--- /dev/null
+/*
+ * 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);
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff