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Date: Fri, 14 Jun 2013 17:13:54 -0500
From: Scott Wood <scottwood@freescale.com>
Subject: Re: [PATCH 5/5] powerpc/fsl_msi: add 'msiregs' kernel parameter
To: Minghuan Lian <Minghuan.Lian@freescale.com>
References: <1371194159-17332-1-git-send-email-Minghuan.Lian@freescale.com>
 <1371194159-17332-5-git-send-email-Minghuan.Lian@freescale.com>
In-Reply-To: <1371194159-17332-5-git-send-email-Minghuan.Lian@freescale.com>
 (from Minghuan.Lian@freescale.com on Fri Jun 14 02:15:59 2013)
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Cc: Minghuan Lian <Minghuan.Lian@freescale.com>, linuxppc-dev@lists.ozlabs.org,
 Zang Roy-R61911 <r61911@freescale.com>
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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=