| /* |
| * 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 <asm/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 *ofdev) |
| { |
| void __iomem *rng_regs; |
| struct device_node *rng_np = ofdev->dev.of_node; |
| struct resource res; |
| int err = 0; |
| |
| err = of_address_to_resource(rng_np, 0, &res); |
| if (err) |
| return -ENODEV; |
| |
| rng_regs = ioremap(res.start, 0x100); |
| |
| if (!rng_regs) |
| return -ENOMEM; |
| |
| pasemi_rng.priv = (unsigned long)rng_regs; |
| |
| pr_info("Registering PA Semi RNG\n"); |
| |
| err = hwrng_register(&pasemi_rng); |
| |
| if (err) |
| iounmap(rng_regs); |
| |
| return err; |
| } |
| |
| static int rng_remove(struct platform_device *dev) |
| { |
| void __iomem *rng_regs = (void __iomem *)pasemi_rng.priv; |
| |
| hwrng_unregister(&pasemi_rng); |
| iounmap(rng_regs); |
| |
| return 0; |
| } |
| |
| static struct of_device_id rng_match[] = { |
| { .compatible = "1682m-rng", }, |
| { .compatible = "pasemi,pwrficient-rng", }, |
| { }, |
| }; |
| |
| static struct platform_driver rng_driver = { |
| .driver = { |
| .name = "pasemi-rng", |
| .owner = THIS_MODULE, |
| .of_match_table = rng_match, |
| }, |
| .probe = rng_probe, |
| .remove = rng_remove, |
| }; |
| |
| 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"); |