Diff: flash/flash.c

Revision:

0:0a841b89d614

diff -r 000000000000 -r 0a841b89d614 flash/flash.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/flash/flash.c	Mon Oct 11 10:34:55 2010 +0000
@@ -0,0 +1,112 @@
+/****************************************************************************
+ *    Copyright 2010 Andy Kirkham, Stellar Technologies Ltd
+ *    
+ *    This file is part of the Satellite Observers Workbench (SOWB).
+ *
+ *    SOWB is free software: you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation, either version 3 of the License, or
+ *    (at your option) any later version.
+ *
+ *    SOWB is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with SOWB.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    $Id: main.cpp 5 2010-07-12 20:51:11Z ajk $
+ *    
+ ***************************************************************************/
+
+#include "sowb.h"
+#include "debug.h"
+#include "ssp0.h"
+#include "gpio.h"
+#include "flash.h"
+#include "user.h"
+
+extern bool sector_erase_in_progress;
+extern bool page_write_in_progress;
+
+char flash_buffer[2][FLASH_PAGE_SIZE];
+int current_buffer;
+unsigned int flash_address;
+
+/** flash_init
+ */
+void flash_init(void) {
+    
+    /* Initialise the SSP0 to talk to the flash device. */    
+    SSP0_init();
+    
+    DEBUG_INIT_START;
+    
+    /* Clear out the page buffers. */
+    memset(flash_buffer, 0, 2 * FLASH_PAGE_SIZE);
+    
+    /* Default the buffer in use. */
+    current_buffer = 0;
+    
+    /* Default pointer set-up. */
+    flash_address = 0;
+    
+    /* Prime our buffers for expected future access. */
+    flash_read_page(0, flash_buffer[0], true);
+    flash_read_page(1, flash_buffer[1], true);
+    
+    /* Although not part of the flash system, SOWB includes
+       a 25AA02E48 device from Microchip that holds a globally
+       unique 48bit (6byte) MAC address. We use this for the
+       SOWB "STL authentic product" serial number and in future
+       may be used as the ethernet MAC address if we ever write 
+       code to support Ethernet. This device is also connected
+       to SSP1 and so we'll _init() it here now. */
+    //_25AA02E48_init();
+    
+    DEBUG_INIT_END;
+}
+
+/** flash_process
+ */
+void flash_process(void) {
+    /* Currently does nothing. */
+}
+
+/** flash_getc
+ */
+char flash_getc(bool peek) {
+    char c;
+    
+    /* Flash being deleted, undefined memory. */
+    if (sector_erase_in_progress) return 0xFF;
+    
+    /* Wait for any page loads to complete. */
+    while (page_write_in_progress) user_call_process();
+    
+    /* Get the character from the internal buffer. */
+    c = flash_buffer[current_buffer][flash_address];
+    
+    /* If this is just a peek then return the character without
+       incrementing the memory pointers etc etc. */
+    if (peek) return c;
+    
+    /* Inc the address pointer and load a new page if needed. Note,
+       we load the page in background using DMA. */
+    flash_address++;
+    if ((flash_address & 0xFF) == 0) {
+        flash_read_page(current_buffer >> 8, flash_buffer[current_buffer], false);
+        current_buffer = current_buffer ? 0 : 1;        
+    }
+    
+    return c;
+}
+
+/** flash_seek
+ */
+void flash_seek(unsigned int addr) {
+    flash_read_page((addr >> 8) + 0, flash_buffer[0], true);
+    flash_read_page((addr >> 8) + 1, flash_buffer[1], true);
+    flash_address = addr;
+}