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 #define RNG_CTRL                        0x00
  17 #define RNG_EN                          (1 << 0)
  18
  19 #define RNG_STAT                        0x04
  20 #define RNG_AVAIL_MASK                  (0xff000000)
  21
  22 #define RNG_DATA                        0x08
  23 #define RNG_THRES                       0x0c
  24 #define RNG_MASK                        0x10
  25
  26 struct bcm63xx_rng_priv {
  27         struct clk *clk;
  28         void __iomem *regs;
  29 };
  30
  31 #define to_rng_priv(rng)        ((struct bcm63xx_rng_priv *)rng->priv)
  32
  33 static int bcm63xx_rng_init(struct hwrng *rng)
  34 {
  35         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
  36         u32 val;
  37
  38         val = __raw_readl(priv->regs + RNG_CTRL);
  39         val |= RNG_EN;
  40         __raw_writel(val, priv->regs + RNG_CTRL);
  41
  42         return 0;
  43 }
  44
  45 static void bcm63xx_rng_cleanup(struct hwrng *rng)
  46 {
  47         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
  48         u32 val;
  49
  50         val = __raw_readl(priv->regs + RNG_CTRL);
  51         val &= ~RNG_EN;
  52         __raw_writel(val, priv->regs + RNG_CTRL);
  53 }
  54
  55 static int bcm63xx_rng_data_present(struct hwrng *rng, int wait)
  56 {
  57         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
  58
  59         return __raw_readl(priv->regs + RNG_STAT) & RNG_AVAIL_MASK;
  60 }
  61
  62 static int bcm63xx_rng_data_read(struct hwrng *rng, u32 *data)
  63 {
  64         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
  65
  66         *data = __raw_readl(priv->regs + RNG_DATA);
  67
  68         return 4;
  69 }
  70
  71 static int bcm63xx_rng_probe(struct platform_device *pdev)
  72 {
  73         struct resource *r;
  74         struct clk *clk;
  75         int ret;
  76         struct bcm63xx_rng_priv *priv;
  77         struct hwrng *rng;
  78
  79         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  80         if (!r) {
  81                 dev_err(&pdev->dev, "no iomem resource\n");
  82                 ret = -ENXIO;
  83                 goto out;
  84         }
  85
  86         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
  87         if (!priv) {
  88                 dev_err(&pdev->dev, "no memory for private structure\n");
  89                 ret = -ENOMEM;
  90                 goto out;
  91         }
  92
  93         rng = kzalloc(sizeof(*rng), GFP_KERNEL);
  94         if (!rng) {
  95                 dev_err(&pdev->dev, "no memory for rng structure\n");
  96                 ret = -ENOMEM;
  97                 goto out_free_priv;
  98         }
  99
 100         platform_set_drvdata(pdev, rng);
 101         rng->priv = (unsigned long)priv;
 102         rng->name = pdev->name;
 103         rng->init = bcm63xx_rng_init;
 104         rng->cleanup = bcm63xx_rng_cleanup;
 105         rng->data_present = bcm63xx_rng_data_present;
 106         rng->data_read = bcm63xx_rng_data_read;
 107
 108         clk = clk_get(&pdev->dev, "ipsec");
 109         if (IS_ERR(clk)) {
 110                 dev_err(&pdev->dev, "no clock for device\n");
 111                 ret = PTR_ERR(clk);
 112                 goto out_free_rng;
 113         }
 114
 115         priv->clk = clk;
 116
 117         if (!devm_request_mem_region(&pdev->dev, r->start,
 118                                         resource_size(r), pdev->name)) {
 119                 dev_err(&pdev->dev, "request mem failed");
 120                 ret = -ENOMEM;
 121                 goto out_free_rng;
 122         }
 123
 124         priv->regs = devm_ioremap_nocache(&pdev->dev, r->start,
 125                                         resource_size(r));
 126         if (!priv->regs) {
 127                 dev_err(&pdev->dev, "ioremap failed");
 128                 ret = -ENOMEM;
 129                 goto out_free_rng;
 130         }
 131
 132         clk_enable(clk);
 133
 134         ret = hwrng_register(rng);
 135         if (ret) {
 136                 dev_err(&pdev->dev, "failed to register rng device\n");
 137                 goto out_clk_disable;
 138         }
 139
 140         dev_info(&pdev->dev, "registered RNG driver\n");
 141
 142         return 0;
 143
 144 out_clk_disable:
 145         clk_disable(clk);
 146 out_free_rng:
 147         kfree(rng);
 148 out_free_priv:
 149         kfree(priv);
 150 out:
 151         return ret;
 152 }
 153
 154 static int bcm63xx_rng_remove(struct platform_device *pdev)
 155 {
 156         struct hwrng *rng = platform_get_drvdata(pdev);
 157         struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
 158
 159         hwrng_unregister(rng);
 160         clk_disable(priv->clk);
 161         kfree(priv);
 162         kfree(rng);
 163
 164         return 0;
 165 }
 166
 167 static struct platform_driver bcm63xx_rng_driver = {
 168         .probe          = bcm63xx_rng_probe,
 169         .remove         = bcm63xx_rng_remove,
 170         .driver         = {
 171                 .name   = "bcm63xx-rng",
 172         },
 173 };
 174
 175 module_platform_driver(bcm63xx_rng_driver);
 176
 177 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 178 MODULE_DESCRIPTION("Broadcom BCM63xx RNG driver");
 179 MODULE_LICENSE("GPL");