android_kernel_xiaomi_sm8350/drivers/rtc/rtc-pl031.c

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/*
* drivers/rtc/rtc-pl031.c
*
* Real Time Clock interface for ARM AMBA PrimeCell 031 RTC
*
* Author: Deepak Saxena <dsaxena@plexity.net>
*
* Copyright 2006 (c) MontaVista Software, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/string.h>
#include <linux/pm.h>
#include <linux/bitops.h>
#include <linux/amba/bus.h>
#include <asm/io.h>
#include <asm/hardware.h>
#include <asm/irq.h>
#include <asm/rtc.h>
/*
* Register definitions
*/
#define RTC_DR 0x00 /* Data read register */
#define RTC_MR 0x04 /* Match register */
#define RTC_LR 0x08 /* Data load register */
#define RTC_CR 0x0c /* Control register */
#define RTC_IMSC 0x10 /* Interrupt mask and set register */
#define RTC_RIS 0x14 /* Raw interrupt status register */
#define RTC_MIS 0x18 /* Masked interrupt status register */
#define RTC_ICR 0x1c /* Interrupt clear register */
struct pl031_local {
struct rtc_device *rtc;
void __iomem *base;
};
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 09:55:46 -04:00
static irqreturn_t pl031_interrupt(int irq, void *dev_id)
{
struct rtc_device *rtc = dev_id;
rtc_update_irq(rtc, 1, RTC_AF);
return IRQ_HANDLED;
}
static int pl031_open(struct device *dev)
{
/*
* We request IRQ in pl031_probe, so nothing to do here...
*/
return 0;
}
static void pl031_release(struct device *dev)
{
}
static int pl031_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
struct pl031_local *ldata = dev_get_drvdata(dev);
switch (cmd) {
case RTC_AIE_OFF:
__raw_writel(1, ldata->base + RTC_MIS);
return 0;
case RTC_AIE_ON:
__raw_writel(0, ldata->base + RTC_MIS);
return 0;
}
return -ENOIOCTLCMD;
}
static int pl031_read_time(struct device *dev, struct rtc_time *tm)
{
struct pl031_local *ldata = dev_get_drvdata(dev);
rtc_time_to_tm(__raw_readl(ldata->base + RTC_DR), tm);
return 0;
}
static int pl031_set_time(struct device *dev, struct rtc_time *tm)
{
unsigned long time;
struct pl031_local *ldata = dev_get_drvdata(dev);
rtc_tm_to_time(tm, &time);
__raw_writel(time, ldata->base + RTC_LR);
return 0;
}
static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct pl031_local *ldata = dev_get_drvdata(dev);
rtc_time_to_tm(__raw_readl(ldata->base + RTC_MR), &alarm->time);
alarm->pending = __raw_readl(ldata->base + RTC_RIS);
alarm->enabled = __raw_readl(ldata->base + RTC_IMSC);
return 0;
}
static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct pl031_local *ldata = dev_get_drvdata(dev);
unsigned long time;
rtc_tm_to_time(&alarm->time, &time);
__raw_writel(time, ldata->base + RTC_MR);
__raw_writel(!alarm->enabled, ldata->base + RTC_MIS);
return 0;
}
static const struct rtc_class_ops pl031_ops = {
.open = pl031_open,
.release = pl031_release,
.ioctl = pl031_ioctl,
.read_time = pl031_read_time,
.set_time = pl031_set_time,
.read_alarm = pl031_read_alarm,
.set_alarm = pl031_set_alarm,
};
static int pl031_remove(struct amba_device *adev)
{
struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
if (ldata) {
dev_set_drvdata(&adev->dev, NULL);
free_irq(adev->irq[0], ldata->rtc);
rtc_device_unregister(ldata->rtc);
iounmap(ldata->base);
kfree(ldata);
}
return 0;
}
static int pl031_probe(struct amba_device *adev, void *id)
{
int ret;
struct pl031_local *ldata;
ldata = kmalloc(sizeof(struct pl031_local), GFP_KERNEL);
if (!ldata) {
ret = -ENOMEM;
goto out;
}
dev_set_drvdata(&adev->dev, ldata);
ldata->base = ioremap(adev->res.start,
adev->res.end - adev->res.start + 1);
if (!ldata->base) {
ret = -ENOMEM;
goto out_no_remap;
}
if (request_irq(adev->irq[0], pl031_interrupt, IRQF_DISABLED,
"rtc-pl031", ldata->rtc)) {
ret = -EIO;
goto out_no_irq;
}
ldata->rtc = rtc_device_register("pl031", &adev->dev, &pl031_ops,
THIS_MODULE);
if (IS_ERR(ldata->rtc)) {
ret = PTR_ERR(ldata->rtc);
goto out_no_rtc;
}
return 0;
out_no_rtc:
free_irq(adev->irq[0], ldata->rtc);
out_no_irq:
iounmap(ldata->base);
out_no_remap:
dev_set_drvdata(&adev->dev, NULL);
kfree(ldata);
out:
return ret;
}
static struct amba_id pl031_ids[] __initdata = {
{
.id = 0x00041031,
.mask = 0x000fffff, },
{0, 0},
};
static struct amba_driver pl031_driver = {
.drv = {
.name = "rtc-pl031",
},
.id_table = pl031_ids,
.probe = pl031_probe,
.remove = pl031_remove,
};
static int __init pl031_init(void)
{
return amba_driver_register(&pl031_driver);
}
static void __exit pl031_exit(void)
{
amba_driver_unregister(&pl031_driver);
}
module_init(pl031_init);
module_exit(pl031_exit);
MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net");
MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
MODULE_LICENSE("GPL");