linux-kernel - Re: [PATCH 8/9] PCI: Ignore BAR contents when firmware left decoding disabled

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Message-ID: <CAErSpo42K6W8b+7A7dyxUp-rNQttMQY7jcbpgyGv9sctyAqJCA@mail.gmail.com>
Date:	Wed, 19 Mar 2014 15:16:17 -0600
From:	Bjorn Helgaas <bhelgaas@...gle.com>
To:	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Ming Lei <tom.leiming@...il.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Pekka Enberg <penberg@...nel.org>,
	Sasha Levin <sasha.levin@...cle.com>
Subject: Re: [PATCH 8/9] PCI: Ignore BAR contents when firmware left decoding disabled

On Wed, Mar 19, 2014 at 12:54 PM, Bjorn Helgaas <bhelgaas@...gle.com> wrote:
> [+cc Ming, Rusty, Pekka, Sasha]
> ...
> I plan to replace this patch with the following, which only sets
> IORESOURCE_UNSET when we already have been clearing the bus region start
> address.  (This probably should have been a separate patch to begin with,
> mea culpa.)
>
> This is intended for the v3.15 merge window, so I made the minimal change
> to reduce risk.

I put this patch in my pci/resource branch and re-merged it into my
"next" branch.  This rebased both pci/resource and next, which is
unfortunate, but I think it's the cleanest and least risky way at this
point.

Bjorn

> PCI: Mark 64-bit resource as IORESOURCE_UNSET if we only support 32-bit
>
> From: Bjorn Helgaas <bhelgaas@...gle.com>
>
> If we don't support 64-bit addresses, i.e., CONFIG_PHYS_ADDR_T_64BIT is not
> set, we can't deal with BARs above 4GB.  In this case we already pretend
> the BAR contained zero; this patch also sets IORESOURCE_UNSET so we can try
> to reallocate it later.
>
> I don't think this is exactly correct: what we care about here are *bus*
> addresses, not CPU addresses, so the tests of sizeof(resource_size_t)
> probably should be on sizeof(dma_addr_t) instead.  But this is what's been
> in -next, so we'll fix that later.
>
> Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
> ---
>  drivers/pci/probe.c |    1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 6e34498ec9f0..78335efbbb74 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -252,6 +252,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
>                         /* Address above 32-bit boundary; disable the BAR */
>                         pci_write_config_dword(dev, pos, 0);
>                         pci_write_config_dword(dev, pos + 4, 0);
> +                       res->flags |= IORESOURCE_UNSET;
>                         region.start = 0;
>                         region.end = sz64;
>                         bar_disabled = true;
--
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