Subject: Re: [PATCH 5/5] powerpc/fsl_msi: add 'msiregs' kernel parameter

From: Scott Wood <[email-masked]>
Date: Fri, 14 Jun 2013 17:13:54 -0500

On 06/14/2013 02:15:59 AM, Minghuan Lian wrote:
> 1. Only MSIIR1 can index 16 MSI registers, but when using MSIIR1
> the IRQs of a register are not continuous. for example, the first
> register irq values are 0x0, 0x10, 0x20, 0x30 ... 0x1f0. So it
> is hard to use 'msi-available-ranges' property to indicate the
> available ranges and 'msi-available-ranges' property has been
> removed from dts node, so this patch removes the related code.
>=20
> 2. Add 'msiregs' kernel parameter instead of 'msi-available-ranges'
> functionality.

The reason we used a device tree property was because this is for =20
virtualization and AMP scenarios where this instance of Linux does not =20
own all of the MSI registers.

I don't see any reasonable way to partition an MPIC v4.3 MSI group -- =20
but there are more groups, so it's not that bad.  What's the use case =20
for this patch?

-Scott=