| /* |
| * Copyright (c) 2011 Peter Korsgaard <jacmet@sunsite.dk> |
| * |
| * This file is licensed under the terms of the GNU General Public |
| * License version 2. This program is licensed "as is" without any |
| * warranty of any kind, whether express or implied. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/err.h> |
| #include <linux/clk.h> |
| #include <linux/io.h> |
| #include <linux/hw_random.h> |
| #include <linux/platform_device.h> |
| |
| #define TRNG_CR 0x00 |
| #define TRNG_ISR 0x1c |
| #define TRNG_ODATA 0x50 |
| |
| #define TRNG_KEY 0x524e4700 /* RNG */ |
| |
| struct atmel_trng { |
| struct clk *clk; |
| void __iomem *base; |
| struct hwrng rng; |
| }; |
| |
| static int atmel_trng_read(struct hwrng *rng, void *buf, size_t max, |
| bool wait) |
| { |
| struct atmel_trng *trng = container_of(rng, struct atmel_trng, rng); |
| u32 *data = buf; |
| |
| /* data ready? */ |
| if (readl(trng->base + TRNG_ODATA) & 1) { |
| *data = readl(trng->base + TRNG_ODATA); |
| return 4; |
| } else |
| return 0; |
| } |
| |
| static int atmel_trng_probe(struct platform_device *pdev) |
| { |
| struct atmel_trng *trng; |
| struct resource *res; |
| int ret; |
| |
| res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| if (!res) |
| return -EINVAL; |
| |
| trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL); |
| if (!trng) |
| return -ENOMEM; |
| |
| if (!devm_request_mem_region(&pdev->dev, res->start, |
| resource_size(res), pdev->name)) |
| return -EBUSY; |
| |
| trng->base = devm_ioremap(&pdev->dev, res->start, resource_size(res)); |
| if (!trng->base) |
| return -EBUSY; |
| |
| trng->clk = clk_get(&pdev->dev, NULL); |
| if (IS_ERR(trng->clk)) |
| return PTR_ERR(trng->clk); |
| |
| ret = clk_enable(trng->clk); |
| if (ret) |
| goto err_enable; |
| |
| writel(TRNG_KEY | 1, trng->base + TRNG_CR); |
| trng->rng.name = pdev->name; |
| trng->rng.read = atmel_trng_read; |
| |
| ret = hwrng_register(&trng->rng); |
| if (ret) |
| goto err_register; |
| |
| platform_set_drvdata(pdev, trng); |
| |
| return 0; |
| |
| err_register: |
| clk_disable(trng->clk); |
| err_enable: |
| clk_put(trng->clk); |
| |
| return ret; |
| } |
| |
| static int __devexit atmel_trng_remove(struct platform_device *pdev) |
| { |
| struct atmel_trng *trng = platform_get_drvdata(pdev); |
| |
| hwrng_unregister(&trng->rng); |
| |
| writel(TRNG_KEY, trng->base + TRNG_CR); |
| clk_disable(trng->clk); |
| clk_put(trng->clk); |
| |
| platform_set_drvdata(pdev, NULL); |
| |
| return 0; |
| } |
| |
| #ifdef CONFIG_PM |
| static int atmel_trng_suspend(struct device *dev) |
| { |
| struct atmel_trng *trng = dev_get_drvdata(dev); |
| |
| clk_disable(trng->clk); |
| |
| return 0; |
| } |
| |
| static int atmel_trng_resume(struct device *dev) |
| { |
| struct atmel_trng *trng = dev_get_drvdata(dev); |
| |
| return clk_enable(trng->clk); |
| } |
| |
| static const struct dev_pm_ops atmel_trng_pm_ops = { |
| .suspend = atmel_trng_suspend, |
| .resume = atmel_trng_resume, |
| }; |
| #endif /* CONFIG_PM */ |
| |
| static struct platform_driver atmel_trng_driver = { |
| .probe = atmel_trng_probe, |
| .remove = __devexit_p(atmel_trng_remove), |
| .driver = { |
| .name = "atmel-trng", |
| .owner = THIS_MODULE, |
| #ifdef CONFIG_PM |
| .pm = &atmel_trng_pm_ops, |
| #endif /* CONFIG_PM */ |
| }, |
| }; |
| |
| static int __init atmel_trng_init(void) |
| { |
| return platform_driver_register(&atmel_trng_driver); |
| } |
| module_init(atmel_trng_init); |
| |
| static void __exit atmel_trng_exit(void) |
| { |
| platform_driver_unregister(&atmel_trng_driver); |
| } |
| module_exit(atmel_trng_exit); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>"); |
| MODULE_DESCRIPTION("Atmel true random number generator driver"); |