4.18-stable review patch. If anyone has any objections, please let me know.
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From: Honghui Zhang honghui.zhang@mediatek.com
[ Upstream commit 074d6f32689ce05a084b6fa3db38445745bf11cc ]
The Mediatek's host controller has two slots, each with its own control registers. The host driver needs to identify what slot is connected to what port in order to access the device's configuration space.
Current code retrieving slot connected to a given endpoint device.
Assuming each slot is connected to one endpoint device as below:
host bridge bus 0 --> __________|_______ | | | | slot 0 slot 1 bus 1 -->| bus 2 --> | | | EP 0 EP 1
During PCI enumeration, system software will scan all the PCI devices on every bus starting from devfn 0. Using PCI_SLOT(devfn) for matching an endpoint to its slot is erroneous in that the devfn does not contain the hierarchical bus numbering in it. In order to match an endpoint with its slot (and related port), the PCI tree must be walked up to the root bus (where the root ports are situated) and then the PCI_SLOT(devfn) matching logic can be correctly applied for matching.
This patch fixes the mtk_pcie_find_port() slot matching logic by adding appropriate PCI tree walking code to retrieve the slot/port a given endpoint is connected to.
Signed-off-by: Honghui Zhang honghui.zhang@mediatek.com [lorenzo.pieralisi@arm.com: rewrote the commit log] Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Acked-by: Ryder Lee ryder.lee@mediatek.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pci/controller/pcie-mediatek.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
--- a/drivers/pci/controller/pcie-mediatek.c +++ b/drivers/pci/controller/pcie-mediatek.c @@ -337,6 +337,17 @@ static struct mtk_pcie_port *mtk_pcie_fi { struct mtk_pcie *pcie = bus->sysdata; struct mtk_pcie_port *port; + struct pci_dev *dev = NULL; + + /* + * Walk the bus hierarchy to get the devfn value + * of the port in the root bus. + */ + while (bus && bus->number) { + dev = bus->self; + bus = dev->bus; + devfn = dev->devfn; + }
list_for_each_entry(port, &pcie->ports, list) if (port->slot == PCI_SLOT(devfn))