1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
|
/*
* Random Number Generator driver for the Keystone SOC
*
* Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com
*
* Authors: Sandeep Nair
* Vitaly Andrianov
*
* 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.
*/
#include <linux/hw_random.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/pm_runtime.h>
#include <linux/err.h>
#include <linux/regmap.h>
#include <linux/mfd/syscon.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/delay.h>
#define SA_CMD_STATUS_OFS 0x8
/* TRNG enable control in SA System module*/
#define SA_CMD_STATUS_REG_TRNG_ENABLE BIT(3)
/* TRNG start control in TRNG module */
#define TRNG_CNTL_REG_TRNG_ENABLE BIT(10)
/* Data ready indicator in STATUS register */
#define TRNG_STATUS_REG_READY BIT(0)
/* Data ready clear control in INTACK register */
#define TRNG_INTACK_REG_READY BIT(0)
/*
* Number of samples taken to gather entropy during startup.
* If value is 0, the number of samples is 2^24 else
* equals value times 2^8.
*/
#define TRNG_DEF_STARTUP_CYCLES 0
#define TRNG_CNTL_REG_STARTUP_CYCLES_SHIFT 16
/*
* Minimum number of samples taken to regenerate entropy
* If value is 0, the number of samples is 2^24 else
* equals value times 2^6.
*/
#define TRNG_DEF_MIN_REFILL_CYCLES 1
#define TRNG_CFG_REG_MIN_REFILL_CYCLES_SHIFT 0
/*
* Maximum number of samples taken to regenerate entropy
* If value is 0, the number of samples is 2^24 else
* equals value times 2^8.
*/
#define TRNG_DEF_MAX_REFILL_CYCLES 0
#define TRNG_CFG_REG_MAX_REFILL_CYCLES_SHIFT 16
/* Number of CLK input cycles between samples */
#define TRNG_DEF_CLK_DIV_CYCLES 0
#define TRNG_CFG_REG_SAMPLE_DIV_SHIFT 8
/* Maximum retries to get rng data */
#define SA_MAX_RNG_DATA_RETRIES 5
/* Delay between retries (in usecs) */
#define SA_RNG_DATA_RETRY_DELAY 5
struct trng_regs {
u32 output_l;
u32 output_h;
u32 status;
u32 intmask;
u32 intack;
u32 control;
u32 config;
};
struct ks_sa_rng {
struct device *dev;
struct hwrng rng;
struct clk *clk;
struct regmap *regmap_cfg;
struct trng_regs *reg_rng;
};
static int ks_sa_rng_init(struct hwrng *rng)
{
u32 value;
struct device *dev = (struct device *)rng->priv;
struct ks_sa_rng *ks_sa_rng = dev_get_drvdata(dev);
/* Enable RNG module */
regmap_write_bits(ks_sa_rng->regmap_cfg, SA_CMD_STATUS_OFS,
SA_CMD_STATUS_REG_TRNG_ENABLE,
SA_CMD_STATUS_REG_TRNG_ENABLE);
/* Configure RNG module */
writel(0, &ks_sa_rng->reg_rng->control);
value = TRNG_DEF_STARTUP_CYCLES << TRNG_CNTL_REG_STARTUP_CYCLES_SHIFT;
writel(value, &ks_sa_rng->reg_rng->control);
value = (TRNG_DEF_MIN_REFILL_CYCLES <<
TRNG_CFG_REG_MIN_REFILL_CYCLES_SHIFT) |
(TRNG_DEF_MAX_REFILL_CYCLES <<
TRNG_CFG_REG_MAX_REFILL_CYCLES_SHIFT) |
(TRNG_DEF_CLK_DIV_CYCLES <<
TRNG_CFG_REG_SAMPLE_DIV_SHIFT);
writel(value, &ks_sa_rng->reg_rng->config);
/* Disable all interrupts from TRNG */
writel(0, &ks_sa_rng->reg_rng->intmask);
/* Enable RNG */
value = readl(&ks_sa_rng->reg_rng->control);
value |= TRNG_CNTL_REG_TRNG_ENABLE;
writel(value, &ks_sa_rng->reg_rng->control);
return 0;
}
static void ks_sa_rng_cleanup(struct hwrng *rng)
{
struct device *dev = (struct device *)rng->priv;
struct ks_sa_rng *ks_sa_rng = dev_get_drvdata(dev);
/* Disable RNG */
writel(0, &ks_sa_rng->reg_rng->control);
regmap_write_bits(ks_sa_rng->regmap_cfg, SA_CMD_STATUS_OFS,
SA_CMD_STATUS_REG_TRNG_ENABLE, 0);
}
static int ks_sa_rng_data_read(struct hwrng *rng, u32 *data)
{
struct device *dev = (struct device *)rng->priv;
struct ks_sa_rng *ks_sa_rng = dev_get_drvdata(dev);
/* Read random data */
data[0] = readl(&ks_sa_rng->reg_rng->output_l);
data[1] = readl(&ks_sa_rng->reg_rng->output_h);
writel(TRNG_INTACK_REG_READY, &ks_sa_rng->reg_rng->intack);
return sizeof(u32) * 2;
}
static int ks_sa_rng_data_present(struct hwrng *rng, int wait)
{
struct device *dev = (struct device *)rng->priv;
struct ks_sa_rng *ks_sa_rng = dev_get_drvdata(dev);
u32 ready;
int j;
for (j = 0; j < SA_MAX_RNG_DATA_RETRIES; j++) {
ready = readl(&ks_sa_rng->reg_rng->status);
ready &= TRNG_STATUS_REG_READY;
if (ready || !wait)
break;
udelay(SA_RNG_DATA_RETRY_DELAY);
}
return ready;
}
static int ks_sa_rng_probe(struct platform_device *pdev)
{
struct ks_sa_rng *ks_sa_rng;
struct device *dev = &pdev->dev;
int ret;
struct resource *mem;
ks_sa_rng = devm_kzalloc(dev, sizeof(*ks_sa_rng), GFP_KERNEL);
if (!ks_sa_rng)
return -ENOMEM;
ks_sa_rng->dev = dev;
ks_sa_rng->rng = (struct hwrng) {
.name = "ks_sa_hwrng",
.init = ks_sa_rng_init,
.data_read = ks_sa_rng_data_read,
.data_present = ks_sa_rng_data_present,
.cleanup = ks_sa_rng_cleanup,
};
ks_sa_rng->rng.priv = (unsigned long)dev;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
ks_sa_rng->reg_rng = devm_ioremap_resource(dev, mem);
if (IS_ERR(ks_sa_rng->reg_rng))
return PTR_ERR(ks_sa_rng->reg_rng);
ks_sa_rng->regmap_cfg =
syscon_regmap_lookup_by_phandle(dev->of_node,
"ti,syscon-sa-cfg");
if (IS_ERR(ks_sa_rng->regmap_cfg)) {
dev_err(dev, "syscon_node_to_regmap failed\n");
return -EINVAL;
}
pm_runtime_enable(dev);
ret = pm_runtime_get_sync(dev);
if (ret < 0) {
dev_err(dev, "Failed to enable SA power-domain\n");
pm_runtime_disable(dev);
return ret;
}
platform_set_drvdata(pdev, ks_sa_rng);
return devm_hwrng_register(&pdev->dev, &ks_sa_rng->rng);
}
static int ks_sa_rng_remove(struct platform_device *pdev)
{
pm_runtime_put_sync(&pdev->dev);
pm_runtime_disable(&pdev->dev);
return 0;
}
static const struct of_device_id ks_sa_rng_dt_match[] = {
{
.compatible = "ti,keystone-rng",
},
{ },
};
MODULE_DEVICE_TABLE(of, ks_sa_rng_dt_match);
static struct platform_driver ks_sa_rng_driver = {
.driver = {
.name = "ks-sa-rng",
.of_match_table = ks_sa_rng_dt_match,
},
.probe = ks_sa_rng_probe,
.remove = ks_sa_rng_remove,
};
module_platform_driver(ks_sa_rng_driver);
MODULE_DESCRIPTION("Keystone NETCP SA H/W Random Number Generator driver");
MODULE_AUTHOR("Vitaly Andrianov <vitalya@ti.com>");
MODULE_LICENSE("GPL");
|
