drivers/char/hw_random/bcm63xx-rng.c

   1 /*
   2  * Broadcom BCM63xx Random Number Generator support
   3  *
   4  * Copyright (C) 2011, Florian Fainelli <florian@openwrt.org>
   5  * Copyright (C) 2009, Broadcom Corporation
   6  *
   7  */
   8 #include <linux/module.h>
   9 #include <linux/slab.h>
  10 #include <linux/io.h>
  11 #include <linux/err.h>
  12 #include <linux/clk.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/hw_random.h>
  15
  16 #include <bcm63xx_regs.h>
  17
  18 struct bcm63xx_rng_priv {
  19         struct clk *clk;
  20         void __iomem *regs;
  21 };
  22
  23 #define to_rng_priv(rng)        ((struct bcm63xx_rng_priv *)rng->priv)
  24
  25 static int bcm63xx_rng_init(struct hwrng *rng)
  26 {
  27         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
  28         u32 val;
  29
  30         val = __raw_readl(priv->regs + RNG_CTRL);
  31         val |= RNG_EN;
  32         __raw_writel(val, priv->regs + RNG_CTRL);
  33
  34         return 0;
  35 }
  36
  37 static void bcm63xx_rng_cleanup(struct hwrng *rng)
  38 {
  39         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
  40         u32 val;
  41
  42         val = __raw_readl(priv->regs + RNG_CTRL);
  43         val &= ~RNG_EN;
  44         __raw_writel(val, priv->regs + RNG_CTRL);
  45 }
  46
  47 static int bcm63xx_rng_data_present(struct hwrng *rng, int wait)
  48 {
  49         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
  50
  51         return __raw_readl(priv->regs + RNG_STAT) & RNG_AVAIL_MASK;
  52 }
  53
  54 static int bcm63xx_rng_data_read(struct hwrng *rng, u32 *data)
  55 {
  56         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
  57
  58         *data = __raw_readl(priv->regs + RNG_DATA);
  59
  60         return 4;
  61 }
  62
  63 static int bcm63xx_rng_probe(struct platform_device *pdev)
  64 {
  65         struct resource *r;
  66         struct clk *clk;
  67         int ret;
  68         struct bcm63xx_rng_priv *priv;
  69         struct hwrng *rng;
  70
  71         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  72         if (!r) {
  73                 dev_err(&pdev->dev, "no iomem resource\n");
  74                 ret = -ENXIO;
  75                 goto out;
  76         }
  77
  78         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
  79         if (!priv) {
  80                 dev_err(&pdev->dev, "no memory for private structure\n");
  81                 ret = -ENOMEM;
  82                 goto out;
  83         }
  84
  85         rng = kzalloc(sizeof(*rng), GFP_KERNEL);
  86         if (!rng) {
  87                 dev_err(&pdev->dev, "no memory for rng structure\n");
  88                 ret = -ENOMEM;
  89                 goto out_free_priv;
  90         }
  91
  92         platform_set_drvdata(pdev, rng);
  93         rng->priv = (unsigned long)priv;
  94         rng->name = pdev->name;
  95         rng->init = bcm63xx_rng_init;
  96         rng->cleanup = bcm63xx_rng_cleanup;
  97         rng->data_present = bcm63xx_rng_data_present;
  98         rng->data_read = bcm63xx_rng_data_read;
  99
 100         clk = clk_get(&pdev->dev, "ipsec");
 101         if (IS_ERR(clk)) {
 102                 dev_err(&pdev->dev, "no clock for device\n");
 103                 ret = PTR_ERR(clk);
 104                 goto out_free_rng;
 105         }
 106
 107         priv->clk = clk;
 108
 109         if (!devm_request_mem_region(&pdev->dev, r->start,
 110                                         resource_size(r), pdev->name)) {
 111                 dev_err(&pdev->dev, "request mem failed");
 112                 ret = -ENOMEM;
 113                 goto out_free_rng;
 114         }
 115
 116         priv->regs = devm_ioremap_nocache(&pdev->dev, r->start,
 117                                         resource_size(r));
 118         if (!priv->regs) {
 119                 dev_err(&pdev->dev, "ioremap failed");
 120                 ret = -ENOMEM;
 121                 goto out_free_rng;
 122         }
 123
 124         clk_enable(clk);
 125
 126         ret = hwrng_register(rng);
 127         if (ret) {
 128                 dev_err(&pdev->dev, "failed to register rng device\n");
 129                 goto out_clk_disable;
 130         }
 131
 132         dev_info(&pdev->dev, "registered RNG driver\n");
 133
 134         return 0;
 135
 136 out_clk_disable:
 137         clk_disable(clk);
 138 out_free_rng:
 139         kfree(rng);
 140 out_free_priv:
 141         kfree(priv);
 142 out:
 143         return ret;
 144 }
 145
 146 static int bcm63xx_rng_remove(struct platform_device *pdev)
 147 {
 148         struct hwrng *rng = platform_get_drvdata(pdev);
 149         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
 150
 151         hwrng_unregister(rng);
 152         clk_disable(priv->clk);
 153         kfree(priv);
 154         kfree(rng);
 155
 156         return 0;
 157 }
 158
 159 static struct platform_driver bcm63xx_rng_driver = {
 160         .probe          = bcm63xx_rng_probe,
 161         .remove         = bcm63xx_rng_remove,
 162         .driver         = {
 163                 .name   = "bcm63xx-rng",
 164         },
 165 };
 166
 167 module_platform_driver(bcm63xx_rng_driver);
 168
 169 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 170 MODULE_DESCRIPTION("Broadcom BCM63xx RNG driver");
 171 MODULE_LICENSE("GPL");