Add support for the Z180 MMU and generic hooks for processes

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5428 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 405 insertions, 0 deletions

diff --git a/nuttx/arch/z80/src/z180/z180_mmu.c b/nuttx/arch/z80/src/z180/z180_mmu.c
new file mode 100644
index 000000000..c71f59755
--- /dev/null
+++ b/nuttx/arch/z80/src/z180/z180_mmu.c
@@ -0,0 +1,405 @@
+/****************************************************************************
+ * arch/z80/src/z180/z180_mmu.c
+ *
+ *   Copyright (C) 2012 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.
+ *
+ ****************************************************************************/
+
+/* See arch/z80/src/z180/z180_mmu.txt for additional information */
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <nuttx/gram.h>
+
+#include "z180_mmu.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+/* Configuration ************************************************************/
+
+#ifndef CONFIG_ADDRENV
+#  warning "OS address environment support is required (CONFIG_ADDRENV)"
+#endif
+
+#ifndef CONFIG_GRAN
+#  warning "This file requires the granual allocator (CONFIG_GRAN)"
+#endif
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+#ifndef CONFIG_GRAN_SINGLE
+static GRAN_HANDLE g_physhandle;
+#endif
+static struct z180_cbr_s g_cbrs[CONFIG_MAX_TASKS];
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: z180_mmu_findcbr
+ *
+ * Description:
+ *   Find an unused struture in g_cbrs (i.e., one with reference count == 0).
+ *   If a structure is found, its reference count is set to one and a pointer
+ *   to the structure is returned.
+ *
+ ****************************************************************************/
+
+static FAR struct z180_cbr_s *z180_mmu_findcbr(void)
+{
+  int i;
+
+  for (i = 0; i < CONFIG_MAX_TASKS; i++)
+    {
+      FAR struct z180_cbr_s *cbr = &g_cbrs[i];
+      if (cbr->crefs == 0)
+        {
+          cbr->crefs = 1;
+          return cbr;
+        }
+    }
+
+  return NULL;
+}
+
+/****************************************************************************
+ * Name: z180_mmu_freecbr
+ *
+ * Description:
+ *   Free a struture in g_cbrs by setting its reference count to 0;
+ *
+ ****************************************************************************/
+
+#define z180_mmu_freecbr(cbr) (cbr)->crefs = 0
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: z180_mmu_lowinit
+ *
+ * Description:
+ *   Low-level, power-up initialization of the z180 MMU.  this must be
+ *   called very early in the boot process to get the basic operating
+ *   memory configuration correct.  This function does *not* perform all
+ *   necessray MMU initialization... only the basics needed at power-up.
+ *   z180_mmu_init() must be called later to complete the entire MMU
+ *   initialization.
+ *
+ ****************************************************************************/
+
+void z180_mmu_lowinit(void) __naked
+{
+  __asm
+	ld	c, #Z180_MMU_CBR		; port
+	ld	a, #Z180_CBAR_VALUE		; value
+	out	(c), a
+
+	ld	c, #Z180_MMU_BBR		; port
+	ld	a, #Z180_BBR_VALUE		; value
+	out	(c), a
+  __endasm;
+}
+
+/****************************************************************************
+ * Name: z180_mmu_init
+ *
+ * Description:
+ *   Perform higher level initializatin of the MMU and physical memory
+ *   memory management logic.
+ *
+ ****************************************************************************/
+
+int z180_mmu_init(void)
+{
+  /* Here we use the granule allocator as a page allocator.  We lie and
+   * say that 1 page is 1 byte.
+   */
+
+#ifdef CONFIG_GRAN_SINGLE
+return gran_initialize((FAR void *)Z180_PHYSHEAP_STARTPAGE,
+                       Z180_PHYSHEAP_NPAGES, 0, 0);
+#else
+g_physhandle = gran_initialize((FAR void *)Z180_PHYSHEAP_STARTPAGE,
+                               Z180_PHYSHEAP_NPAGES, 0, 0);
+return g_physhandle ? OK : -ENOMEM;
+#endif
+}
+
+/****************************************************************************
+ * Name: up_addrenv_create
+ *
+ * Description:
+ *   This function is called from the binary loader logic when a new
+ *   task is created in RAM in order to instantiate an address environment for
+ *   the task.
+ *
+ * Input Parameters:
+ *   tcb - The TCB of the task needing the address environment.
+ *   envsize - The size (in bytes) of the address environment needed by the
+ *     task.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int up_addrenv_create(FAR _TCB *tcb, size_t envsize)
+{
+  FAR struct z180_cbr_s *cbr;
+  irqstate_t flags;
+  uintptr_t alloc;
+  unsigned int npages;
+  int ret;
+
+  /* Make sure that there is no address environment in place on this TCB */
+
+  DEBUGASSERT(tcb->xcp.cbr == NULL);
+
+  /* Convert the size from bytes to numbers of pages */
+
+  npages = PHYS_ALIGNUP(envsize);
+  if (npages < 1)
+    {
+      /* No address environment... but I suppose that is not an error */
+
+      sdbg("ERROR: npages is zero\n");
+      return OK;
+    }
+  
+  /* Allocate a structure in the common .bss to hold information about the
+   * task's address environment.  NOTE that this is not a part of the TCB,
+   * but rather a break-away structure that can be shared by the task as
+   * well as other threads.  That is necessary because the life of the
+   * address of environment might be longer than the life of the task.
+   */
+
+  flags = irqsave();
+  cbr = z180_mmu_findcbr();
+  if (!cbr)
+    {
+      sdbg("ERROR: No free CBR structures\n");
+      ret = -ENOMEM;
+      goto errout_with_irq
+    }
+
+  /* Now allocate the physical memory to back up the address environment */
+
+
+#ifdef CONFIG_GRAN_SINGLE
+  alloc = (uintptr_t)gran_alloc(npages);
+#else
+  alloc = (uintptr_t)gran_alloc(g_physhandle, npages);
+#endif
+  if (!alloc)
+    {
+      sdbg("ERROR: Failed to allocate %d pages\n", npages);
+      ret = -ENOMEM;
+      goto errout_with_cbr;
+    }
+
+  /* Save the information in the CBR structure.  Note that alloc is in
+   * 4KB pages, already in the right form for the CBR.
+   */
+
+  DEBUGASSERT(alloc <= 0xff);
+
+  cbr->cbr     = alloc;
+  cbr->pages   = npages;
+  tcb->xcp.cbr = cbr;
+
+  irqrestore(flags);
+  return OK;
+
+errout_with_cbr:
+  z180_mmu_freecbr(cbr);
+  
+errout_with_irq:
+  irqrestore(flags);
+  return ret;
+}
+
+/****************************************************************************
+ * Name: up_addrenv_clone
+ *
+ * Description:
+ *   This function is called from the core scheduler logic when a thread
+ *   is created that needs to share the address ennvironment of its parent
+ *   task.  In this case, the parent's address environment needs to be
+ *   "cloned" for the child.
+ *
+ * Input Parameters:
+ *   ptcb - The TCB of the parent task that has the address environment.
+ *   ctcb - The TCB of the child thread needing the address environment.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_ADDRENV
+int up_addrenv_clone(FAR const _TCB *ptcb, FAR _TCB *ctcb)
+{
+  irqstate_t flags;
+
+  /* Make sure that the child has no address environment.  It is okay if
+   * if the parent does not have one.
+   */
+
+  DEBUGASSERT(ctcb->xcp.cbr == NULL);
+
+  flags = irqsave();
+  if (ptcb->xcp.cbr)
+    {
+      /* Clone the CBR by incrementing the reference counting and saving a
+       * copy in the child thread's TCB.
+       */
+
+      ptcb->xcp.cbr.crefs++;
+      ctcb->xcp.cbr = ptcb->xcp.cbr;
+    }
+
+  irqrestore(flags);
+  return OK;
+}
+#endif
+
+/****************************************************************************
+ * Name: up_addrenv_instantiate
+ *
+ * Description:
+ *   After an address environment has been established for a task (via
+ *   up_addrenv_create().  This function may be called to to instantiate
+ *   that address environment in the virtual address space.  this might be
+ *   necessary, for example, to load the code for the task from a file or
+ *   to access address environment private data.
+ *
+ * Input Parameters:
+ *   tcb - The TCB of the task or thread whose the address environment will
+ *     be instantiated.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_ADDRENV
+int up_addrenv_instantiate(FAR _TCB *tcb)
+{
+  irqstate_t flags;
+
+  /* Check if the task has an address environment. */
+
+  flags = irqsave();
+  if (tcb->xcp.cbr)
+    {
+      /* Yes... write the CBR value into CBR register */
+
+      outp(Z180_MMU_CBR, tcb->xcp.cbr.cbr);
+      /* Clone the CBR by incrementing the reference counting and saving a
+       * copy in the child thread's TCB.
+       */
+
+      ptcb->xcp.cbr.crefs++;
+      ctcb->xcp.cbr = ptcb->xcp.cbr;
+    }
+
+  irqrestore(flags);
+  return OK;
+}
+#endif
+
+/****************************************************************************
+ * Name: up_addrenv_release
+ *
+ * Description:
+ *   This function is called when a task or thread exits in order to release
+ *   its reference to an address environment.  When there are no further
+ *   references to an address environment, that address environment should
+ *   be destroyed.
+ *
+ * Input Parameters:
+ *   tcb - The TCB of the task or thread whose the address environment will
+ *     be released.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_ADDRENV
+int up_addrenv_release(FAR _TCB *tcb)
+{
+  FAR struct z180_cbr_s *cbr;
+  irqstate_t flags;
+
+  /* Check if the task has an address environment. */
+
+  flags = irqsave();
+  cbr   = tcb->xcp.cbr;
+  if (cbr)
+    {
+      /* Nullify the reference to the CBR structgure and decrement the number
+       * of references on the CBR.
+       */
+
+      tcb->xcp.cbr = NULL;
+
+      /* If the reference count would decrement to zero, then free the CBR
+       * structure.
+       */
+
+      if (cbr->crefs <= 1)
+        {
+          z180_mmu_freecbr(cbr);
+        }
+      else
+        {
+          /* Otherwise, just decrement the reference count */
+
+          cbr->crefs--;
+        }
+    }
+
+  irqrestore(flags);
+  return OK;
+}
+#endif
+