linux-kernel - [PATCH V3 11/21] pci, acpi: Move ACPI host bridge device companion assignment to core code.

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Date:	Wed, 13 Jan 2016 14:20:57 +0100
From:	Tomasz Nowicki <tn@...ihalf.com>
To:	bhelgaas@...gle.com, arnd@...db.de, will.deacon@....com,
	catalin.marinas@....com, rjw@...ysocki.net, hanjun.guo@...aro.org,
	Lorenzo.Pieralisi@....com, okaya@...eaurora.org,
	jiang.liu@...ux.intel.com, Stefano.Stabellini@...citrix.com
Cc:	robert.richter@...iumnetworks.com, mw@...ihalf.com,
	Liviu.Dudau@....com, ddaney@...iumnetworks.com, tglx@...utronix.de,
	wangyijing@...wei.com, Suravee.Suthikulpanit@....com,
	msalter@...hat.com, linux-pci@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-acpi@...r.kernel.org,
	linux-kernel@...r.kernel.org, linaro-acpi@...ts.linaro.org,
	jchandra@...adcom.com, jcm@...hat.com,
	Tomasz Nowicki <tn@...ihalf.com>
Subject: [PATCH V3 11/21] pci, acpi: Move ACPI host bridge device companion assignment to core code.

Currently we have two platforms (x86 & ia64) capable of PCI ACPI host
bridge initialization. They both use sysdata pill to pass down parent
device reference and both relay on NULL parent in pci_create_root_bus()
to validate sysdata content.

It looks hacky and prevent us from getting some frimware specific
info for PCI host controller e.g. bus domain number.
However, it seems we can overcome that blocker by passing down parent
device via pci_create_root_bus parameter (as the ACPI device type)
and using ACPI_COMPANION_SET in core code for ACPI boot method.
ACPI_COMPANION_SET is safe to run for all cases DT, ACPI and DT&ACPI.

Suggested-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Signed-off-by: Tomasz Nowicki <tn@...ihalf.com>
---
 drivers/acpi/pci_root.c | 5 ++++-
 drivers/pci/probe.c     | 2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index ae3fe4e..a65c8c2 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -846,7 +846,10 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 
 	pci_acpi_root_add_resources(info);
 	pci_add_resource(&info->resources, &root->secondary);
-	bus = pci_create_root_bus(NULL, busnum, ops->pci_ops,
+
+	/* Root bridge device needs to be sure of parent ACPI type */
+	ACPI_COMPANION_SET(&device->dev, device);
+	bus = pci_create_root_bus(&device->dev, busnum, ops->pci_ops,
 				  sysdata, &info->resources);
 	if (!bus)
 		goto out_release_info;
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 553a029..cad836f 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2107,6 +2107,8 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
 	bridge->dev.parent = parent;
 	bridge->dev.release = pci_release_host_bridge_dev;
 	dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus);
+	ACPI_COMPANION_SET(&bridge->dev,
+			   parent ? to_acpi_device_node(parent->fwnode) : NULL);
 	error = pcibios_root_bridge_prepare(bridge);
 	if (error) {
 		kfree(bridge);
-- 
1.9.1