From: Paul Walmsley Date: Tue, 14 Dec 2010 19:42:35 +0000 (-0700) Subject: OMAP2+: hwmod: upgrade per-hwmod mutex to a spinlock X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=dc6d1cda044b24c3d9f8e4af0431887ebe3488ef;p=linux-beck.git OMAP2+: hwmod: upgrade per-hwmod mutex to a spinlock Change the per-hwmod mutex to a spinlock. (The per-hwmod lock serializes most post-initialization hwmod operations such as enable, idle, and shutdown.) Spinlocks are needed, because in some cases, hwmods must be enabled from timer interrupt disabled-context, such as an ISR. The current use-case that is driving this is the OMAP GPIO block ISR: it can trigger interrupts even with its clocks disabled, but these clocks are needed for register accesses in the ISR to succeed. This patch also effectively reverts commit 848240223c35fcc71c424ad51a8e8aef42d3879c - this patch makes _omap_hwmod_enable() and _omap_hwmod_init() static, renames them back to _enable() and _idle(), and changes their callers to call the spinlocking versions. Previously, since omap_hwmod_{enable,init}() attempted to take mutexes, these functions could not be called while the timer interrupt was disabled; but now that the functions use spinlocks and save and restore the IRQ state, it is appropriate to call them directly. Kevin Hilman originally proposed this patch - thanks Kevin. Signed-off-by: Paul Walmsley Cc: Kevin Hilman Cc: Benoît Cousson --- diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c index 12a0b9a30a30..31990e92c573 100644 --- a/arch/arm/mach-omap2/omap_hwmod.c +++ b/arch/arm/mach-omap2/omap_hwmod.c @@ -135,6 +135,7 @@ #include #include #include +#include #include #include @@ -1192,17 +1193,14 @@ static int _reset(struct omap_hwmod *oh) } /** - * _omap_hwmod_enable - enable an omap_hwmod + * _enable - enable an omap_hwmod * @oh: struct omap_hwmod * * * Enables an omap_hwmod @oh such that the MPU can access the hwmod's - * register target. (This function has a full name -- - * _omap_hwmod_enable() rather than simply _enable() -- because it is - * currently required by the pm34xx.c idle loop.) Returns -EINVAL if - * the hwmod is in the wrong state or passes along the return value of - * _wait_target_ready(). + * register target. Returns -EINVAL if the hwmod is in the wrong + * state or passes along the return value of _wait_target_ready(). */ -int _omap_hwmod_enable(struct omap_hwmod *oh) +static int _enable(struct omap_hwmod *oh) { int r; @@ -1249,16 +1247,14 @@ int _omap_hwmod_enable(struct omap_hwmod *oh) } /** - * _omap_hwmod_idle - idle an omap_hwmod + * _idle - idle an omap_hwmod * @oh: struct omap_hwmod * * * Idles an omap_hwmod @oh. This should be called once the hwmod has - * no further work. (This function has a full name -- - * _omap_hwmod_idle() rather than simply _idle() -- because it is - * currently required by the pm34xx.c idle loop.) Returns -EINVAL if - * the hwmod is in the wrong state or returns 0. + * no further work. Returns -EINVAL if the hwmod is in the wrong + * state or returns 0. */ -int _omap_hwmod_idle(struct omap_hwmod *oh) +static int _idle(struct omap_hwmod *oh) { if (oh->_state != _HWMOD_STATE_ENABLED) { WARN(1, "omap_hwmod: %s: idle state can only be entered from " @@ -1304,11 +1300,11 @@ static int _shutdown(struct omap_hwmod *oh) if (oh->class->pre_shutdown) { prev_state = oh->_state; if (oh->_state == _HWMOD_STATE_IDLE) - _omap_hwmod_enable(oh); + _enable(oh); ret = oh->class->pre_shutdown(oh); if (ret) { if (prev_state == _HWMOD_STATE_IDLE) - _omap_hwmod_idle(oh); + _idle(oh); return ret; } } @@ -1381,7 +1377,7 @@ static int _setup(struct omap_hwmod *oh, void *data) if ((oh->flags & HWMOD_INIT_NO_RESET) && oh->rst_lines_cnt == 1) return 0; - r = _omap_hwmod_enable(oh); + r = _enable(oh); if (r) { pr_warning("omap_hwmod: %s: cannot be enabled (%d)\n", oh->name, oh->_state); @@ -1393,7 +1389,7 @@ static int _setup(struct omap_hwmod *oh, void *data) /* * OCP_SYSCONFIG bits need to be reprogrammed after a softreset. - * The _omap_hwmod_enable() function should be split to + * The _enable() function should be split to * avoid the rewrite of the OCP_SYSCONFIG register. */ if (oh->class->sysc) { @@ -1415,7 +1411,7 @@ static int _setup(struct omap_hwmod *oh, void *data) postsetup_state = _HWMOD_STATE_ENABLED; if (postsetup_state == _HWMOD_STATE_IDLE) - _omap_hwmod_idle(oh); + _idle(oh); else if (postsetup_state == _HWMOD_STATE_DISABLED) _shutdown(oh); else if (postsetup_state != _HWMOD_STATE_ENABLED) @@ -1521,7 +1517,7 @@ int omap_hwmod_register(struct omap_hwmod *oh) list_add_tail(&oh->node, &omap_hwmod_list); - mutex_init(&oh->_mutex); + spin_lock_init(&oh->_lock); oh->_state = _HWMOD_STATE_REGISTERED; @@ -1681,18 +1677,18 @@ int omap_hwmod_unregister(struct omap_hwmod *oh) int omap_hwmod_enable(struct omap_hwmod *oh) { int r; + unsigned long flags; if (!oh) return -EINVAL; - mutex_lock(&oh->_mutex); - r = _omap_hwmod_enable(oh); - mutex_unlock(&oh->_mutex); + spin_lock_irqsave(&oh->_lock, flags); + r = _enable(oh); + spin_unlock_irqrestore(&oh->_lock, flags); return r; } - /** * omap_hwmod_idle - idle an omap_hwmod * @oh: struct omap_hwmod * @@ -1702,12 +1698,14 @@ int omap_hwmod_enable(struct omap_hwmod *oh) */ int omap_hwmod_idle(struct omap_hwmod *oh) { + unsigned long flags; + if (!oh) return -EINVAL; - mutex_lock(&oh->_mutex); - _omap_hwmod_idle(oh); - mutex_unlock(&oh->_mutex); + spin_lock_irqsave(&oh->_lock, flags); + _idle(oh); + spin_unlock_irqrestore(&oh->_lock, flags); return 0; } @@ -1722,12 +1720,14 @@ int omap_hwmod_idle(struct omap_hwmod *oh) */ int omap_hwmod_shutdown(struct omap_hwmod *oh) { + unsigned long flags; + if (!oh) return -EINVAL; - mutex_lock(&oh->_mutex); + spin_lock_irqsave(&oh->_lock, flags); _shutdown(oh); - mutex_unlock(&oh->_mutex); + spin_unlock_irqrestore(&oh->_lock, flags); return 0; } @@ -1740,9 +1740,11 @@ int omap_hwmod_shutdown(struct omap_hwmod *oh) */ int omap_hwmod_enable_clocks(struct omap_hwmod *oh) { - mutex_lock(&oh->_mutex); + unsigned long flags; + + spin_lock_irqsave(&oh->_lock, flags); _enable_clocks(oh); - mutex_unlock(&oh->_mutex); + spin_unlock_irqrestore(&oh->_lock, flags); return 0; } @@ -1755,9 +1757,11 @@ int omap_hwmod_enable_clocks(struct omap_hwmod *oh) */ int omap_hwmod_disable_clocks(struct omap_hwmod *oh) { - mutex_lock(&oh->_mutex); + unsigned long flags; + + spin_lock_irqsave(&oh->_lock, flags); _disable_clocks(oh); - mutex_unlock(&oh->_mutex); + spin_unlock_irqrestore(&oh->_lock, flags); return 0; } @@ -1801,13 +1805,14 @@ void omap_hwmod_ocp_barrier(struct omap_hwmod *oh) int omap_hwmod_reset(struct omap_hwmod *oh) { int r; + unsigned long flags; if (!oh) return -EINVAL; - mutex_lock(&oh->_mutex); + spin_lock_irqsave(&oh->_lock, flags); r = _reset(oh); - mutex_unlock(&oh->_mutex); + spin_unlock_irqrestore(&oh->_lock, flags); return r; } @@ -2004,13 +2009,15 @@ int omap_hwmod_del_initiator_dep(struct omap_hwmod *oh, */ int omap_hwmod_enable_wakeup(struct omap_hwmod *oh) { + unsigned long flags; + if (!oh->class->sysc || !(oh->class->sysc->sysc_flags & SYSC_HAS_ENAWAKEUP)) return -EINVAL; - mutex_lock(&oh->_mutex); + spin_lock_irqsave(&oh->_lock, flags); _enable_wakeup(oh); - mutex_unlock(&oh->_mutex); + spin_unlock_irqrestore(&oh->_lock, flags); return 0; } @@ -2029,13 +2036,15 @@ int omap_hwmod_enable_wakeup(struct omap_hwmod *oh) */ int omap_hwmod_disable_wakeup(struct omap_hwmod *oh) { + unsigned long flags; + if (!oh->class->sysc || !(oh->class->sysc->sysc_flags & SYSC_HAS_ENAWAKEUP)) return -EINVAL; - mutex_lock(&oh->_mutex); + spin_lock_irqsave(&oh->_lock, flags); _disable_wakeup(oh); - mutex_unlock(&oh->_mutex); + spin_unlock_irqrestore(&oh->_lock, flags); return 0; } @@ -2055,13 +2064,14 @@ int omap_hwmod_disable_wakeup(struct omap_hwmod *oh) int omap_hwmod_assert_hardreset(struct omap_hwmod *oh, const char *name) { int ret; + unsigned long flags; if (!oh) return -EINVAL; - mutex_lock(&oh->_mutex); + spin_lock_irqsave(&oh->_lock, flags); ret = _assert_hardreset(oh, name); - mutex_unlock(&oh->_mutex); + spin_unlock_irqrestore(&oh->_lock, flags); return ret; } @@ -2081,13 +2091,14 @@ int omap_hwmod_assert_hardreset(struct omap_hwmod *oh, const char *name) int omap_hwmod_deassert_hardreset(struct omap_hwmod *oh, const char *name) { int ret; + unsigned long flags; if (!oh) return -EINVAL; - mutex_lock(&oh->_mutex); + spin_lock_irqsave(&oh->_lock, flags); ret = _deassert_hardreset(oh, name); - mutex_unlock(&oh->_mutex); + spin_unlock_irqrestore(&oh->_lock, flags); return ret; } @@ -2106,13 +2117,14 @@ int omap_hwmod_deassert_hardreset(struct omap_hwmod *oh, const char *name) int omap_hwmod_read_hardreset(struct omap_hwmod *oh, const char *name) { int ret; + unsigned long flags; if (!oh) return -EINVAL; - mutex_lock(&oh->_mutex); + spin_lock_irqsave(&oh->_lock, flags); ret = _read_hardreset(oh, name); - mutex_unlock(&oh->_mutex); + spin_unlock_irqrestore(&oh->_lock, flags); return ret; } @@ -2180,6 +2192,7 @@ int omap_hwmod_for_each_by_class(const char *classname, int omap_hwmod_set_postsetup_state(struct omap_hwmod *oh, u8 state) { int ret; + unsigned long flags; if (!oh) return -EINVAL; @@ -2189,7 +2202,7 @@ int omap_hwmod_set_postsetup_state(struct omap_hwmod *oh, u8 state) state != _HWMOD_STATE_IDLE) return -EINVAL; - mutex_lock(&oh->_mutex); + spin_lock_irqsave(&oh->_lock, flags); if (oh->_state != _HWMOD_STATE_REGISTERED) { ret = -EINVAL; @@ -2200,7 +2213,7 @@ int omap_hwmod_set_postsetup_state(struct omap_hwmod *oh, u8 state) ret = 0; ohsps_unlock: - mutex_unlock(&oh->_mutex); + spin_unlock_irqrestore(&oh->_lock, flags); return ret; } diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c index 9dc077e2d8af..0548bbd43407 100644 --- a/arch/arm/mach-omap2/serial.c +++ b/arch/arm/mach-omap2/serial.c @@ -106,21 +106,16 @@ struct omap_uart_state { static LIST_HEAD(uart_list); static u8 num_uarts; -/* - * Since these idle/enable hooks are used in the idle path itself - * which has interrupts disabled, use the non-locking versions of - * the hwmod enable/disable functions. - */ static int uart_idle_hwmod(struct omap_device *od) { - _omap_hwmod_idle(od->hwmods[0]); + omap_hwmod_idle(od->hwmods[0]); return 0; } static int uart_enable_hwmod(struct omap_device *od) { - _omap_hwmod_enable(od->hwmods[0]); + omap_hwmod_enable(od->hwmods[0]); return 0; } diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h index e4c4fd4cc1ed..b588f4779806 100644 --- a/arch/arm/plat-omap/include/plat/omap_hwmod.h +++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h @@ -32,7 +32,7 @@ #include #include #include -#include +#include #include struct omap_device; @@ -472,7 +472,7 @@ struct omap_hwmod_class { * @_postsetup_state: internal-use state to leave the hwmod in after _setup() * @flags: hwmod flags (documented below) * @omap_chip: OMAP chips this hwmod is present on - * @_mutex: mutex serializing operations on this hwmod + * @_lock: spinlock serializing operations on this hwmod * @node: list node for hwmod list (internal use) * * @main_clk refers to this module's "main clock," which for our @@ -502,7 +502,7 @@ struct omap_hwmod { void *dev_attr; u32 _sysc_cache; void __iomem *_mpu_rt_va; - struct mutex _mutex; + spinlock_t _lock; struct list_head node; u16 flags; u8 _mpu_port_index;