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Re: [Qemu-devel] Ping [PATCH 0/2] Add TPCI200 and IP-Octal 232 IndustryP
From: |
Avi Kivity |
Subject: |
Re: [Qemu-devel] Ping [PATCH 0/2] Add TPCI200 and IP-Octal 232 IndustryPack emulation |
Date: |
Wed, 10 Oct 2012 13:35:06 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120911 Thunderbird/15.0.1 |
On 10/10/2012 12:24 PM, Alberto Garcia wrote:
> On Sun, Oct 07, 2012 at 12:13:53PM +0200, Avi Kivity wrote:
>
>> 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.
>
> Hey, I finally found some time to look into this, the problem that I
> see is that the PCI carrier doesn't just map each space into its local
> address spaces, in addition to that:
>
> 1) it changes the data and addresses according to the endianness
> configuration in the local configuration registers (PCI BAR0).
> See adjust_addr()/adjust_value() and page 20 of the user manual.
>
> http://www.tews.com/Products/ArticleGroup/TPCI/TPCI200.html
This is supported (albeit not cleanly) by the memory API. There is the
MemoryRegionOps::endianess attribute, you can have a mem16_be_space and
mem16_le_space; use
memory_region_add_subregion()/memory_region_del_subregion() to map
le_space or be_space as needed to the BAR.
>
> 2) read accesses to the local address space 1 are also used to
> acknowledge interrupts (manual page 33 and tpci200_read_las1()).
>
You can map a small subregion over those addresses. What is the value
read? does it need to go to the int space and read it, or is it some
fixed value?
>
>
> On a related note, I was wondering whether it would be simpler to get
> rid of tpci200_cfg_ops and replace the current implementation of the
> local configuration registers with something like this:
>
> memory_region_init_ram_ptr(&s->mmio, "tpci200_mmio", 128, s->local_cfg);
> memory_region_init_alias(&s->io, "tpci200_io", &s->mmio, 0, 128);
> pci_register_bar(&s->dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->mmio);
> pci_register_bar(&s->dev, 1, PCI_BASE_ADDRESS_SPACE_IO, &s->io);
>
> (s->local_cfg would contain the config registers data)
>
> But it doesn't seem to work.
This is supposed to work. What does 'info mtree' show? What happens if
you grow the size up to a page size? Do both BARs fail, or just the IO BAR?
--
error compiling committee.c: too many arguments to function
Re: [Qemu-devel] Ping [PATCH 0/2] Add TPCI200 and IP-Octal 232 IndustryPack emulation, Andreas Färber, 2012/10/05