forked from torvalds/linux
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
clocksource: Add MStar MSC313e timer support
The MSC313e-compatible SoCs have 3 timer hardware blocks. All of these are free running 32-bit increasing counters and can generate interrupts. This commit adds basic support for these timers, the first timer block being used as clocksource/sched_clock and delay, while the others will be used as clockevents. Signed-off-by: Romain Perier <romain.perier@gmail.com> Co-developed-by: Daniel Palmer <daniel@0x0f.com> Signed-off-by: Daniel Palmer <daniel@0x0f.com>
- Loading branch information
Showing
4 changed files
with
240 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,228 @@ | ||
// SPDX-License-Identifier: GPL-2.0 | ||
/* | ||
* MStar timer driver | ||
* | ||
* Copyright (C) 2021 Daniel Palmer | ||
* Copyright (C) 2021 Romain Perier | ||
* | ||
*/ | ||
|
||
#include <linux/clk.h> | ||
#include <linux/clockchips.h> | ||
#include <linux/interrupt.h> | ||
#include <linux/irq.h> | ||
#include <linux/irqreturn.h> | ||
#include <linux/sched_clock.h> | ||
#include <linux/of.h> | ||
#include <linux/of_address.h> | ||
#include <linux/of_irq.h> | ||
#include <linux/delay.h> | ||
|
||
#include "timer-of.h" | ||
|
||
#define TIMER_NAME "msc313e_timer" | ||
|
||
#define MSC313E_REG_CTRL 0x00 | ||
#define MSC313E_REG_CTRL_TIMER_EN BIT(0) | ||
#define MSC313E_REG_CTRL_TIMER_TRIG BIT(1) | ||
#define MSC313E_REG_CTRL_TIMER_INT_EN BIT(8) | ||
#define MSC313E_REG_TIMER_MAX_LOW 0x08 | ||
#define MSC313E_REG_TIMER_MAX_HIGH 0x0c | ||
#define MSC313E_REG_COUNTER_LOW 0x10 | ||
#define MSC313E_REG_COUNTER_HIGH 0x14 | ||
|
||
#define TIMER_SYNC_TICKS 3 | ||
|
||
struct msc313e_delay { | ||
void __iomem *base; | ||
struct delay_timer delay; | ||
}; | ||
|
||
static void __iomem *msc313e_clksrc; | ||
static struct msc313e_delay msc313e_delay; | ||
|
||
static void msc313e_timer_stop(void __iomem *base) | ||
{ | ||
writew(0, base + MSC313E_REG_CTRL); | ||
} | ||
|
||
static void msc313e_timer_start(void __iomem *base, bool periodic) | ||
{ | ||
u16 reg; | ||
|
||
reg = readw(base + MSC313E_REG_CTRL); | ||
if (periodic) | ||
reg |= MSC313E_REG_CTRL_TIMER_EN; | ||
else | ||
reg |= MSC313E_REG_CTRL_TIMER_TRIG; | ||
writew(reg | MSC313E_REG_CTRL_TIMER_INT_EN, base + MSC313E_REG_CTRL); | ||
} | ||
|
||
static void msc313e_timer_setup(void __iomem *base, unsigned long delay) | ||
{ | ||
writew(delay >> 16, base + MSC313E_REG_TIMER_MAX_HIGH); | ||
writew(delay & 0xffff, base + MSC313E_REG_TIMER_MAX_LOW); | ||
} | ||
|
||
static unsigned long msc313e_timer_current_value(void __iomem *base) | ||
{ | ||
unsigned long result; | ||
|
||
result = readw(base + MSC313E_REG_COUNTER_LOW); | ||
result |= readw(base + MSC313E_REG_COUNTER_HIGH) << 16; | ||
|
||
return result; | ||
} | ||
|
||
static int msc313e_timer_clkevt_shutdown(struct clock_event_device *evt) | ||
{ | ||
struct timer_of *timer = to_timer_of(evt); | ||
|
||
msc313e_timer_stop(timer_of_base(timer)); | ||
|
||
return 0; | ||
} | ||
|
||
static int msc313e_timer_clkevt_set_oneshot(struct clock_event_device *evt) | ||
{ | ||
struct timer_of *timer = to_timer_of(evt); | ||
|
||
msc313e_timer_stop(timer_of_base(timer)); | ||
msc313e_timer_start(timer_of_base(timer), false); | ||
|
||
return 0; | ||
} | ||
|
||
static int msc313e_timer_clkevt_set_periodic(struct clock_event_device *evt) | ||
{ | ||
struct timer_of *timer = to_timer_of(evt); | ||
|
||
msc313e_timer_stop(timer_of_base(timer)); | ||
msc313e_timer_setup(timer_of_base(timer), timer_of_period(timer)); | ||
msc313e_timer_start(timer_of_base(timer), true); | ||
|
||
return 0; | ||
} | ||
|
||
static int msc313e_timer_clkevt_next_event(unsigned long evt, struct clock_event_device *clkevt) | ||
{ | ||
struct timer_of *timer = to_timer_of(clkevt); | ||
|
||
msc313e_timer_stop(timer_of_base(timer)); | ||
msc313e_timer_setup(timer_of_base(timer), evt); | ||
msc313e_timer_start(timer_of_base(timer), false); | ||
|
||
return 0; | ||
} | ||
|
||
static irqreturn_t msc313e_timer_clkevt_irq(int irq, void *dev_id) | ||
{ | ||
struct clock_event_device *evt = dev_id; | ||
|
||
evt->event_handler(evt); | ||
|
||
return IRQ_HANDLED; | ||
} | ||
|
||
static u64 msc313e_timer_clksrc_read(struct clocksource *cs) | ||
{ | ||
return msc313e_timer_current_value(msc313e_clksrc) & cs->mask; | ||
} | ||
|
||
static unsigned long msc313e_read_delay_timer_read(void) | ||
{ | ||
return msc313e_timer_current_value(msc313e_delay.base); | ||
} | ||
|
||
static u64 msc313e_timer_sched_clock_read(void) | ||
{ | ||
return msc313e_timer_current_value(msc313e_clksrc); | ||
} | ||
|
||
static struct clock_event_device msc313e_clkevt = { | ||
.name = TIMER_NAME, | ||
.rating = 300, | ||
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, | ||
.set_state_shutdown = msc313e_timer_clkevt_shutdown, | ||
.set_state_periodic = msc313e_timer_clkevt_set_periodic, | ||
.set_state_oneshot = msc313e_timer_clkevt_set_oneshot, | ||
.tick_resume = msc313e_timer_clkevt_shutdown, | ||
.set_next_event = msc313e_timer_clkevt_next_event, | ||
}; | ||
|
||
static int __init msc313e_clkevt_init(struct device_node *np) | ||
{ | ||
int ret; | ||
struct timer_of *to; | ||
|
||
to = kzalloc(sizeof(*to), GFP_KERNEL); | ||
if (!to) | ||
return -ENOMEM; | ||
|
||
to->flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE; | ||
to->of_irq.handler = msc313e_timer_clkevt_irq; | ||
ret = timer_of_init(np, to); | ||
if (ret) | ||
return ret; | ||
|
||
msc313e_clkevt.cpumask = cpu_possible_mask; | ||
msc313e_clkevt.irq = to->of_irq.irq; | ||
to->clkevt = msc313e_clkevt; | ||
|
||
clockevents_config_and_register(&to->clkevt, timer_of_rate(to), | ||
TIMER_SYNC_TICKS, 0xffffffff); | ||
return 0; | ||
} | ||
|
||
static int __init msc313e_clksrc_init(struct device_node *np) | ||
{ | ||
struct timer_of to = { 0 }; | ||
int ret; | ||
u16 reg; | ||
|
||
to.flags = TIMER_OF_BASE | TIMER_OF_CLOCK; | ||
ret = timer_of_init(np, &to); | ||
if (ret) | ||
return ret; | ||
|
||
msc313e_delay.base = timer_of_base(&to); | ||
msc313e_delay.delay.read_current_timer = msc313e_read_delay_timer_read; | ||
msc313e_delay.delay.freq = timer_of_rate(&to); | ||
|
||
msc313e_clksrc = timer_of_base(&to); | ||
reg = readw(msc313e_clksrc + MSC313E_REG_CTRL); | ||
reg |= MSC313E_REG_CTRL_TIMER_EN; | ||
writew(reg, msc313e_clksrc + MSC313E_REG_CTRL); | ||
|
||
register_current_timer_delay(&msc313e_delay.delay); | ||
|
||
sched_clock_register(msc313e_timer_sched_clock_read, 32, timer_of_rate(&to)); | ||
return clocksource_mmio_init(timer_of_base(&to), TIMER_NAME, timer_of_rate(&to), 300, 32, | ||
msc313e_timer_clksrc_read); | ||
} | ||
|
||
static int __init msc313e_timer_init(struct device_node *np) | ||
{ | ||
int ret = 0; | ||
static int num_called; | ||
|
||
switch (num_called) { | ||
case 0: | ||
ret = msc313e_clksrc_init(np); | ||
if (ret) | ||
return ret; | ||
break; | ||
|
||
default: | ||
ret = msc313e_clkevt_init(np); | ||
if (ret) | ||
return ret; | ||
break; | ||
} | ||
|
||
num_called++; | ||
|
||
return 0; | ||
} | ||
|
||
TIMER_OF_DECLARE(msc313, "mstar,msc313e-timer", msc313e_timer_init); |