diff options
Diffstat (limited to 'drivers/char/hw_random/pasemi-rng.c')
| -rw-r--r-- | drivers/char/hw_random/pasemi-rng.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/drivers/char/hw_random/pasemi-rng.c b/drivers/char/hw_random/pasemi-rng.c new file mode 100644 index 000000000..545df485b --- /dev/null +++ b/drivers/char/hw_random/pasemi-rng.c @@ -0,0 +1,133 @@ +/* + * Copyright (C) 2006-2007 PA Semi, Inc + * + * Maintained by: Olof Johansson <olof@lixom.net> + * + * Driver for the PWRficient onchip rng + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/hw_random.h> +#include <linux/delay.h> +#include <linux/of_address.h> +#include <linux/of_platform.h> +#include <linux/io.h> + +#define SDCRNG_CTL_REG 0x00 +#define SDCRNG_CTL_FVLD_M 0x0000f000 +#define SDCRNG_CTL_FVLD_S 12 +#define SDCRNG_CTL_KSZ 0x00000800 +#define SDCRNG_CTL_RSRC_CRG 0x00000010 +#define SDCRNG_CTL_RSRC_RRG 0x00000000 +#define SDCRNG_CTL_CE 0x00000004 +#define SDCRNG_CTL_RE 0x00000002 +#define SDCRNG_CTL_DR 0x00000001 +#define SDCRNG_CTL_SELECT_RRG_RNG (SDCRNG_CTL_RE | SDCRNG_CTL_RSRC_RRG) +#define SDCRNG_CTL_SELECT_CRG_RNG (SDCRNG_CTL_CE | SDCRNG_CTL_RSRC_CRG) +#define SDCRNG_VAL_REG 0x20 + +#define MODULE_NAME "pasemi_rng" + +static int pasemi_rng_data_present(struct hwrng *rng, int wait) +{ + void __iomem *rng_regs = (void __iomem *)rng->priv; + int data, i; + + for (i = 0; i < 20; i++) { + data = (in_le32(rng_regs + SDCRNG_CTL_REG) + & SDCRNG_CTL_FVLD_M) ? 1 : 0; + if (data || !wait) + break; + udelay(10); + } + return data; +} + +static int pasemi_rng_data_read(struct hwrng *rng, u32 *data) +{ + void __iomem *rng_regs = (void __iomem *)rng->priv; + *data = in_le32(rng_regs + SDCRNG_VAL_REG); + return 4; +} + +static int pasemi_rng_init(struct hwrng *rng) +{ + void __iomem *rng_regs = (void __iomem *)rng->priv; + u32 ctl; + + ctl = SDCRNG_CTL_DR | SDCRNG_CTL_SELECT_RRG_RNG | SDCRNG_CTL_KSZ; + out_le32(rng_regs + SDCRNG_CTL_REG, ctl); + out_le32(rng_regs + SDCRNG_CTL_REG, ctl & ~SDCRNG_CTL_DR); + + return 0; +} + +static void pasemi_rng_cleanup(struct hwrng *rng) +{ + void __iomem *rng_regs = (void __iomem *)rng->priv; + u32 ctl; + + ctl = SDCRNG_CTL_RE | SDCRNG_CTL_CE; + out_le32(rng_regs + SDCRNG_CTL_REG, + in_le32(rng_regs + SDCRNG_CTL_REG) & ~ctl); +} + +static struct hwrng pasemi_rng = { + .name = MODULE_NAME, + .init = pasemi_rng_init, + .cleanup = pasemi_rng_cleanup, + .data_present = pasemi_rng_data_present, + .data_read = pasemi_rng_data_read, +}; + +static int rng_probe(struct platform_device *pdev) +{ + void __iomem *rng_regs; + struct resource *res; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + rng_regs = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(rng_regs)) + return PTR_ERR(rng_regs); + + pasemi_rng.priv = (unsigned long)rng_regs; + + pr_info("Registering PA Semi RNG\n"); + return devm_hwrng_register(&pdev->dev, &pasemi_rng); +} + +static const struct of_device_id rng_match[] = { + { .compatible = "1682m-rng", }, + { .compatible = "pasemi,pwrficient-rng", }, + { }, +}; +MODULE_DEVICE_TABLE(of, rng_match); + +static struct platform_driver rng_driver = { + .driver = { + .name = "pasemi-rng", + .of_match_table = rng_match, + }, + .probe = rng_probe, +}; + +module_platform_driver(rng_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>"); +MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor"); |