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SAMA5 TRNG: Add a /dev/random driver based on the SAMA5D3 TRNG peripheral

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This commit is contained in:
Gregory Nutt 2013-10-20 11:38:31 -06:00
parent 891c463381
commit 0ebdbfbc88
8 changed files with 536 additions and 2 deletions
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3
ChangeLog
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@ -5827,4 +5827,5 @@
SAMA5 RTC driver (2013-10-19).
* arch/arm/src/sama5/sam_wdt.c and .h: Add a SAMA5 watchdog timer
drvier. Untested on initial check-in (2013-10-19).
* arch/arm/src/sama5/sam_trng.c, sam_trng.h, and chip/sam_trng.h: Add
a /dev/random driver based on the SAMA5D3 TRNG peripheral (2013-10-20).

1
arch/arm/src/sama5/Kconfig
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@ -276,6 +276,7 @@ config SAMA5_TDES
config SAMA5_TRNG
bool "True Random Number Generator (TRNG)"
default n
select DEV_RANDOM
config SAMA5_ARM
bool "Performance Monitor Unit (ARM)"

4
arch/arm/src/sama5/Make.defs
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@ -118,6 +118,10 @@ ifeq ($(CONFIG_SAMA5_WDT),y)
CHIP_CSRCS += sam_wdt.c
endif
ifeq ($(CONFIG_SAMA5_TRNG),y)
CHIP_CSRCS += sam_trng.c
endif
ifeq ($(CONFIG_SAMA5_SPI0),y)
CHIP_CSRCS += sam_spi.c
else

84
arch/arm/src/sama5/chip/sam_trng.h Normal file
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@ -0,0 +1,84 @@
/************************************************************************************
* arch/arm/src/sama5/chip/sam_trng.h
*
* Copyright (C) 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
************************************************************************************/
#ifndef __ARCH_ARM_SRC_SAMA5_CHIP_SAM_TRNG_H
#define __ARCH_ARM_SRC_SAMA5_CHIP_SAM_TRNG_H
/************************************************************************************
* Included Files
************************************************************************************/
#include <nuttx/config.h>
#include "chip/sam_memorymap.h"
/************************************************************************************
* Pre-processor Definitions
************************************************************************************/
/* TRNG Register Offsets ************************************************************/
#define SAM_TRNG_CR_OFFSET 0x0000 /* Control Register */
#define SAM_TRNG_IER_OFFSET 0x0010 /* Interrupt Enable Register */
#define SAM_TRNG_IDR_OFFSET 0x0014 /* Interrupt Disable Register */
#define SAM_TRNG_IMR_OFFSET 0x0018 /* Interrupt Mask Register */
#define SAM_TRNG_ISR_OFFSET 0x001c /* Interrupt Status Register */
#define SAM_TRNG_ODATA_OFFSET 0x0050 /* Output Data Register */
/* TRNG Register Addresses **********************************************************/
#define SAM_TRNG_CR (SAM_TRNG_VBASE+SAM_TRNG_CR_OFFSET)
#define SAM_TRNG_IER (SAM_TRNG_VBASE+SAM_TRNG_IER_OFFSET)
#define SAM_TRNG_IDR (SAM_TRNG_VBASE+SAM_TRNG_IDR_OFFSET)
#define SAM_TRNG_IMR (SAM_TRNG_VBASE+SAM_TRNG_IMR_OFFSET)
#define SAM_TRNG_ISR (SAM_TRNG_VBASE+SAM_TRNG_ISR_OFFSET)
#define SAM_TRNG_ODATA (SAM_TRNG_VBASE+SAM_TRNG_ODATA_OFFSET)
/* TRNG Register Bit Definitions ****************************************************/
/* Control Register */
#define TRNG_CR_ENABLE (1 << 0) /* Bit 0: nables the TRNG */
#define TRNG_CR_KEY_SHIFT (8) /* Bits 8-31: Security key */
#define TRNG_CR_KEY_MASK (0xffffff << TRNG_CR_KEY_SHIFT)
# define TRNG_CR_KEY (0x524e47 << TRNG_CR_KEY_SHIFT) /* RNG in ASCII */
/* Interrupt Enable Register, Interrupt Disable Register, Interrupt Mask Register,
* and Interrupt Status Register
*/
#define TRNG_INT_DATRDY (1 << 0) /* Bit 0: Data ready */
/* Output Data Register (32-bit output data) */
#endif /* __ARCH_ARM_SRC_SAMA5_CHIP_SAM_TRNG_H */

353
arch/arm/src/sama5/sam_trng.c Normal file
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@ -0,0 +1,353 @@
/****************************************************************************
* arch/arm/src/sama5/sam_trng.c
*
* Copyright (C) 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Derives, in part, from Max Holtzberg's STM32 RNG Nuttx driver:
*
* Copyright (C) 2012 Max Holtzberg. All rights reserved.
* Author: Max Holtzberg <mh@uvc.de>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include "up_arch.h"
#include "up_internal.h"
#include "sam_periphclks.h"
#include "sam_trng.h"
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* Interrupts */
static int sam_interrupt(int irq, void *context);
/* Character driver methods */
static ssize_t sam_read(struct file *filep, char *buffer, size_t);
/****************************************************************************
* Private Types
****************************************************************************/
struct trng_dev_s
{
sem_t exclsem; /* Enforces exclusive access to the TRNG */
sem_t waitsem; /* Wait for buffer full */
uint32_t *samples; /* Current buffer being filled */
size_t maxsamples; /* Size of the current buffer (in 32-bit words) */
volatile size_t nsamples; /* Number of samples currently buffered */
volatile bool first; /* The first random number must be handled differently */
};
/****************************************************************************
* Private Data
****************************************************************************/
static struct trng_dev_s g_trngdev;
static const struct file_operations g_trngops =
{
0, /* open */
0, /* close */
sam_read, /* read */
0, /* write */
0, /* seek */
0 /* ioctl */
#ifndef CONFIG_DISABLE_POLL
,0 /* poll */
#endif
};
/****************************************************************************
* Private functions
****************************************************************************/
/****************************************************************************
* Name: sam_interrupt
*
* Description:
* The TRNG interrupt handler
*
* Input Parameters:
*
* Returned Value:
*
*
****************************************************************************/
static int sam_interrupt(int irq, void *context)
{
uint32_t odata;
/* Verify that sample data is available */
if ((getreg32(SAM_TRNG_ISR) & CONFIG_SAMA5_TRNG) == 0)
{
/* No? Then why are we here? */
return OK;
}
/* Read the random sample */
odata = getreg32(SAM_TRNG_ODATA);
/* As required by the FIPS PUB (Federal Information Processing Standard
* Publication) 140-2, the first random number generated after setting the
* RNGEN bit should not be used, but saved for comparison with the next
* generated random number. Each subsequent generated random number has to be
* compared with the previously generated number. The test fails if any two
* compared numbers are equal (continuous random number generator test).
*/
if (g_trngdev.nsamples == 0)
{
/* This is the first sample we have taken. Save it for subsequent
* comparison.
*/
g_trngdev.samples[0] = odata;
g_trngdev.nsamples = 1;
return OK;
}
/* This is not the first sample. Check if the new sample differs from the
* preceding sample.
*/
else if (odata == g_trngdev.samples[g_trngdev.nsamples - 1])
{
/* Two ssamples with the same value. Discard this one and try again. */
return OK;
}
/* The numbers differ. Have we discarded the first sample yet? */
if (g_trngdev.first)
{
/* No, discard it now by replacing it with the new sample */
g_trngdev.samples[0] = odata;
g_trngdev.nsamples = 1;
g_trngdev.first = false;
}
/* Yes.. the first sample has been dicarded */
else
{
/* Add the new random number to the buffer */
g_trngdev.samples[g_trngdev.nsamples] = odata;
g_trngdev.nsamples++;
}
/* Have all of the requested samples been saved? */
if (g_trngdev.nsamples == g_trngdev.maxsamples)
{
/* Yes.. disable any further interrupts */
putreg32(TRNG_INT_DATRDY, SAM_TRNG_IER);
/* And wakeup the waiting read thread. */
sem_post(&g_trngdev.waitsem);
}
return OK;
}
/****************************************************************************
* Name: sam_read
*
* Description:
* This is the standard, NuttX character driver read method
*
* Input Parameters:
* filep - The VFS file instance
* buffer - Buffer in which to return the random samples
* buflen - The length of the buffer
*
* Returned Value:
*
****************************************************************************/
static ssize_t sam_read(struct file *filep, char *buffer, size_t buflen)
{
ssize_t retval;
int ret;
fvdbg("buffer=%p buflen=%d\n", buffer, (int)buflen);
/* Get exclusive access to the TRNG harware */
if (sem_wait(&g_trngdev.exclsem) != OK)
{
/* This is probably -EINTR meaning that we were awakened by a signal */
return -errno;
}
/* Save the buffer information. */
DEBUGASSERT(((uintptr_t)buffer & 3) == 0);
g_trngdev.samples = (uint32_t*)buffer;
g_trngdev.maxsamples = buflen >> 2;
g_trngdev.nsamples = 0;
g_trngdev.first = true;
/* Enable TRNG interrupts */
putreg32(TRNG_INT_DATRDY, SAM_TRNG_IER);
/* Wait until the buffer is filled */
while (g_trngdev.nsamples < g_trngdev.maxsamples)
{
ret = sem_wait(&g_trngdev.waitsem);
fvdbg("Awakened: nsamples=%d maxsamples=%d ret=%d\n",
g_trngdev.nsamples, g_trngdev.maxsamples, ret);
if (ret < 0)
{
/* We must have been awakened by a signal */
if (g_trngdev.nsamples > 0)
{
break;
}
else
{
retval = -errno;
goto errout;
}
}
}
/* Success... calculate the number of bytes to return */
retval = g_trngdev.nsamples << 2;
errout:
/* Disable TRNG interrupts */
putreg32(TRNG_INT_DATRDY, SAM_TRNG_IDR);
/* Release our lock on the TRNG hardware */
sem_post(&g_trngdev.exclsem);
fvdbg("Return %d\n", (int)retval);
return retval;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_rnginitialize
*
* Description:
* Initialize the TRNG hardware and register the /dev/randome driver.
*
* Input Parameters:
* None
*
* Returned Value:
* None
*
****************************************************************************/
void up_rnginitialize(void)
{
int ret;
fvdbg("Initializing TRNG hardware\n");
/* Initialize the device structure */
memset(&g_trngdev, 0, sizeof(struct trng_dev_s));
sem_init(&g_trngdev.exclsem, 0, 1);
sem_init(&g_trngdev.waitsem, 0, 0);
/* Enable clocking to the TRNG */
sam_trng_enableclk();
/* Initialize the TRNG interrupt */
if (irq_attach(SAM_IRQ_TRNG, sam_interrupt))
{
fdbg("ERROR: Failed to attach to IRQ%d\n", SAM_IRQ_TRNG);
return;
}
/* Disable the interrupts at the TRNG */
putreg32(TRNG_INT_DATRDY, SAM_TRNG_IDR);
/* Register the character driver */
ret = register_driver("/dev/random", &g_trngops, 0644, NULL);
if (ret < 0)
{
fdbg("ERROR: Failed to register /dev/random\n");
return;
}
/* Enable the TRNG interrupt at the AIC */
up_enable_irq(SAM_IRQ_TRNG);
}

75
arch/arm/src/sama5/sam_trng.h Normal file
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@ -0,0 +1,75 @@
/****************************************************************************
* arch/arm/src/sama5/sam_trng.h
*
* Copyright (C) 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#ifndef __ARCH_ARM_SRC_SAMA5_SAM_TRNG_H
#define __ARCH_ARM_SRC_SAMA5_SAM_TRNG_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include "chip.h"
#include "chip/sam_trng.h"
#if defined(CONFIG_DEV_RANDOM) && defined(CONFIG_SAMA5_TRNG)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifndef __ASSEMBLY__
#undef EXTERN
#if defined(__cplusplus)
#define EXTERN extern "C"
extern "C" {
#else
#define EXTERN extern
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
#undef EXTERN
#if defined(__cplusplus)
}
#endif
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_DEV_RANDOM && CONFIG_SAMA5_TRNG */
#endif /* __ARCH_ARM_SRC_SAMA5_SAM_TRNG_H */

2
arch/arm/src/sama5/sam_wdt.c
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@ -427,7 +427,7 @@ static int sam_getstatus(FAR struct watchdog_lowerhalf_s *lower,
wdvdbg("Status :\n");
wdvdbg(" flags : %08x\n", status->flags);
wdvdbg(" timeout : %d\n", status->timeout);
wdvdbg(" timeleft : %d\n", status->flags);
wdvdbg(" timeleft : %d\n", status->timeleft);
return OK;
}

16
configs/sama5d3x-ek/README.txt
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@ -2226,6 +2226,22 @@ Configurations
beware that the default version also disables the watchdog. You will
need a special version of norboot with CONFIG_SAMA5_WDT=y.
19. This example can be configured to enable the SAMA5 TRNG peripheral so
that it provides /dev/random. The following configuration will enable
the TRNG, /dev/random, and the simple test of /dev/random at
apps/examples/ranadom:
System Type:
CONFIG_SAMA5_TRNG=y : Enable the TRNG peripheral
Drivers (automatically selected):
CONFIG_DEV_RANDOM=y : Enable /dev/random
Applications -> Examples
CONFIG_EXAMPLES_RANDOM=y : Enable apps/examples/random
CONFIG_EXAMPLES_MAXSAMPLES=64 : Default settings are probably OK
CONFIG_EXAMPLES_NSAMPLES=8
STATUS:
PCK FREQUENCY