rtciobrg.c
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/*
* RTC I/O Bridge interfaces for CSR SiRFprimaII
* ARM access the registers of SYSRTC, GPSRTC and PWRC through this module
*
* Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
*
* Licensed under GPLv2 or later.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#define SIRFSOC_CPUIOBRG_CTRL 0x00
#define SIRFSOC_CPUIOBRG_WRBE 0x04
#define SIRFSOC_CPUIOBRG_ADDR 0x08
#define SIRFSOC_CPUIOBRG_DATA 0x0c
/*
* suspend asm codes will access this address to make system deepsleep
* after DRAM becomes self-refresh
*/
void __iomem *sirfsoc_rtciobrg_base;
static DEFINE_SPINLOCK(rtciobrg_lock);
/*
* symbols without lock are only used by suspend asm codes
* and these symbols are not exported too
*/
void sirfsoc_rtc_iobrg_wait_sync(void)
{
while (readl_relaxed(sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_CTRL))
cpu_relax();
}
void sirfsoc_rtc_iobrg_besyncing(void)
{
unsigned long flags;
spin_lock_irqsave(&rtciobrg_lock, flags);
sirfsoc_rtc_iobrg_wait_sync();
spin_unlock_irqrestore(&rtciobrg_lock, flags);
}
EXPORT_SYMBOL_GPL(sirfsoc_rtc_iobrg_besyncing);
u32 __sirfsoc_rtc_iobrg_readl(u32 addr)
{
sirfsoc_rtc_iobrg_wait_sync();
writel_relaxed(0x00, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_WRBE);
writel_relaxed(addr, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_ADDR);
writel_relaxed(0x01, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_CTRL);
sirfsoc_rtc_iobrg_wait_sync();
return readl_relaxed(sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_DATA);
}
u32 sirfsoc_rtc_iobrg_readl(u32 addr)
{
unsigned long flags, val;
spin_lock_irqsave(&rtciobrg_lock, flags);
val = __sirfsoc_rtc_iobrg_readl(addr);
spin_unlock_irqrestore(&rtciobrg_lock, flags);
return val;
}
EXPORT_SYMBOL_GPL(sirfsoc_rtc_iobrg_readl);
void sirfsoc_rtc_iobrg_pre_writel(u32 val, u32 addr)
{
sirfsoc_rtc_iobrg_wait_sync();
writel_relaxed(0xf1, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_WRBE);
writel_relaxed(addr, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_ADDR);
writel_relaxed(val, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_DATA);
}
void sirfsoc_rtc_iobrg_writel(u32 val, u32 addr)
{
unsigned long flags;
spin_lock_irqsave(&rtciobrg_lock, flags);
sirfsoc_rtc_iobrg_pre_writel(val, addr);
writel_relaxed(0x01, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_CTRL);
sirfsoc_rtc_iobrg_wait_sync();
spin_unlock_irqrestore(&rtciobrg_lock, flags);
}
EXPORT_SYMBOL_GPL(sirfsoc_rtc_iobrg_writel);
static const struct of_device_id rtciobrg_ids[] = {
{ .compatible = "sirf,prima2-rtciobg" },
{}
};
static int __devinit sirfsoc_rtciobrg_probe(struct platform_device *op)
{
struct device_node *np = op->dev.of_node;
sirfsoc_rtciobrg_base = of_iomap(np, 0);
if (!sirfsoc_rtciobrg_base)
panic("unable to map rtc iobrg registers\n");
return 0;
}
static struct platform_driver sirfsoc_rtciobrg_driver = {
.probe = sirfsoc_rtciobrg_probe,
.driver = {
.name = "sirfsoc-rtciobrg",
.owner = THIS_MODULE,
.of_match_table = rtciobrg_ids,
},
};
static int __init sirfsoc_rtciobrg_init(void)
{
return platform_driver_register(&sirfsoc_rtciobrg_driver);
}
postcore_initcall(sirfsoc_rtciobrg_init);
MODULE_AUTHOR("Zhiwu Song <zhiwu.song@csr.com>, "
"Barry Song <baohua.song@csr.com>");
MODULE_DESCRIPTION("CSR SiRFprimaII rtc io bridge");
MODULE_LICENSE("GPL");