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Date: Sun, 07 Oct 2012 12:13:53 +0200
From: Avi Kivity <avi@redhat.com>
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Subject: Re: [Qemu-devel] Ping [PATCH 0/2] Add TPCI200 and IP-Octal 232
 IndustryPack emulation
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To: Blue Swirl <blauwirbel@gmail.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>, Alberto Garcia <agarcia@igalia.com>, qemu-devel@nongnu.org, Paul Brook <paul@codesourcery.com>, Paolo Bonzini <pbonzini@redhat.com>, =?UTF-8?B?QW5kcmVhcyBGw6RyYmVy?= <afaerber@suse.de>

On 10/05/2012 06:24 PM, Blue Swirl wrote:
> 
> I'd suppose addressing devices in the bus could be implemented more
> efficiently with better use of memory API, now some of it is
> reimplemented. Maybe Avi can propose something?

Luckily the low-order bits are used for offsets, and the high-order bits
are used for selecting the sub-device.

So you could easily have

 struct IPackDevice {
     DeviceState qdev;
     int32_t slot;
     /* IRQ objects for the IndustryPack INT0# and INT1# */
     qemu_irq *irq;
     MemoryRegion io_space;
     MemoryRegion id_space;
     MemoryRegion int_space;
     MemoryRegion mem8_space;  /* for las3 */
     MemoryRegion mem16_space; /* for las2 */
 };

The PCI device would then just map each space (with
memory_region_add_subregion()) into las1/las2/las3 such that the high
bits select the device/space.  The low bits would automatically become
the offset into the space.



-- 
error compiling committee.c: too many arguments to function