From 08491bace990298e26b9e702fdc26adde26d888b Mon Sep 17 00:00:00 2001
From: josh <josh@5b3e749e-e535-0410-8002-a9bb6afbdfca>
Date: Tue, 26 Jan 2010 05:25:46 +0000
Subject: [PATCH] still reworking physical page allocator

git-svn-id: svn://anubis/hos/trunk@95 5b3e749e-e535-0410-8002-a9bb6afbdfca
---
 kernel/mm/mm.cc | 80 +++++++++++++++++++++++++++++++++----------------
 1 file changed, 55 insertions(+), 25 deletions(-)

diff --git a/kernel/mm/mm.cc b/kernel/mm/mm.cc
index f3cdec5..0401fae 100644
--- a/kernel/mm/mm.cc
+++ b/kernel/mm/mm.cc
@@ -122,11 +122,12 @@ void mm_bootstrap()
 
     for (int i = 0; i <= last_page_alloc_page; i++)
     {
-        mm_early_map(mm_heap_base, page_alloc_page_numbers[i], 0, 1);
-        /* move the heap back to after the page allocation pages */
-        mm_heap_base += PAGE_SIZE;
+        mm_early_map(&page_alloc_pages[i], page_alloc_page_numbers[i], 0, 1);
     }
 
+    /* move the heap back to after the page allocation pages */
+    mm_heap_base = &page_alloc_pages[last_page_alloc_page + 1];
+
     if (mm_num_free_pages < 10)
     {
         k_early_panic("Not enough free pages of RAM!");
@@ -153,7 +154,7 @@ void mm_bootstrap()
         /* map page_base to page_base - KERNEL_OFFSET */
         mm_early_map(page_base, page_base - KERNEL_OFFSET, 0, 1);
     }
-    
+
     /* map console memory */
     mm_early_map(CONSOLE_MEMORY, CONSOLE_MEMORY, 0, 1);
 
@@ -195,23 +196,23 @@ void mm_bootstrap()
  *************************************************************************/
 static void record_phys_page(u32_t base_address)
 {
-    static mm_page_alloc_page_t * current_page_alloc_page = NULL;
-    if (page_alloc_page_index < 0
-            || page_alloc_page_index >= NUM_PAGETABLE_ENTRIES)
+    if (page_alloc_page_index < 0)
     {
         /* allocate a new page alloc page */
-        mm_page_alloc_page_t * old_page_alloc_page = current_page_alloc_page;
-        current_page_alloc_page = (mm_page_alloc_page_t *)
-            (base_address + KERNEL_OFFSET);
-        current_page_alloc_page->next = old_page_alloc_page;
-        page_alloc_page_index =
-            sizeof(current_page_alloc_page->pages)
-                / sizeof(current_page_alloc_page->pages[0]) - 1;
-        page_alloc_page_numbers[last_page_alloc_page++] = base_address;
+        last_page_alloc_page++;
+        page_alloc_pages_index++;
+        page_alloc_page_numbers[last_page_alloc_page] = base_address;
     }
     else
     {
-        current_page_alloc_page->pages[page_alloc_page_index--] = base_address;
+        page_alloc_page_t * current_page_alloc_page = (page_alloc_page_t *)
+            (page_alloc_page_numbers[page_alloc_pages_index] + KERNEL_OFFSET);
+        page_alloc_page_index++;
+        (*current_page_alloc_page)[page_alloc_page_index] = base_address;
+        if (page_alloc_page_index == NUM_PAGETABLE_ENTRIES - 1)
+        {
+            page_alloc_page_index = -1;
+        }
     }
 }
 
@@ -294,23 +295,52 @@ int mm_map(u32_t virtual_address, u32_t physical_address,
  * Returns the physical base address of a page in RAM                     *
  * or 0 if no pages were available                                        *
  *************************************************************************/
-u32_t mm_page_alloc()
+u32_t mm_early_page_alloc()
 {
     u32_t page_address = 0;
-    if (current_page_alloc_page != NULL)
+    if (page_alloc_pages_index >= 0)
     {
-        if (page_alloc_page_index == sizeof(current_page_alloc_page->pages)
-                / sizeof(current_page_alloc_page->pages[0]) - 1)
+        if (page_alloc_page_index >= 0)
         {
-            page_address = ((u32_t) current_page_alloc_page) - KERNEL_OFFSET;
-            current_page_alloc_page = current_page_alloc_page->next;
-            page_alloc_page_index = 0;
+            page_alloc_page_t * current_pap = (page_alloc_page_t *)
+                (page_alloc_page_numbers[page_alloc_pages_index]
+                    + KERNEL_OFFSET);
+            page_address = (*current_pap)[page_alloc_page_index];
+            page_alloc_page_index--;
         }
         else
         {
-            page_alloc_page_index++;
+            /* return the page allocation page itself */
+            page_address = page_alloc_page_numbers[page_alloc_pages_index];
+            page_alloc_pages_index--;
+            page_alloc_page_index = NUM_PAGETABLE_ENTRIES - 1;
+        }
+        mm_num_free_pages--;
+    }
+    return page_address;
+}
+
+/**************************************************************************
+ * Returns the physical base address of a page in RAM                     *
+ * or 0 if no pages were available                                        *
+ *************************************************************************/
+u32_t mm_page_alloc()
+{
+    u32_t page_address = 0;
+    if (page_alloc_pages_index >= 0)
+    {
+        if (page_alloc_page_index >= 0)
+        {
             page_address =
-                current_page_alloc_page->pages[page_alloc_page_index];
+                page_alloc_pages[page_alloc_pages_index][page_alloc_page_index];
+            page_alloc_page_index--;
+        }
+        else
+        {
+            /* return the page allocation page itself */
+            page_address = page_alloc_page_numbers[page_alloc_pages_index];
+            page_alloc_pages_index--;
+            page_alloc_page_index = NUM_PAGETABLE_ENTRIES - 1;
         }
         mm_num_free_pages--;
     }