From: Leonardo Bras <leobras.c@gmail.com>
To: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>,
Alexey Kardashevskiy <aik@ozlabs.ru>,
devicetree@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
PCI <linux-pci@vger.kernel.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH 1/1] of/pci: Add IORESOURCE_MEM_64 to resource flags for 64-bit memory addresses
Date: Fri, 16 Apr 2021 17:57:59 -0300 [thread overview]
Message-ID: <7b089cd48b90f2445c7cb80da1ce8638607c46fc.camel@gmail.com> (raw)
In-Reply-To: <CAL_Jsq+WwAeziGN4EfPAWfA0fieAjfcxfi29=StOx0GeKjAe_g@mail.gmail.com>
Hello Rob, thanks for this feedback!
On Thu, 2021-04-15 at 13:59 -0500, Rob Herring wrote:
> +PPC and PCI lists
>
> On Thu, Apr 15, 2021 at 1:01 PM Leonardo Bras <leobras.c@gmail.com> wrote:
> >
> > Many other resource flag parsers already add this flag when the input
> > has bits 24 & 25 set, so update this one to do the same.
>
> Many others? Looks like sparc and powerpc to me.
>
s390 also does that, but it look like it comes from a device-tree.
> Those would be the
> ones I worry about breaking. Sparc doesn't use of/address.c so it's
> fine. Powerpc version of the flags code was only fixed in 2019, so I
> don't think powerpc will care either.
In powerpc I reach this function with this stack, while configuring a
virtio-net device for a qemu/KVM pseries guest:
pci_process_bridge_OF_ranges+0xac/0x2d4
pSeries_discover_phbs+0xc4/0x158
discover_phbs+0x40/0x60
do_one_initcall+0x60/0x2d0
kernel_init_freeable+0x308/0x3a8
kernel_init+0x2c/0x168
ret_from_kernel_thread+0x5c/0x70
For this, both MMIO32 and MMIO64 resources will have flags 0x200.
>
> I noticed both sparc and powerpc set PCI_BASE_ADDRESS_MEM_TYPE_64 in
> the flags. AFAICT, that's not set anywhere outside of arch code. So
> never for riscv, arm and arm64 at least. That leads me to
> pci_std_update_resource() which is where the PCI code sets BARs and
> just copies the flags in PCI_BASE_ADDRESS_MEM_MASK ignoring
> IORESOURCE_* flags. So it seems like 64-bit is still not handled and
> neither is prefetch.
>
I am not sure if you mean here:
a) it's ok to add IORESOURCE_MEM_64 here, because it does not affect
anything else, or
b) it should be using PCI_BASE_ADDRESS_MEM_TYPE_64
(or IORESOURCE_MEM_64 | PCI_BASE_ADDRESS_MEM_TYPE_64) instead, since
it's how it's added in powerpc/sparc, and else there is no point.
Again, thanks for helping!
Best regards,
Leonardo Bras
next prev parent reply other threads:[~2021-04-16 20:58 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-15 18:00 [PATCH 1/1] of/pci: Add IORESOURCE_MEM_64 to resource flags for 64-bit memory addresses Leonardo Bras
2021-04-15 18:59 ` Rob Herring
2021-04-16 20:57 ` Leonardo Bras [this message]
2021-04-19 15:44 ` Rob Herring
2021-04-20 0:35 ` Leonardo Bras
2021-04-20 1:39 ` Rob Herring
2021-04-20 2:02 ` Leonardo Bras
2021-04-20 22:34 ` Rob Herring
2021-04-21 14:14 ` Leonardo Bras
2021-04-16 21:27 ` Leonardo Bras
2021-06-09 18:50 ` Bjorn Helgaas
2021-04-21 12:51 ` Rob Herring
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