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1========================================2Writing Device Drivers for Zorro Devices3========================================4 5:Author: Written by Geert Uytterhoeven <geert@linux-m68k.org>6:Last revised: September 5, 20037 8 9Introduction10------------11 12The Zorro bus is the bus used in the Amiga family of computers. Thanks to13AutoConfig(tm), it's 100% Plug-and-Play.14 15There are two types of Zorro buses, Zorro II and Zorro III:16 17 - The Zorro II address space is 24-bit and lies within the first 16 MB of the18 Amiga's address map.19 20 - Zorro III is a 32-bit extension of Zorro II, which is backwards compatible21 with Zorro II. The Zorro III address space lies outside the first 16 MB.22 23 24Probing for Zorro Devices25-------------------------26 27Zorro devices are found by calling ``zorro_find_device()``, which returns a28pointer to the ``next`` Zorro device with the specified Zorro ID. A probe loop29for the board with Zorro ID ``ZORRO_PROD_xxx`` looks like::30 31 struct zorro_dev *z = NULL;32 33 while ((z = zorro_find_device(ZORRO_PROD_xxx, z))) {34 if (!zorro_request_region(z->resource.start+MY_START, MY_SIZE,35 "My explanation"))36 ...37 }38 39``ZORRO_WILDCARD`` acts as a wildcard and finds any Zorro device. If your driver40supports different types of boards, you can use a construct like::41 42 struct zorro_dev *z = NULL;43 44 while ((z = zorro_find_device(ZORRO_WILDCARD, z))) {45 if (z->id != ZORRO_PROD_xxx1 && z->id != ZORRO_PROD_xxx2 && ...)46 continue;47 if (!zorro_request_region(z->resource.start+MY_START, MY_SIZE,48 "My explanation"))49 ...50 }51 52 53Zorro Resources54---------------55 56Before you can access a Zorro device's registers, you have to make sure it's57not yet in use. This is done using the I/O memory space resource management58functions::59 60 request_mem_region()61 release_mem_region()62 63Shortcuts to claim the whole device's address space are provided as well::64 65 zorro_request_device66 zorro_release_device67 68 69Accessing the Zorro Address Space70---------------------------------71 72The address regions in the Zorro device resources are Zorro bus address73regions. Due to the identity bus-physical address mapping on the Zorro bus,74they are CPU physical addresses as well.75 76The treatment of these regions depends on the type of Zorro space:77 78 - Zorro II address space is always mapped and does not have to be mapped79 explicitly using z_ioremap().80 81 Conversion from bus/physical Zorro II addresses to kernel virtual addresses82 and vice versa is done using::83 84 virt_addr = ZTWO_VADDR(bus_addr);85 bus_addr = ZTWO_PADDR(virt_addr);86 87 - Zorro III address space must be mapped explicitly using z_ioremap() first88 before it can be accessed::89 90 virt_addr = z_ioremap(bus_addr, size);91 ...92 z_iounmap(virt_addr);93 94 95References96----------97 98#. linux/include/linux/zorro.h99#. linux/include/uapi/linux/zorro.h100#. linux/include/uapi/linux/zorro_ids.h101#. linux/arch/m68k/include/asm/zorro.h102#. linux/drivers/zorro103#. /proc/bus/zorro104 105