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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * RNG driver for Freescale RNGA
4 *
5 * Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
6 * Author: Alan Carvalho de Assis <acassis@gmail.com>
7 */
8
9/*
10 *
11 * This driver is based on other RNG drivers.
12 */
13
14#include <linux/clk.h>
15#include <linux/delay.h>
16#include <linux/hw_random.h>
17#include <linux/io.h>
18#include <linux/module.h>
19#include <linux/of.h>
20#include <linux/platform_device.h>
21
22/* RNGA Registers */
23#define RNGA_CONTROL 0x00
24#define RNGA_STATUS 0x04
25#define RNGA_ENTROPY 0x08
26#define RNGA_OUTPUT_FIFO 0x0c
27#define RNGA_MODE 0x10
28#define RNGA_VERIFICATION_CONTROL 0x14
29#define RNGA_OSC_CONTROL_COUNTER 0x18
30#define RNGA_OSC1_COUNTER 0x1c
31#define RNGA_OSC2_COUNTER 0x20
32#define RNGA_OSC_COUNTER_STATUS 0x24
33
34/* RNGA Registers Range */
35#define RNG_ADDR_RANGE 0x28
36
37/* RNGA Control Register */
38#define RNGA_CONTROL_SLEEP 0x00000010
39#define RNGA_CONTROL_CLEAR_INT 0x00000008
40#define RNGA_CONTROL_MASK_INTS 0x00000004
41#define RNGA_CONTROL_HIGH_ASSURANCE 0x00000002
42#define RNGA_CONTROL_GO 0x00000001
43
44#define RNGA_STATUS_LEVEL_MASK 0x0000ff00
45
46/* RNGA Status Register */
47#define RNGA_STATUS_OSC_DEAD 0x80000000
48#define RNGA_STATUS_SLEEP 0x00000010
49#define RNGA_STATUS_ERROR_INT 0x00000008
50#define RNGA_STATUS_FIFO_UNDERFLOW 0x00000004
51#define RNGA_STATUS_LAST_READ_STATUS 0x00000002
52#define RNGA_STATUS_SECURITY_VIOLATION 0x00000001
53
54struct mxc_rng {
55 struct device *dev;
56 struct hwrng rng;
57 void __iomem *mem;
58 struct clk *clk;
59};
60
61static int mxc_rnga_data_present(struct hwrng *rng, int wait)
62{
63 int i;
64 struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
65
66 for (i = 0; i < 20; i++) {
67 /* how many random numbers are in FIFO? [0-16] */
68 int level = (__raw_readl(mxc_rng->mem + RNGA_STATUS) &
69 RNGA_STATUS_LEVEL_MASK) >> 8;
70 if (level || !wait)
71 return !!level;
72 udelay(10);
73 }
74 return 0;
75}
76
77static int mxc_rnga_data_read(struct hwrng *rng, u32 * data)
78{
79 int err;
80 u32 ctrl;
81 struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
82
83 /* retrieve a random number from FIFO */
84 *data = __raw_readl(mxc_rng->mem + RNGA_OUTPUT_FIFO);
85
86 /* some error while reading this random number? */
87 err = __raw_readl(mxc_rng->mem + RNGA_STATUS) & RNGA_STATUS_ERROR_INT;
88
89 /* if error: clear error interrupt, but doesn't return random number */
90 if (err) {
91 dev_dbg(mxc_rng->dev, "Error while reading random number!\n");
92 ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
93 __raw_writel(ctrl | RNGA_CONTROL_CLEAR_INT,
94 mxc_rng->mem + RNGA_CONTROL);
95 return 0;
96 } else
97 return 4;
98}
99
100static int mxc_rnga_init(struct hwrng *rng)
101{
102 u32 ctrl, osc;
103 struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
104
105 /* wake up */
106 ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
107 __raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, mxc_rng->mem + RNGA_CONTROL);
108
109 /* verify if oscillator is working */
110 osc = __raw_readl(mxc_rng->mem + RNGA_STATUS);
111 if (osc & RNGA_STATUS_OSC_DEAD) {
112 dev_err(mxc_rng->dev, "RNGA Oscillator is dead!\n");
113 return -ENODEV;
114 }
115
116 /* go running */
117 ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
118 __raw_writel(ctrl | RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL);
119
120 return 0;
121}
122
123static void mxc_rnga_cleanup(struct hwrng *rng)
124{
125 u32 ctrl;
126 struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
127
128 ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
129
130 /* stop rnga */
131 __raw_writel(ctrl & ~RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL);
132}
133
134static int __init mxc_rnga_probe(struct platform_device *pdev)
135{
136 int err;
137 struct mxc_rng *mxc_rng;
138
139 mxc_rng = devm_kzalloc(&pdev->dev, sizeof(*mxc_rng), GFP_KERNEL);
140 if (!mxc_rng)
141 return -ENOMEM;
142
143 mxc_rng->dev = &pdev->dev;
144 mxc_rng->rng.name = "mxc-rnga";
145 mxc_rng->rng.init = mxc_rnga_init;
146 mxc_rng->rng.cleanup = mxc_rnga_cleanup;
147 mxc_rng->rng.data_present = mxc_rnga_data_present;
148 mxc_rng->rng.data_read = mxc_rnga_data_read;
149
150 mxc_rng->clk = devm_clk_get(&pdev->dev, NULL);
151 if (IS_ERR(mxc_rng->clk)) {
152 dev_err(&pdev->dev, "Could not get rng_clk!\n");
153 return PTR_ERR(mxc_rng->clk);
154 }
155
156 err = clk_prepare_enable(mxc_rng->clk);
157 if (err)
158 return err;
159
160 mxc_rng->mem = devm_platform_ioremap_resource(pdev, 0);
161 if (IS_ERR(mxc_rng->mem)) {
162 err = PTR_ERR(mxc_rng->mem);
163 goto err_ioremap;
164 }
165
166 err = hwrng_register(&mxc_rng->rng);
167 if (err) {
168 dev_err(&pdev->dev, "MXC RNGA registering failed (%d)\n", err);
169 goto err_ioremap;
170 }
171
172 return 0;
173
174err_ioremap:
175 clk_disable_unprepare(mxc_rng->clk);
176 return err;
177}
178
179static void __exit mxc_rnga_remove(struct platform_device *pdev)
180{
181 struct mxc_rng *mxc_rng = platform_get_drvdata(pdev);
182
183 hwrng_unregister(&mxc_rng->rng);
184
185 clk_disable_unprepare(mxc_rng->clk);
186}
187
188static const struct of_device_id mxc_rnga_of_match[] = {
189 { .compatible = "fsl,imx21-rnga", },
190 { .compatible = "fsl,imx31-rnga", },
191 { /* sentinel */ },
192};
193MODULE_DEVICE_TABLE(of, mxc_rnga_of_match);
194
195static struct platform_driver mxc_rnga_driver = {
196 .driver = {
197 .name = "mxc_rnga",
198 .of_match_table = mxc_rnga_of_match,
199 },
200 .remove_new = __exit_p(mxc_rnga_remove),
201};
202
203module_platform_driver_probe(mxc_rnga_driver, mxc_rnga_probe);
204
205MODULE_AUTHOR("Freescale Semiconductor, Inc.");
206MODULE_DESCRIPTION("H/W RNGA driver for i.MX");
207MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * RNG driver for Freescale RNGA
4 *
5 * Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
6 * Author: Alan Carvalho de Assis <acassis@gmail.com>
7 */
8
9/*
10 *
11 * This driver is based on other RNG drivers.
12 */
13
14#include <linux/clk.h>
15#include <linux/delay.h>
16#include <linux/hw_random.h>
17#include <linux/io.h>
18#include <linux/module.h>
19#include <linux/of.h>
20#include <linux/platform_device.h>
21
22/* RNGA Registers */
23#define RNGA_CONTROL 0x00
24#define RNGA_STATUS 0x04
25#define RNGA_ENTROPY 0x08
26#define RNGA_OUTPUT_FIFO 0x0c
27#define RNGA_MODE 0x10
28#define RNGA_VERIFICATION_CONTROL 0x14
29#define RNGA_OSC_CONTROL_COUNTER 0x18
30#define RNGA_OSC1_COUNTER 0x1c
31#define RNGA_OSC2_COUNTER 0x20
32#define RNGA_OSC_COUNTER_STATUS 0x24
33
34/* RNGA Registers Range */
35#define RNG_ADDR_RANGE 0x28
36
37/* RNGA Control Register */
38#define RNGA_CONTROL_SLEEP 0x00000010
39#define RNGA_CONTROL_CLEAR_INT 0x00000008
40#define RNGA_CONTROL_MASK_INTS 0x00000004
41#define RNGA_CONTROL_HIGH_ASSURANCE 0x00000002
42#define RNGA_CONTROL_GO 0x00000001
43
44#define RNGA_STATUS_LEVEL_MASK 0x0000ff00
45
46/* RNGA Status Register */
47#define RNGA_STATUS_OSC_DEAD 0x80000000
48#define RNGA_STATUS_SLEEP 0x00000010
49#define RNGA_STATUS_ERROR_INT 0x00000008
50#define RNGA_STATUS_FIFO_UNDERFLOW 0x00000004
51#define RNGA_STATUS_LAST_READ_STATUS 0x00000002
52#define RNGA_STATUS_SECURITY_VIOLATION 0x00000001
53
54struct mxc_rng {
55 struct device *dev;
56 struct hwrng rng;
57 void __iomem *mem;
58 struct clk *clk;
59};
60
61static int mxc_rnga_data_present(struct hwrng *rng, int wait)
62{
63 int i;
64 struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
65
66 for (i = 0; i < 20; i++) {
67 /* how many random numbers are in FIFO? [0-16] */
68 int level = (__raw_readl(mxc_rng->mem + RNGA_STATUS) &
69 RNGA_STATUS_LEVEL_MASK) >> 8;
70 if (level || !wait)
71 return !!level;
72 udelay(10);
73 }
74 return 0;
75}
76
77static int mxc_rnga_data_read(struct hwrng *rng, u32 * data)
78{
79 int err;
80 u32 ctrl;
81 struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
82
83 /* retrieve a random number from FIFO */
84 *data = __raw_readl(mxc_rng->mem + RNGA_OUTPUT_FIFO);
85
86 /* some error while reading this random number? */
87 err = __raw_readl(mxc_rng->mem + RNGA_STATUS) & RNGA_STATUS_ERROR_INT;
88
89 /* if error: clear error interrupt, but doesn't return random number */
90 if (err) {
91 dev_dbg(mxc_rng->dev, "Error while reading random number!\n");
92 ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
93 __raw_writel(ctrl | RNGA_CONTROL_CLEAR_INT,
94 mxc_rng->mem + RNGA_CONTROL);
95 return 0;
96 } else
97 return 4;
98}
99
100static int mxc_rnga_init(struct hwrng *rng)
101{
102 u32 ctrl, osc;
103 struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
104
105 /* wake up */
106 ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
107 __raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, mxc_rng->mem + RNGA_CONTROL);
108
109 /* verify if oscillator is working */
110 osc = __raw_readl(mxc_rng->mem + RNGA_STATUS);
111 if (osc & RNGA_STATUS_OSC_DEAD) {
112 dev_err(mxc_rng->dev, "RNGA Oscillator is dead!\n");
113 return -ENODEV;
114 }
115
116 /* go running */
117 ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
118 __raw_writel(ctrl | RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL);
119
120 return 0;
121}
122
123static void mxc_rnga_cleanup(struct hwrng *rng)
124{
125 u32 ctrl;
126 struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
127
128 ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
129
130 /* stop rnga */
131 __raw_writel(ctrl & ~RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL);
132}
133
134static int __init mxc_rnga_probe(struct platform_device *pdev)
135{
136 int err;
137 struct mxc_rng *mxc_rng;
138
139 mxc_rng = devm_kzalloc(&pdev->dev, sizeof(*mxc_rng), GFP_KERNEL);
140 if (!mxc_rng)
141 return -ENOMEM;
142
143 mxc_rng->dev = &pdev->dev;
144 mxc_rng->rng.name = "mxc-rnga";
145 mxc_rng->rng.init = mxc_rnga_init;
146 mxc_rng->rng.cleanup = mxc_rnga_cleanup;
147 mxc_rng->rng.data_present = mxc_rnga_data_present;
148 mxc_rng->rng.data_read = mxc_rnga_data_read;
149
150 mxc_rng->clk = devm_clk_get(&pdev->dev, NULL);
151 if (IS_ERR(mxc_rng->clk)) {
152 dev_err(&pdev->dev, "Could not get rng_clk!\n");
153 return PTR_ERR(mxc_rng->clk);
154 }
155
156 err = clk_prepare_enable(mxc_rng->clk);
157 if (err)
158 return err;
159
160 mxc_rng->mem = devm_platform_ioremap_resource(pdev, 0);
161 if (IS_ERR(mxc_rng->mem)) {
162 err = PTR_ERR(mxc_rng->mem);
163 goto err_ioremap;
164 }
165
166 err = hwrng_register(&mxc_rng->rng);
167 if (err) {
168 dev_err(&pdev->dev, "MXC RNGA registering failed (%d)\n", err);
169 goto err_ioremap;
170 }
171
172 return 0;
173
174err_ioremap:
175 clk_disable_unprepare(mxc_rng->clk);
176 return err;
177}
178
179static int __exit mxc_rnga_remove(struct platform_device *pdev)
180{
181 struct mxc_rng *mxc_rng = platform_get_drvdata(pdev);
182
183 hwrng_unregister(&mxc_rng->rng);
184
185 clk_disable_unprepare(mxc_rng->clk);
186
187 return 0;
188}
189
190static const struct of_device_id mxc_rnga_of_match[] = {
191 { .compatible = "fsl,imx21-rnga", },
192 { .compatible = "fsl,imx31-rnga", },
193 { /* sentinel */ },
194};
195MODULE_DEVICE_TABLE(of, mxc_rnga_of_match);
196
197static struct platform_driver mxc_rnga_driver = {
198 .driver = {
199 .name = "mxc_rnga",
200 .of_match_table = mxc_rnga_of_match,
201 },
202 .remove = __exit_p(mxc_rnga_remove),
203};
204
205module_platform_driver_probe(mxc_rnga_driver, mxc_rnga_probe);
206
207MODULE_AUTHOR("Freescale Semiconductor, Inc.");
208MODULE_DESCRIPTION("H/W RNGA driver for i.MX");
209MODULE_LICENSE("GPL");