123 lines
2.4 KiB
C
123 lines
2.4 KiB
C
/*
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* drivers/char/hw_random/stm-rng.c
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*
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* RNG driver for ST Microelectronics STx7xxx SoCs
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*
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* Author: Carl Shaw <carl.shaw@st.com>
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*
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* Copyright (c) 2007-2008 ST Microelectronics R&D Ltd.
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*
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* Based on omap RNG driver
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/random.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/platform_device.h>
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#include <linux/hw_random.h>
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#include <asm/io.h>
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#define STM_RNG_STATUS_REG 0x20
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#define STM_RNG_DATA_REG 0x24
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static void __iomem *rng_base;
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static u32 stm_rng_read_reg(int reg)
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{
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return __raw_readl(rng_base + reg);
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}
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static int stm_rng_data_present(struct hwrng *rng)
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{
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return ((stm_rng_read_reg(STM_RNG_STATUS_REG) & 3) == 0);
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}
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static int stm_rng_data_read(struct hwrng *rng, u32 *data)
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{
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*data = stm_rng_read_reg(STM_RNG_DATA_REG);
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return 2;
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}
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static struct hwrng stm_rng_ops = {
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.name = "stm",
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.data_present = stm_rng_data_present,
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.data_read = stm_rng_data_read,
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};
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static int __init stm_rng_probe(struct platform_device *pdev)
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{
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struct resource *res;
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int ret;
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BUG_ON(rng_base);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res) {
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printk(KERN_ERR "STM hw_random device probe failed."
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"Please Check your SoC config.\n");
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return -ENOENT;
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}
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rng_base = (u32 __iomem *)ioremap(res->start, 0x28);
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if (!rng_base) {
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printk(KERN_ERR "STM hw_random device: cannot ioremap\n");
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return -ENOMEM;
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}
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ret = hwrng_register(&stm_rng_ops);
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if (ret) {
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iounmap(rng_base);
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rng_base = NULL;
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return ret;
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}
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dev_info(&pdev->dev, "STM Random Number Generator ver. 0.1\n");
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return 0;
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}
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static int __exit stm_rng_remove(struct platform_device *pdev)
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{
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hwrng_unregister(&stm_rng_ops);
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iounmap(rng_base);
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rng_base = NULL;
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return 0;
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}
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static struct platform_driver stm_rng_driver = {
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.driver = {
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.name = "stm-hwrandom",
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.owner = THIS_MODULE,
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},
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.probe = stm_rng_probe,
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.remove = __exit_p(stm_rng_remove),
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};
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static int __init stm_rng_init(void)
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{
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return platform_driver_register(&stm_rng_driver);
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}
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static void __exit stm_rng_exit(void)
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{
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platform_driver_unregister(&stm_rng_driver);
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}
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module_init(stm_rng_init);
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module_exit(stm_rng_exit);
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MODULE_AUTHOR("ST Microelectronics <carl.shaw@st.com>");
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MODULE_LICENSE("GPL");
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