source: soft/giet_vm/giet_drivers/ioc_driver.h @ 512

///////////////////////////////////////////////////////////////////////////////
// File     : ioc_driver.h
// Date     : 01/11/2013
// Author   : alain greiner
// Copyright (c) UPMC-LIP6
///////////////////////////////////////////////////////////////////////////////
// The ioc_driver.c and ioc_driver.h files are part ot the GIET-VM kernel.
//
// This abstact driver define a generic API, supporting various physical
// block device controlers, including:
// - vci_block_device : single channel                     => bdv_driver
// - vci_ahci         : multi channels                     => hba_driver
// - sd_card          : single channel                     => sdc_driver
// - ramdisk (single channel meory mapped virtual disk)    => rdk_driver
//
// It can exist only one block-device type in the architecture, that must be
// defined by one of the following configuration variables in hard_config.h file:
// USE_IOC_BDV, USE_IOC_SDC, USE_IOC_HBA, USE_IOC_RDK.
//
// Any physical block device driver must provide the 5 five functions defined
// by this generic driver.
//
// The _ioc_read() and _ioc_write() functions are always blocking for
// the calling user program.
//
// These functions compute the physical address of the memory buffer before 
// calling the proper physical device. We know that the user buffer is mapped 
// to a contiguous physical buffer because, for each vseg, the page tables
// are statically constructed to use contiguous physical memory.
//
// These functions can be called in 3 modes:
//
// - In BOOT mode, these functions use the buffer virtual address
//   as a physical address if the MMU is not activated.
//   They make a V2P translation if the MMU is activated.
//   This mode is used to load the map.bin file (before memory activation),
//   or to load the various .elf files (after MMU activation).
//
// - In KERNEL mode, these functions make a V2P translation to
//   compute the buffer physical address.
//   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 make a V2P translation to
//   compute the buffer physical address. 
//   The user access right to the memory buffer are checked.  
//   This mode must be used for a "read" or "write" system call.
//
// 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.
// Exit if these conditions are not verified.
//
// The SEG_IOC_BASE virtual base address must be defined in hard_config.h,
// as it is used by the BDV, HBA and SPI drivers.
//
// If the RAMDISK is used, an extra memory segment with virtual base address
// SEG_RDK_BASE, used by RDK driver, must be defined in hard_config.h.
//
// The IOMMU is not supported yet, but the method is the following:
// A fixed size 2 Mbytes vseg is allocated to the IOC peripheral, in the I/O 
// virtual space, and the user buffer is dynamically remapped to one single
// big page in the IOMMU page table.
// The user buffer is unmapped by the _ioc_completed() function when 
// the transfer is completed.
///////////////////////////////////////////////////////////////////////////////

#ifndef _GIET_IOC_DRIVER_H_
#define _GIET_IOC_DRIVER_H_

///////////////////////////////////////////////////////////////////////////////
// IOC (vci_block device) registers offsets
///////////////////////////////////////////////////////////////////////////////

enum IOC_driver_modes
{
    IOC_BOOT_MODE   = 0,     //  Polling IOC_STATUS / no access right checking
    IOC_KERNEL_MODE = 1,     //  Descheduling + IRQ / no access right checking
    IOC_USER_MODE   = 2,     //  Descheduling + IRQ / access right checking
};

///////////////////////////////////////////////////////////////////////////////
//      External global variables
///////////////////////////////////////////////////////////////////////////////

extern volatile unsigned int _ioc_iommu_ix1;
extern volatile unsigned int _ioc_iommu_npages; 

///////////////////////////////////////////////////////////////////////////////
//      External functions                            
///////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////
// This function cheks block size, and desactivates interrupts.
// Return 0 for success, non zero if error.
///////////////////////////////////////////////////////////////////////////////
extern unsigned int _ioc_init( unsigned int channel );

///////////////////////////////////////////////////////////////////////////////
// Transfer data from a memory buffer to the disk. 
// - 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 _ioc_write( unsigned int channel,
                                unsigned int mode,
                                unsigned int lba, 
                                const void*  buffer, 
                                unsigned int count );

///////////////////////////////////////////////////////////////////////////////
// Transfer data from the disk 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 _ioc_read(  unsigned int channel,
                                unsigned int mode,
                                unsigned int lba, 
                                void*        buffer,
                                unsigned int count );

///////////////////////////////////////////////////////////////////////////////
// This function returns in the status variable, the transfert status, and
// acknowledge the IRQ if required.
// Returns 0 if success, > 0 if error
///////////////////////////////////////////////////////////////////////////////
extern unsigned int _ioc_get_status( unsigned int channel );

///////////////////////////////////////////////////////////////////////////////
// This function returns the block_size for the block device.
///////////////////////////////////////////////////////////////////////////////
extern unsigned int _ioc_get_block_size();


#endif

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