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Alan Carvalho de Assis45001e92009-04-02 12:38:41 -03001/*
2 * RNG driver for Freescale RNGA
3 *
4 * Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
5 * Author: Alan Carvalho de Assis <acassis@gmail.com>
6 */
7
8/*
9 * The code contained herein is licensed under the GNU General Public
10 * License. You may obtain a copy of the GNU General Public License
11 * Version 2 or later at the following locations:
12 *
13 * http://www.opensource.org/licenses/gpl-license.html
14 * http://www.gnu.org/copyleft/gpl.html
15 *
16 * This driver is based on other RNG drivers.
17 */
18
19#include <linux/module.h>
20#include <linux/init.h>
21#include <linux/kernel.h>
22#include <linux/clk.h>
23#include <linux/err.h>
24#include <linux/ioport.h>
25#include <linux/platform_device.h>
26#include <linux/hw_random.h>
Benoît Thébaudeau36211892012-06-13 18:15:34 +020027#include <linux/delay.h>
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -030028#include <linux/io.h>
29
30/* RNGA Registers */
31#define RNGA_CONTROL 0x00
32#define RNGA_STATUS 0x04
33#define RNGA_ENTROPY 0x08
34#define RNGA_OUTPUT_FIFO 0x0c
35#define RNGA_MODE 0x10
36#define RNGA_VERIFICATION_CONTROL 0x14
37#define RNGA_OSC_CONTROL_COUNTER 0x18
38#define RNGA_OSC1_COUNTER 0x1c
39#define RNGA_OSC2_COUNTER 0x20
40#define RNGA_OSC_COUNTER_STATUS 0x24
41
42/* RNGA Registers Range */
43#define RNG_ADDR_RANGE 0x28
44
45/* RNGA Control Register */
46#define RNGA_CONTROL_SLEEP 0x00000010
47#define RNGA_CONTROL_CLEAR_INT 0x00000008
48#define RNGA_CONTROL_MASK_INTS 0x00000004
49#define RNGA_CONTROL_HIGH_ASSURANCE 0x00000002
50#define RNGA_CONTROL_GO 0x00000001
51
52#define RNGA_STATUS_LEVEL_MASK 0x0000ff00
53
54/* RNGA Status Register */
55#define RNGA_STATUS_OSC_DEAD 0x80000000
56#define RNGA_STATUS_SLEEP 0x00000010
57#define RNGA_STATUS_ERROR_INT 0x00000008
58#define RNGA_STATUS_FIFO_UNDERFLOW 0x00000004
59#define RNGA_STATUS_LAST_READ_STATUS 0x00000002
60#define RNGA_STATUS_SECURITY_VIOLATION 0x00000001
61
Fabio Estevam821873a2012-09-04 18:35:22 -030062struct mxc_rng {
63 struct device *dev;
64 struct hwrng rng;
65 void __iomem *mem;
66 struct clk *clk;
67};
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -030068
Benoît Thébaudeau36211892012-06-13 18:15:34 +020069static int mxc_rnga_data_present(struct hwrng *rng, int wait)
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -030070{
Benoît Thébaudeau36211892012-06-13 18:15:34 +020071 int i;
Fabio Estevam821873a2012-09-04 18:35:22 -030072 struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -030073
Benoît Thébaudeau36211892012-06-13 18:15:34 +020074 for (i = 0; i < 20; i++) {
75 /* how many random numbers are in FIFO? [0-16] */
Fabio Estevam821873a2012-09-04 18:35:22 -030076 int level = (__raw_readl(mxc_rng->mem + RNGA_STATUS) &
Benoît Thébaudeau36211892012-06-13 18:15:34 +020077 RNGA_STATUS_LEVEL_MASK) >> 8;
78 if (level || !wait)
79 return !!level;
80 udelay(10);
81 }
82 return 0;
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -030083}
84
85static int mxc_rnga_data_read(struct hwrng *rng, u32 * data)
86{
87 int err;
88 u32 ctrl;
Fabio Estevam821873a2012-09-04 18:35:22 -030089 struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -030090
91 /* retrieve a random number from FIFO */
Fabio Estevam821873a2012-09-04 18:35:22 -030092 *data = __raw_readl(mxc_rng->mem + RNGA_OUTPUT_FIFO);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -030093
94 /* some error while reading this random number? */
Fabio Estevam821873a2012-09-04 18:35:22 -030095 err = __raw_readl(mxc_rng->mem + RNGA_STATUS) & RNGA_STATUS_ERROR_INT;
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -030096
97 /* if error: clear error interrupt, but doesn't return random number */
98 if (err) {
Fabio Estevam821873a2012-09-04 18:35:22 -030099 dev_dbg(mxc_rng->dev, "Error while reading random number!\n");
100 ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300101 __raw_writel(ctrl | RNGA_CONTROL_CLEAR_INT,
Fabio Estevam821873a2012-09-04 18:35:22 -0300102 mxc_rng->mem + RNGA_CONTROL);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300103 return 0;
104 } else
105 return 4;
106}
107
108static int mxc_rnga_init(struct hwrng *rng)
109{
110 u32 ctrl, osc;
Fabio Estevam821873a2012-09-04 18:35:22 -0300111 struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300112
113 /* wake up */
Fabio Estevam821873a2012-09-04 18:35:22 -0300114 ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
115 __raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, mxc_rng->mem + RNGA_CONTROL);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300116
117 /* verify if oscillator is working */
Fabio Estevam821873a2012-09-04 18:35:22 -0300118 osc = __raw_readl(mxc_rng->mem + RNGA_STATUS);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300119 if (osc & RNGA_STATUS_OSC_DEAD) {
Fabio Estevam821873a2012-09-04 18:35:22 -0300120 dev_err(mxc_rng->dev, "RNGA Oscillator is dead!\n");
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300121 return -ENODEV;
122 }
123
124 /* go running */
Fabio Estevam821873a2012-09-04 18:35:22 -0300125 ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
126 __raw_writel(ctrl | RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300127
128 return 0;
129}
130
131static void mxc_rnga_cleanup(struct hwrng *rng)
132{
133 u32 ctrl;
Fabio Estevam821873a2012-09-04 18:35:22 -0300134 struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300135
Fabio Estevam821873a2012-09-04 18:35:22 -0300136 ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300137
138 /* stop rnga */
Fabio Estevam821873a2012-09-04 18:35:22 -0300139 __raw_writel(ctrl & ~RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300140}
141
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300142static int __init mxc_rnga_probe(struct platform_device *pdev)
143{
144 int err = -ENODEV;
Fabio Estevam264878e2013-03-13 00:57:27 -0300145 struct resource *res;
Fabio Estevam821873a2012-09-04 18:35:22 -0300146 struct mxc_rng *mxc_rng;
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300147
Fabio Estevam821873a2012-09-04 18:35:22 -0300148 mxc_rng = devm_kzalloc(&pdev->dev, sizeof(struct mxc_rng),
149 GFP_KERNEL);
150 if (!mxc_rng)
151 return -ENOMEM;
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300152
Fabio Estevam821873a2012-09-04 18:35:22 -0300153 mxc_rng->dev = &pdev->dev;
154 mxc_rng->rng.name = "mxc-rnga";
155 mxc_rng->rng.init = mxc_rnga_init;
156 mxc_rng->rng.cleanup = mxc_rnga_cleanup,
157 mxc_rng->rng.data_present = mxc_rnga_data_present,
158 mxc_rng->rng.data_read = mxc_rnga_data_read,
159
160 mxc_rng->clk = devm_clk_get(&pdev->dev, NULL);
161 if (IS_ERR(mxc_rng->clk)) {
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300162 dev_err(&pdev->dev, "Could not get rng_clk!\n");
Fabio Estevam821873a2012-09-04 18:35:22 -0300163 err = PTR_ERR(mxc_rng->clk);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300164 goto out;
165 }
166
Fabio Estevam821873a2012-09-04 18:35:22 -0300167 clk_prepare_enable(mxc_rng->clk);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300168
169 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
Fabio Estevam264878e2013-03-13 00:57:27 -0300170 mxc_rng->mem = devm_ioremap_resource(&pdev->dev, res);
171 if (IS_ERR(mxc_rng->mem)) {
172 err = PTR_ERR(mxc_rng->mem);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300173 goto err_ioremap;
174 }
175
Fabio Estevam821873a2012-09-04 18:35:22 -0300176 err = hwrng_register(&mxc_rng->rng);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300177 if (err) {
178 dev_err(&pdev->dev, "MXC RNGA registering failed (%d)\n", err);
Fabio Estevam821873a2012-09-04 18:35:22 -0300179 goto err_ioremap;
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300180 }
181
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300182 dev_info(&pdev->dev, "MXC RNGA Registered.\n");
183
184 return 0;
185
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300186err_ioremap:
Fabio Estevam821873a2012-09-04 18:35:22 -0300187 clk_disable_unprepare(mxc_rng->clk);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300188
189out:
190 return err;
191}
192
193static int __exit mxc_rnga_remove(struct platform_device *pdev)
194{
Fabio Estevam821873a2012-09-04 18:35:22 -0300195 struct mxc_rng *mxc_rng = platform_get_drvdata(pdev);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300196
Fabio Estevam821873a2012-09-04 18:35:22 -0300197 hwrng_unregister(&mxc_rng->rng);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300198
Fabio Estevam821873a2012-09-04 18:35:22 -0300199 clk_disable_unprepare(mxc_rng->clk);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300200
201 return 0;
202}
203
204static struct platform_driver mxc_rnga_driver = {
205 .driver = {
206 .name = "mxc_rnga",
207 .owner = THIS_MODULE,
208 },
209 .remove = __exit_p(mxc_rnga_remove),
210};
211
Fabio Porceddae7c21992013-03-14 18:09:33 +0100212module_platform_driver_probe(mxc_rnga_driver, mxc_rnga_probe);
Alan Carvalho de Assis45001e92009-04-02 12:38:41 -0300213
214MODULE_AUTHOR("Freescale Semiconductor, Inc.");
215MODULE_DESCRIPTION("H/W RNGA driver for i.MX");
216MODULE_LICENSE("GPL");