From: Bjorn Helgaas <helgaas@kernel.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linux-pci@vger.kernel.org,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Sinan Kaya <okaya@kernel.org>, Ali Saidi <alisaidi@amazon.com>,
Zeev Zilberman <zeev@amazon.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 4/4] arm64: pci: acpi: Preserve PCI resources configuration when asked by ACPI
Date: Fri, 21 Jun 2019 15:08:48 -0500 [thread overview]
Message-ID: <20190621200848.GE127746@google.com> (raw)
In-Reply-To: <20190615002359.29577-4-benh@kernel.crashing.org>
arm64: PCI: Preserve firmware configuration when necessary
On Sat, Jun 15, 2019 at 10:23:59AM +1000, Benjamin Herrenschmidt wrote:
> When _DSM #5 returns 0 for a host bridge, we need to claim the existing
> resources rather than reassign everything.
Use imperative mood. I'd remove the reference to _DSM #5. This patch
does not directly reference _DSM, and it's conceivable a kernel
command line parameter or other mechanism could set
host->preserve_config.
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> ---
> arch/arm64/kernel/pci.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
> index 1419b1b4e9b9..a2c608a3fc41 100644
> --- a/arch/arm64/kernel/pci.c
> +++ b/arch/arm64/kernel/pci.c
> @@ -168,6 +168,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
> struct acpi_pci_generic_root_info *ri;
> struct pci_bus *bus, *child;
> struct acpi_pci_root_ops *root_ops;
> + struct pci_host_bridge *hb;
>
> ri = kzalloc(sizeof(*ri), GFP_KERNEL);
> if (!ri)
> @@ -193,6 +194,16 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
> if (!bus)
> return NULL;
>
> + hb = pci_find_host_bridge(bus);
> +
> + /* If ACPI tells us to preserve the resource configuration, claim now */
> + if (hb->preserve_config)
> + pci_bus_claim_resources(bus);
> +
> + /*
> + * Assign whatever was left unassigned. If we didn't claim above, this will
> + * reassign everything.
Wrap the comment so it fits in 80 columns (unless local arch/arm64 style
allows wider lines, but I don't see any other wide lines in the file).
This series generally looks good to me.
> + */
> pci_assign_unassigned_root_bus_resources(bus);
>
> list_for_each_entry(child, &bus->children, node)
> --
> 2.17.1
>
next prev parent reply other threads:[~2019-06-21 20:08 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-15 0:23 [PATCH 1/4] arm64: pci: acpi: Use pci_assign_unassigned_root_bus_resources() Benjamin Herrenschmidt
2019-06-15 0:23 ` [PATCH 2/4] pci: acpi: Read _DSM #5 from ACPI on root bridges Benjamin Herrenschmidt
2019-06-21 20:07 ` Bjorn Helgaas
2019-06-15 0:23 ` [PATCH 3/4] pci: Do not auto-enable PCI reallocation when _DSM #5 returns 0 Benjamin Herrenschmidt
2019-06-21 20:07 ` Bjorn Helgaas
2019-06-15 0:23 ` [PATCH 4/4] arm64: pci: acpi: Preserve PCI resources configuration when asked by ACPI Benjamin Herrenschmidt
2019-06-21 14:57 ` Lorenzo Pieralisi
2019-06-21 23:07 ` Benjamin Herrenschmidt
2019-06-21 15:44 ` Ard Biesheuvel
2019-06-21 20:08 ` Bjorn Helgaas [this message]
2019-06-20 17:13 ` [PATCH 1/4] arm64: pci: acpi: Use pci_assign_unassigned_root_bus_resources() Lorenzo Pieralisi
2019-06-20 22:55 ` Benjamin Herrenschmidt
2019-06-21 20:06 ` Bjorn Helgaas
2019-06-21 20:48 ` Bjorn Helgaas
2019-06-21 22:58 ` Benjamin Herrenschmidt
2019-06-21 23:00 ` Benjamin Herrenschmidt
2019-06-21 23:15 ` Bjorn Helgaas
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