684f741446
The module is a bridge between the RTC clock domain and the CPU interface clock domain. ARM access the register of SYSRTC, GPSRTC and PWRC through this module. Signed-off-by: Zhiwu Song <zhiwu.song@csr.com> Signed-off-by: Barry Song <Baohua.Song@csr.com> Reviewed-by: Jamie Iles <jamie@jamieiles.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
140 lines
3.4 KiB
C
140 lines
3.4 KiB
C
/*
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* RTC I/O Bridge interfaces for CSR SiRFprimaII
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* ARM access the registers of SYSRTC, GPSRTC and PWRC through this module
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*
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* Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
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*
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* Licensed under GPLv2 or later.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_device.h>
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#include <linux/of_platform.h>
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#define SIRFSOC_CPUIOBRG_CTRL 0x00
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#define SIRFSOC_CPUIOBRG_WRBE 0x04
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#define SIRFSOC_CPUIOBRG_ADDR 0x08
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#define SIRFSOC_CPUIOBRG_DATA 0x0c
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/*
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* suspend asm codes will access this address to make system deepsleep
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* after DRAM becomes self-refresh
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*/
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void __iomem *sirfsoc_rtciobrg_base;
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static DEFINE_SPINLOCK(rtciobrg_lock);
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/*
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* symbols without lock are only used by suspend asm codes
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* and these symbols are not exported too
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*/
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void sirfsoc_rtc_iobrg_wait_sync(void)
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{
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while (readl_relaxed(sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_CTRL))
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cpu_relax();
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}
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void sirfsoc_rtc_iobrg_besyncing(void)
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{
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unsigned long flags;
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spin_lock_irqsave(&rtciobrg_lock, flags);
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sirfsoc_rtc_iobrg_wait_sync();
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spin_unlock_irqrestore(&rtciobrg_lock, flags);
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}
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EXPORT_SYMBOL_GPL(sirfsoc_rtc_iobrg_besyncing);
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u32 __sirfsoc_rtc_iobrg_readl(u32 addr)
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{
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sirfsoc_rtc_iobrg_wait_sync();
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writel_relaxed(0x00, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_WRBE);
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writel_relaxed(addr, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_ADDR);
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writel_relaxed(0x01, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_CTRL);
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sirfsoc_rtc_iobrg_wait_sync();
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return readl_relaxed(sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_DATA);
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}
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u32 sirfsoc_rtc_iobrg_readl(u32 addr)
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{
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unsigned long flags, val;
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spin_lock_irqsave(&rtciobrg_lock, flags);
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val = __sirfsoc_rtc_iobrg_readl(addr);
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spin_unlock_irqrestore(&rtciobrg_lock, flags);
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return val;
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}
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EXPORT_SYMBOL_GPL(sirfsoc_rtc_iobrg_readl);
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void sirfsoc_rtc_iobrg_pre_writel(u32 val, u32 addr)
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{
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sirfsoc_rtc_iobrg_wait_sync();
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writel_relaxed(0xf1, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_WRBE);
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writel_relaxed(addr, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_ADDR);
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writel_relaxed(val, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_DATA);
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}
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void sirfsoc_rtc_iobrg_writel(u32 val, u32 addr)
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{
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unsigned long flags;
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spin_lock_irqsave(&rtciobrg_lock, flags);
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sirfsoc_rtc_iobrg_pre_writel(val, addr);
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writel_relaxed(0x01, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_CTRL);
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sirfsoc_rtc_iobrg_wait_sync();
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spin_unlock_irqrestore(&rtciobrg_lock, flags);
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}
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EXPORT_SYMBOL_GPL(sirfsoc_rtc_iobrg_writel);
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static const struct of_device_id rtciobrg_ids[] = {
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{ .compatible = "sirf,prima2-rtciobg" },
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{}
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};
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static int __devinit sirfsoc_rtciobrg_probe(struct platform_device *op)
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{
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struct device_node *np = op->dev.of_node;
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sirfsoc_rtciobrg_base = of_iomap(np, 0);
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if (!sirfsoc_rtciobrg_base)
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panic("unable to map rtc iobrg registers\n");
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return 0;
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}
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static struct platform_driver sirfsoc_rtciobrg_driver = {
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.probe = sirfsoc_rtciobrg_probe,
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.driver = {
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.name = "sirfsoc-rtciobrg",
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.owner = THIS_MODULE,
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.of_match_table = rtciobrg_ids,
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},
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};
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static int __init sirfsoc_rtciobrg_init(void)
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{
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return platform_driver_register(&sirfsoc_rtciobrg_driver);
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}
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postcore_initcall(sirfsoc_rtciobrg_init);
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MODULE_AUTHOR("Zhiwu Song <zhiwu.song@csr.com>, "
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"Barry Song <baohua.song@csr.com>");
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MODULE_DESCRIPTION("CSR SiRFprimaII rtc io bridge");
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MODULE_LICENSE("GPL");
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