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alistair23-linux/drivers/clocksource/timer-fttmr010.c
Linus Torvalds 2bcc673101 Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 
Pull timer updates from Thomas Gleixner:
 "Yet another big pile of changes:

   - More year 2038 work from Arnd slowly reaching the point where we
     need to think about the syscalls themself.

   - A new timer function which allows to conditionally (re)arm a timer
     only when it's either not running or the new expiry time is sooner
     than the armed expiry time. This allows to use a single timer for
     multiple timeout requirements w/o caring about the first expiry
     time at the call site.

   - A new NMI safe accessor to clock real time for the printk timestamp
     work. Can be used by tracing, perf as well if required.

   - A large number of timer setup conversions from Kees which got
     collected here because either maintainers requested so or they
     simply got ignored. As Kees pointed out already there are a few
     trivial merge conflicts and some redundant commits which was
     unavoidable due to the size of this conversion effort.

   - Avoid a redundant iteration in the timer wheel softirq processing.

   - Provide a mechanism to treat RTC implementations depending on their
     hardware properties, i.e. don't inflict the write at the 0.5
     seconds boundary which originates from the PC CMOS RTC to all RTCs.
     No functional change as drivers need to be updated separately.

   - The usual small updates to core code clocksource drivers. Nothing
     really exciting"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (111 commits)
  timers: Add a function to start/reduce a timer
  pstore: Use ktime_get_real_fast_ns() instead of __getnstimeofday()
  timer: Prepare to change all DEFINE_TIMER() callbacks
  netfilter: ipvs: Convert timers to use timer_setup()
  scsi: qla2xxx: Convert timers to use timer_setup()
  block/aoe: discover_timer: Convert timers to use timer_setup()
  ide: Convert timers to use timer_setup()
  drbd: Convert timers to use timer_setup()
  mailbox: Convert timers to use timer_setup()
  crypto: Convert timers to use timer_setup()
  drivers/pcmcia: omap1: Fix error in automated timer conversion
  ARM: footbridge: Fix typo in timer conversion
  drivers/sgi-xp: Convert timers to use timer_setup()
  drivers/pcmcia: Convert timers to use timer_setup()
  drivers/memstick: Convert timers to use timer_setup()
  drivers/macintosh: Convert timers to use timer_setup()
  hwrng/xgene-rng: Convert timers to use timer_setup()
  auxdisplay: Convert timers to use timer_setup()
  sparc/led: Convert timers to use timer_setup()
  mips: ip22/32: Convert timers to use timer_setup()
  ...
2017-11-13 17:56:58 -08:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Faraday Technology FTTMR010 timer driver
* Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
*
* Based on a rewrite of arch/arm/mach-gemini/timer.c:
* Copyright (C) 2001-2006 Storlink, Corp.
* Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
*/
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/sched_clock.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/delay.h>
/*
* Register definitions for the timers
*/
#define TIMER1_COUNT (0x00)
#define TIMER1_LOAD (0x04)
#define TIMER1_MATCH1 (0x08)
#define TIMER1_MATCH2 (0x0c)
#define TIMER2_COUNT (0x10)
#define TIMER2_LOAD (0x14)
#define TIMER2_MATCH1 (0x18)
#define TIMER2_MATCH2 (0x1c)
#define TIMER3_COUNT (0x20)
#define TIMER3_LOAD (0x24)
#define TIMER3_MATCH1 (0x28)
#define TIMER3_MATCH2 (0x2c)
#define TIMER_CR (0x30)
#define TIMER_INTR_STATE (0x34)
#define TIMER_INTR_MASK (0x38)
#define TIMER_1_CR_ENABLE BIT(0)
#define TIMER_1_CR_CLOCK BIT(1)
#define TIMER_1_CR_INT BIT(2)
#define TIMER_2_CR_ENABLE BIT(3)
#define TIMER_2_CR_CLOCK BIT(4)
#define TIMER_2_CR_INT BIT(5)
#define TIMER_3_CR_ENABLE BIT(6)
#define TIMER_3_CR_CLOCK BIT(7)
#define TIMER_3_CR_INT BIT(8)
#define TIMER_1_CR_UPDOWN BIT(9)
#define TIMER_2_CR_UPDOWN BIT(10)
#define TIMER_3_CR_UPDOWN BIT(11)
/*
* The Aspeed AST2400 moves bits around in the control register
* and lacks bits for setting the timer to count upwards.
*/
#define TIMER_1_CR_ASPEED_ENABLE BIT(0)
#define TIMER_1_CR_ASPEED_CLOCK BIT(1)
#define TIMER_1_CR_ASPEED_INT BIT(2)
#define TIMER_2_CR_ASPEED_ENABLE BIT(4)
#define TIMER_2_CR_ASPEED_CLOCK BIT(5)
#define TIMER_2_CR_ASPEED_INT BIT(6)
#define TIMER_3_CR_ASPEED_ENABLE BIT(8)
#define TIMER_3_CR_ASPEED_CLOCK BIT(9)
#define TIMER_3_CR_ASPEED_INT BIT(10)
#define TIMER_1_INT_MATCH1 BIT(0)
#define TIMER_1_INT_MATCH2 BIT(1)
#define TIMER_1_INT_OVERFLOW BIT(2)
#define TIMER_2_INT_MATCH1 BIT(3)
#define TIMER_2_INT_MATCH2 BIT(4)
#define TIMER_2_INT_OVERFLOW BIT(5)
#define TIMER_3_INT_MATCH1 BIT(6)
#define TIMER_3_INT_MATCH2 BIT(7)
#define TIMER_3_INT_OVERFLOW BIT(8)
#define TIMER_INT_ALL_MASK 0x1ff
struct fttmr010 {
void __iomem *base;
unsigned int tick_rate;
bool count_down;
u32 t1_enable_val;
struct clock_event_device clkevt;
#ifdef CONFIG_ARM
struct delay_timer delay_timer;
#endif
};
/*
* A local singleton used by sched_clock and delay timer reads, which are
* fast and stateless
*/
static struct fttmr010 *local_fttmr;
static inline struct fttmr010 *to_fttmr010(struct clock_event_device *evt)
{
return container_of(evt, struct fttmr010, clkevt);
}
static unsigned long fttmr010_read_current_timer_up(void)
{
return readl(local_fttmr->base + TIMER2_COUNT);
}
static unsigned long fttmr010_read_current_timer_down(void)
{
return ~readl(local_fttmr->base + TIMER2_COUNT);
}
static u64 notrace fttmr010_read_sched_clock_up(void)
{
return fttmr010_read_current_timer_up();
}
static u64 notrace fttmr010_read_sched_clock_down(void)
{
return fttmr010_read_current_timer_down();
}
static int fttmr010_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
struct fttmr010 *fttmr010 = to_fttmr010(evt);
u32 cr;
/* Stop */
cr = readl(fttmr010->base + TIMER_CR);
cr &= ~fttmr010->t1_enable_val;
writel(cr, fttmr010->base + TIMER_CR);
/* Setup the match register forward/backward in time */
cr = readl(fttmr010->base + TIMER1_COUNT);
if (fttmr010->count_down)
cr -= cycles;
else
cr += cycles;
writel(cr, fttmr010->base + TIMER1_MATCH1);
/* Start */
cr = readl(fttmr010->base + TIMER_CR);
cr |= fttmr010->t1_enable_val;
writel(cr, fttmr010->base + TIMER_CR);
return 0;
}
static int fttmr010_timer_shutdown(struct clock_event_device *evt)
{
struct fttmr010 *fttmr010 = to_fttmr010(evt);
u32 cr;
/* Stop */
cr = readl(fttmr010->base + TIMER_CR);
cr &= ~fttmr010->t1_enable_val;
writel(cr, fttmr010->base + TIMER_CR);
return 0;
}
static int fttmr010_timer_set_oneshot(struct clock_event_device *evt)
{
struct fttmr010 *fttmr010 = to_fttmr010(evt);
u32 cr;
/* Stop */
cr = readl(fttmr010->base + TIMER_CR);
cr &= ~fttmr010->t1_enable_val;
writel(cr, fttmr010->base + TIMER_CR);
/* Setup counter start from 0 or ~0 */
writel(0, fttmr010->base + TIMER1_COUNT);
if (fttmr010->count_down)
writel(~0, fttmr010->base + TIMER1_LOAD);
else
writel(0, fttmr010->base + TIMER1_LOAD);
/* Enable interrupt */
cr = readl(fttmr010->base + TIMER_INTR_MASK);
cr &= ~(TIMER_1_INT_OVERFLOW | TIMER_1_INT_MATCH2);
cr |= TIMER_1_INT_MATCH1;
writel(cr, fttmr010->base + TIMER_INTR_MASK);
return 0;
}
static int fttmr010_timer_set_periodic(struct clock_event_device *evt)
{
struct fttmr010 *fttmr010 = to_fttmr010(evt);
u32 period = DIV_ROUND_CLOSEST(fttmr010->tick_rate, HZ);
u32 cr;
/* Stop */
cr = readl(fttmr010->base + TIMER_CR);
cr &= ~fttmr010->t1_enable_val;
writel(cr, fttmr010->base + TIMER_CR);
/* Setup timer to fire at 1/HZ intervals. */
if (fttmr010->count_down) {
writel(period, fttmr010->base + TIMER1_LOAD);
writel(0, fttmr010->base + TIMER1_MATCH1);
} else {
cr = 0xffffffff - (period - 1);
writel(cr, fttmr010->base + TIMER1_COUNT);
writel(cr, fttmr010->base + TIMER1_LOAD);
/* Enable interrupt on overflow */
cr = readl(fttmr010->base + TIMER_INTR_MASK);
cr &= ~(TIMER_1_INT_MATCH1 | TIMER_1_INT_MATCH2);
cr |= TIMER_1_INT_OVERFLOW;
writel(cr, fttmr010->base + TIMER_INTR_MASK);
}
/* Start the timer */
cr = readl(fttmr010->base + TIMER_CR);
cr |= fttmr010->t1_enable_val;
writel(cr, fttmr010->base + TIMER_CR);
return 0;
}
/*
* IRQ handler for the timer
*/
static irqreturn_t fttmr010_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
evt->event_handler(evt);
return IRQ_HANDLED;
}
static int __init fttmr010_common_init(struct device_node *np, bool is_aspeed)
{
struct fttmr010 *fttmr010;
int irq;
struct clk *clk;
int ret;
u32 val;
/*
* These implementations require a clock reference.
* FIXME: we currently only support clocking using PCLK
* and using EXTCLK is not supported in the driver.
*/
clk = of_clk_get_by_name(np, "PCLK");
if (IS_ERR(clk)) {
pr_err("could not get PCLK\n");
return PTR_ERR(clk);
}
ret = clk_prepare_enable(clk);
if (ret) {
pr_err("failed to enable PCLK\n");
return ret;
}
fttmr010 = kzalloc(sizeof(*fttmr010), GFP_KERNEL);
if (!fttmr010) {
ret = -ENOMEM;
goto out_disable_clock;
}
fttmr010->tick_rate = clk_get_rate(clk);
fttmr010->base = of_iomap(np, 0);
if (!fttmr010->base) {
pr_err("Can't remap registers\n");
ret = -ENXIO;
goto out_free;
}
/* IRQ for timer 1 */
irq = irq_of_parse_and_map(np, 0);
if (irq <= 0) {
pr_err("Can't parse IRQ\n");
ret = -EINVAL;
goto out_unmap;
}
/*
* The Aspeed AST2400 moves bits around in the control register,
* otherwise it works the same.
*/
if (is_aspeed) {
fttmr010->t1_enable_val = TIMER_1_CR_ASPEED_ENABLE |
TIMER_1_CR_ASPEED_INT;
/* Downward not available */
fttmr010->count_down = true;
} else {
fttmr010->t1_enable_val = TIMER_1_CR_ENABLE | TIMER_1_CR_INT;
}
/*
* Reset the interrupt mask and status
*/
writel(TIMER_INT_ALL_MASK, fttmr010->base + TIMER_INTR_MASK);
writel(0, fttmr010->base + TIMER_INTR_STATE);
/*
* Enable timer 1 count up, timer 2 count up, except on Aspeed,
* where everything just counts down.
*/
if (is_aspeed)
val = TIMER_2_CR_ASPEED_ENABLE;
else {
val = TIMER_2_CR_ENABLE;
if (!fttmr010->count_down)
val |= TIMER_1_CR_UPDOWN | TIMER_2_CR_UPDOWN;
}
writel(val, fttmr010->base + TIMER_CR);
/*
* Setup free-running clocksource timer (interrupts
* disabled.)
*/
local_fttmr = fttmr010;
writel(0, fttmr010->base + TIMER2_COUNT);
writel(0, fttmr010->base + TIMER2_MATCH1);
writel(0, fttmr010->base + TIMER2_MATCH2);
if (fttmr010->count_down) {
writel(~0, fttmr010->base + TIMER2_LOAD);
clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
"FTTMR010-TIMER2",
fttmr010->tick_rate,
300, 32, clocksource_mmio_readl_down);
sched_clock_register(fttmr010_read_sched_clock_down, 32,
fttmr010->tick_rate);
} else {
writel(0, fttmr010->base + TIMER2_LOAD);
clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
"FTTMR010-TIMER2",
fttmr010->tick_rate,
300, 32, clocksource_mmio_readl_up);
sched_clock_register(fttmr010_read_sched_clock_up, 32,
fttmr010->tick_rate);
}
/*
* Setup clockevent timer (interrupt-driven) on timer 1.
*/
writel(0, fttmr010->base + TIMER1_COUNT);
writel(0, fttmr010->base + TIMER1_LOAD);
writel(0, fttmr010->base + TIMER1_MATCH1);
writel(0, fttmr010->base + TIMER1_MATCH2);
ret = request_irq(irq, fttmr010_timer_interrupt, IRQF_TIMER,
"FTTMR010-TIMER1", &fttmr010->clkevt);
if (ret) {
pr_err("FTTMR010-TIMER1 no IRQ\n");
goto out_unmap;
}
fttmr010->clkevt.name = "FTTMR010-TIMER1";
/* Reasonably fast and accurate clock event */
fttmr010->clkevt.rating = 300;
fttmr010->clkevt.features = CLOCK_EVT_FEAT_PERIODIC |
CLOCK_EVT_FEAT_ONESHOT;
fttmr010->clkevt.set_next_event = fttmr010_timer_set_next_event;
fttmr010->clkevt.set_state_shutdown = fttmr010_timer_shutdown;
fttmr010->clkevt.set_state_periodic = fttmr010_timer_set_periodic;
fttmr010->clkevt.set_state_oneshot = fttmr010_timer_set_oneshot;
fttmr010->clkevt.tick_resume = fttmr010_timer_shutdown;
fttmr010->clkevt.cpumask = cpumask_of(0);
fttmr010->clkevt.irq = irq;
clockevents_config_and_register(&fttmr010->clkevt,
fttmr010->tick_rate,
1, 0xffffffff);
#ifdef CONFIG_ARM
/* Also use this timer for delays */
if (fttmr010->count_down)
fttmr010->delay_timer.read_current_timer =
fttmr010_read_current_timer_down;
else
fttmr010->delay_timer.read_current_timer =
fttmr010_read_current_timer_up;
fttmr010->delay_timer.freq = fttmr010->tick_rate;
register_current_timer_delay(&fttmr010->delay_timer);
#endif
return 0;
out_unmap:
iounmap(fttmr010->base);
out_free:
kfree(fttmr010);
out_disable_clock:
clk_disable_unprepare(clk);
return ret;
}
static __init int aspeed_timer_init(struct device_node *np)
{
return fttmr010_common_init(np, true);
}
static __init int fttmr010_timer_init(struct device_node *np)
{
return fttmr010_common_init(np, false);
}
TIMER_OF_DECLARE(fttmr010, "faraday,fttmr010", fttmr010_timer_init);
TIMER_OF_DECLARE(gemini, "cortina,gemini-timer", fttmr010_timer_init);
TIMER_OF_DECLARE(moxart, "moxa,moxart-timer", fttmr010_timer_init);
TIMER_OF_DECLARE(ast2400, "aspeed,ast2400-timer", aspeed_timer_init);
TIMER_OF_DECLARE(ast2500, "aspeed,ast2500-timer", aspeed_timer_init);
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