From 7f40c260df86b9d145a4ddb13879787c266c5232 Mon Sep 17 00:00:00 2001 From: Suman Anna Date: Thu, 30 May 2019 21:13:19 -0500 Subject: [PATCH 1/7] dt-bindings: hwlock: Update OMAP binding for TI K3 SoCs The TI K3 AM65x and J721E family of SoCs have a HwSpinlock IP that is similar to the existing HwSpinlock IP present in OMAP architecture based SoCs with minor differences. Update the existing OMAP HwSpinlock binding for this IP on TI K3 AM65x and J721E SoCs. The same compatible from AM65x SoCs is reused for J721E SoCs. Signed-off-by: Suman Anna Signed-off-by: Bjorn Andersson --- .../bindings/hwlock/omap-hwspinlock.txt | 25 +++++++++++++++---- 1 file changed, 20 insertions(+), 5 deletions(-) diff --git a/Documentation/devicetree/bindings/hwlock/omap-hwspinlock.txt b/Documentation/devicetree/bindings/hwlock/omap-hwspinlock.txt index 2c9804f4f4ac..8d365f89694c 100644 --- a/Documentation/devicetree/bindings/hwlock/omap-hwspinlock.txt +++ b/Documentation/devicetree/bindings/hwlock/omap-hwspinlock.txt @@ -1,12 +1,16 @@ -OMAP4+ HwSpinlock Driver -======================== +TI HwSpinlock for OMAP and K3 based SoCs +========================================= Required properties: -- compatible: Should be "ti,omap4-hwspinlock" for - OMAP44xx, OMAP54xx, AM33xx, AM43xx, DRA7xx SoCs +- compatible: Should be one of the following, + "ti,omap4-hwspinlock" for + OMAP44xx, OMAP54xx, AM33xx, AM43xx, DRA7xx SoCs + "ti,am654-hwspinlock" for + K3 AM65x and J721E SoCs - reg: Contains the hwspinlock module register address space (base address and length) - ti,hwmods: Name of the hwmod associated with the hwspinlock device + (for OMAP architecture based SoCs only) - #hwlock-cells: Should be 1. The OMAP hwspinlock users will use a 0-indexed relative hwlock number as the argument specifier value for requesting a specific hwspinlock @@ -17,10 +21,21 @@ Please look at the generic hwlock binding for usage information for consumers, Example: -/* OMAP4 */ +1. OMAP4 SoCs hwspinlock: spinlock@4a0f6000 { compatible = "ti,omap4-hwspinlock"; reg = <0x4a0f6000 0x1000>; ti,hwmods = "spinlock"; #hwlock-cells = <1>; }; + +2. AM65x SoCs and J721E SoCs +&cbass_main { + cbass_main_navss: interconnect0 { + hwspinlock: spinlock@30e00000 { + compatible = "ti,am654-hwspinlock"; + reg = <0x00 0x30e00000 0x00 0x1000>; + #hwlock-cells = <1>; + }; + }; +}; From 6fa154e282f9c86ff3e2f8df478f1df92881a6e2 Mon Sep 17 00:00:00 2001 From: Suman Anna Date: Thu, 30 May 2019 21:13:20 -0500 Subject: [PATCH 2/7] hwspinlock/omap: Add support for TI K3 SoCs A HwSpinlock IP is also present on the newer TI K3 AM65x and J721E family of SoCs within the Main NavSS sub-module. Reuse the existing OMAP Hwspinlock driver to extend the support for this IP on K3 AM65x SoCs as well. The IP has slightly different bit-fields in the SYSCONFIG and SYSSTATUS registers. Signed-off-by: Suman Anna Signed-off-by: Bjorn Andersson --- drivers/hwspinlock/Kconfig | 2 +- drivers/hwspinlock/omap_hwspinlock.c | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/hwspinlock/Kconfig b/drivers/hwspinlock/Kconfig index 7869c67e5b6b..37740e992cfa 100644 --- a/drivers/hwspinlock/Kconfig +++ b/drivers/hwspinlock/Kconfig @@ -9,7 +9,7 @@ menuconfig HWSPINLOCK config HWSPINLOCK_OMAP tristate "OMAP Hardware Spinlock device" depends on HWSPINLOCK - depends on ARCH_OMAP4 || SOC_OMAP5 || SOC_DRA7XX || SOC_AM33XX || SOC_AM43XX + depends on ARCH_OMAP4 || SOC_OMAP5 || SOC_DRA7XX || SOC_AM33XX || SOC_AM43XX || ARCH_K3 help Say y here to support the OMAP Hardware Spinlock device (firstly introduced in OMAP4). diff --git a/drivers/hwspinlock/omap_hwspinlock.c b/drivers/hwspinlock/omap_hwspinlock.c index 625844e0abef..a4d7a7bc863a 100644 --- a/drivers/hwspinlock/omap_hwspinlock.c +++ b/drivers/hwspinlock/omap_hwspinlock.c @@ -171,6 +171,7 @@ static int omap_hwspinlock_remove(struct platform_device *pdev) static const struct of_device_id omap_hwspinlock_of_match[] = { { .compatible = "ti,omap4-hwspinlock", }, + { .compatible = "ti,am654-hwspinlock", }, { /* end */ }, }; MODULE_DEVICE_TABLE(of, omap_hwspinlock_of_match); From d4d98bba3ea58e80b9f500cbd98b38b98e8167f2 Mon Sep 17 00:00:00 2001 From: Suman Anna Date: Thu, 30 May 2019 21:13:21 -0500 Subject: [PATCH 3/7] hwspinlock/omap: Add a trace during probe Add a debug level trace statement in the OMAP HwSpinlock driver probe function to print the number of hwlocks on a successful registration. Signed-off-by: Suman Anna Signed-off-by: Bjorn Andersson --- drivers/hwspinlock/omap_hwspinlock.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/hwspinlock/omap_hwspinlock.c b/drivers/hwspinlock/omap_hwspinlock.c index a4d7a7bc863a..14e1a532ebb5 100644 --- a/drivers/hwspinlock/omap_hwspinlock.c +++ b/drivers/hwspinlock/omap_hwspinlock.c @@ -140,6 +140,9 @@ static int omap_hwspinlock_probe(struct platform_device *pdev) if (ret) goto reg_fail; + dev_dbg(&pdev->dev, "Registered %d locks with HwSpinlock core\n", + num_locks); + return 0; reg_fail: From fbd7330c9fd8ef00bf231ec7e57b0f05384f462d Mon Sep 17 00:00:00 2001 From: Fabien Dessenne Date: Fri, 8 Mar 2019 17:53:46 +0100 Subject: [PATCH 4/7] hwspinlock: ignore disabled device Do not wait for hwspinlock device registration if it is not available for use. Acked-by: Suman Anna Signed-off-by: Fabien Dessenne Signed-off-by: Bjorn Andersson --- drivers/hwspinlock/hwspinlock_core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/hwspinlock/hwspinlock_core.c b/drivers/hwspinlock/hwspinlock_core.c index 2bad40d42210..d806307f19c2 100644 --- a/drivers/hwspinlock/hwspinlock_core.c +++ b/drivers/hwspinlock/hwspinlock_core.c @@ -333,6 +333,11 @@ int of_hwspin_lock_get_id(struct device_node *np, int index) if (ret) return ret; + if (!of_device_is_available(args.np)) { + ret = -ENOENT; + goto out; + } + /* Find the hwspinlock device: we need its base_id */ ret = -EPROBE_DEFER; rcu_read_lock(); From 5cd69f13deef804d113d31c5c744396b1a1b8a9a Mon Sep 17 00:00:00 2001 From: Fabien Dessenne Date: Thu, 7 Mar 2019 16:42:16 +0100 Subject: [PATCH 5/7] hwspinlock: stm32: implement the relax() ops Implement this optional ops, called by hwspinlock core while spinning on a lock, between two successive invocations of trylock(). Reviewed-by: Benjamin Gaignard Signed-off-by: Fabien Dessenne Signed-off-by: Bjorn Andersson --- drivers/hwspinlock/stm32_hwspinlock.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/hwspinlock/stm32_hwspinlock.c b/drivers/hwspinlock/stm32_hwspinlock.c index 441839288893..c8eacf4f9692 100644 --- a/drivers/hwspinlock/stm32_hwspinlock.c +++ b/drivers/hwspinlock/stm32_hwspinlock.c @@ -5,6 +5,7 @@ */ #include +#include #include #include #include @@ -42,9 +43,15 @@ static void stm32_hwspinlock_unlock(struct hwspinlock *lock) writel(STM32_MUTEX_COREID, lock_addr); } +static void stm32_hwspinlock_relax(struct hwspinlock *lock) +{ + ndelay(50); +} + static const struct hwspinlock_ops stm32_hwspinlock_ops = { .trylock = stm32_hwspinlock_trylock, .unlock = stm32_hwspinlock_unlock, + .relax = stm32_hwspinlock_relax, }; static int stm32_hwspinlock_probe(struct platform_device *pdev) From bce6f5221374ba451a337d0a3773e6eb99dad3e8 Mon Sep 17 00:00:00 2001 From: Fabien Dessenne Date: Thu, 7 Mar 2019 16:58:22 +0100 Subject: [PATCH 6/7] hwspinlock: document the hwspinlock 'raw' API Document the hwspin_lock_timeout_raw(), hwspin_trylock_raw() and hwspin_unlock_raw() API. Signed-off-by: Fabien Dessenne Signed-off-by: Bjorn Andersson --- Documentation/hwspinlock.txt | 42 ++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/Documentation/hwspinlock.txt b/Documentation/hwspinlock.txt index ed640a278185..c3403f9ae27a 100644 --- a/Documentation/hwspinlock.txt +++ b/Documentation/hwspinlock.txt @@ -134,6 +134,23 @@ notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs). The function will never sleep. +:: + + int hwspin_lock_timeout_raw(struct hwspinlock *hwlock, unsigned int timeout); + +Lock a previously-assigned hwspinlock with a timeout limit (specified in +msecs). If the hwspinlock is already taken, the function will busy loop +waiting for it to be released, but give up when the timeout elapses. + +Caution: User must protect the routine of getting hardware lock with mutex +or spinlock to avoid dead-lock, that will let user can do some time-consuming +or sleepable operations under the hardware lock. + +Returns 0 when successful and an appropriate error code otherwise (most +notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs). + +The function will never sleep. + :: int hwspin_trylock(struct hwspinlock *hwlock); @@ -184,6 +201,21 @@ Returns 0 on success and an appropriate error code otherwise (most notably -EBUSY if the hwspinlock was already taken). The function will never sleep. +:: + + int hwspin_trylock_raw(struct hwspinlock *hwlock); + +Attempt to lock a previously-assigned hwspinlock, but immediately fail if +it is already taken. + +Caution: User must protect the routine of getting hardware lock with mutex +or spinlock to avoid dead-lock, that will let user can do some time-consuming +or sleepable operations under the hardware lock. + +Returns 0 on success and an appropriate error code otherwise (most +notably -EBUSY if the hwspinlock was already taken). +The function will never sleep. + :: void hwspin_unlock(struct hwspinlock *hwlock); @@ -220,6 +252,16 @@ Upon a successful return from this function, preemption is reenabled, and the state of the local interrupts is restored to the state saved at the given flags. This function will never sleep. +:: + + void hwspin_unlock_raw(struct hwspinlock *hwlock); + +Unlock a previously-locked hwspinlock. + +The caller should **never** unlock an hwspinlock which is already unlocked. +Doing so is considered a bug (there is no protection against this). +This function will never sleep. + :: int hwspin_lock_get_id(struct hwspinlock *hwlock); From 360aa640a59f269b784848c0b2d6d462952750d9 Mon Sep 17 00:00:00 2001 From: Fabien Dessenne Date: Thu, 7 Mar 2019 16:58:23 +0100 Subject: [PATCH 7/7] hwspinlock: add the 'in_atomic' API Add the 'in_atomic' mode which can be called from an atomic context. This mode relies on the existing 'raw' mode (no lock, no preemption/irq disabling) with the difference that the timeout is not based on jiffies (jiffies won't increase when irq are disabled) but handled with busy-waiting udelay() calls. Signed-off-by: Fabien Dessenne Signed-off-by: Bjorn Andersson --- Documentation/hwspinlock.txt | 39 ++++++++++++++++++ drivers/hwspinlock/hwspinlock_core.c | 43 ++++++++++++++------ include/linux/hwspinlock.h | 61 ++++++++++++++++++++++++++-- 3 files changed, 127 insertions(+), 16 deletions(-) diff --git a/Documentation/hwspinlock.txt b/Documentation/hwspinlock.txt index c3403f9ae27a..6f03713b7003 100644 --- a/Documentation/hwspinlock.txt +++ b/Documentation/hwspinlock.txt @@ -151,6 +151,22 @@ notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs). The function will never sleep. +:: + + int hwspin_lock_timeout_in_atomic(struct hwspinlock *hwlock, unsigned int to); + +Lock a previously-assigned hwspinlock with a timeout limit (specified in +msecs). If the hwspinlock is already taken, the function will busy loop +waiting for it to be released, but give up when the timeout elapses. + +This function shall be called only from an atomic context and the timeout +value shall not exceed a few msecs. + +Returns 0 when successful and an appropriate error code otherwise (most +notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs). + +The function will never sleep. + :: int hwspin_trylock(struct hwspinlock *hwlock); @@ -216,6 +232,19 @@ Returns 0 on success and an appropriate error code otherwise (most notably -EBUSY if the hwspinlock was already taken). The function will never sleep. +:: + + int hwspin_trylock_in_atomic(struct hwspinlock *hwlock); + +Attempt to lock a previously-assigned hwspinlock, but immediately fail if +it is already taken. + +This function shall be called only from an atomic context. + +Returns 0 on success and an appropriate error code otherwise (most +notably -EBUSY if the hwspinlock was already taken). +The function will never sleep. + :: void hwspin_unlock(struct hwspinlock *hwlock); @@ -262,6 +291,16 @@ The caller should **never** unlock an hwspinlock which is already unlocked. Doing so is considered a bug (there is no protection against this). This function will never sleep. +:: + + void hwspin_unlock_in_atomic(struct hwspinlock *hwlock); + +Unlock a previously-locked hwspinlock. + +The caller should **never** unlock an hwspinlock which is already unlocked. +Doing so is considered a bug (there is no protection against this). +This function will never sleep. + :: int hwspin_lock_get_id(struct hwspinlock *hwlock); diff --git a/drivers/hwspinlock/hwspinlock_core.c b/drivers/hwspinlock/hwspinlock_core.c index d806307f19c2..8862445aa858 100644 --- a/drivers/hwspinlock/hwspinlock_core.c +++ b/drivers/hwspinlock/hwspinlock_core.c @@ -9,6 +9,7 @@ #define pr_fmt(fmt) "%s: " fmt, __func__ +#include #include #include #include @@ -23,6 +24,9 @@ #include "hwspinlock_internal.h" +/* retry delay used in atomic context */ +#define HWSPINLOCK_RETRY_DELAY_US 100 + /* radix tree tags */ #define HWSPINLOCK_UNUSED (0) /* tags an hwspinlock as unused */ @@ -68,11 +72,11 @@ static DEFINE_MUTEX(hwspinlock_tree_lock); * user need some time-consuming or sleepable operations under the hardware * lock, they need one sleepable lock (like mutex) to protect the operations. * - * If the mode is not HWLOCK_RAW, upon a successful return from this function, - * preemption (and possibly interrupts) is disabled, so the caller must not - * sleep, and is advised to release the hwspinlock as soon as possible. This is - * required in order to minimize remote cores polling on the hardware - * interconnect. + * If the mode is neither HWLOCK_IN_ATOMIC nor HWLOCK_RAW, upon a successful + * return from this function, preemption (and possibly interrupts) is disabled, + * so the caller must not sleep, and is advised to release the hwspinlock as + * soon as possible. This is required in order to minimize remote cores polling + * on the hardware interconnect. * * The user decides whether local interrupts are disabled or not, and if yes, * whether he wants their previous state to be saved. It is up to the user @@ -112,6 +116,7 @@ int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags) ret = spin_trylock_irq(&hwlock->lock); break; case HWLOCK_RAW: + case HWLOCK_IN_ATOMIC: ret = 1; break; default: @@ -136,6 +141,7 @@ int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags) spin_unlock_irq(&hwlock->lock); break; case HWLOCK_RAW: + case HWLOCK_IN_ATOMIC: /* Nothing to do */ break; default: @@ -179,11 +185,14 @@ EXPORT_SYMBOL_GPL(__hwspin_trylock); * user need some time-consuming or sleepable operations under the hardware * lock, they need one sleepable lock (like mutex) to protect the operations. * - * If the mode is not HWLOCK_RAW, upon a successful return from this function, - * preemption is disabled (and possibly local interrupts, too), so the caller - * must not sleep, and is advised to release the hwspinlock as soon as possible. - * This is required in order to minimize remote cores polling on the - * hardware interconnect. + * If the mode is HWLOCK_IN_ATOMIC (called from an atomic context) the timeout + * is handled with busy-waiting delays, hence shall not exceed few msecs. + * + * If the mode is neither HWLOCK_IN_ATOMIC nor HWLOCK_RAW, upon a successful + * return from this function, preemption (and possibly interrupts) is disabled, + * so the caller must not sleep, and is advised to release the hwspinlock as + * soon as possible. This is required in order to minimize remote cores polling + * on the hardware interconnect. * * The user decides whether local interrupts are disabled or not, and if yes, * whether he wants their previous state to be saved. It is up to the user @@ -198,7 +207,7 @@ int __hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int to, int mode, unsigned long *flags) { int ret; - unsigned long expire; + unsigned long expire, atomic_delay = 0; expire = msecs_to_jiffies(to) + jiffies; @@ -212,8 +221,15 @@ int __hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int to, * The lock is already taken, let's check if the user wants * us to try again */ - if (time_is_before_eq_jiffies(expire)) - return -ETIMEDOUT; + if (mode == HWLOCK_IN_ATOMIC) { + udelay(HWSPINLOCK_RETRY_DELAY_US); + atomic_delay += HWSPINLOCK_RETRY_DELAY_US; + if (atomic_delay > to * 1000) + return -ETIMEDOUT; + } else { + if (time_is_before_eq_jiffies(expire)) + return -ETIMEDOUT; + } /* * Allow platform-specific relax handlers to prevent @@ -276,6 +292,7 @@ void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags) spin_unlock_irq(&hwlock->lock); break; case HWLOCK_RAW: + case HWLOCK_IN_ATOMIC: /* Nothing to do */ break; default: diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h index 0afe693be5f4..bfe7c1f1ac6d 100644 --- a/include/linux/hwspinlock.h +++ b/include/linux/hwspinlock.h @@ -14,9 +14,10 @@ #include /* hwspinlock mode argument */ -#define HWLOCK_IRQSTATE 0x01 /* Disable interrupts, save state */ -#define HWLOCK_IRQ 0x02 /* Disable interrupts, don't save state */ -#define HWLOCK_RAW 0x03 +#define HWLOCK_IRQSTATE 0x01 /* Disable interrupts, save state */ +#define HWLOCK_IRQ 0x02 /* Disable interrupts, don't save state */ +#define HWLOCK_RAW 0x03 +#define HWLOCK_IN_ATOMIC 0x04 /* Called while in atomic context */ struct device; struct device_node; @@ -222,6 +223,23 @@ static inline int hwspin_trylock_raw(struct hwspinlock *hwlock) return __hwspin_trylock(hwlock, HWLOCK_RAW, NULL); } +/** + * hwspin_trylock_in_atomic() - attempt to lock a specific hwspinlock + * @hwlock: an hwspinlock which we want to trylock + * + * This function attempts to lock an hwspinlock, and will immediately fail + * if the hwspinlock is already taken. + * + * This function shall be called only from an atomic context. + * + * Returns 0 if we successfully locked the hwspinlock, -EBUSY if + * the hwspinlock was already taken, and -EINVAL if @hwlock is invalid. + */ +static inline int hwspin_trylock_in_atomic(struct hwspinlock *hwlock) +{ + return __hwspin_trylock(hwlock, HWLOCK_IN_ATOMIC, NULL); +} + /** * hwspin_trylock() - attempt to lock a specific hwspinlock * @hwlock: an hwspinlock which we want to trylock @@ -312,6 +330,28 @@ int hwspin_lock_timeout_raw(struct hwspinlock *hwlock, unsigned int to) return __hwspin_lock_timeout(hwlock, to, HWLOCK_RAW, NULL); } +/** + * hwspin_lock_timeout_in_atomic() - lock an hwspinlock with timeout limit + * @hwlock: the hwspinlock to be locked + * @to: timeout value in msecs + * + * This function locks the underlying @hwlock. If the @hwlock + * is already taken, the function will busy loop waiting for it to + * be released, but give up when @timeout msecs have elapsed. + * + * This function shall be called only from an atomic context and the timeout + * value shall not exceed a few msecs. + * + * Returns 0 when the @hwlock was successfully taken, and an appropriate + * error code otherwise (most notably an -ETIMEDOUT if the @hwlock is still + * busy after @timeout msecs). The function will never sleep. + */ +static inline +int hwspin_lock_timeout_in_atomic(struct hwspinlock *hwlock, unsigned int to) +{ + return __hwspin_lock_timeout(hwlock, to, HWLOCK_IN_ATOMIC, NULL); +} + /** * hwspin_lock_timeout() - lock an hwspinlock with timeout limit * @hwlock: the hwspinlock to be locked @@ -386,6 +426,21 @@ static inline void hwspin_unlock_raw(struct hwspinlock *hwlock) __hwspin_unlock(hwlock, HWLOCK_RAW, NULL); } +/** + * hwspin_unlock_in_atomic() - unlock hwspinlock + * @hwlock: a previously-acquired hwspinlock which we want to unlock + * + * This function will unlock a specific hwspinlock. + * + * @hwlock must be already locked (e.g. by hwspin_trylock()) before calling + * this function: it is a bug to call unlock on a @hwlock that is already + * unlocked. + */ +static inline void hwspin_unlock_in_atomic(struct hwspinlock *hwlock) +{ + __hwspin_unlock(hwlock, HWLOCK_IN_ATOMIC, NULL); +} + /** * hwspin_unlock() - unlock hwspinlock * @hwlock: a previously-acquired hwspinlock which we want to unlock