| Message ID | 20200302200426.6492-4-t-kristo@ti.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | watchdog: add TI K3 SoC watchdog support | expand |
On Mon, Mar 02, 2020 at 10:04:25PM +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@ti.com> > --- > 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 | 254 +++++++++++++++++++++++++++++++++++++ > 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 +1,254 @@ > +// 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 = devm_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); > + if (!wdt->freq) { > + dev_err(dev, "Failed to get fck rate.\n"); > + return -EINVAL; > + } > + > + devm_clk_put(dev, clk); > + Are you sure about this ? Doesn't this mean that the clock may be stopped ? Normally the reason for using devm_ functions during probe is that release functions are called automatically when the device is removed. Calling the release function dorectly is unusual and most of the time wrong. Thanks, Guenter > + 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@ti.com>"); > +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
On 03/03/2020 23:18, Guenter Roeck wrote: > On Mon, Mar 02, 2020 at 10:04:25PM +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@ti.com> >> --- >> 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 | 254 +++++++++++++++++++++++++++++++++++++ >> 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 +1,254 @@ >> +// 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 = devm_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); >> + if (!wdt->freq) { >> + dev_err(dev, "Failed to get fck rate.\n"); >> + return -EINVAL; >> + } >> + >> + devm_clk_put(dev, clk); >> + > Are you sure about this ? Doesn't this mean that the clock may be stopped ? > Normally the reason for using devm_ functions during probe is that release > functions are called automatically when the device is removed. Calling > the release function dorectly is unusual and most of the time wrong. clk_get / clk_put does not enable / disable a clock by itself, this is just used to fetch a clock handle. But you are right, we are never calling clk_enable on it either, because at least the 32kHz clock we are interested in is of type always-on and can never be disabled. I can keep the clock handle and call enable/disable on it in the probe/remove if you think that would be neater. -Tero > > Thanks, > Guenter > >> + 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@ti.com>"); >> +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
On 3/3/20 10:57 PM, Tero Kristo wrote: > On 03/03/2020 23:18, Guenter Roeck wrote: >> On Mon, Mar 02, 2020 at 10:04:25PM +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@ti.com> >>> --- >>> 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 | 254 +++++++++++++++++++++++++++++++++++++ >>> 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 +1,254 @@ >>> +// 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 = devm_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); >>> + if (!wdt->freq) { >>> + dev_err(dev, "Failed to get fck rate.\n"); >>> + return -EINVAL; >>> + } >>> + >>> + devm_clk_put(dev, clk); >>> + >> Are you sure about this ? Doesn't this mean that the clock may be stopped ? >> Normally the reason for using devm_ functions during probe is that release >> functions are called automatically when the device is removed. Calling >> the release function dorectly is unusual and most of the time wrong. > > clk_get / clk_put does not enable / disable a clock by itself, this is just used to fetch a clock handle. But you are right, we are never calling clk_enable on it either, because at least the 32kHz clock we are interested in is of type always-on and can never be disabled. > > I can keep the clock handle and call enable/disable on it in the probe/remove if you think that would be neater. > If it isn't needed to be held, you should use clk_get / clk_put, and not the devm_ functions. Guenter
On 04/03/2020 11:23, Guenter Roeck wrote: > On 3/3/20 10:57 PM, Tero Kristo wrote: >> On 03/03/2020 23:18, Guenter Roeck wrote: >>> On Mon, Mar 02, 2020 at 10:04:25PM +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@ti.com> >>>> --- >>>> 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 | 254 +++++++++++++++++++++++++++++++++++++ >>>> 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 +1,254 @@ >>>> +// 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 = devm_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); >>>> + if (!wdt->freq) { >>>> + dev_err(dev, "Failed to get fck rate.\n"); >>>> + return -EINVAL; >>>> + } >>>> + >>>> + devm_clk_put(dev, clk); >>>> + >>> Are you sure about this ? Doesn't this mean that the clock may be stopped ? >>> Normally the reason for using devm_ functions during probe is that release >>> functions are called automatically when the device is removed. Calling >>> the release function dorectly is unusual and most of the time wrong. >> >> clk_get / clk_put does not enable / disable a clock by itself, this is just used to fetch a clock handle. But you are right, we are never calling clk_enable on it either, because at least the 32kHz clock we are interested in is of type always-on and can never be disabled. >> >> I can keep the clock handle and call enable/disable on it in the probe/remove if you think that would be neater. >> > > If it isn't needed to be held, you should use clk_get / clk_put, > and not the devm_ functions. Ok, changed this and posted v3 of patch #3 only. -Tero -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
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 +1,254 @@ +// 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 = devm_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); + if (!wdt->freq) { + dev_err(dev, "Failed to get fck rate.\n"); + return -EINVAL; + } + + devm_clk_put(dev, clk); + + 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@ti.com>"); +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");
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@ti.com> --- 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 | 254 +++++++++++++++++++++++++++++++++++++ 3 files changed, 261 insertions(+) create mode 100644 drivers/watchdog/rti_wdt.c