From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 3/3] PCI: Layerscape: Add Layerscape PCIe driver
Date: Tue, 16 Sep 2014 18:33:52 +0200 [thread overview]
Message-ID: <201409161833.53176.arnd@arndb.de> (raw)
In-Reply-To: <54187590.4070101@freescale.com>
On Tuesday 16 September 2014, Lian Minghuan-B31939 wrote:
> >>>> + ranges = <0x81000000 0x0 0x00000000 0x40 0x10000000 0x0 0x00010000 /* downstream I/O */
> >>>> + 0x82000000 0x0 0x00000000 0x41 0x00000000 0x1 0x00000000>; /* non-prefetchable memory */
> >>> Are these ranges hardcoded in the SoC, or are they the result of iATU
> >>> settings? If the latter, who configures it and why no prefetchable
> >>> region?
> >> [Minghuan] 400000_0000 - 480000_0000 is hardcode assigned to PEX1.
> >> I separates from this 32 region 1M for IO, 4G for non-prefetchable memory.
> >> 4G is the max size iATU supported.
> >> IO and memory region will be set to iATU by pci-designware.c
> >> Because both powerpc and imx do not set prefechable memory,
> >> so I do not assign prefetchable memory either.
> > If there's spare room in the addres space for a prefetchable region, why
> > not make one, regardless of what PPC and IMX do?
> >
> > FWIW, I believe that ARMv8 can make better use of a prefetchable region
> > due to the "gathering" storage attribute, so even if you don't use one
> > on LS1021A consider using one on ARMv8-based LS chips.
> [Minghuan] Ok, I will add 4G prefetchable memory region.
I guess that means you still can't support devices that require 64-bit
BARs, right? 4GB may be too small for some devices.
Do I read this right that you could have multiple adjacent 4GB areas
but are limited on registers to set up these areas?
Arnd
next prev parent reply other threads:[~2014-09-16 16:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-11 21:08 [PATCH v2 1/3] PCI: designware: Rename get_msi_data to get_msi_addr Minghuan Lian
2014-09-11 21:09 ` [PATCH v2 2/3] PCI: designware: Add get_msi_data to pcie_host_ops Minghuan Lian
2014-09-11 21:09 ` [PATCH v2 3/3] PCI: Layerscape: Add Layerscape PCIe driver Minghuan Lian
2014-09-11 21:24 ` Scott Wood
2014-09-12 11:10 ` Lian Minghuan-B31939
2014-09-16 4:19 ` Scott Wood
2014-09-16 17:38 ` Lian Minghuan-B31939
2014-09-16 16:33 ` Arnd Bergmann [this message]
2014-09-17 10:26 ` Lian Minghuan-B31939
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