From 5a83bd319a22d53eb82d43c738d471a5a8079b36 Mon Sep 17 00:00:00 2001
From: Michal Idziorek <m.i@gmx.at>
Date: Thu, 7 Aug 2014 18:40:11 +0200
Subject: added some physical memory management

---
 kernel/mem.c | 161 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 161 insertions(+)
 create mode 100644 kernel/mem.c

(limited to 'kernel/mem.c')

diff --git a/kernel/mem.c b/kernel/mem.c
new file mode 100644
index 0000000..1bb4109
--- /dev/null
+++ b/kernel/mem.c
@@ -0,0 +1,161 @@
+#include "kernel.h"
+
+//! 8 blocks per byte
+#define PMMNGR_BLOCKS_PER_BYTE 8
+ 
+//! block size (4k)
+#define PMMNGR_BLOCK_SIZE	4096
+ 
+//! block alignment
+#define PMMNGR_BLOCK_ALIGN	PMMNGR_BLOCK_SIZE
+
+// memory map bit array. Each bit represents a memory block
+static uint32_t	_mmngr_memory_map[129*1024];
+static uint32_t mem_free_blocks;
+
+// bit funcs!
+
+void mmap_set(int bit) 
+{
+      _mmngr_memory_map[bit / 32] |= (1 << (bit % 32));
+}
+
+void mmap_unset(int bit)
+{
+      _mmngr_memory_map[bit / 32] &= ~ (1 << (bit % 32));
+}
+
+int  mmap_test(int bit)
+{
+     return _mmngr_memory_map[bit / 32] &  (1 << (bit % 32));
+}
+
+///
+
+int mmap_first_free () {
+ 
+    //! find the first free bit
+    uint32_t i;
+    int j;
+
+
+    for (i=0; i< 128 ; i++)
+	if (_mmngr_memory_map[i] != 0xffffffff)
+	    for (j=0; j<32; j++) {		//! test each bit in the dword
+ 
+		int bit = 1 << j;
+		if (! (_mmngr_memory_map[i] & bit) )
+		    return i*4*8+j;
+	    }
+ 
+    return -1;
+}
+
+void pmmngr_init () {
+ 
+    //! By default, all of memory is in use
+    //    memset (_mmngr_memory_map, 0xf, 128 );
+    int i;
+    for(i=0;i++;i<128*1024)
+    {
+	_mmngr_memory_map[i]=0xffffffff;
+    }
+}
+
+void pmmngr_init_region (uint32_t  base, uint32_t size)
+{
+
+ 
+    uint32_t align = base / PMMNGR_BLOCK_SIZE;
+    uint32_t blocks = size / PMMNGR_BLOCK_SIZE;
+
+    for (; blocks>0; blocks--) 
+    {
+	// hack to lock first ~4MB of memory
+	if(align<1000)
+	{
+	    align++;
+	    continue;
+	}
+
+
+	mmap_unset (align++);
+	mem_free_blocks++;
+	//_mmngr_used_blocks--;
+    }
+
+    //mmap_set (0);	//first block is always set. This insures allocs cant be 0
+}
+
+void mem_test(int start, int end, int steps)
+{
+    int *p=start;
+    for(;p<end;p+=steps)
+    {
+	scr_put_string("testing memory at ");
+	scr_put_hex32(p);
+
+	//
+	*p=p;
+	volatile x=*p;
+	if(x==p) scr_put_string(" OK");
+	//
+
+	scr_put_string_nl("");
+    }
+}
+
+void mem_init(uint16_t *memmap)
+{
+    mem_free_blocks=0;
+
+    // count available memory
+    uint32_t avail_mem=0;
+
+    //print memory map;
+    while(1)
+    {
+	if(memmap[8]==0)break;
+
+	scr_put_hex(memmap[8]);
+	scr_put_string(" : ");
+
+
+	scr_put_hex(memmap[1]);
+	scr_put_string(" ");
+	scr_put_hex(memmap[0]);
+	scr_put_string(" ");
+
+	scr_put_string(" - ");
+	scr_put_hex(memmap[5]);
+	scr_put_string(" ");
+	scr_put_hex(memmap[4]);
+
+	scr_put_string_nl("");
+
+	if(memmap[8]==1)
+	{
+	    avail_mem+=memmap[4]+(memmap[5]<<16); 
+	    pmmngr_init_region(memmap[0]+(memmap[1]<<16),memmap[4]+((memmap[5])<<16));
+	}
+
+	memmap+=12;
+    }
+
+    scr_put_string("Total Available Mem: ");
+    scr_put_hex(avail_mem>>16);
+    scr_put_string(" ");
+    scr_put_hex(avail_mem&0xffff);
+    scr_put_string_nl(" byte");
+
+    scr_put_string("Total of free (4KB) blocks: ");
+    scr_put_hex(mem_free_blocks>>16);
+    scr_put_hex(mem_free_blocks&0xffff);
+    scr_put_string_nl("");
+
+    //crossing 512MB boundary! 
+    // (do not do this in real, coz it probably is reserved)
+    //mem_test(0x1fee1000,0x2000f000,0x800);
+
+}
+
-- 
cgit v1.2.3