From: Viresh Kumar viresh.kumar@linaro.org

Currently, the ->set_mode() method of a clockevent device is not allowed to fail, so it has no return value. In order to add new clockevent modes, and allow the setting of those modes to fail, we need the clockevent core to be able to detect when setting a mode fails.

To allow detection of mode setting failures, introduce a new method ->set_dev_mode() which can return an error if the given mode is not supported or fails.

Since all current modes are still not allowed to fail, the core code simply WARNs if any modes fail. Future patches that add new mode support will add proper error recovery based on failure conditions.

Signed-off-by: Viresh Kumar viresh.kumar@linaro.org Reviewed-by: Kevin Hilman khilman@linaro.org [khilman: rework changelogs, minor formatting/checkpatch cleanups] Signed-off-by: Kevin Hilman khilman@linaro.org --- include/linux/clockchips.h | 5 ++++- kernel/time/clockevents.c | 21 ++++++++++++++++++--- kernel/time/timer_list.c | 5 ++++- 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h index 2e4cb67f6e56..d969659cf688 100644 --- a/include/linux/clockchips.h +++ b/include/linux/clockchips.h @@ -81,7 +81,8 @@ enum clock_event_mode { * @mode: operating mode assigned by the management code * @features: features * @retries: number of forced programming retries - * @set_mode: set mode function + * @set_dev_mode: set dev mode function + * @set_mode: set mode function (deprecated, use set_dev_mode instead) * @broadcast: function to broadcast events * @min_delta_ticks: minimum delta value in ticks stored for reconfiguration * @max_delta_ticks: maximum delta value in ticks stored for reconfiguration @@ -109,6 +110,8 @@ struct clock_event_device { unsigned long retries;

void (*broadcast)(const struct cpumask *mask); + int (*set_dev_mode)(enum clock_event_mode mode, + struct clock_event_device *); void (*set_mode)(enum clock_event_mode mode, struct clock_event_device *); void (*suspend)(struct clock_event_device *); diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 9c94c19f1305..1d5ce3ce9228 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -105,7 +105,16 @@ void clockevents_set_mode(struct clock_event_device *dev, enum clock_event_mode mode) { if (dev->mode != mode) { - dev->set_mode(mode, dev); + if (dev->set_dev_mode) { + int ret = dev->set_dev_mode(mode, dev); + + /* Currently available modes shouldn't fail */ + WARN_ONCE(ret, "Requested mode: %d, error: %d\n", + mode, ret); + } else { + dev->set_mode(mode, dev); + } + dev->mode = mode;

/* @@ -448,8 +457,14 @@ int __clockevents_update_freq(struct clock_event_device *dev, u32 freq) if (dev->mode == CLOCK_EVT_MODE_ONESHOT) return clockevents_program_event(dev, dev->next_event, false);

- if (dev->mode == CLOCK_EVT_MODE_PERIODIC) - dev->set_mode(CLOCK_EVT_MODE_PERIODIC, dev); + if (dev->mode == CLOCK_EVT_MODE_PERIODIC) { + /* Shouldn't fail while switching to PERIODIC MODE */ + if (dev->set_dev_mode) + WARN_ON_ONCE(dev->set_dev_mode(CLOCK_EVT_MODE_PERIODIC, + dev)); + else + dev->set_mode(CLOCK_EVT_MODE_PERIODIC, dev); + }

return 0; } diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c index 61ed862cdd37..957a04951ef0 100644 --- a/kernel/time/timer_list.c +++ b/kernel/time/timer_list.c @@ -229,7 +229,10 @@ print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu) SEQ_printf(m, "\n");

SEQ_printf(m, " set_mode: "); - print_name_offset(m, dev->set_mode); + if (dev->set_dev_mode) + print_name_offset(m, dev->set_dev_mode); + else + print_name_offset(m, dev->set_mode); SEQ_printf(m, "\n");

SEQ_printf(m, " event_handler: ");

From: Viresh Kumar viresh.kumar@linaro.org

Clockevents core now supports ->set_dev_mode() (as a replacement to ->set_mode()), with capability to return error codes.

This patch migrates few clockevent drivers to the new method to demonstrate how to convert to the new interface.

Drivers are modified to return -ENOSYS when requested to switch to unsupported mode and return 0 on success. This patch shouldn't result in any other functional change in drivers.

Most of the changes are automated with help of Coccinelle (http://coccinelle.lip6.fr/) and the ones left are around the switch block which are handled manually. Some additional changes (like adding 'int ret = 0' and 'return ret') as well as whitespace fixups were also done manually after coccinelle.

A simplified version of the semantic patch is:

// <smpl> @@ identifier m,c,setmode; @@ -void +int setmode(enum clock_event_mode m, struct clock_event_device *c);

@@ identifier setmode; @@ -void +int setmode(enum clock_event_mode, struct clock_event_device *);

@fixret@ identifier m,c,setmode; @@ -void +int setmode(enum clock_event_mode m, struct clock_event_device *c) { ... + return 0; }

@depends on fixret@ identifier ced; identifier fixret.setmode; @@ ... struct clock_event_device ced = { ..., -.set_mode +.set_dev_mode = setmode, };

@depends on fixret@ expression ced; identifier fixret.setmode; @@ - ced->set_mode + ced->set_dev_mode = setmode

@depends on fixret@ identifier fixret.setmode; @@ { . -set_mode +set_dev_mode = setmode }

@depends on fixret@ expression ced; identifier fixret.setmode; @@ - ced.set_mode + ced.set_dev_mode = setmode

// </smpl>

Signed-off-by: Viresh Kumar viresh.kumar@linaro.org Reviewed-by: Kevin Hilman khilman@linaro.org [khilman: rework changelog, minor formatting, checkpatch cleanups] Signed-off-by: Kevin Hilman khilman@linaro.org --- drivers/clocksource/arm_arch_timer.c | 46 +++++++++++++++++--------------- drivers/clocksource/bcm2835_timer.c | 10 +++---- drivers/clocksource/bcm_kona_timer.c | 15 ++++++++--- drivers/clocksource/i8253.c | 11 +++++--- drivers/clocksource/time-armada-370-xp.c | 21 +++++++++++---- 5 files changed, 65 insertions(+), 38 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 2133f9d59d06..3d586e4b74b1 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -179,8 +179,8 @@ static irqreturn_t arch_timer_handler_virt_mem(int irq, void *dev_id) return timer_handler(ARCH_TIMER_MEM_VIRT_ACCESS, evt); }

-static __always_inline void timer_set_mode(const int access, int mode, - struct clock_event_device *clk) +static __always_inline int timer_set_mode(const int access, int mode, + struct clock_event_device *clk) { unsigned long ctrl; switch (mode) { @@ -190,33 +190,37 @@ static __always_inline void timer_set_mode(const int access, int mode, ctrl &= ~ARCH_TIMER_CTRL_ENABLE; arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk); break; - default: + case CLOCK_EVT_MODE_ONESHOT: + case CLOCK_EVT_MODE_RESUME: break; + default: + return -ENOSYS; } + return 0; }

-static void arch_timer_set_mode_virt(enum clock_event_mode mode, - struct clock_event_device *clk) +static int arch_timer_set_mode_virt(enum clock_event_mode mode, + struct clock_event_device *clk) { - timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode, clk); + return timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode, clk); }

-static void arch_timer_set_mode_phys(enum clock_event_mode mode, - struct clock_event_device *clk) +static int arch_timer_set_mode_phys(enum clock_event_mode mode, + struct clock_event_device *clk) { - timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode, clk); + return timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode, clk); }

-static void arch_timer_set_mode_virt_mem(enum clock_event_mode mode, - struct clock_event_device *clk) +static int arch_timer_set_mode_virt_mem(enum clock_event_mode mode, + struct clock_event_device *clk) { - timer_set_mode(ARCH_TIMER_MEM_VIRT_ACCESS, mode, clk); + return timer_set_mode(ARCH_TIMER_MEM_VIRT_ACCESS, mode, clk); }

-static void arch_timer_set_mode_phys_mem(enum clock_event_mode mode, - struct clock_event_device *clk) +static int arch_timer_set_mode_phys_mem(enum clock_event_mode mode, + struct clock_event_device *clk) { - timer_set_mode(ARCH_TIMER_MEM_PHYS_ACCESS, mode, clk); + return timer_set_mode(ARCH_TIMER_MEM_PHYS_ACCESS, mode, clk); }

static __always_inline void set_next_event(const int access, unsigned long evt, @@ -271,11 +275,11 @@ static void __arch_timer_setup(unsigned type, clk->cpumask = cpumask_of(smp_processor_id()); if (arch_timer_use_virtual) { clk->irq = arch_timer_ppi[VIRT_PPI]; - clk->set_mode = arch_timer_set_mode_virt; + clk->set_dev_mode = arch_timer_set_mode_virt; clk->set_next_event = arch_timer_set_next_event_virt; } else { clk->irq = arch_timer_ppi[PHYS_SECURE_PPI]; - clk->set_mode = arch_timer_set_mode_phys; + clk->set_dev_mode = arch_timer_set_mode_phys; clk->set_next_event = arch_timer_set_next_event_phys; } } else { @@ -284,17 +288,17 @@ static void __arch_timer_setup(unsigned type, clk->rating = 400; clk->cpumask = cpu_all_mask; if (arch_timer_mem_use_virtual) { - clk->set_mode = arch_timer_set_mode_virt_mem; + clk->set_dev_mode = arch_timer_set_mode_virt_mem; clk->set_next_event = arch_timer_set_next_event_virt_mem; } else { - clk->set_mode = arch_timer_set_mode_phys_mem; + clk->set_dev_mode = arch_timer_set_mode_phys_mem; clk->set_next_event = arch_timer_set_next_event_phys_mem; } }

- clk->set_mode(CLOCK_EVT_MODE_SHUTDOWN, clk); + clk->set_dev_mode(CLOCK_EVT_MODE_SHUTDOWN, clk);

clockevents_config_and_register(clk, arch_timer_rate, 0xf, 0x7fffffff); } @@ -497,7 +501,7 @@ static void arch_timer_stop(struct clock_event_device *clk) disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]); }

- clk->set_mode(CLOCK_EVT_MODE_UNUSED, clk); + clk->set_dev_mode(CLOCK_EVT_MODE_UNUSED, clk); }

static int arch_timer_cpu_notify(struct notifier_block *self, diff --git a/drivers/clocksource/bcm2835_timer.c b/drivers/clocksource/bcm2835_timer.c index 26ed331b1aad..04ae14ca81ab 100644 --- a/drivers/clocksource/bcm2835_timer.c +++ b/drivers/clocksource/bcm2835_timer.c @@ -54,8 +54,8 @@ static u64 notrace bcm2835_sched_read(void) return readl_relaxed(system_clock); }

-static void bcm2835_time_set_mode(enum clock_event_mode mode, - struct clock_event_device *evt_dev) +static int bcm2835_time_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt_dev) { switch (mode) { case CLOCK_EVT_MODE_ONESHOT: @@ -64,9 +64,9 @@ static void bcm2835_time_set_mode(enum clock_event_mode mode, case CLOCK_EVT_MODE_RESUME: break; default: - WARN(1, "%s: unhandled event mode %d\n", __func__, mode); - break; + return -ENOSYS; } + return 0; }

static int bcm2835_time_set_next_event(unsigned long event, @@ -129,7 +129,7 @@ static void __init bcm2835_timer_init(struct device_node *node) timer->evt.name = node->name; timer->evt.rating = 300; timer->evt.features = CLOCK_EVT_FEAT_ONESHOT; - timer->evt.set_mode = bcm2835_time_set_mode; + timer->evt.set_dev_mode = bcm2835_time_set_mode; timer->evt.set_next_event = bcm2835_time_set_next_event; timer->evt.cpumask = cpumask_of(0); timer->act.name = node->name; diff --git a/drivers/clocksource/bcm_kona_timer.c b/drivers/clocksource/bcm_kona_timer.c index 0595dc6c453e..807915e9e2f8 100644 --- a/drivers/clocksource/bcm_kona_timer.c +++ b/drivers/clocksource/bcm_kona_timer.c @@ -128,25 +128,32 @@ static int kona_timer_set_next_event(unsigned long clc, return 0; }

-static void kona_timer_set_mode(enum clock_event_mode mode, - struct clock_event_device *unused) +static int kona_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *unused) { + int ret = 0; + switch (mode) { case CLOCK_EVT_MODE_ONESHOT: /* by default mode is one shot don't do any thing */ break; + default: + ret = -ENOSYS; + /* fall through so timer is disabled */ case CLOCK_EVT_MODE_UNUSED: case CLOCK_EVT_MODE_SHUTDOWN: - default: + case CLOCK_EVT_MODE_RESUME: kona_timer_disable_and_clear(timers.tmr_regs); + break; } + return ret; }

static struct clock_event_device kona_clockevent_timer = { .name = "timer 1", .features = CLOCK_EVT_FEAT_ONESHOT, .set_next_event = kona_timer_set_next_event, - .set_mode = kona_timer_set_mode + .set_dev_mode = kona_timer_set_mode };

static void __init kona_timer_clockevents_init(void) diff --git a/drivers/clocksource/i8253.c b/drivers/clocksource/i8253.c index 14ee3efcc404..ea28efbfe9cf 100644 --- a/drivers/clocksource/i8253.c +++ b/drivers/clocksource/i8253.c @@ -105,9 +105,11 @@ int __init clocksource_i8253_init(void) * * This is also called after resume to bring the PIT into operation again. */ -static void init_pit_timer(enum clock_event_mode mode, - struct clock_event_device *evt) +static int init_pit_timer(enum clock_event_mode mode, + struct clock_event_device *evt) { + int ret = 0; + raw_spin_lock(&i8253_lock);

switch (mode) { @@ -136,8 +138,11 @@ static void init_pit_timer(enum clock_event_mode mode, case CLOCK_EVT_MODE_RESUME: /* Nothing to do here */ break; + default: + ret = -ENOSYS; } raw_spin_unlock(&i8253_lock); + return ret; }

/* @@ -162,7 +167,7 @@ static int pit_next_event(unsigned long delta, struct clock_event_device *evt) struct clock_event_device i8253_clockevent = { .name = "pit", .features = CLOCK_EVT_FEAT_PERIODIC, - .set_mode = init_pit_timer, + .set_dev_mode = init_pit_timer, .set_next_event = pit_next_event, };

diff --git a/drivers/clocksource/time-armada-370-xp.c b/drivers/clocksource/time-armada-370-xp.c index 0451e62fac7a..4ea3d4c9d651 100644 --- a/drivers/clocksource/time-armada-370-xp.c +++ b/drivers/clocksource/time-armada-370-xp.c @@ -120,12 +120,14 @@ armada_370_xp_clkevt_next_event(unsigned long delta, return 0; }

-static void +static int armada_370_xp_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev) { - if (mode == CLOCK_EVT_MODE_PERIODIC) { + int ret = 0;

+ switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: /* * Setup timer to fire at 1/HZ intervals. */ @@ -136,7 +138,14 @@ armada_370_xp_clkevt_mode(enum clock_event_mode mode, * Enable timer. */ local_timer_ctrl_clrset(0, TIMER0_RELOAD_EN | enable_mask); - } else { + break; + default: + ret = -ENOSYS; + /* fall through so timer is disabled, ACK'd */ + case CLOCK_EVT_MODE_ONESHOT: + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_RESUME: /* * Disable timer. */ @@ -146,7 +155,9 @@ armada_370_xp_clkevt_mode(enum clock_event_mode mode, * ACK pending timer interrupt. */ writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS); + break; } + return ret; }

static int armada_370_xp_clkevt_irq; @@ -184,7 +195,7 @@ static int armada_370_xp_timer_setup(struct clock_event_device *evt) evt->shift = 32, evt->rating = 300, evt->set_next_event = armada_370_xp_clkevt_next_event, - evt->set_mode = armada_370_xp_clkevt_mode, + evt->set_dev_mode = armada_370_xp_clkevt_mode, evt->irq = armada_370_xp_clkevt_irq; evt->cpumask = cpumask_of(cpu);

@@ -196,7 +207,7 @@ static int armada_370_xp_timer_setup(struct clock_event_device *evt)

static void armada_370_xp_timer_stop(struct clock_event_device *evt) { - evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); + evt->set_dev_mode(CLOCK_EVT_MODE_UNUSED, evt); disable_percpu_irq(evt->irq); }