diff options
Diffstat (limited to 'drivers/char/hw_random/omap-rng.c')
| -rw-r--r-- | drivers/char/hw_random/omap-rng.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/drivers/char/hw_random/omap-rng.c b/drivers/char/hw_random/omap-rng.c new file mode 100644 index 000000000000..819516b35a79 --- /dev/null +++ b/drivers/char/hw_random/omap-rng.c @@ -0,0 +1,208 @@ +/* + * driver/char/hw_random/omap-rng.c + * + * RNG driver for TI OMAP CPU family + * + * Author: Deepak Saxena <dsaxena@plexity.net> + * + * Copyright 2005 (c) MontaVista Software, Inc. + * + * Mostly based on original driver: + * + * Copyright (C) 2005 Nokia Corporation + * Author: Juha Yrj��<juha.yrjola@nokia.com> + * + * 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. + * + * TODO: + * + * - Make status updated be interrupt driven so we don't poll + * + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/random.h> +#include <linux/err.h> +#include <linux/device.h> +#include <linux/hw_random.h> + +#include <asm/io.h> +#include <asm/hardware/clock.h> + +#define RNG_OUT_REG 0x00 /* Output register */ +#define RNG_STAT_REG 0x04 /* Status register + [0] = STAT_BUSY */ +#define RNG_ALARM_REG 0x24 /* Alarm register + [7:0] = ALARM_COUNTER */ +#define RNG_CONFIG_REG 0x28 /* Configuration register + [11:6] = RESET_COUNT + [5:3] = RING2_DELAY + [2:0] = RING1_DELAY */ +#define RNG_REV_REG 0x3c /* Revision register + [7:0] = REV_NB */ +#define RNG_MASK_REG 0x40 /* Mask and reset register + [2] = IT_EN + [1] = SOFTRESET + [0] = AUTOIDLE */ +#define RNG_SYSSTATUS 0x44 /* System status + [0] = RESETDONE */ + +static void __iomem *rng_base; +static struct clk *rng_ick; +static struct device *rng_dev; + +static u32 omap_rng_read_reg(int reg) +{ + return __raw_readl(rng_base + reg); +} + +static void omap_rng_write_reg(int reg, u32 val) +{ + __raw_writel(val, rng_base + reg); +} + +/* REVISIT: Does the status bit really work on 16xx? */ +static int omap_rng_data_present(struct hwrng *rng) +{ + return omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1; +} + +static int omap_rng_data_read(struct hwrng *rng, u32 *data) +{ + *data = omap_rng_read_reg(RNG_OUT_REG); + + return 4; +} + +static struct hwrng omap_rng_ops = { + .name = "omap", + .data_present = omap_rng_data_present, + .data_read = omap_rng_data_read, +}; + +static int __init omap_rng_probe(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct resource *res, *mem; + int ret; + + /* + * A bit ugly, and it will never actually happen but there can + * be only one RNG and this catches any bork + */ + BUG_ON(rng_dev); + + if (cpu_is_omap24xx()) { + rng_ick = clk_get(NULL, "rng_ick"); + if (IS_ERR(rng_ick)) { + dev_err(dev, "Could not get rng_ick\n"); + ret = PTR_ERR(rng_ick); + return ret; + } + else { + clk_use(rng_ick); + } + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + + if (!res) + return -ENOENT; + + mem = request_mem_region(res->start, res->end - res->start + 1, + pdev->name); + if (mem == NULL) + return -EBUSY; + + dev_set_drvdata(dev, mem); + rng_base = (u32 __iomem *)io_p2v(res->start); + + ret = hwrng_register(&omap_rng_ops); + if (ret) { + release_resource(mem); + rng_base = NULL; + return ret; + } + + dev_info(dev, "OMAP Random Number Generator ver. %02x\n", + omap_rng_read_reg(RNG_REV_REG)); + omap_rng_write_reg(RNG_MASK_REG, 0x1); + + rng_dev = dev; + + return 0; +} + +static int __exit omap_rng_remove(struct device *dev) +{ + struct resource *mem = dev_get_drvdata(dev); + + hwrng_unregister(&omap_rng_ops); + + omap_rng_write_reg(RNG_MASK_REG, 0x0); + + if (cpu_is_omap24xx()) { + clk_unuse(rng_ick); + clk_put(rng_ick); + } + + release_resource(mem); + rng_base = NULL; + + return 0; +} + +#ifdef CONFIG_PM + +static int omap_rng_suspend(struct device *dev, pm_message_t message, u32 level) +{ + omap_rng_write_reg(RNG_MASK_REG, 0x0); + + return 0; +} + +static int omap_rng_resume(struct device *dev, pm_message_t message, u32 level) +{ + omap_rng_write_reg(RNG_MASK_REG, 0x1); + + return 1; +} + +#else + +#define omap_rng_suspend NULL +#define omap_rng_resume NULL + +#endif + + +static struct device_driver omap_rng_driver = { + .name = "omap_rng", + .bus = &platform_bus_type, + .probe = omap_rng_probe, + .remove = __exit_p(omap_rng_remove), + .suspend = omap_rng_suspend, + .resume = omap_rng_resume +}; + +static int __init omap_rng_init(void) +{ + if (!cpu_is_omap16xx() && !cpu_is_omap24xx()) + return -ENODEV; + + return driver_register(&omap_rng_driver); +} + +static void __exit omap_rng_exit(void) +{ + driver_unregister(&omap_rng_driver); +} + +module_init(omap_rng_init); +module_exit(omap_rng_exit); + +MODULE_AUTHOR("Deepak Saxena (and others)"); +MODULE_LICENSE("GPL"); |