5.15-stable review patch. If anyone has any objections, please let me know.
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From: Niklas Cassel cassel@kernel.org
[ Upstream commit 72e34b8593e08a0ee759b7a038e0b178418ea6f8 ]
The commit message in commit fc9a77040b04 ("PCI: designware-ep: Configure Resizable BAR cap to advertise the smallest size") claims that it modifies the Resizable BAR capability to only advertise support for 1 MB size BARs.
However, the commit writes all zeroes to PCI_REBAR_CAP (the register which contains the possible BAR sizes that a BAR be resized to).
According to the spec, it is illegal to not have a bit set in PCI_REBAR_CAP, and 1 MB is the smallest size allowed.
Set bit 4 in PCI_REBAR_CAP, so that we actually advertise support for a 1 MB BAR size.
Before: Capabilities: [2e8 v1] Physical Resizable BAR BAR 0: current size: 1MB BAR 1: current size: 1MB BAR 2: current size: 1MB BAR 3: current size: 1MB BAR 4: current size: 1MB BAR 5: current size: 1MB After: Capabilities: [2e8 v1] Physical Resizable BAR BAR 0: current size: 1MB, supported: 1MB BAR 1: current size: 1MB, supported: 1MB BAR 2: current size: 1MB, supported: 1MB BAR 3: current size: 1MB, supported: 1MB BAR 4: current size: 1MB, supported: 1MB BAR 5: current size: 1MB, supported: 1MB
Fixes: fc9a77040b04 ("PCI: designware-ep: Configure Resizable BAR cap to advertise the smallest size") Link: https://lore.kernel.org/linux-pci/20240307111520.3303774-1-cassel@kernel.org Signed-off-by: Niklas Cassel cassel@kernel.org Signed-off-by: Krzysztof Wilczyński kwilczynski@kernel.org Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Cc: stable@vger.kernel.org # 5.2 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/controller/dwc/pcie-designware-ep.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c index fcb1fdb22ffbc..fc92d30a0ad99 100644 --- a/drivers/pci/controller/dwc/pcie-designware-ep.c +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c @@ -658,8 +658,13 @@ int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep) nbars = (reg & PCI_REBAR_CTRL_NBAR_MASK) >> PCI_REBAR_CTRL_NBAR_SHIFT;
+ /* + * PCIe r6.0, sec 7.8.6.2 require us to support at least one + * size in the range from 1 MB to 512 GB. Advertise support + * for 1 MB BAR size only. + */ for (i = 0; i < nbars; i++, offset += PCI_REBAR_CTRL) - dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, 0x0); + dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, BIT(4)); }
dw_pcie_setup(pci);