linux-imx

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The Amiga Buddha and Catweasel IDE Driver (part of ide.c) was written by

Geert Uytterhoeven based on the following specifications:

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Register map of the Buddha IDE controller and the

Buddha-part of the Catweasel Zorro-II version

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The Autoconfiguration has been implemented just as Commodore

described  in  their  manuals, no tricks have been used (for

example leaving some address lines out of the equations...).

If you want to configure the board yourself (for example let

a  Linux  kernel  configure the card), look at the Commodore

Docs.  Reading the nibbles should give this information:

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Vendor number: 4626 ($1212)

product number: 0 (42 for Catweasel Z-II)

Serial number: 0

Rom-vector: $1000

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The  card  should be a Z-II board, size 64K, not for freemem

list, Rom-Vektor is valid, no second Autoconfig-board on the

same card, no space preference, supports "Shutup_forever".

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Setting  the  base address should be done in two steps, just

as  the Amiga Kickstart does:  The lower nibble of the 8-Bit

address is written to $4a, then the whole Byte is written to

$48, while it doesn't matter how often you're writing to $4a

as  long as $48 is not touched.  After $48 has been written,

the  whole card disappears from $e8 and is mapped to the new

address just written.  Make sure $4a is written before $48,

otherwise your chance is only 1:16 to find the board :-).

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The local memory-map is even active when mapped to $e8:

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$0-$7e      Autokonfig-space, see Z-II docs.

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$80-$7fd    reserved

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$7fe        Speed-select Register: Read & Write

        (description see further down)

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$800-$8ff   IDE-Select 0 (Port 0, Register set 0)

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$900-$9ff   IDE-Select 1 (Port 0, Register set 1)

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$a00-$aff   IDE-Select 2 (Port 1, Register set 0)

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$b00-$bff   IDE-Select 3 (Port 1, Register set 1)

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$c00-$cff   IDE-Select 4 (Port 2, Register set 0,

                          Catweasel only!)

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$d00-$dff   IDE-Select 5 (Port 3, Register set 1,

                  Catweasel only!)

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$e00-$eff   local expansion port, on Catweasel Z-II the 

        Catweasel registers are also mapped here.

        Never touch, use multidisk.device!

$f00        read only, Byte-access: Bit 7 shows the 

        level of the IRQ-line of IDE port 0. 

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$f01-$f3f   mirror of $f00

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$f40        read only, Byte-access: Bit 7 shows the 

        level of the IRQ-line of IDE port 1. 

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$f41-$f7f   mirror of $f40

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$f80        read only, Byte-access: Bit 7 shows the 

        level of the IRQ-line of IDE port 2. 

        (Catweasel only!)

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$f81-$fbf   mirror of $f80

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$fc0        write-only: Writing any value to this

        register enables IRQs to be passed from the 

        IDE ports to the Zorro bus. This mechanism 

        has been implemented to be compatible with 

        harddisks that are either defective or have

        a buggy firmware and pull the IRQ line up 

        while starting up. If interrupts would 

        always be passed to the bus, the computer 

        might not start up. Once enabled, this flag 

        can not be disabled again. The level of the 

        flag can not be determined by software 

        (what for? Write to me if it's necessary!).

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$fc1-$fff   mirror of $fc0

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