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_io.h>
  17 #include <bcm63xx_regs.h>
  18
  19 struct bcm63xx_rng_priv {
  20         struct clk *clk;
  21         void __iomem *regs;
  22 };
  23
  24 #define to_rng_priv(rng)        ((struct bcm63xx_rng_priv *)rng->priv)
  25
  26 static int bcm63xx_rng_init(struct hwrng *rng)
  27 {
  28         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
  29         u32 val;
  30
  31         val = bcm_readl(priv->regs + RNG_CTRL);
  32         val |= RNG_EN;
  33         bcm_writel(val, priv->regs + RNG_CTRL);
  34
  35         return 0;
  36 }
  37
  38 static void bcm63xx_rng_cleanup(struct hwrng *rng)
  39 {
  40         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
  41         u32 val;
  42
  43         val = bcm_readl(priv->regs + RNG_CTRL);
  44         val &= ~RNG_EN;
  45         bcm_writel(val, priv->regs + RNG_CTRL);
  46 }
  47
  48 static int bcm63xx_rng_data_present(struct hwrng *rng, int wait)
  49 {
  50         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
  51
  52         return bcm_readl(priv->regs + RNG_STAT) & RNG_AVAIL_MASK;
  53 }
  54
  55 static int bcm63xx_rng_data_read(struct hwrng *rng, u32 *data)
  56 {
  57         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
  58
  59         *data = bcm_readl(priv->regs + RNG_DATA);
  60
  61         return 4;
  62 }
  63
  64 static int bcm63xx_rng_probe(struct platform_device *pdev)
  65 {
  66         struct resource *r;
  67         struct clk *clk;
  68         int ret;
  69         struct bcm63xx_rng_priv *priv;
  70         struct hwrng *rng;
  71
  72         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  73         if (!r) {
  74                 dev_err(&pdev->dev, "no iomem resource\n");
  75                 ret = -ENXIO;
  76                 goto out;
  77         }
  78
  79         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
  80         if (!priv) {
  81                 dev_err(&pdev->dev, "no memory for private structure\n");
  82                 ret = -ENOMEM;
  83                 goto out;
  84         }
  85
  86         rng = kzalloc(sizeof(*rng), GFP_KERNEL);
  87         if (!rng) {
  88                 dev_err(&pdev->dev, "no memory for rng structure\n");
  89                 ret = -ENOMEM;
  90                 goto out_free_priv;
  91         }
  92
  93         platform_set_drvdata(pdev, rng);
  94         rng->priv = (unsigned long)priv;
  95         rng->name = pdev->name;
  96         rng->init = bcm63xx_rng_init;
  97         rng->cleanup = bcm63xx_rng_cleanup;
  98         rng->data_present = bcm63xx_rng_data_present;
  99         rng->data_read = bcm63xx_rng_data_read;
 100
 101         clk = clk_get(&pdev->dev, "ipsec");
 102         if (IS_ERR(clk)) {
 103                 dev_err(&pdev->dev, "no clock for device\n");
 104                 ret = PTR_ERR(clk);
 105                 goto out_free_rng;
 106         }
 107
 108         priv->clk = clk;
 109
 110         if (!devm_request_mem_region(&pdev->dev, r->start,
 111                                         resource_size(r), pdev->name)) {
 112                 dev_err(&pdev->dev, "request mem failed");
 113                 ret = -ENOMEM;
 114                 goto out_free_rng;
 115         }
 116
 117         priv->regs = devm_ioremap_nocache(&pdev->dev, r->start,
 118                                         resource_size(r));
 119         if (!priv->regs) {
 120                 dev_err(&pdev->dev, "ioremap failed");
 121                 ret = -ENOMEM;
 122                 goto out_free_rng;
 123         }
 124
 125         clk_enable(clk);
 126
 127         ret = hwrng_register(rng);
 128         if (ret) {
 129                 dev_err(&pdev->dev, "failed to register rng device\n");
 130                 goto out_clk_disable;
 131         }
 132
 133         dev_info(&pdev->dev, "registered RNG driver\n");
 134
 135         return 0;
 136
 137 out_clk_disable:
 138         clk_disable(clk);
 139 out_free_rng:
 140         platform_set_drvdata(pdev, NULL);
 141         kfree(rng);
 142 out_free_priv:
 143         kfree(priv);
 144 out:
 145         return ret;
 146 }
 147
 148 static int bcm63xx_rng_remove(struct platform_device *pdev)
 149 {
 150         struct hwrng *rng = platform_get_drvdata(pdev);
 151         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
 152
 153         hwrng_unregister(rng);
 154         clk_disable(priv->clk);
 155         kfree(priv);
 156         kfree(rng);
 157         platform_set_drvdata(pdev, NULL);
 158
 159         return 0;
 160 }
 161
 162 static struct platform_driver bcm63xx_rng_driver = {
 163         .probe          = bcm63xx_rng_probe,
 164         .remove         = bcm63xx_rng_remove,
 165         .driver         = {
 166                 .name   = "bcm63xx-rng",
 167                 .owner  = THIS_MODULE,
 168         },
 169 };
 170
 171 module_platform_driver(bcm63xx_rng_driver);
 172
 173 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 174 MODULE_DESCRIPTION("Broadcom BCM63xx RNG driver");
 175 MODULE_LICENSE("GPL");