Changeset 437 for soft/giet_vm/giet_drivers/bdv_driver.h

Timestamp:

Nov 3, 2014, 10:53:00 AM (10 years ago)

Author:

alain

Message:

Introducing dynamic allocation of peripheral channel(TTY, NIC, TIM, CMA)
Removint the ICU driver : ICU component not supported anymore.
Removing the FBF driver.

File:

• soft/giet_vm/giet_drivers/bdv_driver.h (modified) (3 diffs)

soft/giet_vm/giet_drivers/bdv_driver.h

@@ -5 +5 @@
 // Maintainer: cesar fuguet
 // Copyright (c) UPMC-LIP6
+///////////////////////////////////////////////////////////////////////////////////
+// The bdv_driver.c and bdv_driver.h files are part ot the GIET-VM kernel.
+// This driver supports the SocLib vci_block_device component, that is
+// a single channel, block oriented, external storage contrÃŽler.
+//
+// The _bdv_read() and _bdv_write() functions are always blocking.
+// They can be called in 3 modes:
+//
+// - In BOOT mode, these functions use a polling policy on the BDV STATUS 
+//   register to detect transfer completion, as interrupts are not activated. 
+//   This mode is used by the boot code to load the map.bin file into memory
+//   (before MMU activation), or to load the .elf files (after MMU activation). 
+//
+// - In KERNEL mode, these functions use a descheduling strategy:
+//   The ISR executed when transfer completes should restart the calling task.
+//   There is no checking of user access right to the memory buffer. 
+//   This mode must be used, for an "open" system call.
+//
+// - In USER mode, these functions use a descheduling strategy:
+//   The ISR executed when transfer completes should restart the calling task, 
+//   The user access right to the memory buffer must be checked.
+//   This mode must be used for a "read/write" system call.
+//
+// As the BDV component can be used by several programs running in parallel,
+// the _bdv_lock variable guaranties exclusive access to the device.  The
+// _bdv_read() and _bdv_write() functions use atomic LL/SC to get the lock.
+//
+// Finally, the memory buffer must fulfill the following conditions:
+// - The buffer must be word aligned, 
+// - The buffer must be mapped in user space for an user access, 
+// - The buffer must be writable in case of (to_mem) access,
+// - The total number of physical pages occupied by the user buffer cannot
+//   be larger than 512 pages if the IOMMU is activated,
+// - All physical pages occupied by the user buffer must be contiguous
+//   if the IOMMU is not activated.
+// An error code is returned if these conditions are not verified.
+//
+// The SEG_IOC_BASE address must be defined in the hard_config.h file.
 ///////////////////////////////////////////////////////////////////////////////////
 
@@ -56 +94 @@
 
 ///////////////////////////////////////////////////////////////////////////////////
-// BDV access functions (vci_block_device)
+//            Access functions
 ///////////////////////////////////////////////////////////////////////////////////
 
+///////////////////////////////////////////////////////////////////////////////////
+// This function cheks block size == 512, and desactivates the interrupts.
+// Return 0 for success, > 0 if error
+///////////////////////////////////////////////////////////////////////////////////
 extern unsigned int _bdv_init();
 
+///////////////////////////////////////////////////////////////////////////////////
+// Transfer data from the block device to a memory buffer. 
+// - mode     : BOOT / KERNEL / USER
+// - lba      : first block index on the block device
+// - buffer   : base address of the memory buffer (must be word aligned)
+// - count    : number of blocks to be transfered.
+// Returns 0 if success, > 0 if error.
+////////////////////////////////////////////////////////////////////////////////////
+extern unsigned int _bdv_read(  unsigned int       mode,
+                                unsigned int       lba, 
+                                unsigned long long buffer,
+                                unsigned int       count );
+
+///////////////////////////////////////////////////////////////////////////////////
+// Transfer data from a memory buffer to the block device. 
+// - mode     : BOOT / KERNEL / USER
+// - lba      : first block index on the block device
+// - buffer   : base address of the memory buffer (must be word aligned)
+// - count    : number of blocks to be transfered.
+// Returns 0 if success, > 0 if error.
+///////////////////////////////////////////////////////////////////////////////////
 extern unsigned int _bdv_write( unsigned int       mode,
                                 unsigned int       lba, 
@@ -66 +129 @@
                                 unsigned int       count );
 
-extern unsigned int _bdv_read(  unsigned int       mode,
-                                unsigned int       lba, 
-                                unsigned long long buffer,
-                                unsigned int       count );
-
+///////////////////////////////////////////////////////////////////////////////////
+// Returns device status.
+///////////////////////////////////////////////////////////////////////////////////
 extern unsigned int _bdv_get_status();
 
+///////////////////////////////////////////////////////////////////////////////////
+// Returns block size.
+///////////////////////////////////////////////////////////////////////////////////
 extern unsigned int _bdv_get_block_size();
 
+///////////////////////////////////////////////////////////////////////////////////
+// This ISR save the status, acknowledge the IRQ, and activates the task 
+// waiting on IO transfer. It can be an HWI or a SWI.
+//
+// TODO the _set_task_slot access should be replaced by an atomic LL/SC
+//      when the CTX_RUN bool will be replaced by a bit_vector. 
+///////////////////////////////////////////////////////////////////////////////////
 extern void _bdv_isr( unsigned irq_type,
                       unsigned irq_id,
                       unsigned channel );
 
-///////////////////////////////////////////////////////////////////////////////////
 
 #endif