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From:   Kishon Vijay Abraham I <kishon@ti.com>
To:     Thomas Gleixner <tglx@linutronix.de>,
        Marc Zyngier <maz@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>
CC:     <linux-kernel@vger.kernel.org>, <linux-pci@vger.kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        <lokeshvutla@ti.com>
Subject: [PATCH 2/3] PCI: Export find_pci_root_bus()
Date:   Mon, 20 Sep 2021 12:11:32 +0530
Message-ID: <20210920064133.14115-3-kishon@ti.com>
In-Reply-To: <20210920064133.14115-1-kishon@ti.com>
References: <20210920064133.14115-1-kishon@ti.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Export find_pci_root_bus() in order for other subsystems (like
IRQCHIP) to find the root bus of a particual PCIe device.

This is done in preparation for GIC ITS to walk the PCIe bus for
calculating the total number of interrupt vectors that has to be
supported by a specific GIC ITS device ID, specifically when
"msi-map-mask" is populated in device tree.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
 drivers/pci/host-bridge.c | 3 ++-
 include/linux/pci.h       | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index afa50b446567..4ec34d040c02 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c
@@ -9,13 +9,14 @@
 
 #include "pci.h"
 
-static struct pci_bus *find_pci_root_bus(struct pci_bus *bus)
+struct pci_bus *find_pci_root_bus(struct pci_bus *bus)
 {
 	while (bus->parent)
 		bus = bus->parent;
 
 	return bus;
 }
+EXPORT_SYMBOL_GPL(find_pci_root_bus);
 
 struct pci_host_bridge *pci_find_host_bridge(struct pci_bus *bus)
 {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8500fec56e50..b33ef3e08a2f 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1475,6 +1475,7 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
 
 void __pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
 		    void *userdata, u32 rid, u32 mask);
+struct pci_bus *find_pci_root_bus(struct pci_bus *bus);
 int pci_cfg_space_size(struct pci_dev *dev);
 unsigned char pci_bus_max_busnr(struct pci_bus *bus);
 void pci_setup_bridge(struct pci_bus *bus);
-- 
2.17.1