diff options
Diffstat (limited to 'drivers/char/hw_random/picoxcell-rng.c')
| -rw-r--r-- | drivers/char/hw_random/picoxcell-rng.c | 181 |
1 files changed, 0 insertions, 181 deletions
diff --git a/drivers/char/hw_random/picoxcell-rng.c b/drivers/char/hw_random/picoxcell-rng.c deleted file mode 100644 index eab5448ad56..00000000000 --- a/drivers/char/hw_random/picoxcell-rng.c +++ /dev/null @@ -1,181 +0,0 @@ -/* - * Copyright (c) 2010-2011 Picochip Ltd., Jamie Iles - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * All enquiries to support@picochip.com - */ -#include <linux/clk.h> -#include <linux/delay.h> -#include <linux/err.h> -#include <linux/hw_random.h> -#include <linux/io.h> -#include <linux/kernel.h> -#include <linux/module.h> -#include <linux/platform_device.h> - -#define DATA_REG_OFFSET 0x0200 -#define CSR_REG_OFFSET 0x0278 -#define CSR_OUT_EMPTY_MASK (1 << 24) -#define CSR_FAULT_MASK (1 << 1) -#define TRNG_BLOCK_RESET_MASK (1 << 0) -#define TAI_REG_OFFSET 0x0380 - -/* - * The maximum amount of time in microseconds to spend waiting for data if the - * core wants us to wait. The TRNG should generate 32 bits every 320ns so a - * timeout of 20us seems reasonable. The TRNG does builtin tests of the data - * for randomness so we can't always assume there is data present. - */ -#define PICO_TRNG_TIMEOUT 20 - -static void __iomem *rng_base; -static struct clk *rng_clk; -static struct device *rng_dev; - -static inline u32 picoxcell_trng_read_csr(void) -{ - return __raw_readl(rng_base + CSR_REG_OFFSET); -} - -static inline bool picoxcell_trng_is_empty(void) -{ - return picoxcell_trng_read_csr() & CSR_OUT_EMPTY_MASK; -} - -/* - * Take the random number generator out of reset and make sure the interrupts - * are masked. We shouldn't need to get large amounts of random bytes so just - * poll the status register. The hardware generates 32 bits every 320ns so we - * shouldn't have to wait long enough to warrant waiting for an IRQ. - */ -static void picoxcell_trng_start(void) -{ - __raw_writel(0, rng_base + TAI_REG_OFFSET); - __raw_writel(0, rng_base + CSR_REG_OFFSET); -} - -static void picoxcell_trng_reset(void) -{ - __raw_writel(TRNG_BLOCK_RESET_MASK, rng_base + CSR_REG_OFFSET); - __raw_writel(TRNG_BLOCK_RESET_MASK, rng_base + TAI_REG_OFFSET); - picoxcell_trng_start(); -} - -/* - * Get some random data from the random number generator. The hw_random core - * layer provides us with locking. - */ -static int picoxcell_trng_read(struct hwrng *rng, void *buf, size_t max, - bool wait) -{ - int i; - - /* Wait for some data to become available. */ - for (i = 0; i < PICO_TRNG_TIMEOUT && picoxcell_trng_is_empty(); ++i) { - if (!wait) - return 0; - - udelay(1); - } - - if (picoxcell_trng_read_csr() & CSR_FAULT_MASK) { - dev_err(rng_dev, "fault detected, resetting TRNG\n"); - picoxcell_trng_reset(); - return -EIO; - } - - if (i == PICO_TRNG_TIMEOUT) - return 0; - - *(u32 *)buf = __raw_readl(rng_base + DATA_REG_OFFSET); - return sizeof(u32); -} - -static struct hwrng picoxcell_trng = { - .name = "picoxcell", - .read = picoxcell_trng_read, -}; - -static int picoxcell_trng_probe(struct platform_device *pdev) -{ - int ret; - struct resource *mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); - - rng_base = devm_ioremap_resource(&pdev->dev, mem); - if (IS_ERR(rng_base)) - return PTR_ERR(rng_base); - - rng_clk = devm_clk_get(&pdev->dev, NULL); - if (IS_ERR(rng_clk)) { - dev_warn(&pdev->dev, "no clk\n"); - return PTR_ERR(rng_clk); - } - - ret = clk_enable(rng_clk); - if (ret) { - dev_warn(&pdev->dev, "unable to enable clk\n"); - return ret; - } - - picoxcell_trng_start(); - ret = hwrng_register(&picoxcell_trng); - if (ret) - goto err_register; - - rng_dev = &pdev->dev; - dev_info(&pdev->dev, "pixoxcell random number generator active\n"); - - return 0; - -err_register: - clk_disable(rng_clk); - return ret; -} - -static int picoxcell_trng_remove(struct platform_device *pdev) -{ - hwrng_unregister(&picoxcell_trng); - clk_disable(rng_clk); - - return 0; -} - -#ifdef CONFIG_PM -static int picoxcell_trng_suspend(struct device *dev) -{ - clk_disable(rng_clk); - - return 0; -} - -static int picoxcell_trng_resume(struct device *dev) -{ - return clk_enable(rng_clk); -} - -static const struct dev_pm_ops picoxcell_trng_pm_ops = { - .suspend = picoxcell_trng_suspend, - .resume = picoxcell_trng_resume, -}; -#endif /* CONFIG_PM */ - -static struct platform_driver picoxcell_trng_driver = { - .probe = picoxcell_trng_probe, - .remove = picoxcell_trng_remove, - .driver = { - .name = "picoxcell-trng", - .owner = THIS_MODULE, -#ifdef CONFIG_PM - .pm = &picoxcell_trng_pm_ops, -#endif /* CONFIG_PM */ - }, -}; - -module_platform_driver(picoxcell_trng_driver); - -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Jamie Iles"); -MODULE_DESCRIPTION("Picochip picoXcell TRNG driver"); |