michaelh/zephyr
1
0
Fork 0
Code Releases Activity

drivers: entropy: add driver for the neorv32 trng

Browse source 
Add entropy driver for the NEORV32 True Random Number Generator (TRNG).

Signed-off-by: Henrik Brix Andersen <henrik@brixandersen.dk>
This commit is contained in:
Henrik Brix Andersen 2021-10-06 22:10:36 +02:00 • committed by Christopher Friedt
commit 91233dba70
5 changed files with 171 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

1
drivers/entropy/CMakeLists.txt
View file

@ -16,3 +16,4 @@ zephyr_library_sources_ifdef(CONFIG_FAKE_ENTROPY_NATIVE_POSIX fake_entropy_nati
zephyr_library_sources_ifdef(CONFIG_USERSPACE entropy_handlers.c)
zephyr_library_sources_ifdef(CONFIG_ENTROPY_RV32M1_TRNG entropy_rv32m1_trng.c)
zephyr_library_sources_ifdef(CONFIG_ENTROPY_GECKO_TRNG entropy_gecko_trng.c)
zephyr_library_sources_ifdef(CONFIG_ENTROPY_NEORV32_TRNG entropy_neorv32_trng.c)

1
drivers/entropy/Kconfig
View file

@ -31,6 +31,7 @@ source "drivers/entropy/Kconfig.native_posix"
source "drivers/entropy/Kconfig.rv32m1"
source "drivers/entropy/Kconfig.litex"
source "drivers/entropy/Kconfig.gecko"
source "drivers/entropy/Kconfig.neorv32"
config ENTROPY_HAS_DRIVER
bool

13
drivers/entropy/Kconfig.neorv32 Normal file
View file

@ -0,0 +1,13 @@
# NEORV32 TRNG configuration
# Copyright (c) 2021 Henrik Brix Andersen <henrik@brixandersen.dk>
# SPDX-License-Identifier: Apache-2.0
config ENTROPY_NEORV32_TRNG
bool "NEORV32 TRNG"
default $(dt_compat_enabled,neorv32-trng)
depends on SOC_SERIES_NEORV32 && SYSCON
select ENTROPY_HAS_DRIVER
help
This option enables the True Random Number Generator (TRNG) driver for
the NEORV32.

152
drivers/entropy/entropy_neorv32_trng.c Normal file
View file

@ -0,0 +1,152 @@
/*
* Copyright (c) 2021 Henrik Brix Andersen <henrik@brixandersen.dk>
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT neorv32_trng
#include <device.h>
#include <drivers/syscon.h>
#include <drivers/entropy.h>
#include <sys/sys_io.h>
#include <logging/log.h>
LOG_MODULE_REGISTER(neorv32_trng, CONFIG_ENTROPY_LOG_LEVEL);
/* TRNG CTRL register bits */
#define NEORV32_TRNG_CTRL_DATA_MASK BIT_MASK(8)
#define NEORV32_TRNG_CTRL_EN BIT(30)
#define NEORV32_TRNG_CTRL_VALID BIT(31)
struct neorv32_trng_config {
const struct device *syscon;
mm_reg_t base;
};
static inline uint32_t neorv32_trng_read_ctrl(const struct device *dev)
{
const struct neorv32_trng_config *config = dev->config;
return sys_read32(config->base);
}
static inline void neorv32_trng_write_ctrl(const struct device *dev, uint32_t ctrl)
{
const struct neorv32_trng_config *config = dev->config;
sys_write32(ctrl, config->base);
}
static int neorv32_trng_get_entropy(const struct device *dev, uint8_t *buffer, uint16_t len)
{
uint32_t ctrl;
while (len > 0) {
ctrl = neorv32_trng_read_ctrl(dev);
if ((ctrl & NEORV32_TRNG_CTRL_VALID) != 0) {
*buffer++ = ctrl & NEORV32_TRNG_CTRL_DATA_MASK;
len--;
}
}
return 0;
}
static int neorv32_trng_get_entropy_isr(const struct device *dev, uint8_t *buffer,
uint16_t len, uint32_t flags)
{
uint32_t ctrl;
int err;
if ((flags & ENTROPY_BUSYWAIT) == 0) {
ctrl = neorv32_trng_read_ctrl(dev);
if ((ctrl & NEORV32_TRNG_CTRL_VALID) != 0) {
*buffer = ctrl & NEORV32_TRNG_CTRL_DATA_MASK;
return 1;
}
/* No entropy available */
return 0;
}
err = neorv32_trng_get_entropy(dev, buffer, len);
if (err < 0) {
return err;
}
return len;
}
static int neorv32_trng_init(const struct device *dev)
{
const struct neorv32_trng_config *config = dev->config;
uint32_t features;
int err;
if (!device_is_ready(config->syscon)) {
LOG_ERR("syscon device not ready");
return -EINVAL;
}
err = syscon_read_reg(config->syscon, NEORV32_SYSINFO_FEATURES, &features);
if (err < 0) {
LOG_ERR("failed to determine implemented features (err %d)", err);
return err;
}
if ((features & NEORV32_SYSINFO_FEATURES_IO_TRNG) == 0) {
LOG_ERR("neorv32 trng not supported");
return -ENODEV;
}
neorv32_trng_write_ctrl(dev, NEORV32_TRNG_CTRL_EN);
return 0;
}
#ifdef CONFIG_PM_DEVICE
static int neorv32_trng_pm_action(const struct device *dev, enum pm_device_action action)
{
switch (action) {
case PM_DEVICE_ACTION_SUSPEND:
neorv32_trng_write_ctrl(dev, 0);
break;
case PM_DEVICE_ACTION_RESUME:
neorv32_trng_write_ctrl(dev, NEORV32_TRNG_CTRL_EN);
break;
default:
return -ENOTSUP;
}
return 0;
}
#endif /* CONFIG_PM_DEVICE */
static const struct entropy_driver_api neorv32_trng_driver_api = {
.get_entropy = neorv32_trng_get_entropy,
.get_entropy_isr = neorv32_trng_get_entropy_isr,
};
#ifdef CONFIG_PM_DEVICE
#define NEORV32_TRNG_PM_ACTION_CB neorv32_trng_pm_action
#else /* CONFIG_PM_DEVICE */
#define NEORV32_TRNG_PM_ACTION_CB NULL
#endif /* ! CONFIG_PM_DEVICE */
#define NEORV32_TRNG_INIT(n) \
static const struct neorv32_trng_config neorv32_trng_##n##_config = { \
.syscon = DEVICE_DT_GET(DT_INST_PHANDLE(n, syscon)), \
.base = DT_INST_REG_ADDR(n), \
}; \
\
DEVICE_DT_INST_DEFINE(n, &neorv32_trng_init, \
NEORV32_TRNG_PM_ACTION_CB, \
NULL, \
&neorv32_trng_##n##_config, \
PRE_KERNEL_1, \
CONFIG_ENTROPY_INIT_PRIORITY, \
&neorv32_trng_driver_api);
DT_INST_FOREACH_STATUS_OKAY(NEORV32_TRNG_INIT)

4
soc/riscv/riscv-privilege/neorv32/Kconfig.defconfig.series
View file

@ -25,4 +25,8 @@ config SERIAL_INIT_PRIORITY
default 55
depends on SERIAL
config ENTROPY_INIT_PRIORITY
default 55
depends on ENTROPY_GENERATOR
endif # SOC_SERIES_NEORV32