diff options
Diffstat (limited to 'drivers/char/hw_random/bcm2835-rng.c')
| -rw-r--r-- | drivers/char/hw_random/bcm2835-rng.c | 199 |
1 files changed, 148 insertions, 51 deletions
diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c index 43577ca780e3..6d6ac409efcf 100644 --- a/drivers/char/hw_random/bcm2835-rng.c +++ b/drivers/char/hw_random/bcm2835-rng.c @@ -1,25 +1,23 @@ -/** +// SPDX-License-Identifier: GPL-2.0 +/* * Copyright (c) 2010-2012 Broadcom. All rights reserved. * Copyright (c) 2013 Lubomir Rintel - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License ("GPL") - * version 2, as published by the Free Software Foundation. */ #include <linux/hw_random.h> -#include <linux/init.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/module.h> -#include <linux/of_address.h> -#include <linux/of_platform.h> +#include <linux/of.h> #include <linux/platform_device.h> #include <linux/printk.h> +#include <linux/clk.h> +#include <linux/reset.h> #define RNG_CTRL 0x0 #define RNG_STATUS 0x4 #define RNG_DATA 0x8 +#define RNG_INT_MASK 0x10 /* enable rng */ #define RNG_RBGEN 0x1 @@ -27,84 +25,183 @@ /* the initial numbers generated are "less random" so will be discarded */ #define RNG_WARMUP_COUNT 0x40000 +#define RNG_INT_OFF 0x1 + +struct bcm2835_rng_priv { + struct hwrng rng; + void __iomem *base; + bool mask_interrupts; + struct clk *clk; + struct reset_control *reset; +}; + +static inline struct bcm2835_rng_priv *to_rng_priv(struct hwrng *rng) +{ + return container_of(rng, struct bcm2835_rng_priv, rng); +} + +static inline u32 rng_readl(struct bcm2835_rng_priv *priv, u32 offset) +{ + /* MIPS chips strapped for BE will automagically configure the + * peripheral registers for CPU-native byte order. + */ + if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) + return __raw_readl(priv->base + offset); + else + return readl(priv->base + offset); +} + +static inline void rng_writel(struct bcm2835_rng_priv *priv, u32 val, + u32 offset) +{ + if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) + __raw_writel(val, priv->base + offset); + else + writel(val, priv->base + offset); +} + static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) { - void __iomem *rng_base = (void __iomem *)rng->priv; + struct bcm2835_rng_priv *priv = to_rng_priv(rng); + u32 max_words = max / sizeof(u32); + u32 num_words, count; - while ((__raw_readl(rng_base + RNG_STATUS) >> 24) == 0) { + while ((rng_readl(priv, RNG_STATUS) >> 24) == 0) { if (!wait) return 0; - cpu_relax(); + hwrng_yield(rng); } - *(u32 *)buf = __raw_readl(rng_base + RNG_DATA); - return sizeof(u32); + num_words = rng_readl(priv, RNG_STATUS) >> 24; + if (num_words > max_words) + num_words = max_words; + + for (count = 0; count < num_words; count++) + ((u32 *)buf)[count] = rng_readl(priv, RNG_DATA); + + return num_words * sizeof(u32); +} + +static int bcm2835_rng_init(struct hwrng *rng) +{ + struct bcm2835_rng_priv *priv = to_rng_priv(rng); + int ret = 0; + u32 val; + + ret = clk_prepare_enable(priv->clk); + if (ret) + return ret; + + ret = reset_control_reset(priv->reset); + if (ret) { + clk_disable_unprepare(priv->clk); + return ret; + } + + if (priv->mask_interrupts) { + /* mask the interrupt */ + val = rng_readl(priv, RNG_INT_MASK); + val |= RNG_INT_OFF; + rng_writel(priv, val, RNG_INT_MASK); + } + + /* set warm-up count & enable */ + rng_writel(priv, RNG_WARMUP_COUNT, RNG_STATUS); + rng_writel(priv, RNG_RBGEN, RNG_CTRL); + + return ret; } -static struct hwrng bcm2835_rng_ops = { - .name = "bcm2835", - .read = bcm2835_rng_read, +static void bcm2835_rng_cleanup(struct hwrng *rng) +{ + struct bcm2835_rng_priv *priv = to_rng_priv(rng); + + /* disable rng hardware */ + rng_writel(priv, 0, RNG_CTRL); + + clk_disable_unprepare(priv->clk); +} + +struct bcm2835_rng_of_data { + bool mask_interrupts; +}; + +static const struct bcm2835_rng_of_data nsp_rng_of_data = { + .mask_interrupts = true, }; +static const struct of_device_id bcm2835_rng_of_match[] = { + { .compatible = "brcm,bcm2835-rng"}, + { .compatible = "brcm,bcm-nsp-rng", .data = &nsp_rng_of_data }, + { .compatible = "brcm,bcm5301x-rng", .data = &nsp_rng_of_data }, + { .compatible = "brcm,bcm6368-rng"}, + {}, +}; +MODULE_DEVICE_TABLE(of, bcm2835_rng_of_match); + static int bcm2835_rng_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; - struct device_node *np = dev->of_node; - void __iomem *rng_base; + struct bcm2835_rng_priv *priv; int err; + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + /* map peripheral */ - rng_base = of_iomap(np, 0); - if (!rng_base) { - dev_err(dev, "failed to remap rng regs"); - return -ENODEV; + priv->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + /* Clock is optional on most platforms */ + priv->clk = devm_clk_get_optional(dev, NULL); + if (IS_ERR(priv->clk)) + return PTR_ERR(priv->clk); + + priv->reset = devm_reset_control_get_optional_exclusive(dev, NULL); + if (IS_ERR(priv->reset)) + return PTR_ERR(priv->reset); + + priv->rng.name = pdev->name; + priv->rng.init = bcm2835_rng_init; + priv->rng.read = bcm2835_rng_read; + priv->rng.cleanup = bcm2835_rng_cleanup; + + if (dev_of_node(dev)) { + const struct bcm2835_rng_of_data *of_data; + + /* Check for rng init function, execute it */ + of_data = of_device_get_match_data(dev); + if (of_data) + priv->mask_interrupts = of_data->mask_interrupts; } - bcm2835_rng_ops.priv = (unsigned long)rng_base; /* register driver */ - err = hwrng_register(&bcm2835_rng_ops); - if (err) { + err = devm_hwrng_register(dev, &priv->rng); + if (err) dev_err(dev, "hwrng registration failed\n"); - iounmap(rng_base); - } else { + else dev_info(dev, "hwrng registered\n"); - /* set warm-up count & enable */ - __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS); - __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL); - } return err; } -static int bcm2835_rng_remove(struct platform_device *pdev) -{ - void __iomem *rng_base = (void __iomem *)bcm2835_rng_ops.priv; - - /* disable rng hardware */ - __raw_writel(0, rng_base + RNG_CTRL); - - /* unregister driver */ - hwrng_unregister(&bcm2835_rng_ops); - iounmap(rng_base); - - return 0; -} - -static const struct of_device_id bcm2835_rng_of_match[] = { - { .compatible = "brcm,bcm2835-rng", }, - {}, +static const struct platform_device_id bcm2835_rng_devtype[] = { + { .name = "bcm2835-rng" }, + { .name = "bcm63xx-rng" }, + { /* sentinel */ } }; -MODULE_DEVICE_TABLE(of, bcm2835_rng_of_match); +MODULE_DEVICE_TABLE(platform, bcm2835_rng_devtype); static struct platform_driver bcm2835_rng_driver = { .driver = { .name = "bcm2835-rng", - .owner = THIS_MODULE, .of_match_table = bcm2835_rng_of_match, }, .probe = bcm2835_rng_probe, - .remove = bcm2835_rng_remove, + .id_table = bcm2835_rng_devtype, }; module_platform_driver(bcm2835_rng_driver); |