Merged in masayuki2009/nuttx.nuttx/lc823450_dvfs (pull request #566)

lc823450 dvfs

Approved-by: Gregory Nutt <gnutt@nuttx.org>

arch/arm/src/lc823450/Kconfig

@@ -246,5 +246,8 @@ config HRT_TIMER
 	bool "High resolution timer"
 	default n
 
+config DVFS
+	bool "Dynamic Voltage and Frequencey Scaling"
+	default n
 
 endmenu

arch/arm/src/lc823450/Make.defs

@@ -146,7 +146,8 @@ endif
 endif
 
 ifeq ($(CONFIG_DVFS),y)
-CHIP_CSRCS += lc823450_dvfs.c
+CHIP_CSRCS += lc823450_dvfs2.c
+CHIP_CSRCS += lc823450_procfs_dvfs.c
 endif
 
 ifeq ($(CONFIG_PM),y)

arch/arm/src/lc823450/lc823450_dvfs2.c

@@ -0,0 +1,429 @@
+/****************************************************************************
+ * arch/arm/src/lc823450/lc823450_dvfs2.c
+ *
+ *   Copyright (C) 2015-2017 Sony Corporation. All rights reserved.
+ *   Author: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
+ *   Author: Masatoshi Tateishi <Masatoshi.Tateishi@jp.sony.com>
+ *
+ * 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 <nuttx/config.h>
+
+#include <nuttx/arch.h>
+#include <nuttx/clock.h>
+#include <arch/board/board.h>
+#include <string.h>
+
+#include "up_arch.h"
+
+#include "lc823450_clockconfig.h"
+#include "lc823450_syscontrol.h"
+#include "lc823450_intc.h"
+#include "lc823450_sdc.h"
+#include "lc823450_dvfs2.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define FREQ_160 0
+#define FREQ_080 1
+#define FREQ_040 2
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+typedef struct freq_entry
+{
+  uint16_t freq;
+  uint16_t pll1;
+  uint16_t mdiv;
+  uint16_t hdiv;
+} t_freq_entry;
+
+static struct freq_entry _dvfs_act_tbl[3] =
+{
+  { 160, OSCCNT_MCSEL, OSCCNT_MAINDIV_1, 3},  /* PLL1 */
+  {  80, OSCCNT_MCSEL, OSCCNT_MAINDIV_2, 1},  /* PLL1 */
+  {  40, OSCCNT_MCSEL, OSCCNT_MAINDIV_4, 0},  /* PLL1 */
+};
+
+static struct freq_entry _dvfs_idl_tbl[3] =
+{
+  {  24,            0, OSCCNT_MAINDIV_1, 0},  /* XT1  */
+  {  12,            0, OSCCNT_MAINDIV_2, 0},  /* XT1  */
+  {   6,            0, OSCCNT_MAINDIV_4, 0},  /* XT1  */
+};
+
+static uint16_t _dvfs_cur_idx  = 0; /* current speed index */
+static uint16_t _dvfs_cur_hdiv = 3;
+static uint16_t _dvfs_cur_mdiv = OSCCNT_MAINDIV_1;
+
+#if 0
+static uint16_t _dvfs_init_timeout = (5 * 100); /* in ticks */
+#endif
+
+#if defined(CONFIG_SMP) && (CONFIG_SMP_NCPUS == 2)
+static uint8_t  _dvfs_cpu_is_active[CONFIG_SMP_NCPUS];
+#endif
+
+static void lc823450_dvfs_set_div(int idx, int tbl);
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+int8_t   g_dvfs_enabled  = 0;
+uint16_t g_dvfs_cur_freq = 160;
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: lc823450_dvfs_update_lpm
+ ****************************************************************************/
+
+static void lc823450_dvfs_update_lpm(int freq)
+{
+  /* TODO */
+}
+
+#if defined(CONFIG_SMP) && (CONFIG_SMP_NCPUS == 2)
+static int _dvfs_another_cpu_state(int me)
+{
+  if (0 == me)
+    {
+      return _dvfs_cpu_is_active[1];
+    }
+  else
+    {
+      return _dvfs_cpu_is_active[0];
+    }
+}
+#endif
+
+/****************************************************************************
+ * Name: lc823450_dvfs_set_div
+ * Set dividers in the OSC block
+ * target tbl: 0=active, 1=idle
+ ****************************************************************************/
+
+static void lc823450_dvfs_set_div(int idx, int tbl)
+{
+  uint32_t target;
+  uint32_t t_hdiv;
+  uint32_t t_mdiv;
+
+  if (0 == tbl)
+    {
+      target  = _dvfs_act_tbl[idx].freq;
+      t_hdiv  = _dvfs_act_tbl[idx].hdiv;
+      t_mdiv  = _dvfs_act_tbl[idx].mdiv;
+    }
+  else
+    {
+      target  = _dvfs_idl_tbl[idx].freq;
+      t_hdiv  = _dvfs_idl_tbl[idx].hdiv;
+      t_mdiv  = _dvfs_idl_tbl[idx].mdiv;
+    }
+
+  if (100 < target)
+    {
+      /* Set ROM wait cycle (CPU=1wait) */
+
+      modifyreg32(MEMEN4, 0, MEMEN4_HWAIT);
+    }
+
+    /* adjust AHB */
+
+  if (t_hdiv > _dvfs_cur_hdiv)
+    {
+      uint32_t pclkdiv = t_hdiv;
+#ifdef CONFIG_LC823450_SDRAM
+      pclkdiv += (t_hdiv << 16);
+#endif
+      putreg32(pclkdiv, PERICLKDIV);
+    }
+
+  uint32_t regval = getreg32(OSCCNT);
+
+  /* NOTE: In LC823450, MCSEL is reflected first then MAINDIV */
+  /* To avoid spec violation, 2-step clock change is needed */
+
+  /* step 1 : change MAINDIV if needed */
+
+  if (t_mdiv > _dvfs_cur_mdiv)
+    {
+      regval &= ~OSCCNT_MAINDIV_MASK;
+      regval |= t_mdiv;
+
+      /* change the MAINDIV first */
+
+      putreg32(regval, OSCCNT);
+    }
+
+    /* step 2 : change MCSEL and MAINDIV */
+
+  regval = getreg32(OSCCNT);
+  regval &= ~(OSCCNT_MCSEL | OSCCNT_MAINDIV_MASK);
+
+  if (0 == tbl)
+    {
+      regval |= _dvfs_act_tbl[idx].pll1;
+    }
+  else
+    {
+      regval |= _dvfs_idl_tbl[idx].pll1;
+    }
+
+  regval |= t_mdiv;
+
+  /* set MCSEL and MAINDIV again */
+
+  putreg32(regval, OSCCNT);
+
+  /* update loops_per_msec for up_udelay(), up_mdelay() */
+
+  if (0 == tbl)
+    {
+      lc823450_dvfs_update_lpm(_dvfs_act_tbl[idx].freq);
+    }
+  else
+    {
+      lc823450_dvfs_update_lpm(_dvfs_idl_tbl[idx].freq);
+    }
+
+  /* adjust AHB */
+
+  if (t_hdiv < _dvfs_cur_hdiv)
+    {
+      uint32_t pclkdiv = t_hdiv;
+#ifdef CONFIG_LC823450_SDRAM
+      pclkdiv += (t_hdiv << 16);
+#endif
+      putreg32(pclkdiv, PERICLKDIV);
+    }
+
+  _dvfs_cur_idx   = idx;
+  _dvfs_cur_hdiv  = t_hdiv;
+  _dvfs_cur_mdiv  = t_mdiv;
+  g_dvfs_cur_freq = target;
+
+  if (100 > target)
+    {
+      /* Clear ROM wait cycle (CPU=0wait) */
+
+      modifyreg32(MEMEN4, MEMEN4_HWAIT, 0);
+    }
+
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: lc823450_get_apb
+ * Assumption: CPU=APB
+ ****************************************************************************/
+
+uint32_t lc823450_get_apb(void)
+{
+  return g_dvfs_cur_freq * 1000000;
+}
+
+/****************************************************************************
+ * Name: lc823450_dvfs_tick_callback
+ * This callback is called in the timer interupt
+ ****************************************************************************/
+
+void lc823450_dvfs_tick_callback(void)
+{
+#if 0
+  if (_dvfs_init_timeout)
+    {
+      _dvfs_init_timeout--;
+
+      if (0 == _dvfs_init_timeout)
+        {
+          g_dvfs_enabled = 1;
+        }
+    }
+#endif
+}
+
+/****************************************************************************
+ * Name: lc823450_dvfs_enter_idle
+ ****************************************************************************/
+
+void lc823450_dvfs_enter_idle(void)
+{
+  irqstate_t flags = spin_lock_irqsave();
+
+  if (0 == g_dvfs_enabled)
+    {
+      goto exit_with_error;
+    }
+
+#if defined(CONFIG_SMP) && (CONFIG_SMP_NCPUS == 2)
+  int me = up_cpu_index();
+
+  /* Update my state first : 0 (idle) */
+
+  _dvfs_cpu_is_active[me] = 0;
+
+  /* check if another core is still active */
+
+  if (_dvfs_another_cpu_state(me))
+    {
+      /* do not change to idle clock */
+
+      goto exit_with_error;
+    }
+
+#endif
+
+#ifdef CONFIG_DVFS_CHECK_SDC
+  if (lc823450_sdc_locked())
+    {
+      goto exit_with_error;
+    }
+#endif
+
+  /* NOTE: set idle freq : idx=same, change:tbl */
+
+  lc823450_dvfs_set_div(_dvfs_cur_idx, 1);
+
+exit_with_error:
+  spin_unlock_irqrestore(flags);
+}
+
+/****************************************************************************
+ * Name: lc823450_dvfs_exit_idle
+ * This API is called in up_ack_irq() (i.e. interrupt context)
+ ****************************************************************************/
+
+void lc823450_dvfs_exit_idle(int irq)
+{
+  irqstate_t flags = spin_lock_irqsave();
+
+  if (0 == g_dvfs_enabled)
+    {
+      goto exit_with_error;
+    }
+
+#if defined(CONFIG_SMP) && (CONFIG_SMP_NCPUS == 2)
+  int me = up_cpu_index();
+
+  /* Update my state first: 1 (active) */
+
+  _dvfs_cpu_is_active[me] = 1;
+
+  /* Check if another core is already active */
+
+  if (_dvfs_another_cpu_state(me))
+    {
+      /* do nothing */
+
+      goto exit_with_error;
+    }
+#endif
+
+  /* NOTE: set active freq : idx=same, change:tbl */
+
+  lc823450_dvfs_set_div(_dvfs_cur_idx, 0);
+
+exit_with_error:
+  spin_unlock_irqrestore(flags);
+}
+
+/****************************************************************************
+ * Name: lc823450_dvfs_boost
+ * boost the sytem clock to MAX (i.e. 160M)
+ * timeout in msec
+ ****************************************************************************/
+
+int lc823450_dvfs_boost(int timeout)
+{
+  /* TODO */
+  return 0;
+}
+
+/****************************************************************************
+ * Name: lc823450_dvfs_set_freq
+ * NOTE: should be called from dvfs command only
+ ****************************************************************************/
+
+int lc823450_dvfs_set_freq(int freq)
+{
+  int ret = 0;
+  int idx;
+  irqstate_t flags;
+
+  if (0 == g_dvfs_enabled)
+    {
+      return -1;
+    }
+
+  flags = spin_lock_irqsave();
+
+  switch (freq)
+    {
+      case 160:
+        idx = FREQ_160;
+        break;
+
+      case 80:
+        idx = FREQ_080;
+        break;
+
+      case 40:
+        idx = FREQ_040;
+        break;
+
+      default:
+        ret = -1;
+        break;
+    }
+
+  if (0 == ret)
+    {
+      lc823450_dvfs_set_div(idx, 0);
+    }
+
+  spin_unlock_irqrestore(flags);
+  return ret;
+}

arch/arm/src/lc823450/lc823450_dvfs2.h

@@ -0,0 +1,75 @@
+/****************************************************************************
+ * arch/arm/src/lc823450/lc823450_dvfs2.h
+ *
+ *   Copyright (C) 2015-2017 Sony Corporation. All rights reserved.
+ *   Author: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
+ *
+ * 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_LC823450_LC823450_DVFS2_H
+#define __ARCH_ARM_SRC_LC823450_LC823450_DVFS2_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#ifndef __ASSEMBLY__
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+void lc823450_dvfs_set_min(uint8_t id, uint16_t mhz);
+void lc823450_dvfs_enter_idle(void);
+void lc823450_dvfs_exit_idle(int irq);
+int  lc823450_dvfs_set_freq(int freq);
+void lc823450_dvfs_tick_callback(void);
+
+int  dvfs_procfs_register(void);
+
+#if defined(__cplusplus)
+}
+#endif
+#undef EXTERN
+#endif /* __ASSEMBLY__ */
+#endif /* __ARCH_ARM_SRC_LC823450_LC823450_DVFS2_H */

arch/arm/src/lc823450/lc823450_idle.c

@@ -50,7 +50,7 @@
 #include "up_arch.h"
 
 #ifdef CONFIG_DVFS
-#  include "lc823450_dvfs.h"
+#  include "lc823450_dvfs2.h"
 #endif
 
 /****************************************************************************
@@ -62,6 +62,8 @@ static int32_t  g_in_sleep;
 static uint64_t g_sleep_t0;
 #endif /* CONFIG_LC823450_SLEEP_MODE */
 
+static uint32_t g_idle_counter[2];
+
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -124,18 +126,21 @@ void up_idle(void)
   regval &= ~NVIC_SYSCON_SLEEPDEEP;
   putreg32(regval, NVIC_SYSCON);
 
+  leave_critical_section(flags);
+#endif /* CONFIG_LC823450_SLEEP_MODE */
+
 #ifdef CONFIG_DVFS
   lc823450_dvfs_enter_idle();
 #endif
 
-  leave_critical_section(flags);
-#endif /* CONFIG_LC823450_SLEEP_MODE */
-
   board_autoled_off(LED_CPU0 + up_cpu_index());
 
   /* Sleep until an interrupt occurs to save power */
 
   asm("WFI");
+
+  g_idle_counter[up_cpu_index()]++;
+
 #endif
 }
 

arch/arm/src/lc823450/lc823450_irq.c

@@ -58,7 +58,7 @@
 #include "lc823450_intc.h"
 
 #ifdef CONFIG_DVFS
-#  include "lc823450_dvfs.h"
+#  include "lc823450_dvfs2.h"
 #endif
 
 /****************************************************************************

arch/arm/src/lc823450/lc823450_procfs_dvfs.c

@@ -0,0 +1,354 @@
+/****************************************************************************
+ * arch/arm/src/lc823450/lc823450_procfs_dvfs.c
+ *
+ *   Copyright (C) 2018 Sony Corporation. All rights reserved.
+ *   Author: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
+ *
+ * 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 <nuttx/config.h>
+
+#include <sys/types.h>
+#include <sys/statfs.h>
+#include <sys/stat.h>
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <assert.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/arch.h>
+#include <nuttx/sched.h>
+#include <nuttx/kmalloc.h>
+#include <nuttx/fs/fs.h>
+#include <nuttx/fs/procfs.h>
+#include <nuttx/fs/dirent.h>
+
+#include <arch/irq.h>
+
+#include "lc823450_dvfs2.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define DVFS_LINELEN  64
+
+#ifndef MIN
+#  define MIN(a,b) (a < b ? a : b)
+#endif
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct dvfs_file_s
+{
+  struct procfs_file_s  base;    /* Base open file structure */
+  unsigned int linesize;         /* Number of valid characters in line[] */
+  char line[DVFS_LINELEN];       /* Pre-allocated buffer for formatted lines */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static int     dvfs_open(FAR struct file *filep, FAR const char *relpath,
+                         int oflags, mode_t mode);
+static int     dvfs_close(FAR struct file *filep);
+static ssize_t dvfs_read(FAR struct file *filep, FAR char *buffer,
+                         size_t buflen);
+static ssize_t dvfs_write(FAR struct file *filep, FAR const char *buffer,
+                          size_t buflen);
+static int     dvfs_dup(FAR const struct file *oldp,
+                        FAR struct file *newp);
+static int     dvfs_stat(FAR const char *relpath, FAR struct stat *buf);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct procfs_operations dvfs_procfsoperations =
+{
+  dvfs_open,      /* open */
+  dvfs_close,     /* close */
+  dvfs_read,      /* read */
+  dvfs_write,     /* write */
+  dvfs_dup,       /* dup */
+  NULL,           /* opendir */
+  NULL,           /* closedir */
+  NULL,           /* readdir */
+  NULL,           /* rewinddir */
+  dvfs_stat       /* stat */
+};
+
+static const struct procfs_entry_s g_procfs_dvfs =
+{
+  "dvfs",
+  &dvfs_procfsoperations
+};
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+extern int8_t   g_dvfs_enabled;
+extern uint16_t g_dvfs_cur_freq;
+
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: dvfs_open
+ ****************************************************************************/
+
+static int dvfs_open(FAR struct file *filep, FAR const char *relpath,
+                    int oflags, mode_t mode)
+{
+  FAR struct dvfs_file_s *priv;
+
+  finfo("Open '%s'\n", relpath);
+
+  /* "dvfs" is the only acceptable value for the relpath */
+
+  if (strcmp(relpath, "dvfs") != 0)
+    {
+      ferr("ERROR: relpath is '%s'\n", relpath);
+      return -ENOENT;
+    }
+
+  /* Allocate a container to hold the task and attribute selection */
+
+  priv = (FAR struct dvfs_file_s *)kmm_zalloc(sizeof(struct dvfs_file_s));
+  if (!priv)
+    {
+      ferr("ERROR: Failed to allocate file attributes\n");
+      return -ENOMEM;
+    }
+
+  /* Save the index as the open-specific state in filep->f_priv */
+
+  filep->f_priv = (FAR void *)priv;
+  return OK;
+}
+
+/****************************************************************************
+ * Name: dvfs_close
+ ****************************************************************************/
+
+static int dvfs_close(FAR struct file *filep)
+{
+  FAR struct dvfs_file_s *priv;
+
+  /* Recover our private data from the struct file instance */
+
+  priv = (FAR struct dvfs_file_s *)filep->f_priv;
+  DEBUGASSERT(priv);
+
+  /* Release the file attributes structure */
+
+  kmm_free(priv);
+  filep->f_priv = NULL;
+  return OK;
+}
+
+/****************************************************************************
+ * Name: dvfs_read
+ ****************************************************************************/
+
+static ssize_t dvfs_read(FAR struct file *filep, FAR char *buffer,
+                         size_t buflen)
+{
+  FAR struct dvfs_file_s *priv;
+  size_t linesize;
+  size_t copysize;
+  size_t remaining;
+  size_t totalsize;
+  off_t offset = filep->f_pos;
+
+  finfo("buffer=%p buflen=%d\n", buffer, (int)buflen);
+
+  priv = (FAR struct dvfs_file_s *)filep->f_priv;
+  DEBUGASSERT(priv);
+
+  remaining = buflen;
+  totalsize = 0;
+
+  linesize = snprintf(priv->line,
+                      DVFS_LINELEN,
+                      "cur_freq %d \n", g_dvfs_cur_freq);
+  copysize = procfs_memcpy(priv->line, linesize, buffer, remaining, &offset);
+  totalsize += copysize;
+  buffer    += copysize;
+  remaining -= copysize;
+
+  if (totalsize >= buflen)
+    {
+      return totalsize;
+    }
+
+  linesize = snprintf(priv->line,
+                      DVFS_LINELEN,
+                      "enable %d \n", g_dvfs_enabled);
+  copysize = procfs_memcpy(priv->line, linesize, buffer, remaining, &offset);
+  totalsize += copysize;
+
+  /* Update the file offset */
+
+  if (totalsize > 0)
+    {
+      filep->f_pos += totalsize;
+    }
+
+  return totalsize;
+}
+
+/****************************************************************************
+ * Name: procfs_write
+ ****************************************************************************/
+
+static ssize_t dvfs_write(FAR struct file *filep, FAR const char *buffer,
+                          size_t buflen)
+{
+  char line[DVFS_LINELEN];
+  char cmd[16];
+  int  n;
+  int  freq;
+  int  enable;
+
+  n = MIN(buflen, DVFS_LINELEN - 1);
+  strncpy(line, buffer, n);
+  line[n] = '\0';
+
+  n = MIN(strcspn(line, " "), sizeof(cmd) - 1);
+  strncpy(cmd, line, n);
+  cmd[n] = '\0';
+
+  if (0 == strcmp(cmd, "cur_freq"))
+    {
+      freq = atoi(line + (n + 1));
+      (void)lc823450_dvfs_set_freq(freq);
+    }
+  else if (0 == strcmp(cmd, "enable"))
+    {
+      enable = atoi(line + (n + 1));
+      g_dvfs_enabled = enable;
+    }
+  else
+    {
+      printf("%s not supported.\n", cmd);
+    }
+
+  return buflen;
+}
+
+/****************************************************************************
+ * Name: dvfs_dup
+ ****************************************************************************/
+
+static int dvfs_dup(FAR const struct file *oldp, FAR struct file *newp)
+{
+  FAR struct dvfs_file_s *oldpriv;
+  FAR struct dvfs_file_s *newpriv;
+
+  finfo("Dup %p->%p\n", oldp, newp);
+
+  /* Recover our private data from the old struct file instance */
+
+  oldpriv = (FAR struct dvfs_file_s *)oldp->f_priv;
+  DEBUGASSERT(oldpriv);
+
+  /* Allocate a new container to hold the task and attribute selection */
+
+  newpriv = (FAR struct dvfs_file_s *)kmm_zalloc(sizeof(struct dvfs_file_s));
+  if (!newpriv)
+    {
+      ferr("ERROR: Failed to allocate file attributes\n");
+      return -ENOMEM;
+    }
+
+  /* The copy the file attributes from the old attributes to the new */
+
+  memcpy(newpriv, oldpriv, sizeof(struct dvfs_file_s));
+
+  /* Save the new attributes in the new file structure */
+
+  newp->f_priv = (FAR void *)newpriv;
+  return OK;
+}
+
+/****************************************************************************
+ * Name: dvfs_stat
+ ****************************************************************************/
+
+static int dvfs_stat(const char *relpath, struct stat *buf)
+{
+  if (strcmp(relpath, "dvfs") != 0)
+    {
+      ferr("ERROR: relpath is '%s'\n", relpath);
+      return -ENOENT;
+    }
+
+  buf->st_mode    =
+    S_IFREG |
+    S_IROTH | S_IWOTH |
+    S_IRGRP | S_IWGRP |
+    S_IRUSR | S_IWUSR;
+
+  buf->st_size    = 0;
+  buf->st_blksize = 0;
+  buf->st_blocks  = 0;
+
+  return OK;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: dvfs_procfs_register
+ ****************************************************************************/
+
+int dvfs_procfs_register(void)
+{
+  return procfs_register(&g_procfs_dvfs);
+}

arch/arm/src/lc823450/lc823450_timerisr.c

@@ -62,6 +62,13 @@
 #include "lc823450_clockconfig.h"
 #include "lc823450_serial.h"
 
+#ifdef CONFIG_DVFS
+#  include "lc823450_dvfs2.h"
+#endif
+
+#if !defined(CONFIG_LC823450_MTM0_TICK) && defined (CONFIG_DVFS)
+#  error "Use CONFIG_LC823450_MTM0_TICK=y"
+#endif
 
 /****************************************************************************
  * Pre-processor Definitions

configs/lc823450-xgevk/README.txt

@@ -248,6 +248,26 @@ nsh> route
 SEQ TARGET NETMASK ROUTER
    1. 0.0.0.0 0.0.0.0 192.168.1.1
 
+12. DVFS (Dynamic Voltage and Frequency Scaling)
+
+lc823450-xgevk/audio and rndis configurations support DVFS.
+You can check the status via /proc/dvfs
+
+nsh> cat /proc/dvfs
+cur_freq 160
+enable 0
+
+By default, DVFS is disabled. To enable,
+
+nsh> echo "enable 1" > /proc/dvfs
+
+In addition, you can change CPU frequency to 160/80/40. To change the
+frequency, enable the DVFS first then do the following.
+
+nsh> echo "cur_freq 80" > /proc/dvfs.
+
+Currently, DVFS works in manual mode and Vdd1 is fixed to 1.2V
+which will be changed in the future version.
 
 TODO
 ^^^^

configs/lc823450-xgevk/audio/defconfig

@@ -28,6 +28,7 @@ CONFIG_DEBUG_WARN=y
 CONFIG_DEV_ZERO=y
 CONFIG_DISABLE_POSIX_TIMERS=y
 CONFIG_DRIVERS_AUDIO=y
+CONFIG_DVFS=y
 CONFIG_EXAMPLES_HELLO=y
 CONFIG_EXAMPLES_NSH=y
 CONFIG_EXAMPLES_NXHELLO_BPP=1
@@ -40,6 +41,7 @@ CONFIG_FAT_LCNAMES=y
 CONFIG_FAT_LFN=y
 CONFIG_FS_FATTIME=y
 CONFIG_FS_FAT=y
+CONFIG_FS_PROCFS_REGISTER=y
 CONFIG_FS_PROCFS=y
 CONFIG_HRT_TIMER=y
 CONFIG_I2C_RESET=y

configs/lc823450-xgevk/nsh/defconfig

@@ -1,19 +1,15 @@
-# CONFIG_LC823450_SDIF is not set
-# CONFIG_NSH_ARGCAT is not set
-# CONFIG_NX_DISABLE_1BPP is not set
-# CONFIG_SPI_EXCHANGE is not set
 CONFIG_ADC=y
 CONFIG_ANALOG=y
 CONFIG_AQM_1248A=y
-CONFIG_ARCH_BOARD_LC823450_XGEVK=y
+CONFIG_ARCH="arm"
 CONFIG_ARCH_BOARD="lc823450-xgevk"
+CONFIG_ARCH_BOARD_LC823450_XGEVK=y
 CONFIG_ARCH_CHIP_LC823450=y
 CONFIG_ARCH_FLOAT_H=y
 CONFIG_ARCH_INTERRUPTSTACK=2048
 CONFIG_ARCH_STDARG_H=y
-CONFIG_ARCH="arm"
-CONFIG_BOARD_LOOPSPERMSEC=12061
 CONFIG_BOARDCTL_RESET=y
+CONFIG_BOARD_LOOPSPERMSEC=12061
 CONFIG_BUILTIN=y
 CONFIG_C99_BOOL8=y
 CONFIG_CODECS_HASH_MD5=y
@@ -41,12 +37,13 @@ CONFIG_FS_PROCFS=y
 CONFIG_FS_WRITABLE=y
 CONFIG_HRT_TIMER=y
 CONFIG_I2C_RESET=y
-CONFIG_I2C=y
 CONFIG_I2CTOOL_MAXBUS=1
+CONFIG_I2C=y
 CONFIG_INTELHEX_BINARY=y
 CONFIG_LC823450_I2C0=y
 CONFIG_LC823450_I2C1=y
 CONFIG_LC823450_MTM0_TICK=y
+# CONFIG_LC823450_SDIF is not set
 CONFIG_LC823450_SPI_DMA=y
 CONFIG_LC823450_UART0=y
 CONFIG_LC823450_WDT=y
@@ -63,6 +60,7 @@ CONFIG_NETUTILS_CODECS=y
 CONFIG_NFILE_DESCRIPTORS=45
 CONFIG_NFILE_STREAMS=8
 CONFIG_NSH_ARCHINIT=y
+# CONFIG_NSH_ARGCAT is not set
 CONFIG_NSH_BUILTIN_APPS=y
 CONFIG_NSH_DISABLE_BASENAME=y
 CONFIG_NSH_DISABLE_CP=y
@@ -81,8 +79,8 @@ CONFIG_NSH_DISABLE_MKFIFO=y
 CONFIG_NSH_DISABLE_MKRD=y
 CONFIG_NSH_DISABLE_MV=y
 CONFIG_NSH_DISABLE_PUT=y
-CONFIG_NSH_DISABLE_RM=y
 CONFIG_NSH_DISABLE_RMDIR=y
+CONFIG_NSH_DISABLE_RM=y
 CONFIG_NSH_DISABLE_SH=y
 CONFIG_NSH_DISABLE_WGET=y
 CONFIG_NSH_DISABLE_XD=y
@@ -90,8 +88,9 @@ CONFIG_NSH_FILEIOSIZE=512
 CONFIG_NSH_MAXARGUMENTS=10
 CONFIG_NSH_READLINE=y
 CONFIG_NX_BLOCKING=y
-CONFIG_NX=y
+# CONFIG_NX_DISABLE_1BPP is not set
 CONFIG_NXFONT_MONO5X8=y
+CONFIG_NX=y
 CONFIG_PIPES=y
 CONFIG_POSIX_SPAWN_PROXY_STACKSIZE=2048
 CONFIG_PREALLOC_MQ_MSGS=4
@@ -118,6 +117,7 @@ CONFIG_SDCLONE_DISABLE=y
 CONFIG_SERIAL_TERMIOS=y
 CONFIG_SMP_NCPUS=2
 CONFIG_SMP=y
+# CONFIG_SPI_EXCHANGE is not set
 CONFIG_SPINLOCK_IRQ=y
 CONFIG_SPI=y
 CONFIG_START_DAY=3

configs/lc823450-xgevk/rndis/defconfig

@@ -30,6 +30,7 @@ CONFIG_DEBUG_WARN=y
 CONFIG_DEV_ZERO=y
 CONFIG_DISABLE_POSIX_TIMERS=y
 CONFIG_DRIVERS_AUDIO=y
+CONFIG_DVFS=y
 CONFIG_EXAMPLES_HELLO=y
 CONFIG_EXAMPLES_NSH=y
 CONFIG_EXAMPLES_NXHELLO_BPP=1
@@ -42,6 +43,7 @@ CONFIG_FAT_LCNAMES=y
 CONFIG_FAT_LFN=y
 CONFIG_FS_FATTIME=y
 CONFIG_FS_FAT=y
+CONFIG_FS_PROCFS_REGISTER=y
 CONFIG_FS_PROCFS=y
 CONFIG_HRT_TIMER=y
 CONFIG_I2C_RESET=y
@@ -168,6 +170,7 @@ CONFIG_SYSTEM_I2CTOOL=y
 CONFIG_SYSTEM_NXPLAYER=y
 CONFIG_SYSTEM_PING=y
 CONFIG_TASK_NAME_SIZE=24
+CONFIG_TELNET_CHARACTER_MODE=y
 CONFIG_UART0_RXBUFSIZE=512
 CONFIG_UART0_SERIAL_CONSOLE=y
 CONFIG_UART0_TXBUFSIZE=2048

configs/lc823450-xgevk/src/lc823450_bringup.c

@@ -57,6 +57,10 @@
 #  include "lc823450_wdt.h"
 #endif
 
+#ifdef CONFIG_DVFS
+#  include "lc823450_dvfs2.h"
+#endif
+
 #include "lc823450-xgevk.h"
 
 /****************************************************************************
@@ -80,6 +84,11 @@ int lc823450_bringup(void)
 #endif
 
 #ifdef CONFIG_FS_PROCFS
+
+#ifdef CONFIG_DVFS
+  (void)dvfs_procfs_register();
+#endif
+
   /* Mount the procfs file system */
 
   ret = mount(NULL, "/proc", "procfs", 0, NULL);

configs/lc823450-xgevk/usb/defconfig

@@ -1,18 +1,15 @@
-# CONFIG_NSH_ARGCAT is not set
-# CONFIG_NX_DISABLE_1BPP is not set
-# CONFIG_SPI_EXCHANGE is not set
 CONFIG_ADC=y
 CONFIG_ANALOG=y
 CONFIG_AQM_1248A=y
-CONFIG_ARCH_BOARD_LC823450_XGEVK=y
+CONFIG_ARCH="arm"
 CONFIG_ARCH_BOARD="lc823450-xgevk"
+CONFIG_ARCH_BOARD_LC823450_XGEVK=y
 CONFIG_ARCH_CHIP_LC823450=y
 CONFIG_ARCH_FLOAT_H=y
 CONFIG_ARCH_INTERRUPTSTACK=2048
 CONFIG_ARCH_STDARG_H=y
-CONFIG_ARCH="arm"
-CONFIG_BOARD_LOOPSPERMSEC=12061
 CONFIG_BOARDCTL_RESET=y
+CONFIG_BOARD_LOOPSPERMSEC=12061
 CONFIG_BUILTIN=y
 CONFIG_C99_BOOL8=y
 CONFIG_CODECS_HASH_MD5=y
@@ -40,13 +37,13 @@ CONFIG_EXAMPLES_WATCHDOG=y
 CONFIG_EXPERIMENTAL=y
 CONFIG_FAT_LCNAMES=y
 CONFIG_FAT_LFN=y
-CONFIG_FS_FAT=y
 CONFIG_FS_FATTIME=y
+CONFIG_FS_FAT=y
 CONFIG_FS_PROCFS=y
 CONFIG_HRT_TIMER=y
 CONFIG_I2C_RESET=y
-CONFIG_I2C=y
 CONFIG_I2CTOOL_MAXBUS=1
+CONFIG_I2C=y
 CONFIG_INTELHEX_BINARY=y
 CONFIG_LC823450_I2C0=y
 CONFIG_LC823450_I2C1=y
@@ -71,6 +68,7 @@ CONFIG_NETUTILS_CODECS=y
 CONFIG_NFILE_DESCRIPTORS=45
 CONFIG_NFILE_STREAMS=8
 CONFIG_NSH_ARCHINIT=y
+# CONFIG_NSH_ARGCAT is not set
 CONFIG_NSH_BUILTIN_APPS=y
 CONFIG_NSH_CMDOPT_DD_STATS=y
 CONFIG_NSH_DISABLE_EXEC=y
@@ -91,8 +89,9 @@ CONFIG_NSH_FILEIOSIZE=512
 CONFIG_NSH_MAXARGUMENTS=10
 CONFIG_NSH_READLINE=y
 CONFIG_NX_BLOCKING=y
-CONFIG_NX=y
+# CONFIG_NX_DISABLE_1BPP is not set
 CONFIG_NXFONT_MONO5X8=y
+CONFIG_NX=y
 CONFIG_PIPES=y
 CONFIG_POSIX_SPAWN_PROXY_STACKSIZE=2048
 CONFIG_PREALLOC_MQ_MSGS=4
@@ -120,6 +119,7 @@ CONFIG_SENSORS=y
 CONFIG_SERIAL_TERMIOS=y
 CONFIG_SMP_NCPUS=2
 CONFIG_SMP=y
+# CONFIG_SPI_EXCHANGE is not set
 CONFIG_SPINLOCK_IRQ=y
 CONFIG_SPI=y
 CONFIG_START_DAY=3