diff options
Diffstat (limited to 'drivers/clocksource/timer-imx-tpm.c')
| -rw-r--r-- | drivers/clocksource/timer-imx-tpm.c | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-imx-tpm.c b/drivers/clocksource/timer-imx-tpm.c new file mode 100644 index 000000000..b7aa2b817 --- /dev/null +++ b/drivers/clocksource/timer-imx-tpm.c @@ -0,0 +1,257 @@ +// SPDX-License-Identifier: GPL-2.0+ +// +// Copyright 2016 Freescale Semiconductor, Inc. +// Copyright 2017 NXP + +#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_PARAM 0x4 +#define TPM_PARAM_WIDTH_SHIFT 16 +#define TPM_PARAM_WIDTH_MASK (0xff << 16) +#define TPM_SC 0x10 +#define TPM_SC_CMOD_INC_PER_CNT (0x1 << 3) +#define TPM_SC_CMOD_DIV_DEFAULT 0x3 +#define TPM_SC_CMOD_DIV_MAX 0x7 +#define TPM_SC_TOF_MASK (0x1 << 7) +#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_C0SC_CHF_MASK (0x1 << 7) +#define TPM_C0V 0x24 + +static int counter_width; +static int rating; +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, counter_width, rate); + + return clocksource_mmio_init(timer_base + TPM_CNT, "imx-tpm", + rate, rating, counter_width, + 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, +}; + +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.rating = rating; + clockevent_tpm.cpumask = cpumask_of(0); + clockevent_tpm.irq = irq; + clockevents_config_and_register(&clockevent_tpm, rate, 300, + GENMASK(counter_width - 1, 1)); + + 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 ipg 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; + } + + counter_width = (readl(timer_base + TPM_PARAM) & TPM_PARAM_WIDTH_MASK) + >> TPM_PARAM_WIDTH_SHIFT; + /* use rating 200 for 32-bit counter and 150 for 16-bit counter */ + rating = counter_width == 0x20 ? 200 : 150; + + /* + * 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 + */ + /* make sure counter is disabled */ + writel(0, timer_base + TPM_SC); + /* TOF is W1C */ + writel(TPM_SC_TOF_MASK, timer_base + TPM_SC); + writel(0, timer_base + TPM_CNT); + /* CHF is W1C */ + writel(TPM_C0SC_CHF_MASK, timer_base + TPM_C0SC); + + /* + * increase per cnt, + * div 8 for 32-bit counter and div 128 for 16-bit counter + */ + writel(TPM_SC_CMOD_INC_PER_CNT | + (counter_width == 0x20 ? + TPM_SC_CMOD_DIV_DEFAULT : TPM_SC_CMOD_DIV_MAX), + timer_base + TPM_SC); + + /* set MOD register to maximum for free running mode */ + writel(GENMASK(counter_width - 1, 0), 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); |