Changes between Initial Version and Version 1 of kernel_fat32

Timestamp:

Mar 17, 2015, 3:31:59 PM (10 years ago)

Author:

alain

Comment:

--

kernel_fat32

@@ +1 @@
+= GIET-VM  / FAT32 Handler =
+
+This section define the kernel data structure and functions that are used to access a FAT32 file system stored on a mass storage block device (such as BDV, HBA, SDC, or RDK peripherals).
+
+[[PageOutline]]
+
+ * The [source:soft/giet_vm/giet_fat32/fat_sync.c fat_sync.c] and [source:soft/giet_vm/giet_fat32/fat_sync.h fat_sync.h] files define the functions to access the block device with a polling policy on the peripheral status.
+ * The [source:soft/giet_vm/giet_fat32/fat_irq.c fat_irq.c] and [source:soft/giet_vm/giet_fat32/fat_irq.h fat_irq.h] files define the functions to access the block device with a a descheduling / completion IRQ policy. 
+ * The [source:soft/giet_vm/giet_fat32/fat_common.c fat_common.c] and [source:soft/giet_vm/fat_common.h fat_common.h] files define the functions that are independant on the
+blockdevice access mode.
+
+All these functions are prefixed by ''_'' to remind that they can only be executed by a processor in kernel mode.
+
+The [source:soft/giet_vm/giet_kernel/sys_handler.c _syscall_vector] array contains the 64 kernel functions (syscal handlers) defined by the GIET-VM to handle system calls.
+
+== Common FAT32 access functions  ==
+
+== Polling based FAT32 access functions  ==
+
+The following functions are intended to be used by the GIET_VM boot-loader, when the interrupts are not yet enabled. They use a polling strategy on the block device status to detect completion.
+
+=== 1) int '''_fat_sync_open'''( ) ===
+
+=== 2) int '''_fat_sync_read'''( unsigned int fd_id  ,  unsigned int buffer  ,  unsigned int count  , unsigned int offset ) ===
+This function transfer an integer number of blocks from an open file on the block device to a memory buffer, after checking the arguments.
+If the number of requested sectors exceeds the file size, this number of sectors is reduced.
+ * '''fd_id''' : file descriptor index
+ * '''buffer''' : memory buffer virtual base address
+ * '''count''' : number of blocks to transfer
+ * '''offset''' : number of blocks to skip in file
+Returns number of sectors transfered if success, returns -1 if error.
+
+=== 3) int '''_fat_sync_ioc_access( unsigned int to_memory ,  unsigned int lba  ,  unsigned int buf_vaddr  ,  unsigned int count ) ===
+This function computes the buffer physical address, and call the proper block device driver, as specified in the mapping.
+ * '''to_memory''' : to memory transfer if non zero.
+ * '''lba''' : first block index on the block device.
+ * '''buf_vaddr''' : memory buffer virtual base address
+ * '''count''' : number of blocks to transfer
+Returns 0 if success, returns -1 if error.
+
+== Interrupt based FAT32 access functions  ==
+
+