[RFC,v2,2/2] watchdog: pseries-wdt: initial support for PAPR virtual watchdog timers

Message ID	20220509174357.5448-3-cheloha@linux.ibm.com (mailing list archive)
State	Changes Requested
Headers	show Return-Path: <linux-watchdog-owner@kernel.org> From: Scott Cheloha <cheloha@linux.ibm.com> To: linux-watchdog@vger.kernel.org Cc: linux@roeck-us.net, tzungbi@kernel.org, brking@linux.ibm.com, nathanl@linux.ibm.com, aik@ozlabs.ru, npiggin@gmail.com, vaishnavi@linux.ibm.com, wvoigt@us.ibm.com, Scott Cheloha <cheloha@linux.ibm.com> Subject: [RFC v2 2/2] watchdog: pseries-wdt: initial support for PAPR virtual watchdog timers Date: Mon, 9 May 2022 12:43:57 -0500 Message-Id: <20220509174357.5448-3-cheloha@linux.ibm.com> In-Reply-To: <20220509174357.5448-1-cheloha@linux.ibm.com> References: <20220509174357.5448-1-cheloha@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	Add driver for PAPR watchdog timers \| expand [RFC,v2,0/2] Add driver for PAPR watchdog timers [RFC,v2,1/2] powerpc/pseries: hvcall.h: add H_WATCHDOG opcode, H_NOOP return code [RFC,v2,2/2] watchdog: pseries-wdt: initial support for PAPR virtual watchdog timers

diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h index 8dddd34b8ecf..398e0b5e485f 100644 --- a/arch/powerpc/include/asm/firmware.h +++ b/arch/powerpc/include/asm/firmware.h @@ -55,6 +55,7 @@ #define FW_FEATURE_RPT_INVALIDATE ASM_CONST(0x0000010000000000) #define FW_FEATURE_FORM2_AFFINITY ASM_CONST(0x0000020000000000) #define FW_FEATURE_ENERGY_SCALE_INFO ASM_CONST(0x0000040000000000) +#define FW_FEATURE_WATCHDOG ASM_CONST(0x0000080000000000) #ifndef __ASSEMBLY__ @@ -76,7 +77,7 @@ enum { FW_FEATURE_DRC_INFO | FW_FEATURE_BLOCK_REMOVE | FW_FEATURE_PAPR_SCM | FW_FEATURE_ULTRAVISOR | FW_FEATURE_RPT_INVALIDATE | FW_FEATURE_FORM2_AFFINITY | - FW_FEATURE_ENERGY_SCALE_INFO, + FW_FEATURE_ENERGY_SCALE_INFO | FW_FEATURE_WATCHDOG, FW_FEATURE_PSERIES_ALWAYS = 0, FW_FEATURE_POWERNV_POSSIBLE = FW_FEATURE_OPAL | FW_FEATURE_ULTRAVISOR, FW_FEATURE_POWERNV_ALWAYS = 0, diff --git a/arch/powerpc/platforms/pseries/firmware.c b/arch/powerpc/platforms/pseries/firmware.c index 09c119b2f623..080108d129ed 100644 --- a/arch/powerpc/platforms/pseries/firmware.c +++ b/arch/powerpc/platforms/pseries/firmware.c @@ -67,6 +67,7 @@ hypertas_fw_features_table[] = { {FW_FEATURE_PAPR_SCM, "hcall-scm"}, {FW_FEATURE_RPT_INVALIDATE, "hcall-rpt-invalidate"}, {FW_FEATURE_ENERGY_SCALE_INFO, "hcall-energy-scale-info"}, + {FW_FEATURE_WATCHDOG, "hcall-watchdog"}, }; /* Build up the firmware features bitmask using the contents of diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index 955ff8aa1644..6e8b67ea2a33 100644 --- a/arch/powerpc/platforms/pseries/setup.c +++ b/arch/powerpc/platforms/pseries/setup.c @@ -14,6 +14,7 @@ #include <linux/cpu.h> #include <linux/errno.h> +#include <linux/platform_device.h> #include <linux/sched.h> #include <linux/kernel.h> #include <linux/mm.h> @@ -169,6 +170,22 @@ static void __init fwnmi_init(void) #endif } +/* + * Affix a device for the first timer to the platform bus if + * we have firmware support for the H_WATCHDOG hypercall. + */ +static struct platform_device *pseries_wdt_pdev; + +static __init int pseries_wdt_init(void) +{ + if (!firmware_has_feature(FW_FEATURE_WATCHDOG)) + return 0; + pseries_wdt_pdev = platform_device_register_simple("pseries-wdt", + 0, NULL, 0); + return 0; +} +machine_subsys_initcall(pseries, pseries_wdt_init); + static void pseries_8259_cascade(struct irq_desc *desc) { struct irq_chip *chip = irq_desc_get_chip(desc); diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index c4e82a8d863f..c5755f1e4540 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -1932,6 +1932,14 @@ config MEN_A21_WDT # PPC64 Architecture +config PSERIES_WDT + tristate "POWER Architecture Platform Watchdog Timer" + depends on PPC_PSERIES + select WATCHDOG_CORE + help + Driver for virtual watchdog timers provided by PAPR + hypervisors (e.g. pHyp, KVM). + config WATCHDOG_RTAS tristate "RTAS watchdog" depends on PPC_RTAS diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index f7da867e8782..f35660409f17 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -184,6 +184,7 @@ obj-$(CONFIG_BOOKE_WDT) += booke_wdt.o obj-$(CONFIG_MEN_A21_WDT) += mena21_wdt.o # PPC64 Architecture +obj-$(CONFIG_PSERIES_WDT) += pseries-wdt.o obj-$(CONFIG_WATCHDOG_RTAS) += wdrtas.o # S390 Architecture diff --git a/drivers/watchdog/pseries-wdt.c b/drivers/watchdog/pseries-wdt.c new file mode 100644 index 000000000000..501211bd3f26 --- /dev/null +++ b/drivers/watchdog/pseries-wdt.c @@ -0,0 +1,300 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +/* + * Copyright (c) 2022 International Business Machines, Inc. + */ + +#include <linux/bitops.h> +#include <linux/kernel.h> +#include <linux/limits.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> + +#define DRV_NAME "pseries-wdt" + +/* + * The PAPR's MSB->LSB bit ordering is is 0->63. These macros + * simplify defining bitfields as described in the PAPR without + * needing to transpose values to the more C-like 63->0 ordering. + */ +#define SETFIELD(_v, _b, _e) \ + (((unsigned long)(_v) << PPC_BITLSHIFT(_e)) & PPC_BITMASK((_b), (_e))) +#define GETFIELD(_v, _b, _e) \ + (((unsigned long)(_v) & PPC_BITMASK((_b), (_e))) >> PPC_BITLSHIFT(_e)) + +/* + * H_WATCHDOG Hypercall Input + * + * R4: "flags": + * + * A 64-bit value structured as follows: + * + * Bits 0-46: Reserved (must be zero). + */ +#define PSERIES_WDTF_RESERVED PPC_BITMASK(0, 46) + +/* + * Bit 47: "leaveOtherWatchdogsRunningOnTimeout" + * + * 0 Stop outstanding watchdogs on timeout. + * 1 Leave outstanding watchdogs running on timeout. + */ +#define PSERIES_WDTF_LEAVE_OTHER PPC_BIT(47) + +/* + * Bits 48-55: "operation" + * + * 0x01 Start Watchdog + * 0x02 Stop Watchdog + * 0x03 Query Watchdog Capabilities + * 0x04 Query Watchdog LPM Requirement + */ +#define PSERIES_WDTF_OP(op) SETFIELD((op), 48, 55) +#define PSERIES_WDTF_OP_START PSERIES_WDTF_OP(0x1) +#define PSERIES_WDTF_OP_STOP PSERIES_WDTF_OP(0x2) +#define PSERIES_WDTF_OP_QUERY PSERIES_WDTF_OP(0x3) +#define PSERIES_WDTF_OP_QUERY_LPM PSERIES_WDTF_OP(0x4) + +/* + * Bits 56-63: "timeoutAction" + * + * 0x01 Hard poweroff + * 0x02 Hard restart + * 0x03 Dump restart + */ +#define PSERIES_WDTF_ACTION(ac) SETFIELD(ac, 56, 63) +#define PSERIES_WDTF_ACTION_HARD_POWEROFF PSERIES_WDTF_ACTION(0x1) +#define PSERIES_WDTF_ACTION_HARD_RESTART PSERIES_WDTF_ACTION(0x2) +#define PSERIES_WDTF_ACTION_DUMP_RESTART PSERIES_WDTF_ACTION(0x3) + +/* + * R5: "watchdogNumber": + * + * The target watchdog. Watchdog numbers are 1-based. The + * maximum supported watchdog number may be obtained via the + * "Query Watchdog Capabilities" operation. + * + * This input is ignored for the "Query Watchdog Capabilities" + * operation. + * + * R6: "timeoutInMs": + * + * The timeout in milliseconds. The minimum supported timeout may + * be obtained via the "Query Watchdog Capabilities" operation. + * + * This input is ignored for the "Stop Watchdog", "Query Watchdog + * Capabilities", and "Query LPM Requirement" operations. + */ + +/* + * H_WATCHDOG Hypercall Output + * + * R3: Return code + * + * H_SUCCESS The operation completed. + * + * H_BUSY The hypervisor is too busy; retry the operation. + * + * H_PARAMETER The given "flags" are somehow invalid. Either the + * "operation" or "timeoutAction" is invalid, or a + * reserved bit is set. + * + * H_P2 The given "watchdogNumber" is zero or exceeds the + * supported maximum value. + * + * H_P3 The given "timeoutInMs" is below the supported + * minimum value. + * + * H_NOOP The given "watchdogNumber" is already stopped. + * + * H_HARDWARE The operation failed for ineffable reasons. + * + * H_FUNCTION The H_WATCHDOG hypercall is not supported by this + * hypervisor. + * + * R4: + * + * - For the "Query Watchdog Capabilities" operation, a 64-bit + * structure defined as: + * + * Bits 0-15: The minimum supported timeout in milliseconds. + * Bits 16-31: The number of watchdogs supported. + * Bits 32-63: Reserved. + */ +#define PSERIES_WDTQ_MIN_TIMEOUT(cap) GETFIELD((cap), 0, 15) +#define PSERIES_WDTQ_MAX_NUMBER(cap) GETFIELD((cap), 16, 31) +#define PSERIES_WDTQ_RESERVED PPC_BITMASK(32, 63) + +/* + * - For the "Query Watchdog LPM Requirement" operation: + * + * 1 The given "watchdogNumber" must be stopped prior to + * suspending. + * + * 2 The given "watchdogNumber" does not have to be stopped + * prior to suspending. + */ +#define PSERIES_WDTQL_MUST_STOP 1 +#define PSERIES_WDTQL_NEED_NOT_STOP 2 + +static unsigned long action = PSERIES_WDTF_ACTION_HARD_RESTART; +static int action_set(const char *val, const struct kernel_param *kp) +{ + if (strcmp(val, "hard-poweroff") == 0) { + action = PSERIES_WDTF_ACTION_HARD_POWEROFF; + return 0; + } + if (strcmp(val, "hard-restart") == 0) { + action = PSERIES_WDTF_ACTION_HARD_RESTART; + return 0; + } + if (strcmp(val, "dump-restart") == 0) { + action = PSERIES_WDTF_ACTION_DUMP_RESTART; + return 0; + } + return -EINVAL; +} +static const struct kernel_param_ops action_ops = { .set = action_set }; +module_param_cb(action, &action_ops, NULL, S_IRUGO); +MODULE_PARM_DESC(action, "Action taken when watchdog expires: \"hard-poweroff\", \"hard-restart\", or \"dump-restart\" (default=\"hard-restart\")"); + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, S_IRUGO); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +#define WATCHDOG_TIMEOUT 60 +static unsigned int timeout = WATCHDOG_TIMEOUT; +module_param(timeout, uint, S_IRUGO); +MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds (default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); + +struct pseries_wdt { + struct watchdog_device wd; + unsigned long num; /* NB: Watchdog numbers are 1-based */ +}; + +static int pseries_wdt_start(struct watchdog_device *wdd) +{ + struct device *dev = wdd->parent; + struct pseries_wdt *pw = watchdog_get_drvdata(wdd); + unsigned long flags, msecs; + long rc; + + flags = action | PSERIES_WDTF_OP_START; + msecs = wdd->timeout * 1000UL; + rc = plpar_hcall_norets(H_WATCHDOG, flags, pw->num, msecs); + if (rc != H_SUCCESS) { + dev_crit(dev, "H_WATCHDOG: %ld: failed to start timer %lu", + rc, pw->num); + return -EIO; + } + return 0; +} + +static int pseries_wdt_stop(struct watchdog_device *wdd) +{ + struct device *dev = wdd->parent; + struct pseries_wdt *pw = watchdog_get_drvdata(wdd); + long rc; + + rc = plpar_hcall_norets(H_WATCHDOG, PSERIES_WDTF_OP_STOP, pw->num); + if (rc != H_SUCCESS && rc != H_NOOP) { + dev_crit(dev, "H_WATCHDOG: %ld: failed to stop timer %lu", + rc, pw->num); + return -EIO; + } + return 0; +} + +static struct watchdog_info pseries_wdt_info = { + .identity = DRV_NAME, + .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT \ + | WDIOF_PRETIMEOUT, +}; + +static const struct watchdog_ops pseries_wdt_ops = { + .owner = THIS_MODULE, + .ping = pseries_wdt_start, + .start = pseries_wdt_start, + .stop = pseries_wdt_stop, +}; + +static int pseries_wdt_probe(struct platform_device *pdev) +{ + unsigned long ret[PLPAR_HCALL_BUFSIZE] = { 0 }; + unsigned long cap, min_timeout_ms; + long rc; + struct pseries_wdt *pw; + int err; + + rc = plpar_hcall(H_WATCHDOG, ret, PSERIES_WDTF_OP_QUERY); + if (rc != H_SUCCESS) + return (rc == H_FUNCTION) ? -ENODEV : -EIO; + cap = ret[0]; + + /* + * If the underlying id exceeds the number of available timers + * there is a bug in the platform device registration code. + */ + if (pdev->id < 0 || pdev->id >= PSERIES_WDTQ_MAX_NUMBER(cap)) + return -ENODEV; + + pw = devm_kzalloc(&pdev->dev, sizeof *pw, GFP_KERNEL); + if (pw == NULL) + return -ENOMEM; + pw->num = pdev->id + 1; /* 0-based -> 1-based */ + pw->wd.parent = &pdev->dev; + pw->wd.info = &pseries_wdt_info; + pw->wd.ops = &pseries_wdt_ops; + min_timeout_ms = PSERIES_WDTQ_MIN_TIMEOUT(cap); + pw->wd.min_timeout = roundup(min_timeout_ms, 1000) / 1000; + pw->wd.max_timeout = UINT_MAX; + watchdog_init_timeout(&pw->wd, timeout, NULL); + watchdog_set_nowayout(&pw->wd, nowayout); + watchdog_stop_on_reboot(&pw->wd); + watchdog_stop_on_unregister(&pw->wd); + watchdog_set_drvdata(&pw->wd, pw); + + err = devm_watchdog_register_device(&pdev->dev, &pw->wd); + if (err) + return err; + + platform_set_drvdata(pdev, &pw->wd); + + return 0; +} + +static int pseries_wdt_suspend(struct platform_device *pdev, pm_message_t state) +{ + struct watchdog_device *wd = platform_get_drvdata(pdev); + + if (watchdog_active(wd)) + return pseries_wdt_stop(wd); + return 0; +} + +static int pseries_wdt_resume(struct platform_device *pdev) +{ + struct watchdog_device *wd = platform_get_drvdata(pdev); + + if (watchdog_active(wd)) + return pseries_wdt_start(wd); + return 0; +} + +static struct platform_driver pseries_wdt_driver = { + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + }, + .probe = pseries_wdt_probe, + .resume = pseries_wdt_resume, + .suspend = pseries_wdt_suspend, +}; +module_platform_driver(pseries_wdt_driver); + +MODULE_AUTHOR("Alexey Kardashevskiy <aik@ozlabs.ru>"); +MODULE_AUTHOR("Scott Cheloha <cheloha@linux.ibm.com>"); +MODULE_DESCRIPTION("POWER Architecture Platform Watchdog Driver"); +MODULE_LICENSE("GPL");

[RFC,v2,2/2] watchdog: pseries-wdt: initial support for PAPR virtual watchdog timers

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