tisdb(7) —

NAME

tisdb − Texas Instruments TMS34010 Software Development Board driver

DESCRIPTION

The Texas Instruments TMS34010 Software Development Board kernel driver facilitates accessing the Texas Instruments TMS34010 Software Development Board. It is a regular character-based driver that manages one SDB. It is used by programs that draw using the graphics modes of the SDB.

CONFIGURATION

The sdevice(4) file /etc/conf/sdevice.d/tisdb describes the memory addresses of the SDB. The ninth and tenth fields in this file describe the starting and ending memory addresses. These fields are given in hexadecimal. The default sdevice file entry with an memory base address of >C7000 is:

tisdb Y 1 0 0 0 0 0 c7000 c7fff

If you want a memory base address of >E7000 instead, then the following sdevice entry should be used:

tisdb Y 1 0 0 0 0 0 e7000 e7fff

If you change the default sdevice entry, you will have to build a new kernel and boot it for these changes to become effective.

NOTE: Both of the PALS given with the SDB generate a memory address that conflicts with the VGA.

PROGRAMMING INTERFACE

The Texas Instruments TMS34010 Software Development Board device is opened by a call to open. Currently, only minor device 0 is supported. If a non-zero minor device is specified, then an error will occur and errno will be set to ENOENT. A simple check is done to see if the SDB is in the system. If it is not, an error will result and errno will be set to ENXIO. A memory address clash may also cause this error. Only one user is allowed to open the SDB at a time, unless the subsequent user is the superuser. If a subsequent open is attempted by another user who is not the superuser, an error will result and errno will be set to EPERM.

Read and write interfaces are provided to access the memory of the Texas Instruments 34010 processor in the SDB. Seek addresses are specified in bytes. Because addresses on a 34010 processor are given in bits, it is necessary to divide the bit address by 8 to get a byte address. The state of the 34010 is saved before each read and write, and it is restored when they are completed.

The following ioctl calls allow a user program to access the SDB directly:

TISDB_GET_INFO
This ioctl returns a structure containing the addresses of the board described in the section “Configuration” above. The structure returned is:

typedef struct tisdb_info {
char*tisdb_addr;/* physical address */
char*tisdb_endaddr; /* physical address */
} tisdb_info_t;

This structure is filled in with information in the ninth through tenth fields of the sdevice file. It is stored at the location specified by the argument that is passed.

TISDB_MAP_BOARD
This ioctl allows the process to have direct access to the SDB memory. The argument passed is the address of the memory to map to the SDB. It must be page (4096 byte) aligned and span a length specified by the sdevice file (which is also a multiple of 4096 bytes). The memory that had existed at the argument passed will be irretrievably deleted, and the current contents of the SDB memory will be placed at those locations. One way of allocating the virtual memory in the user’s address space that will be mapped to the SDB memory is to call malloc requesting (length + 4096) bytes. Then, using the address that malloc returns, round it up to the next page (4K) boundary and use the result as the argument to this ioctl.

TISDB_UNMAP_BOARD
This ioctl call unmaps the direct access to the SDB memory. The map must have been set up with TISDB_MAP_BOARD by the current process. The argument passed should be the same one given to TISDB_MAP_BOARD. The memory where the SDB memory had been becomes zeros.

FILES

/dev/tisdb

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