On Wed, Mar 04, 2020 at 12:42:14PM +0200, Tero Kristo wrote:
> Texas Instruments K3 SoCs contain an RTI (Real Time Interrupt) module
> which can be used as a watchdog. This IP provides a support for
> windowed watchdog mode, in which the watchdog must be petted within
> a certain time window. If it is petted either too soon, or too late,
> a watchdog error will be triggered.
>
> Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
> v3:
> * changed to use clk_get/put instead of devm_* versions of this
>
> v2:
> * Added better documentation within the driver code
> * Dropped fck handle, instead get the fck rate during probe only
> * Modified the max_hw_heartbeat calculation logic a bit
>
> drivers/watchdog/Kconfig | 8 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/rti_wdt.c | 255 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 261 insertions(+)
> create mode 100644 drivers/watchdog/rti_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index cec868f8db3f..81faf47d44a6 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -583,6 +583,14 @@ config DAVINCI_WATCHDOG
> NOTE: once enabled, this timer cannot be disabled.
> Say N if you are unsure.
>
> +config K3_RTI_WATCHDOG
> + tristate "Texas Instruments K3 RTI watchdog"
> + depends on ARCH_K3 || COMPILE_TEST
> + select WATCHDOG_CORE
> + help
> + Say Y here if you want to include support for the K3 watchdog
> + timer (RTI module) available in the K3 generation of processors.
> +
> config ORION_WATCHDOG
> tristate "Orion watchdog"
> depends on ARCH_ORION5X || ARCH_DOVE || MACH_DOVE || ARCH_MVEBU || (COMPILE_TEST && !ARCH_EBSA110)
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 2ee352bf3372..6de2e4ceef19 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -57,6 +57,7 @@ obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
> obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
> obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
> obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
> +obj-$(CONFIG_K3_RTI_WATCHDOG) += rti_wdt.o
> obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
> obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
> obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o
> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
> new file mode 100644
> index 000000000000..7a46c40891e2
> --- /dev/null
> +++ b/drivers/watchdog/rti_wdt.c
> @@ -0,0 +1,255 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Watchdog driver for the K3 RTI module
> + *
> + * (c) Copyright 2019-2020 Texas Instruments Inc.
> + * All rights reserved.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/types.h>
> +#include <linux/watchdog.h>
> +
> +#define DEFAULT_HEARTBEAT 60
> +
> +/* Max heartbeat is calculated at 32kHz source clock */
> +#define MAX_HEARTBEAT 1000
> +
> +/* Timer register set definition */
> +#define RTIDWDCTRL 0x90
> +#define RTIDWDPRLD 0x94
> +#define RTIWDSTATUS 0x98
> +#define RTIWDKEY 0x9c
> +#define RTIDWDCNTR 0xa0
> +#define RTIWWDRXCTRL 0xa4
> +#define RTIWWDSIZECTRL 0xa8
> +
> +#define RTIWWDRX_NMI 0xa
> +
> +#define RTIWWDSIZE_50P 0x50
> +
> +#define WDENABLE_KEY 0xa98559da
> +
> +#define WDKEY_SEQ0 0xe51a
> +#define WDKEY_SEQ1 0xa35c
> +
> +#define WDT_PRELOAD_SHIFT 13
> +
> +#define WDT_PRELOAD_MAX 0xfff
> +
> +#define DWDST BIT(1)
> +
> +static int heartbeat;
> +
> +/*
> + * struct to hold data for each WDT device
> + * @base - base io address of WD device
> + * @freq - source clock frequency of WDT
> + * @wdd - hold watchdog device as is in WDT core
> + */
> +struct rti_wdt_device {
> + void __iomem *base;
> + unsigned long freq;
> + struct watchdog_device wdd;
> +};
> +
> +static int rti_wdt_start(struct watchdog_device *wdd)
> +{
> + u32 timer_margin;
> + struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
> +
> + /* set timeout period */
> + timer_margin = (u64)wdd->timeout * wdt->freq;
> + timer_margin >>= WDT_PRELOAD_SHIFT;
> + if (timer_margin > WDT_PRELOAD_MAX)
> + timer_margin = WDT_PRELOAD_MAX;
> + writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
> +
> + /*
> + * RTI only supports a windowed mode, where the watchdog can only
> + * be petted during the open window; not too early or not too late.
> + * The HW configuration options only allow for the open window size
> + * to be 50% or less than that; we obviouly want to configure the open
> + * window as large as possible so we select the 50% option. To avoid
> + * any glitches, we accommodate 5% safety margin also, so we setup
> + * the min_hw_hearbeat at 55% of the timeout period.
> + */
> + wdd->min_hw_heartbeat_ms = 11 * wdd->timeout * 1000 / 20;
> +
> + /* Generate NMI when wdt expires */
> + writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
> +
> + /* Open window size 50%; this is the largest window size available */
> + writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
> +
> + readl_relaxed(wdt->base + RTIWWDSIZECTRL);
> +
> + /* enable watchdog */
> + writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
> + return 0;
> +}
> +
> +static int rti_wdt_ping(struct watchdog_device *wdd)
> +{
> + struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
> +
> + /* put watchdog in service state */
> + writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
> + /* put watchdog in active state */
> + writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
> +
> + return 0;
> +}
> +
> +static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
> +{
> + u64 timer_counter;
> + u32 val;
> + struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
> +
> + /* if timeout has occurred then return 0 */
> + val = readl_relaxed(wdt->base + RTIWDSTATUS);
> + if (val & DWDST)
> + return 0;
> +
> + timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
> +
> + do_div(timer_counter, wdt->freq);
> +
> + return timer_counter;
> +}
> +
> +static const struct watchdog_info rti_wdt_info = {
> + .options = WDIOF_KEEPALIVEPING,
> + .identity = "K3 RTI Watchdog",
> +};
> +
> +static const struct watchdog_ops rti_wdt_ops = {
> + .owner = THIS_MODULE,
> + .start = rti_wdt_start,
> + .ping = rti_wdt_ping,
> + .get_timeleft = rti_wdt_get_timeleft,
> +};
> +
> +static int rti_wdt_probe(struct platform_device *pdev)
> +{
> + int ret = 0;
> + struct device *dev = &pdev->dev;
> + struct resource *wdt_mem;
> + struct watchdog_device *wdd;
> + struct rti_wdt_device *wdt;
> + struct clk *clk;
> +
> + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
> + if (!wdt)
> + return -ENOMEM;
> +
> + clk = clk_get(dev, NULL);
> + if (IS_ERR(clk)) {
> + if (PTR_ERR(clk) != -EPROBE_DEFER)
> + dev_err(dev, "failed to get clock\n");
> + return PTR_ERR(clk);
> + }
> +
> + wdt->freq = clk_get_rate(clk);
> +
> + clk_put(clk);
> +
> + if (!wdt->freq) {
> + dev_err(dev, "Failed to get fck rate.\n");
> + return -EINVAL;
> + }
> +
> + pm_runtime_enable(dev);
> + ret = pm_runtime_get_sync(dev);
> + if (ret) {
> + if (ret != -EPROBE_DEFER)
> + dev_err(&pdev->dev, "runtime pm failed\n");
> + return ret;
> + }
> +
> + platform_set_drvdata(pdev, wdt);
> +
> + wdd = &wdt->wdd;
> + wdd->info = &rti_wdt_info;
> + wdd->ops = &rti_wdt_ops;
> + wdd->min_timeout = 1;
> + wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
> + wdt->freq * 1000;
> + wdd->timeout = DEFAULT_HEARTBEAT;
> + wdd->parent = dev;
> +
> + watchdog_init_timeout(wdd, heartbeat, dev);
> +
> + watchdog_set_drvdata(wdd, wdt);
> + watchdog_set_nowayout(wdd, 1);
> + watchdog_set_restart_priority(wdd, 128);
> +
> + wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + wdt->base = devm_ioremap_resource(dev, wdt_mem);
> + if (IS_ERR(wdt->base)) {
> + ret = PTR_ERR(wdt->base);
> + goto err_iomap;
> + }
> +
> + ret = watchdog_register_device(wdd);
> + if (ret) {
> + dev_err(dev, "cannot register watchdog device\n");
> + goto err_iomap;
> + }
> +
> + return 0;
> +
> +err_iomap:
> + pm_runtime_put_sync(&pdev->dev);
> +
> + return ret;
> +}
> +
> +static int rti_wdt_remove(struct platform_device *pdev)
> +{
> + struct rti_wdt_device *wdt = platform_get_drvdata(pdev);
> +
> + watchdog_unregister_device(&wdt->wdd);
> + pm_runtime_put(&pdev->dev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id rti_wdt_of_match[] = {
> + { .compatible = "ti,rti-wdt", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, rti_wdt_of_match);
> +
> +static struct platform_driver rti_wdt_driver = {
> + .driver = {
> + .name = "rti-wdt",
> + .of_match_table = rti_wdt_of_match,
> + },
> + .probe = rti_wdt_probe,
> + .remove = rti_wdt_remove,
> +};
> +
> +module_platform_driver(rti_wdt_driver);
> +
> +MODULE_AUTHOR("Tero Kristo <t-kristo@xxxxxx>");
> +MODULE_DESCRIPTION("K3 RTI Watchdog Driver");
> +
> +module_param(heartbeat, int, 0);
> +MODULE_PARM_DESC(heartbeat,
> + "Watchdog heartbeat period in seconds from 1 to "
> + __MODULE_STRING(MAX_HEARTBEAT) ", default "
> + __MODULE_STRING(DEFAULT_HEARTBEAT));
> +
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:rti-wdt");
> --
> 2.17.1
>
> --
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
