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unicore32 core architecture: timer and time handling
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This patch implements timer and time.
RTC and PWM device drivers are also here.

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
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GuanXuetao committed Mar 17, 2011
1 parent 10c9c10 commit 02b2ee1
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34 changes: 34 additions & 0 deletions arch/unicore32/include/asm/timex.h
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/*
* linux/arch/unicore32/include/asm/timex.h
*
* Code specific to PKUnity SoC and UniCore ISA
*
* Copyright (C) 2001-2010 GUAN Xue-tao
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/

#ifndef __UNICORE_TIMEX_H__
#define __UNICORE_TIMEX_H__

#ifdef CONFIG_ARCH_FPGA

/* in FPGA, APB clock is 33M, and OST clock is 32K, */
/* so, 1M is selected for timer interrupt correctly */
#define CLOCK_TICK_RATE (32*1024)

#endif

#if defined(CONFIG_PUV3_DB0913) \
|| defined(CONFIG_PUV3_NB0916) \
|| defined(CONFIG_PUV3_SMW0919)

#define CLOCK_TICK_RATE (14318000)

#endif

#include <asm-generic/timex.h>

#endif
263 changes: 263 additions & 0 deletions arch/unicore32/kernel/pwm.c
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/*
* linux/arch/unicore32/kernel/pwm.c
*
* Code specific to PKUnity SoC and UniCore ISA
*
* Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
* Copyright (C) 2001-2010 Guan Xuetao
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/pwm.h>

#include <asm/div64.h>
#include <mach/hardware.h>

struct pwm_device {
struct list_head node;
struct platform_device *pdev;

const char *label;
struct clk *clk;
int clk_enabled;

unsigned int use_count;
unsigned int pwm_id;
};

/*
* period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
* duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
*/
int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
{
unsigned long long c;
unsigned long period_cycles, prescale, pv, dc;

if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
return -EINVAL;

c = clk_get_rate(pwm->clk);
c = c * period_ns;
do_div(c, 1000000000);
period_cycles = c;

if (period_cycles < 1)
period_cycles = 1;
prescale = (period_cycles - 1) / 1024;
pv = period_cycles / (prescale + 1) - 1;

if (prescale > 63)
return -EINVAL;

if (duty_ns == period_ns)
dc = OST_PWMDCCR_FDCYCLE;
else
dc = (pv + 1) * duty_ns / period_ns;

/* NOTE: the clock to PWM has to be enabled first
* before writing to the registers
*/
clk_enable(pwm->clk);
OST_PWMPWCR = prescale;
OST_PWMDCCR = pv - dc;
OST_PWMPCR = pv;
clk_disable(pwm->clk);

return 0;
}
EXPORT_SYMBOL(pwm_config);

int pwm_enable(struct pwm_device *pwm)
{
int rc = 0;

if (!pwm->clk_enabled) {
rc = clk_enable(pwm->clk);
if (!rc)
pwm->clk_enabled = 1;
}
return rc;
}
EXPORT_SYMBOL(pwm_enable);

void pwm_disable(struct pwm_device *pwm)
{
if (pwm->clk_enabled) {
clk_disable(pwm->clk);
pwm->clk_enabled = 0;
}
}
EXPORT_SYMBOL(pwm_disable);

static DEFINE_MUTEX(pwm_lock);
static LIST_HEAD(pwm_list);

struct pwm_device *pwm_request(int pwm_id, const char *label)
{
struct pwm_device *pwm;
int found = 0;

mutex_lock(&pwm_lock);

list_for_each_entry(pwm, &pwm_list, node) {
if (pwm->pwm_id == pwm_id) {
found = 1;
break;
}
}

if (found) {
if (pwm->use_count == 0) {
pwm->use_count++;
pwm->label = label;
} else
pwm = ERR_PTR(-EBUSY);
} else
pwm = ERR_PTR(-ENOENT);

mutex_unlock(&pwm_lock);
return pwm;
}
EXPORT_SYMBOL(pwm_request);

void pwm_free(struct pwm_device *pwm)
{
mutex_lock(&pwm_lock);

if (pwm->use_count) {
pwm->use_count--;
pwm->label = NULL;
} else
pr_warning("PWM device already freed\n");

mutex_unlock(&pwm_lock);
}
EXPORT_SYMBOL(pwm_free);

static inline void __add_pwm(struct pwm_device *pwm)
{
mutex_lock(&pwm_lock);
list_add_tail(&pwm->node, &pwm_list);
mutex_unlock(&pwm_lock);
}

static struct pwm_device *pwm_probe(struct platform_device *pdev,
unsigned int pwm_id, struct pwm_device *parent_pwm)
{
struct pwm_device *pwm;
struct resource *r;
int ret = 0;

pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
if (pwm == NULL) {
dev_err(&pdev->dev, "failed to allocate memory\n");
return ERR_PTR(-ENOMEM);
}

pwm->clk = clk_get(NULL, "OST_CLK");
if (IS_ERR(pwm->clk)) {
ret = PTR_ERR(pwm->clk);
goto err_free;
}
pwm->clk_enabled = 0;

pwm->use_count = 0;
pwm->pwm_id = pwm_id;
pwm->pdev = pdev;

r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (r == NULL) {
dev_err(&pdev->dev, "no memory resource defined\n");
ret = -ENODEV;
goto err_free_clk;
}

r = request_mem_region(r->start, resource_size(r), pdev->name);
if (r == NULL) {
dev_err(&pdev->dev, "failed to request memory resource\n");
ret = -EBUSY;
goto err_free_clk;
}

__add_pwm(pwm);
platform_set_drvdata(pdev, pwm);
return pwm;

err_free_clk:
clk_put(pwm->clk);
err_free:
kfree(pwm);
return ERR_PTR(ret);
}

static int __devinit puv3_pwm_probe(struct platform_device *pdev)
{
struct pwm_device *pwm = pwm_probe(pdev, pdev->id, NULL);

if (IS_ERR(pwm))
return PTR_ERR(pwm);

return 0;
}

static int __devexit pwm_remove(struct platform_device *pdev)
{
struct pwm_device *pwm;
struct resource *r;

pwm = platform_get_drvdata(pdev);
if (pwm == NULL)
return -ENODEV;

mutex_lock(&pwm_lock);
list_del(&pwm->node);
mutex_unlock(&pwm_lock);

r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
release_mem_region(r->start, resource_size(r));

clk_put(pwm->clk);
kfree(pwm);
return 0;
}

static struct platform_driver puv3_pwm_driver = {
.driver = {
.name = "PKUnity-v3-PWM",
},
.probe = puv3_pwm_probe,
.remove = __devexit_p(pwm_remove),
};

static int __init pwm_init(void)
{
int ret = 0;

ret = platform_driver_register(&puv3_pwm_driver);
if (ret) {
printk(KERN_ERR "failed to register puv3_pwm_driver\n");
return ret;
}

return ret;
}
arch_initcall(pwm_init);

static void __exit pwm_exit(void)
{
platform_driver_unregister(&puv3_pwm_driver);
}
module_exit(pwm_exit);

MODULE_LICENSE("GPL v2");
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