Documentation/driver-api/zorro.rst

Source file repositories/reference/linux-study-clean/Documentation/driver-api/zorro.rst

File Facts

System
Linux kernel
Corpus path
Documentation/driver-api/zorro.rst
Extension
.rst
Size
2971 bytes
Lines
105
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

while ((z = zorro_find_device(ZORRO_PROD_xxx, z))) {
	if (!zorro_request_region(z->resource.start+MY_START, MY_SIZE,
				  "My explanation"))
	...
    }

``ZORRO_WILDCARD`` acts as a wildcard and finds any Zorro device. If your driver
supports different types of boards, you can use a construct like::

    struct zorro_dev *z = NULL;

    while ((z = zorro_find_device(ZORRO_WILDCARD, z))) {
	if (z->id != ZORRO_PROD_xxx1 && z->id != ZORRO_PROD_xxx2 && ...)
	    continue;
	if (!zorro_request_region(z->resource.start+MY_START, MY_SIZE,
				  "My explanation"))
	...
    }


Zorro Resources
---------------

Before you can access a Zorro device's registers, you have to make sure it's
not yet in use. This is done using the I/O memory space resource management
functions::

    request_mem_region()
    release_mem_region()

Shortcuts to claim the whole device's address space are provided as well::

    zorro_request_device
    zorro_release_device


Accessing the Zorro Address Space
---------------------------------

The address regions in the Zorro device resources are Zorro bus address
regions. Due to the identity bus-physical address mapping on the Zorro bus,
they are CPU physical addresses as well.

The treatment of these regions depends on the type of Zorro space:

  - Zorro II address space is always mapped and does not have to be mapped
    explicitly using z_ioremap().
    
    Conversion from bus/physical Zorro II addresses to kernel virtual addresses
    and vice versa is done using::

	virt_addr = ZTWO_VADDR(bus_addr);
	bus_addr = ZTWO_PADDR(virt_addr);

  - Zorro III address space must be mapped explicitly using z_ioremap() first
    before it can be accessed::
 
	virt_addr = z_ioremap(bus_addr, size);
	...
	z_iounmap(virt_addr);


References
----------

#. linux/include/linux/zorro.h
#. linux/include/uapi/linux/zorro.h
#. linux/include/uapi/linux/zorro_ids.h
#. linux/arch/m68k/include/asm/zorro.h
#. linux/drivers/zorro

Annotation

Implementation Notes