1 files changed, 353 insertions, 0 deletions
diff --git a/nuttx/arch/arm/src/sama5/sam_trng.c b/nuttx/arch/arm/src/sama5/sam_trng.c
new file mode 100644
index 000000000..f865d081d
--- /dev/null
+++ b/nuttx/arch/arm/src/sama5/sam_trng.c
@@ -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);
+}