
+ writel(CLR_TIMER_CSR, npcm7xx_clockevent_data.timer_base + REG_TCSR0);
+
+ writel(RESETINT, npcm7xx_clockevent_data.timer_base + REG_TISR);
+ setup_irq(irq, &npcm7xx_timer0_irq);
+ npcm7xx_clockevent_data.cvd.cpumask = cpumask_of(0);
+
+ clockevents_config_and_register(&npcm7xx_clockevent_data.cvd, rate,
+ 0x1, MAX_TIMER_CNT);
+}
+
+static void __init npcm7xx_clocksource_init(u32 rate)
+{
+ u32 val;
+
+ writel(CLR_TIMER_CSR, npcm7xx_clockevent_data.timer_base + REG_TCSR1);
+ writel(MAX_TIMER_CNT, npcm7xx_clockevent_data.timer_base + REG_TICR1);
+
+ val = readl(npcm7xx_clockevent_data.timer_base + REG_TCSR1);
+ val |= (COUNTEN | PERIOD | MIN_PRESCALE);
+ writel(val, npcm7xx_clockevent_data.timer_base + REG_TCSR1);
+
+ clocksource_mmio_init(npcm7xx_clockevent_data.timer_base + REG_TDR1,
+ "npcm7xx-timer1", rate,
+ 300, (unsigned int)TDR_MASK_BITS,
+ clocksource_mmio_readl_down);
+}
+
+static int __init npcm7xx_timer_init(struct device_node *np)
+{
+ struct clk *clk;
+ int irq, ret;
+ u32 rate;
+
+ irq = irq_of_parse_and_map(np, 0);
+ if (!irq)
+ return -EINVAL;
+
+ npcm7xx_clockevent_data.timer_base = of_iomap(np, 0);
+ if (!npcm7xx_clockevent_data.timer_base)
+ return -ENXIO;
+
+ clk = of_clk_get(np, 0);
+
+ if (IS_ERR(clk)) {
+ ret = of_property_read_u32(np, "clock-frequency", &rate);
+ if (ret)
+ goto err_iounmap;
+ } else {
+ clk_prepare_enable(clk);
+ rate = clk_get_rate(clk);
+ }
+
+ /* Clock input is divided by PRESCALE + 1 before it is fed */
+ /* to the counter */
+ rate = rate / (MIN_PRESCALE + 1);
+
+ npcm7xx_clockevent_data.rate = rate;
+
+ npcm7xx_clocksource_init(rate);
+ npcm7xx_clockevents_init(irq, rate);
+
+ pr_info("Enabling NPCM7xx clocksource timer base: %p, IRQ: %u\n",
+ npcm7xx_clockevent_data.timer_base, irq);
+
+ return 0;
+
+err_iounmap:
+ iounmap(npcm7xx_clockevent_data.timer_base);
+ return ret;
+
+}
+
+TIMER_OF_DECLARE(npcm7xx, "nuvoton,npcm7xx-timer", npcm7xx_timer_init);
+
--
2.14.1