Loading...
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");
|