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authorDong Aisheng <aisheng.dong@nxp.com>2017-08-01 16:40:17 +0800
committerDaniel Lezcano <daniel.lezcano@linaro.org>2017-08-29 11:07:56 +0200
commit059ab7b82eecfc23bc58c491d72ee6b424163578 (patch)
treeadf2612e76cf6331fae6abb7ccab324808941a80 /drivers/clocksource
parent34b0c26cd5458a991626bc8424e029562dceed21 (diff)
clocksource/drivers/imx-tpm: Add imx tpm timer support
IMX Timer/PWM Module (TPM) supports both timer and pwm function while this patch only adds the timer support. PWM would be added later. The TPM counter, compare and capture registers are clocked by an asynchronous clock that can remain enabled in low power modes. NOTE: We observed in a very small probability, the bus fabric contention between GPU and A7 may results a few cycles delay of writing CNT registers which may cause the min_delta event got missed, so we need add a ETIME check here in case it happened. Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Anson Huang <Anson.Huang@nxp.com> Cc: Bai Ping <ping.bai@nxp.com> Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Diffstat (limited to 'drivers/clocksource')
-rw-r--r--drivers/clocksource/Kconfig8
-rw-r--r--drivers/clocksource/Makefile1
-rw-r--r--drivers/clocksource/timer-imx-tpm.c239
3 files changed, 248 insertions, 0 deletions
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index fcae5ca6ac92..0a953fc45a0e 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -598,6 +598,14 @@ config CLKSRC_IMX_GPT
depends on ARM && CLKDEV_LOOKUP
select CLKSRC_MMIO
+config CLKSRC_IMX_TPM
+ bool "Clocksource using i.MX TPM" if COMPILE_TEST
+ depends on ARM && CLKDEV_LOOKUP && GENERIC_CLOCKEVENTS
+ select CLKSRC_MMIO
+ help
+ Enable this option to use IMX Timer/PWM Module (TPM) timer as
+ clocksource.
+
config CLKSRC_ST_LPC
bool "Low power clocksource found in the LPC" if COMPILE_TEST
select TIMER_OF if OF
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 6df949402dfc..dbc1ad14515e 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_CLKSRC_VERSATILE) += versatile.o
obj-$(CONFIG_CLKSRC_MIPS_GIC) += mips-gic-timer.o
obj-$(CONFIG_CLKSRC_TANGO_XTAL) += tango_xtal.o
obj-$(CONFIG_CLKSRC_IMX_GPT) += timer-imx-gpt.o
+obj-$(CONFIG_CLKSRC_IMX_TPM) += timer-imx-tpm.o
obj-$(CONFIG_ASM9260_TIMER) += asm9260_timer.o
obj-$(CONFIG_H8300_TMR8) += h8300_timer8.o
obj-$(CONFIG_H8300_TMR16) += h8300_timer16.o
diff --git a/drivers/clocksource/timer-imx-tpm.c b/drivers/clocksource/timer-imx-tpm.c
new file mode 100644
index 000000000000..21bffdcb2f20
--- /dev/null
+++ b/drivers/clocksource/timer-imx-tpm.c
@@ -0,0 +1,239 @@
+/*
+ * Copyright 2016 Freescale Semiconductor, Inc.
+ * Copyright 2017 NXP
+ *
+ * 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; either version 2
+ * of the License, or (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
+
+#define TPM_SC 0x10
+#define TPM_SC_CMOD_INC_PER_CNT (0x1 << 3)
+#define TPM_SC_CMOD_DIV_DEFAULT 0x3
+#define TPM_CNT 0x14
+#define TPM_MOD 0x18
+#define TPM_STATUS 0x1c
+#define TPM_STATUS_CH0F BIT(0)
+#define TPM_C0SC 0x20
+#define TPM_C0SC_CHIE BIT(6)
+#define TPM_C0SC_MODE_SHIFT 2
+#define TPM_C0SC_MODE_MASK 0x3c
+#define TPM_C0SC_MODE_SW_COMPARE 0x4
+#define TPM_C0V 0x24
+
+static void __iomem *timer_base;
+static struct clock_event_device clockevent_tpm;
+
+static inline void tpm_timer_disable(void)
+{
+ unsigned int val;
+
+ /* channel disable */
+ val = readl(timer_base + TPM_C0SC);
+ val &= ~(TPM_C0SC_MODE_MASK | TPM_C0SC_CHIE);
+ writel(val, timer_base + TPM_C0SC);
+}
+
+static inline void tpm_timer_enable(void)
+{
+ unsigned int val;
+
+ /* channel enabled in sw compare mode */
+ val = readl(timer_base + TPM_C0SC);
+ val |= (TPM_C0SC_MODE_SW_COMPARE << TPM_C0SC_MODE_SHIFT) |
+ TPM_C0SC_CHIE;
+ writel(val, timer_base + TPM_C0SC);
+}
+
+static inline void tpm_irq_acknowledge(void)
+{
+ writel(TPM_STATUS_CH0F, timer_base + TPM_STATUS);
+}
+
+static struct delay_timer tpm_delay_timer;
+
+static inline unsigned long tpm_read_counter(void)
+{
+ return readl(timer_base + TPM_CNT);
+}
+
+static unsigned long tpm_read_current_timer(void)
+{
+ return tpm_read_counter();
+}
+
+static u64 notrace tpm_read_sched_clock(void)
+{
+ return tpm_read_counter();
+}
+
+static int __init tpm_clocksource_init(unsigned long rate)
+{
+ tpm_delay_timer.read_current_timer = &tpm_read_current_timer;
+ tpm_delay_timer.freq = rate;
+ register_current_timer_delay(&tpm_delay_timer);
+
+ sched_clock_register(tpm_read_sched_clock, 32, rate);
+
+ return clocksource_mmio_init(timer_base + TPM_CNT, "imx-tpm",
+ rate, 200, 32, clocksource_mmio_readl_up);
+}
+
+static int tpm_set_next_event(unsigned long delta,
+ struct clock_event_device *evt)
+{
+ unsigned long next, now;
+
+ next = tpm_read_counter();
+ next += delta;
+ writel(next, timer_base + TPM_C0V);
+ now = tpm_read_counter();
+
+ /*
+ * NOTE: We observed in a very small probability, the bus fabric
+ * contention between GPU and A7 may results a few cycles delay
+ * of writing CNT registers which may cause the min_delta event got
+ * missed, so we need add a ETIME check here in case it happened.
+ */
+ return (int)((next - now) <= 0) ? -ETIME : 0;
+}
+
+static int tpm_set_state_oneshot(struct clock_event_device *evt)
+{
+ tpm_timer_enable();
+
+ return 0;
+}
+
+static int tpm_set_state_shutdown(struct clock_event_device *evt)
+{
+ tpm_timer_disable();
+
+ return 0;
+}
+
+static irqreturn_t tpm_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ tpm_irq_acknowledge();
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static struct clock_event_device clockevent_tpm = {
+ .name = "i.MX7ULP TPM Timer",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .set_state_oneshot = tpm_set_state_oneshot,
+ .set_next_event = tpm_set_next_event,
+ .set_state_shutdown = tpm_set_state_shutdown,
+ .rating = 200,
+};
+
+static int __init tpm_clockevent_init(unsigned long rate, int irq)
+{
+ int ret;
+
+ ret = request_irq(irq, tpm_timer_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
+ "i.MX7ULP TPM Timer", &clockevent_tpm);
+
+ clockevent_tpm.cpumask = cpumask_of(0);
+ clockevent_tpm.irq = irq;
+ clockevents_config_and_register(&clockevent_tpm,
+ rate, 300, 0xfffffffe);
+
+ return ret;
+}
+
+static int __init tpm_timer_init(struct device_node *np)
+{
+ struct clk *ipg, *per;
+ int irq, ret;
+ u32 rate;
+
+ timer_base = of_iomap(np, 0);
+ if (!timer_base) {
+ pr_err("tpm: failed to get base address\n");
+ return -ENXIO;
+ }
+
+ irq = irq_of_parse_and_map(np, 0);
+ if (!irq) {
+ pr_err("tpm: failed to get irq\n");
+ ret = -ENOENT;
+ goto err_iomap;
+ }
+
+ ipg = of_clk_get_by_name(np, "ipg");
+ per = of_clk_get_by_name(np, "per");
+ if (IS_ERR(ipg) || IS_ERR(per)) {
+ pr_err("tpm: failed to get igp or per clk\n");
+ ret = -ENODEV;
+ goto err_clk_get;
+ }
+
+ /* enable clk before accessing registers */
+ ret = clk_prepare_enable(ipg);
+ if (ret) {
+ pr_err("tpm: ipg clock enable failed (%d)\n", ret);
+ goto err_clk_get;
+ }
+
+ ret = clk_prepare_enable(per);
+ if (ret) {
+ pr_err("tpm: per clock enable failed (%d)\n", ret);
+ goto err_per_clk_enable;
+ }
+
+ /*
+ * Initialize tpm module to a known state
+ * 1) Counter disabled
+ * 2) TPM counter operates in up counting mode
+ * 3) Timer Overflow Interrupt disabled
+ * 4) Channel0 disabled
+ * 5) DMA transfers disabled
+ */
+ writel(0, timer_base + TPM_SC);
+ writel(0, timer_base + TPM_CNT);
+ writel(0, timer_base + TPM_C0SC);
+
+ /* increase per cnt, div 8 by default */
+ writel(TPM_SC_CMOD_INC_PER_CNT | TPM_SC_CMOD_DIV_DEFAULT,
+ timer_base + TPM_SC);
+
+ /* set MOD register to maximum for free running mode */
+ writel(0xffffffff, timer_base + TPM_MOD);
+
+ rate = clk_get_rate(per) >> 3;
+ ret = tpm_clocksource_init(rate);
+ if (ret)
+ goto err_per_clk_enable;
+
+ ret = tpm_clockevent_init(rate, irq);
+ if (ret)
+ goto err_per_clk_enable;
+
+ return 0;
+
+err_per_clk_enable:
+ clk_disable_unprepare(ipg);
+err_clk_get:
+ clk_put(per);
+ clk_put(ipg);
+err_iomap:
+ iounmap(timer_base);
+ return ret;
+}
+TIMER_OF_DECLARE(imx7ulp, "fsl,imx7ulp-tpm", tpm_timer_init);