Add clock reset logic

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2464 42af7a65-404d-4744-a932-0658087f49c3

arch/arm/src/lpc313x/lpc313x_resetclks.c

+/****************************************************************************
+ * arch/arm/src/lpc313x/lpc313x_resetclks.c
+ *
+ *   Copyright (C) 2009 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <stdint.h>
+
+#include <arch/board/board.h>
+
+#include "lpc313x_cgudrvr.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: lpc313x_resetclks
+ *
+ * Description:
+ *   Put all clocks into a known, initial state
+ *
+ ****************************************************************************/
+
+void lpc313x_resetclks(void)
+{
+  uint32_t regaddr;
+  uint32_t regval;
+  int bcrndx;
+  int esrndx;
+  int i;
+
+  /* Switch all domain reference clocks to FFAST */
+
+  for (i = 0; i < CGU_NDOMAINS; i++)
+    {
+      /* Switch reference clock in to FFAST */
+
+      lpc313x_selectfreqin((enum lpc313x_domainid_e)i, CGU_FS_FFAST);
+
+      /* Check if the domain has a BCR */
+
+      bcrndx = lp313x_bcrndx((enum lpc313x_domainid_e)i);
+      if (bcrndx != BCRNDX_INVALID)
+        {
+          /* Yes.. isable all BCRs */
+
+          putreg32(0, LPC313X_CGU_BCR(bcrndx));
+        }
+    }
+
+  /* Disable all clocks except those that are necessary */
+
+  for (i = CLKID_FIRST; i <= CLKID_LAST; i++)
+  {
+    /* Check if this clock has an ESR register */
+
+    esrndx = lp313x_esrndx((enum lpc313x_clockid_e)i);
+    if (esrndx != ESRNDX_INVALID)
+    {
+      /* Yes.. Clear the clocks ESR to deselect fractional divider */
+
+      putreg32(0, LPC313X_CGU_ESR(esrndx));
+    }
+
+    /* Enable external enabling for all possible clocks to conserve power */
+
+    lpc313x_enableexten((enum lpc313x_clockid_e)i);
+
+    /* Set enable-out's for only the following clocks */
+
+    regaddr = LPC313X_CGU_PCR(i);
+    regval  = getreg32(regaddr);
+    if (i == (int)CLKID_ARM926BUSIFCLK || i == (int)CLKID_MPMCCFGCLK)
+      {
+        regval |=  CGU_PCR_ENOUTEN;
+      }
+    else
+      {
+        regval &= ~CGU_PCR_ENOUTEN;
+      }
+    putreg32(regval, regaddr);
+
+    /* Set/clear the RUN bit in the PCR regiser of  all clocks, depending
+     * upon if the clock is needed by the board logic or not
+     */
+
+    (void)lpc313x_defclk((enum lpc313x_clockid_e)i);
+  }
+
+  /* Disable all fractional dividers */
+
+  for (i = 0; i < CGU_NFRACDIV; i++)
+    {
+      regaddr = LPC313X_CGU_FDC(i);
+      regval  = getreg32(regaddr);
+      regval &= ~CGU_FDC_RUN;
+      putreg32(regval, i);
+    }
+}