arch/arm/mach-prima2/rtciobrg.c

   1 /*
   2  * RTC I/O Bridge interfaces for CSR SiRFprimaII
   3  * ARM access the registers of SYSRTC, GPSRTC and PWRC through this module
   4  *
   5  * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
   6  *
   7  * Licensed under GPLv2 or later.
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/io.h>
  13 #include <linux/of.h>
  14 #include <linux/of_address.h>
  15 #include <linux/of_device.h>
  16 #include <linux/of_platform.h>
  17
  18 #define SIRFSOC_CPUIOBRG_CTRL           0x00
  19 #define SIRFSOC_CPUIOBRG_WRBE           0x04
  20 #define SIRFSOC_CPUIOBRG_ADDR           0x08
  21 #define SIRFSOC_CPUIOBRG_DATA           0x0c
  22
  23 /*
  24  * suspend asm codes will access this address to make system deepsleep
  25  * after DRAM becomes self-refresh
  26  */
  27 void __iomem *sirfsoc_rtciobrg_base;
  28 static DEFINE_SPINLOCK(rtciobrg_lock);
  29
  30 /*
  31  * symbols without lock are only used by suspend asm codes
  32  * and these symbols are not exported too
  33  */
  34 void sirfsoc_rtc_iobrg_wait_sync(void)
  35 {
  36         while (readl_relaxed(sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_CTRL))
  37                 cpu_relax();
  38 }
  39
  40 void sirfsoc_rtc_iobrg_besyncing(void)
  41 {
  42         unsigned long flags;
  43
  44         spin_lock_irqsave(&rtciobrg_lock, flags);
  45
  46         sirfsoc_rtc_iobrg_wait_sync();
  47
  48         spin_unlock_irqrestore(&rtciobrg_lock, flags);
  49 }
  50 EXPORT_SYMBOL_GPL(sirfsoc_rtc_iobrg_besyncing);
  51
  52 u32 __sirfsoc_rtc_iobrg_readl(u32 addr)
  53 {
  54         sirfsoc_rtc_iobrg_wait_sync();
  55
  56         writel_relaxed(0x00, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_WRBE);
  57         writel_relaxed(addr, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_ADDR);
  58         writel_relaxed(0x01, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_CTRL);
  59
  60         sirfsoc_rtc_iobrg_wait_sync();
  61
  62         return readl_relaxed(sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_DATA);
  63 }
  64
  65 u32 sirfsoc_rtc_iobrg_readl(u32 addr)
  66 {
  67         unsigned long flags, val;
  68
  69         spin_lock_irqsave(&rtciobrg_lock, flags);
  70
  71         val = __sirfsoc_rtc_iobrg_readl(addr);
  72
  73         spin_unlock_irqrestore(&rtciobrg_lock, flags);
  74
  75         return val;
  76 }
  77 EXPORT_SYMBOL_GPL(sirfsoc_rtc_iobrg_readl);
  78
  79 void sirfsoc_rtc_iobrg_pre_writel(u32 val, u32 addr)
  80 {
  81         sirfsoc_rtc_iobrg_wait_sync();
  82
  83         writel_relaxed(0xf1, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_WRBE);
  84         writel_relaxed(addr, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_ADDR);
  85
  86         writel_relaxed(val, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_DATA);
  87 }
  88
  89 void sirfsoc_rtc_iobrg_writel(u32 val, u32 addr)
  90 {
  91         unsigned long flags;
  92
  93         spin_lock_irqsave(&rtciobrg_lock, flags);
  94
  95         sirfsoc_rtc_iobrg_pre_writel(val, addr);
  96
  97         writel_relaxed(0x01, sirfsoc_rtciobrg_base + SIRFSOC_CPUIOBRG_CTRL);
  98
  99         sirfsoc_rtc_iobrg_wait_sync();
 100
 101         spin_unlock_irqrestore(&rtciobrg_lock, flags);
 102 }
 103 EXPORT_SYMBOL_GPL(sirfsoc_rtc_iobrg_writel);
 104
 105 static const struct of_device_id rtciobrg_ids[] = {
 106         { .compatible = "sirf,prima2-rtciobg" },
 107         {}
 108 };
 109
 110 static int sirfsoc_rtciobrg_probe(struct platform_device *op)
 111 {
 112         struct device_node *np = op->dev.of_node;
 113
 114         sirfsoc_rtciobrg_base = of_iomap(np, 0);
 115         if (!sirfsoc_rtciobrg_base)
 116                 panic("unable to map rtc iobrg registers\n");
 117
 118         return 0;
 119 }
 120
 121 static struct platform_driver sirfsoc_rtciobrg_driver = {
 122         .probe          = sirfsoc_rtciobrg_probe,
 123         .driver = {
 124                 .name = "sirfsoc-rtciobrg",
 125                 .of_match_table = rtciobrg_ids,
 126         },
 127 };
 128
 129 static int __init sirfsoc_rtciobrg_init(void)
 130 {
 131         return platform_driver_register(&sirfsoc_rtciobrg_driver);
 132 }
 133 postcore_initcall(sirfsoc_rtciobrg_init);
 134
 135 MODULE_AUTHOR("Zhiwu Song <zhiwu.song@csr.com>, "
 136                 "Barry Song <baohua.song@csr.com>");
 137 MODULE_DESCRIPTION("CSR SiRFprimaII rtc io bridge");
 138 MODULE_LICENSE("GPL v2");