diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/clocksource/timer-tegra186.c | 514 |
1 files changed, 514 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-tegra186.c b/drivers/clocksource/timer-tegra186.c new file mode 100644 index 000000000..ea742889e --- /dev/null +++ b/drivers/clocksource/timer-tegra186.c @@ -0,0 +1,514 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2019-2020 NVIDIA Corporation. All rights reserved. + */ + +#include <linux/clocksource.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/pm.h> +#include <linux/watchdog.h> + +/* shared registers */ +#define TKETSC0 0x000 +#define TKETSC1 0x004 +#define TKEUSEC 0x008 +#define TKEOSC 0x00c + +#define TKEIE(x) (0x100 + ((x) * 4)) +#define TKEIE_WDT_MASK(x, y) ((y) << (16 + 4 * (x))) + +/* timer registers */ +#define TMRCR 0x000 +#define TMRCR_ENABLE BIT(31) +#define TMRCR_PERIODIC BIT(30) +#define TMRCR_PTV(x) ((x) & 0x0fffffff) + +#define TMRSR 0x004 +#define TMRSR_INTR_CLR BIT(30) + +#define TMRCSSR 0x008 +#define TMRCSSR_SRC_USEC (0 << 0) + +/* watchdog registers */ +#define WDTCR 0x000 +#define WDTCR_SYSTEM_POR_RESET_ENABLE BIT(16) +#define WDTCR_SYSTEM_DEBUG_RESET_ENABLE BIT(15) +#define WDTCR_REMOTE_INT_ENABLE BIT(14) +#define WDTCR_LOCAL_FIQ_ENABLE BIT(13) +#define WDTCR_LOCAL_INT_ENABLE BIT(12) +#define WDTCR_PERIOD_MASK (0xff << 4) +#define WDTCR_PERIOD(x) (((x) & 0xff) << 4) +#define WDTCR_TIMER_SOURCE_MASK 0xf +#define WDTCR_TIMER_SOURCE(x) ((x) & 0xf) + +#define WDTCMDR 0x008 +#define WDTCMDR_DISABLE_COUNTER BIT(1) +#define WDTCMDR_START_COUNTER BIT(0) + +#define WDTUR 0x00c +#define WDTUR_UNLOCK_PATTERN 0x0000c45a + +struct tegra186_timer_soc { + unsigned int num_timers; + unsigned int num_wdts; +}; + +struct tegra186_tmr { + struct tegra186_timer *parent; + void __iomem *regs; + unsigned int index; + unsigned int hwirq; +}; + +struct tegra186_wdt { + struct watchdog_device base; + + void __iomem *regs; + unsigned int index; + bool locked; + + struct tegra186_tmr *tmr; +}; + +static inline struct tegra186_wdt *to_tegra186_wdt(struct watchdog_device *wdd) +{ + return container_of(wdd, struct tegra186_wdt, base); +} + +struct tegra186_timer { + const struct tegra186_timer_soc *soc; + struct device *dev; + void __iomem *regs; + + struct tegra186_wdt *wdt; + struct clocksource usec; + struct clocksource tsc; + struct clocksource osc; +}; + +static void tmr_writel(struct tegra186_tmr *tmr, u32 value, unsigned int offset) +{ + writel_relaxed(value, tmr->regs + offset); +} + +static void wdt_writel(struct tegra186_wdt *wdt, u32 value, unsigned int offset) +{ + writel_relaxed(value, wdt->regs + offset); +} + +static u32 wdt_readl(struct tegra186_wdt *wdt, unsigned int offset) +{ + return readl_relaxed(wdt->regs + offset); +} + +static struct tegra186_tmr *tegra186_tmr_create(struct tegra186_timer *tegra, + unsigned int index) +{ + unsigned int offset = 0x10000 + index * 0x10000; + struct tegra186_tmr *tmr; + + tmr = devm_kzalloc(tegra->dev, sizeof(*tmr), GFP_KERNEL); + if (!tmr) + return ERR_PTR(-ENOMEM); + + tmr->parent = tegra; + tmr->regs = tegra->regs + offset; + tmr->index = index; + tmr->hwirq = 0; + + return tmr; +} + +static const struct watchdog_info tegra186_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, + .identity = "NVIDIA Tegra186 WDT", +}; + +static void tegra186_wdt_disable(struct tegra186_wdt *wdt) +{ + /* unlock and disable the watchdog */ + wdt_writel(wdt, WDTUR_UNLOCK_PATTERN, WDTUR); + wdt_writel(wdt, WDTCMDR_DISABLE_COUNTER, WDTCMDR); + + /* disable timer */ + tmr_writel(wdt->tmr, 0, TMRCR); +} + +static void tegra186_wdt_enable(struct tegra186_wdt *wdt) +{ + struct tegra186_timer *tegra = wdt->tmr->parent; + u32 value; + + /* unmask hardware IRQ, this may have been lost across powergate */ + value = TKEIE_WDT_MASK(wdt->index, 1); + writel(value, tegra->regs + TKEIE(wdt->tmr->hwirq)); + + /* clear interrupt */ + tmr_writel(wdt->tmr, TMRSR_INTR_CLR, TMRSR); + + /* select microsecond source */ + tmr_writel(wdt->tmr, TMRCSSR_SRC_USEC, TMRCSSR); + + /* configure timer (system reset happens on the fifth expiration) */ + value = TMRCR_PTV(wdt->base.timeout * USEC_PER_SEC / 5) | + TMRCR_PERIODIC | TMRCR_ENABLE; + tmr_writel(wdt->tmr, value, TMRCR); + + if (!wdt->locked) { + value = wdt_readl(wdt, WDTCR); + + /* select the proper timer source */ + value &= ~WDTCR_TIMER_SOURCE_MASK; + value |= WDTCR_TIMER_SOURCE(wdt->tmr->index); + + /* single timer period since that's already configured */ + value &= ~WDTCR_PERIOD_MASK; + value |= WDTCR_PERIOD(1); + + /* enable local interrupt for WDT petting */ + value |= WDTCR_LOCAL_INT_ENABLE; + + /* enable local FIQ and remote interrupt for debug dump */ + if (0) + value |= WDTCR_REMOTE_INT_ENABLE | + WDTCR_LOCAL_FIQ_ENABLE; + + /* enable system debug reset (doesn't properly reboot) */ + if (0) + value |= WDTCR_SYSTEM_DEBUG_RESET_ENABLE; + + /* enable system POR reset */ + value |= WDTCR_SYSTEM_POR_RESET_ENABLE; + + wdt_writel(wdt, value, WDTCR); + } + + wdt_writel(wdt, WDTCMDR_START_COUNTER, WDTCMDR); +} + +static int tegra186_wdt_start(struct watchdog_device *wdd) +{ + struct tegra186_wdt *wdt = to_tegra186_wdt(wdd); + + tegra186_wdt_enable(wdt); + + return 0; +} + +static int tegra186_wdt_stop(struct watchdog_device *wdd) +{ + struct tegra186_wdt *wdt = to_tegra186_wdt(wdd); + + tegra186_wdt_disable(wdt); + + return 0; +} + +static int tegra186_wdt_ping(struct watchdog_device *wdd) +{ + struct tegra186_wdt *wdt = to_tegra186_wdt(wdd); + + tegra186_wdt_disable(wdt); + tegra186_wdt_enable(wdt); + + return 0; +} + +static int tegra186_wdt_set_timeout(struct watchdog_device *wdd, + unsigned int timeout) +{ + struct tegra186_wdt *wdt = to_tegra186_wdt(wdd); + + if (watchdog_active(&wdt->base)) + tegra186_wdt_disable(wdt); + + wdt->base.timeout = timeout; + + if (watchdog_active(&wdt->base)) + tegra186_wdt_enable(wdt); + + return 0; +} + +static const struct watchdog_ops tegra186_wdt_ops = { + .owner = THIS_MODULE, + .start = tegra186_wdt_start, + .stop = tegra186_wdt_stop, + .ping = tegra186_wdt_ping, + .set_timeout = tegra186_wdt_set_timeout, +}; + +static struct tegra186_wdt *tegra186_wdt_create(struct tegra186_timer *tegra, + unsigned int index) +{ + unsigned int offset = 0x10000, source; + struct tegra186_wdt *wdt; + u32 value; + int err; + + offset += tegra->soc->num_timers * 0x10000 + index * 0x10000; + + wdt = devm_kzalloc(tegra->dev, sizeof(*wdt), GFP_KERNEL); + if (!wdt) + return ERR_PTR(-ENOMEM); + + wdt->regs = tegra->regs + offset; + wdt->index = index; + + /* read the watchdog configuration since it might be locked down */ + value = wdt_readl(wdt, WDTCR); + + if (value & WDTCR_LOCAL_INT_ENABLE) + wdt->locked = true; + + source = value & WDTCR_TIMER_SOURCE_MASK; + + wdt->tmr = tegra186_tmr_create(tegra, source); + if (IS_ERR(wdt->tmr)) + return ERR_CAST(wdt->tmr); + + wdt->base.info = &tegra186_wdt_info; + wdt->base.ops = &tegra186_wdt_ops; + wdt->base.min_timeout = 1; + wdt->base.max_timeout = 255; + wdt->base.parent = tegra->dev; + + err = watchdog_init_timeout(&wdt->base, 5, tegra->dev); + if (err < 0) { + dev_err(tegra->dev, "failed to initialize timeout: %d\n", err); + return ERR_PTR(err); + } + + err = devm_watchdog_register_device(tegra->dev, &wdt->base); + if (err < 0) { + dev_err(tegra->dev, "failed to register WDT: %d\n", err); + return ERR_PTR(err); + } + + return wdt; +} + +static u64 tegra186_timer_tsc_read(struct clocksource *cs) +{ + struct tegra186_timer *tegra = container_of(cs, struct tegra186_timer, + tsc); + u32 hi, lo, ss; + + hi = readl_relaxed(tegra->regs + TKETSC1); + + /* + * The 56-bit value of the TSC is spread across two registers that are + * not synchronized. In order to read them atomically, ensure that the + * high 24 bits match before and after reading the low 32 bits. + */ + do { + /* snapshot the high 24 bits */ + ss = hi; + + lo = readl_relaxed(tegra->regs + TKETSC0); + hi = readl_relaxed(tegra->regs + TKETSC1); + } while (hi != ss); + + return (u64)hi << 32 | lo; +} + +static int tegra186_timer_tsc_init(struct tegra186_timer *tegra) +{ + tegra->tsc.name = "tsc"; + tegra->tsc.rating = 300; + tegra->tsc.read = tegra186_timer_tsc_read; + tegra->tsc.mask = CLOCKSOURCE_MASK(56); + tegra->tsc.flags = CLOCK_SOURCE_IS_CONTINUOUS; + + return clocksource_register_hz(&tegra->tsc, 31250000); +} + +static u64 tegra186_timer_osc_read(struct clocksource *cs) +{ + struct tegra186_timer *tegra = container_of(cs, struct tegra186_timer, + osc); + + return readl_relaxed(tegra->regs + TKEOSC); +} + +static int tegra186_timer_osc_init(struct tegra186_timer *tegra) +{ + tegra->osc.name = "osc"; + tegra->osc.rating = 300; + tegra->osc.read = tegra186_timer_osc_read; + tegra->osc.mask = CLOCKSOURCE_MASK(32); + tegra->osc.flags = CLOCK_SOURCE_IS_CONTINUOUS; + + return clocksource_register_hz(&tegra->osc, 38400000); +} + +static u64 tegra186_timer_usec_read(struct clocksource *cs) +{ + struct tegra186_timer *tegra = container_of(cs, struct tegra186_timer, + usec); + + return readl_relaxed(tegra->regs + TKEUSEC); +} + +static int tegra186_timer_usec_init(struct tegra186_timer *tegra) +{ + tegra->usec.name = "usec"; + tegra->usec.rating = 300; + tegra->usec.read = tegra186_timer_usec_read; + tegra->usec.mask = CLOCKSOURCE_MASK(32); + tegra->usec.flags = CLOCK_SOURCE_IS_CONTINUOUS; + + return clocksource_register_hz(&tegra->usec, USEC_PER_SEC); +} + +static irqreturn_t tegra186_timer_irq(int irq, void *data) +{ + struct tegra186_timer *tegra = data; + + if (watchdog_active(&tegra->wdt->base)) { + tegra186_wdt_disable(tegra->wdt); + tegra186_wdt_enable(tegra->wdt); + } + + return IRQ_HANDLED; +} + +static int tegra186_timer_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct tegra186_timer *tegra; + unsigned int irq; + int err; + + tegra = devm_kzalloc(dev, sizeof(*tegra), GFP_KERNEL); + if (!tegra) + return -ENOMEM; + + tegra->soc = of_device_get_match_data(dev); + dev_set_drvdata(dev, tegra); + tegra->dev = dev; + + tegra->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(tegra->regs)) + return PTR_ERR(tegra->regs); + + err = platform_get_irq(pdev, 0); + if (err < 0) + return err; + + irq = err; + + /* create a watchdog using a preconfigured timer */ + tegra->wdt = tegra186_wdt_create(tegra, 0); + if (IS_ERR(tegra->wdt)) { + err = PTR_ERR(tegra->wdt); + dev_err(dev, "failed to create WDT: %d\n", err); + return err; + } + + err = tegra186_timer_tsc_init(tegra); + if (err < 0) { + dev_err(dev, "failed to register TSC counter: %d\n", err); + return err; + } + + err = tegra186_timer_osc_init(tegra); + if (err < 0) { + dev_err(dev, "failed to register OSC counter: %d\n", err); + goto unregister_tsc; + } + + err = tegra186_timer_usec_init(tegra); + if (err < 0) { + dev_err(dev, "failed to register USEC counter: %d\n", err); + goto unregister_osc; + } + + err = devm_request_irq(dev, irq, tegra186_timer_irq, 0, + "tegra186-timer", tegra); + if (err < 0) { + dev_err(dev, "failed to request IRQ#%u: %d\n", irq, err); + goto unregister_usec; + } + + return 0; + +unregister_usec: + clocksource_unregister(&tegra->usec); +unregister_osc: + clocksource_unregister(&tegra->osc); +unregister_tsc: + clocksource_unregister(&tegra->tsc); + return err; +} + +static int tegra186_timer_remove(struct platform_device *pdev) +{ + struct tegra186_timer *tegra = platform_get_drvdata(pdev); + + clocksource_unregister(&tegra->usec); + clocksource_unregister(&tegra->osc); + clocksource_unregister(&tegra->tsc); + + return 0; +} + +static int __maybe_unused tegra186_timer_suspend(struct device *dev) +{ + struct tegra186_timer *tegra = dev_get_drvdata(dev); + + if (watchdog_active(&tegra->wdt->base)) + tegra186_wdt_disable(tegra->wdt); + + return 0; +} + +static int __maybe_unused tegra186_timer_resume(struct device *dev) +{ + struct tegra186_timer *tegra = dev_get_drvdata(dev); + + if (watchdog_active(&tegra->wdt->base)) + tegra186_wdt_enable(tegra->wdt); + + return 0; +} + +static SIMPLE_DEV_PM_OPS(tegra186_timer_pm_ops, tegra186_timer_suspend, + tegra186_timer_resume); + +static const struct tegra186_timer_soc tegra186_timer = { + .num_timers = 10, + .num_wdts = 3, +}; + +static const struct tegra186_timer_soc tegra234_timer = { + .num_timers = 16, + .num_wdts = 3, +}; + +static const struct of_device_id tegra186_timer_of_match[] = { + { .compatible = "nvidia,tegra186-timer", .data = &tegra186_timer }, + { .compatible = "nvidia,tegra234-timer", .data = &tegra234_timer }, + { } +}; +MODULE_DEVICE_TABLE(of, tegra186_timer_of_match); + +static struct platform_driver tegra186_wdt_driver = { + .driver = { + .name = "tegra186-timer", + .pm = &tegra186_timer_pm_ops, + .of_match_table = tegra186_timer_of_match, + }, + .probe = tegra186_timer_probe, + .remove = tegra186_timer_remove, +}; +module_platform_driver(tegra186_wdt_driver); + +MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>"); +MODULE_DESCRIPTION("NVIDIA Tegra186 timers driver"); +MODULE_LICENSE("GPL v2"); |