[U-Boot] [PATCH 14/15] RFC: x86: minnowmax: Add interrupt routing setup

[Bin Meng]

Hi Simon,

On Tue, Jul 28, 2015 at 7:58 PM, Simon Glass <sjg at chromium.org> wrote:
> Hi Bin,
>
> On 28 July 2015 at 01:50, Bin Meng <bmeng.cn at gmail.com> wrote:
>>
>> Hi Simon,
>>
>> On Tue, Jul 28, 2015 at 5:47 AM, Simon Glass <sjg at chromium.org> wrote:
>> > At present minnowmax does not correct set up PCI interrupts. This should be
>> > done in U-Boot so that devices work correctly in Linux.
>> >
>> > Note: This code needs to make use of the recent pirq_routing work. It does
>> > not seem to support all the required features, so this RFC will hopefully
>>
>> What features are missing in the existing PIRQ codes? When I did the
>> PIRQ support, I checked both TunnelCreek and BayTrail chipset
>> datasheet, and found the only difference seems to be the pci
>> configuration space vs. memory-mapped IBASE where the pci irq routing
>> registers reside.
>
> I see that each PCI device can be assigned four routes, making up a
> 16-bit register. But the code I see in pirq_assign_req() only assigns
> a single one, using a byte register.
>

No, the pci irq routing register is still a 8-bit register on
BayTrail, where pirq_assign_irq() programs. The 16-bit register you
mentioned should be done in the platform codes. See
arch/x86/cpu/queensbay/tnc.c::cpu_irq_init(). By the way actually we
can leave those register programmed as they have the optimized default
values for all pci devices after power up, unless we intentionally
want to change them.

Regards,
Bin