Changeset 458

Timestamp:

Dec 5, 2014, 3:48:29 PM (10 years ago)

Author:

alain

Message:

Introducing the new spin-lock (with waiting queue).

Location:

soft/giet_vm/giet_fat32

Files:

• fat32.c (modified) (17 diffs)
• fat32.h (modified) (2 diffs)

soft/giet_vm/giet_fat32/fat32.c

@@ -23 +23 @@
 #include <giet_config.h>
 #include <fat32.h>
-#include <tty_driver.h>
+#include <tty0.h>
 #include <ioc_driver.h>
 #include <utils.h>
@@ -725 +725 @@
     if ( _get_next_cluster( IOC_KERNEL_MODE, free_cluster ) != FREE_CLUSTER)
     {
-        _puts("\n[FAT ERROR] in _fat_allocate() : first free_cluster not free\n");
+        _puts("\n[FAT ERROR] in _fat_allocate() : first free cluster not free\n");
         return -1;
     }
@@ -755 +755 @@
 _putx( last_cluster_file );
 _puts(" / free cluster = ");
-_putx( free-cluster );
+_putx( free_cluster );
 _puts(" / clusters required = ");
-_putx( cluster_to allocate );
+_putx( cluster_to_allocate );
 _puts("\n");
 #endif
@@ -853 +853 @@
 _puts(",");
 _putd( p );
-_puts("] enters for ")
+_puts("] enters for ");
 _puts( file_name );
 _puts(" / is_sfn = ");
@@ -1018 +1018 @@
 _puts(" / cluster = ");
 _putx( searched_cluster );
-_puts("\n") 
+_puts("\n"); 
 #endif
 
@@ -1044 +1044 @@
 
 //////////////////////////////////////////////////////////////////////////
-// This function initializes the FAT structure, including the
-// files descriptors array, from informations found in the boot record.
+// This function initializes the FAT structure, including the open
+// files descriptors array and the lock protecting the FAT,
+// from informations found in the boot record.
+// This should be done only once.
 //////////////////////////////////////////////////////////////////////////
 // Return 0 if success, Return -1 if failure 
@@ -1065 +1067 @@
 _puts(",");
 _putd( p );
-_puts("] enters");
-if ( mode == IOC_BOOT_MODE   ) _puts(" / IOC_BOOT_MODE\n");
-if ( mode == IOC_KERNEL_MODE ) _puts(" / IOC_KERNEL_MODE\n");
-if ( mode == IOC_USER_MODE   ) _puts(" / IOC_USER_MODE\n");
-#endif
-    
+_puts("] enters _fat_init()");
+if ( mode == IOC_BOOT_MODE   ) _puts(" in BOOT_MODE\n");
+if ( mode == IOC_KERNEL_MODE ) _puts(" in KERNEL_MODE\n");
+if ( mode == IOC_USER_MODE   ) _puts(" in USER_MODE\n");
+#endif
+
+    // FAT initialisation should be done only once
+    if ( fat.initialised == FAT_INITIALISED )
+    {
+        _puts("\n[FAT WARNING] Strange initialisation  of a FAT already initialised...\n");
+        return 0;
+    }
+
     // load Boot Record (VBR) into fat cache
     if ( _ioc_read( 0,                   // channel
@@ -1118 +1127 @@
     fat.fat_lba             = _read_entry( BPB_RSVDSECCNT, fat.fat_cache, 1 );
     fat.data_lba            = fat.fat_lba + fat.fat_sectors;
-    fat.fat_lock.value      = 0;
     fat.initialised         = FAT_INITIALISED;
+
+    // initalise the lock protecting the FAT
+    _lock_init( &fat.fat_lock );
 
     // initialise file descriptor array
@@ -1148 +1159 @@
 #if GIET_DEBUG_FAT
 _fat_print();
-_puts("\n[FAT DEBUG] _fat_init() : P[");
+_puts("\n[FAT DEBUG] P[");
 _putd( x );
 _puts(",");
@@ -1154 +1165 @@
 _puts(",");
 _putd( p );
-_puts("] exit\n");
+_puts("] exit _fat_init()\n");
 #endif
 
@@ -1177 +1188 @@
 ///////////////////////////////////////////////////////////////////////////////
 // This function checks that the kernel FAT structure has been initialised.
-// It makes the FAT initialisation if it is the first open request. 
-// This function searches a file identified by the "pathname" argument.
+// It searches a file identified by the "pathname" argument.
 // It starts from root (cluster 2) to scan successively each subdirectory.
 // When the file is not found, but the path is found, and "creat" is set,
@@ -1206 +1216 @@
 unsigned int p       = procid & ((1<<P_WIDTH)-1);
 
+_puts("\n[FAT DEBUG] P[");
+_putd( x );
+_puts(",");
+_putd( y );
+_puts(",");
+_putd( p );
+_puts("] enters _fat_open() for path ");
+_puts( pathname );
+_puts("\n");
+#endif
+
+    // checking creat argument
+    if ( creat )
+    {
+        _puts("[FAT ERROR] in _fat_open() : create not supported yet\n");
+        return -1;
+    }
+
+    // checking FAT initialised
+    if( fat.initialised != FAT_INITIALISED )
+    {
+        _puts("[FAT ERROR] in _fat_open() : FAT not initialised\n");
+        return -1;
+    }
+    // takes the FAT lock for exclusive access
+    _lock_acquire( &fat.fat_lock );
+
+#if GIET_DEBUG_FAT
 _puts("\n[FAT DEBUG] _fat_open() : P[");
 _putd( x );
@@ -1212 +1250 @@
 _puts(",");
 _putd( p );
-_puts("] enters for path ");
-_puts( pathname );
-_puts("\n");
-#endif
-
-    // checking arguments
-    if ( creat )
-    {
-        _puts("[FAT ERROR] in _fat_open() : create not supported yet\n");
-        return -1;
-    }
-
-    // takes the FAT lock for exclusive access
-    _get_lock( &fat.fat_lock );
-
-#if GIET_DEBUG_FAT
-_puts("\n[FAT DEBUG] _fat_open() : P[");
-_putd( x );
-_puts(",");
-_putd( y );
-_puts(",");
-_putd( p );
 _puts("] takes the FAT lock\n");
 #endif
-
-    // FAT initialisation if required
-    if( fat.initialised != FAT_INITIALISED )
-    {
-        if ( _fat_init( mode ) )
-        {
-            _puts("[FAT ERROR] in _fat_open() : Cannot initialize FAT descriptor\n");
-            _release_lock( &fat.fat_lock );
-            return -1;
-        }
-    }
  
     // Scan the directories, starting from the root directory (cluster 2)
@@ -1291 +1296 @@
             _puts( name );
             _puts("\n");
-            _release_lock( &fat.fat_lock );
+            _lock_release( &fat.fat_lock );
             return -1;
         }
@@ -1346 +1351 @@
 
             // release FAT lock
-            _release_lock( &fat.fat_lock );
+            _lock_release( &fat.fat_lock );
 
             return fd_id;
@@ -1355 +1360 @@
             _puts( pathname );
             _puts(" : fd array full\n");
-            _release_lock( &fat.fat_lock );
+            _lock_release( &fat.fat_lock );
             return -1;
         }
@@ -1364 +1369 @@
         _puts( pathname );
         _puts(" : bad cluster\n");
-        _release_lock( &fat.fat_lock );
+        _lock_release( &fat.fat_lock );
         return -1;
     }

soft/giet_vm/giet_fat32/fat32.h

@@ -10 +10 @@
 
 #include "giet_config.h"
-#include "utils.h"
+#include "locks.h"
 
 /*************** Partition Boot Sector Format ******************************************/
@@ -138 +138 @@
 {
     char            fat_cache[512];          // FAT cache: 1 sector = 128 cluster indexes 
-    giet_lock_t     fat_lock;                // lock protecting exclusive access
+    spin_lock_t     fat_lock;                // lock protecting exclusive access
     file_desc_t     fd[GIET_OPEN_FILES_MAX]; // file descriptors array
     unsigned int    initialised;             // contains 0xBABEF00D when FAT initialised