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alistair23-linux/drivers/clocksource/timer-oxnas-rps.c
Thomas Gleixner 9952f6918d treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201 
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms and conditions of the gnu general public license
  version 2 as published by the free software foundation this program
  is distributed in the hope it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not see http www gnu org
  licenses

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 228 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171438.107155473@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:29:52 -07:00

289 lines
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// SPDX-License-Identifier: GPL-2.0-only
/*
* drivers/clocksource/timer-oxnas-rps.c
*
* Copyright (C) 2009 Oxford Semiconductor Ltd
* Copyright (C) 2013 Ma Haijun <mahaijuns@gmail.com>
* Copyright (C) 2016 Neil Armstrong <narmstrong@baylibre.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/clockchips.h>
#include <linux/sched_clock.h>
/* TIMER1 used as tick
* TIMER2 used as clocksource
*/
/* Registers definitions */
#define TIMER_LOAD_REG 0x0
#define TIMER_CURR_REG 0x4
#define TIMER_CTRL_REG 0x8
#define TIMER_CLRINT_REG 0xC
#define TIMER_BITS 24
#define TIMER_MAX_VAL (BIT(TIMER_BITS) - 1)
#define TIMER_PERIODIC BIT(6)
#define TIMER_ENABLE BIT(7)
#define TIMER_DIV1 (0)
#define TIMER_DIV16 (1 << 2)
#define TIMER_DIV256 (2 << 2)
#define TIMER1_REG_OFFSET 0
#define TIMER2_REG_OFFSET 0x20
/* Clockevent & Clocksource data */
struct oxnas_rps_timer {
struct clock_event_device clkevent;
void __iomem *clksrc_base;
void __iomem *clkevt_base;
unsigned long timer_period;
unsigned int timer_prescaler;
struct clk *clk;
int irq;
};
static irqreturn_t oxnas_rps_timer_irq(int irq, void *dev_id)
{
struct oxnas_rps_timer *rps = dev_id;
writel_relaxed(0, rps->clkevt_base + TIMER_CLRINT_REG);
rps->clkevent.event_handler(&rps->clkevent);
return IRQ_HANDLED;
}
static void oxnas_rps_timer_config(struct oxnas_rps_timer *rps,
unsigned long period,
unsigned int periodic)
{
uint32_t cfg = rps->timer_prescaler;
if (period)
cfg |= TIMER_ENABLE;
if (periodic)
cfg |= TIMER_PERIODIC;
writel_relaxed(period, rps->clkevt_base + TIMER_LOAD_REG);
writel_relaxed(cfg, rps->clkevt_base + TIMER_CTRL_REG);
}
static int oxnas_rps_timer_shutdown(struct clock_event_device *evt)
{
struct oxnas_rps_timer *rps =
container_of(evt, struct oxnas_rps_timer, clkevent);
oxnas_rps_timer_config(rps, 0, 0);
return 0;
}
static int oxnas_rps_timer_set_periodic(struct clock_event_device *evt)
{
struct oxnas_rps_timer *rps =
container_of(evt, struct oxnas_rps_timer, clkevent);
oxnas_rps_timer_config(rps, rps->timer_period, 1);
return 0;
}
static int oxnas_rps_timer_set_oneshot(struct clock_event_device *evt)
{
struct oxnas_rps_timer *rps =
container_of(evt, struct oxnas_rps_timer, clkevent);
oxnas_rps_timer_config(rps, rps->timer_period, 0);
return 0;
}
static int oxnas_rps_timer_next_event(unsigned long delta,
struct clock_event_device *evt)
{
struct oxnas_rps_timer *rps =
container_of(evt, struct oxnas_rps_timer, clkevent);
oxnas_rps_timer_config(rps, delta, 0);
return 0;
}
static int __init oxnas_rps_clockevent_init(struct oxnas_rps_timer *rps)
{
ulong clk_rate = clk_get_rate(rps->clk);
ulong timer_rate;
/* Start with prescaler 1 */
rps->timer_prescaler = TIMER_DIV1;
rps->timer_period = DIV_ROUND_UP(clk_rate, HZ);
timer_rate = clk_rate;
if (rps->timer_period > TIMER_MAX_VAL) {
rps->timer_prescaler = TIMER_DIV16;
timer_rate = clk_rate / 16;
rps->timer_period = DIV_ROUND_UP(timer_rate, HZ);
}
if (rps->timer_period > TIMER_MAX_VAL) {
rps->timer_prescaler = TIMER_DIV256;
timer_rate = clk_rate / 256;
rps->timer_period = DIV_ROUND_UP(timer_rate, HZ);
}
rps->clkevent.name = "oxnas-rps";
rps->clkevent.features = CLOCK_EVT_FEAT_PERIODIC |
CLOCK_EVT_FEAT_ONESHOT |
CLOCK_EVT_FEAT_DYNIRQ;
rps->clkevent.tick_resume = oxnas_rps_timer_shutdown;
rps->clkevent.set_state_shutdown = oxnas_rps_timer_shutdown;
rps->clkevent.set_state_periodic = oxnas_rps_timer_set_periodic;
rps->clkevent.set_state_oneshot = oxnas_rps_timer_set_oneshot;
rps->clkevent.set_next_event = oxnas_rps_timer_next_event;
rps->clkevent.rating = 200;
rps->clkevent.cpumask = cpu_possible_mask;
rps->clkevent.irq = rps->irq;
clockevents_config_and_register(&rps->clkevent,
timer_rate,
1,
TIMER_MAX_VAL);
pr_info("Registered clock event rate %luHz prescaler %x period %lu\n",
clk_rate,
rps->timer_prescaler,
rps->timer_period);
return 0;
}
/* Clocksource */
static void __iomem *timer_sched_base;
static u64 notrace oxnas_rps_read_sched_clock(void)
{
return ~readl_relaxed(timer_sched_base);
}
static int __init oxnas_rps_clocksource_init(struct oxnas_rps_timer *rps)
{
ulong clk_rate = clk_get_rate(rps->clk);
int ret;
/* use prescale 16 */
clk_rate = clk_rate / 16;
writel_relaxed(TIMER_MAX_VAL, rps->clksrc_base + TIMER_LOAD_REG);
writel_relaxed(TIMER_PERIODIC | TIMER_ENABLE | TIMER_DIV16,
rps->clksrc_base + TIMER_CTRL_REG);
timer_sched_base = rps->clksrc_base + TIMER_CURR_REG;
sched_clock_register(oxnas_rps_read_sched_clock,
TIMER_BITS, clk_rate);
ret = clocksource_mmio_init(timer_sched_base,
"oxnas_rps_clocksource_timer",
clk_rate, 250, TIMER_BITS,
clocksource_mmio_readl_down);
if (WARN_ON(ret)) {
pr_err("can't register clocksource\n");
return ret;
}
pr_info("Registered clocksource rate %luHz\n", clk_rate);
return 0;
}
static int __init oxnas_rps_timer_init(struct device_node *np)
{
struct oxnas_rps_timer *rps;
void __iomem *base;
int ret;
rps = kzalloc(sizeof(*rps), GFP_KERNEL);
if (!rps)
return -ENOMEM;
rps->clk = of_clk_get(np, 0);
if (IS_ERR(rps->clk)) {
ret = PTR_ERR(rps->clk);
goto err_alloc;
}
ret = clk_prepare_enable(rps->clk);
if (ret)
goto err_clk;
base = of_iomap(np, 0);
if (!base) {
ret = -ENXIO;
goto err_clk_prepare;
}
rps->irq = irq_of_parse_and_map(np, 0);
if (rps->irq < 0) {
ret = -EINVAL;
goto err_iomap;
}
rps->clkevt_base = base + TIMER1_REG_OFFSET;
rps->clksrc_base = base + TIMER2_REG_OFFSET;
/* Disable timers */
writel_relaxed(0, rps->clkevt_base + TIMER_CTRL_REG);
writel_relaxed(0, rps->clksrc_base + TIMER_CTRL_REG);
writel_relaxed(0, rps->clkevt_base + TIMER_LOAD_REG);
writel_relaxed(0, rps->clksrc_base + TIMER_LOAD_REG);
writel_relaxed(0, rps->clkevt_base + TIMER_CLRINT_REG);
writel_relaxed(0, rps->clksrc_base + TIMER_CLRINT_REG);
ret = request_irq(rps->irq, oxnas_rps_timer_irq,
IRQF_TIMER | IRQF_IRQPOLL,
"rps-timer", rps);
if (ret)
goto err_iomap;
ret = oxnas_rps_clocksource_init(rps);
if (ret)
goto err_irqreq;
ret = oxnas_rps_clockevent_init(rps);
if (ret)
goto err_irqreq;
return 0;
err_irqreq:
free_irq(rps->irq, rps);
err_iomap:
iounmap(base);
err_clk_prepare:
clk_disable_unprepare(rps->clk);
err_clk:
clk_put(rps->clk);
err_alloc:
kfree(rps);
return ret;
}
TIMER_OF_DECLARE(ox810se_rps,
"oxsemi,ox810se-rps-timer", oxnas_rps_timer_init);
TIMER_OF_DECLARE(ox820_rps,
"oxsemi,ox820-rps-timer", oxnas_rps_timer_init);
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