Re: [PATCH v4] PCI: of: Clear 64-bit flag for non-prefetchable memory below 4GB
From: Alexandru Elisei <hidden>
Date: 2021-06-15 08:45:27
Also in:
linux-pci, linux-rockchip, lkml
Hi Punit, Thank you for working on this! On 6/15/21 12:04 AM, Punit Agrawal wrote:
Alexandru and Qu reported this resource allocation failure on
ROCKPro64 v2 and ROCK Pi 4B, both based on the RK3399:
pci_bus 0000:00: root bus resource [mem 0xfa000000-0xfbdfffff 64bit]
pci 0000:00:00.0: PCI bridge to [bus 01]
pci 0000:00:00.0: BAR 14: no space for [mem size 0x00100000]
pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x00003fff 64bit]
"BAR 14" is the PCI bridge's 32-bit non-prefetchable window, and our
PCI allocation code isn't smart enough to allocate it in a host
bridge window marked as 64-bit, even though this should work fine.
A DT host bridge description includes the windows from the CPU
address space to the PCI bus space. On a few architectures
(microblaze, powerpc, sparc), the DT may also describe PCI devices
themselves, including their BARs.
Before 9d57e61bf723 ("of/pci: Add IORESOURCE_MEM_64 to resource
flags for 64-bit memory addresses"), of_bus_pci_get_flags() ignored
the fact that some DT addresses described 64-bit windows and BARs.
That was a problem because the virtio virtual NIC has a 32-bit BAR
and a 64-bit BAR, and the driver couldn't distinguish them.
9d57e61bf723 set IORESOURCE_MEM_64 for those 64-bit DT ranges, which
fixed the virtio driver. But it also set IORESOURCE_MEM_64 for host
bridge windows, which exposed the fact that the PCI allocator isn't
smart enough to put 32-bit resources in those 64-bit windows.
Clear IORESOURCE_MEM_64 from host bridge windows since we don't need
that information.I've tested the patch on my rockpro64. Kernel built from tag v5.13-rc6: [ 0.345676] pci 0000:01:00.0: 8.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s PCIe x4 link at 0000:00:00.0 (capable of 31.504 Gb/s with 8.0 GT/s PCIe x4 link) [ 0.359300] pci_bus 0000:01: busn_res: [bus 01-1f] end is updated to 01 [ 0.359343] pci 0000:00:00.0: BAR 14: no space for [mem size 0x00100000] [ 0.359365] pci 0000:00:00.0: BAR 14: failed to assign [mem size 0x00100000] [ 0.359387] pci 0000:01:00.0: BAR 0: no space for [mem size 0x00004000 64bit] [ 0.359407] pci 0000:01:00.0: BAR 0: failed to assign [mem size 0x00004000 64bit] [ 0.359428] pci 0000:00:00.0: PCI bridge to [bus 01] [ 0.359862] pcieport 0000:00:00.0: PME: Signaling with IRQ 76 [ 0.360190] pcieport 0000:00:00.0: AER: enabled with IRQ 76 Kernel built from tag v5.13-rc6 with this patch applied: [ 0.345434] pci 0000:01:00.0: 8.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s PCIe x4 link at 0000:00:00.0 (capable of 31.504 Gb/s with 8.0 GT/s PCIe x4 link) [ 0.359081] pci_bus 0000:01: busn_res: [bus 01-1f] end is updated to 01 [ 0.359128] pci 0000:00:00.0: BAR 14: assigned [mem 0xfa000000-0xfa0fffff] [ 0.359155] pci 0000:01:00.0: BAR 0: assigned [mem 0xfa000000-0xfa003fff 64bit] [ 0.359217] pci 0000:00:00.0: PCI bridge to [bus 01] [ 0.359239] pci 0000:00:00.0: bridge window [mem 0xfa000000-0xfa0fffff] [ 0.359422] pcieport 0000:00:00.0: enabling device (0000 -> 0002) [ 0.359687] pcieport 0000:00:00.0: PME: Signaling with IRQ 76 [ 0.360001] pcieport 0000:00:00.0: AER: enabled with IRQ 76 And the NVME on the PCIE expansion card works as expected: Tested-by: Alexandru Elisei <redacted> Thanks, Alex
quoted hunk ↗ jump to hunk
Fixes: 9d57e61bf723 ("of/pci: Add IORESOURCE_MEM_64 to resource flags for 64-bit memory addresses") Reported-at: https://lore.kernel.org/lkml/7a1e2ebc-f7d8-8431-d844-41a9c36a8911@arm.com/ (local) Reported-by: Alexandru Elisei <redacted> Reported-by: Qu Wenruo <redacted> Suggested-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Punit Agrawal <redacted> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Rob Herring <robh+dt@kernel.org> --- Hi, The patch is an updated version to fix the PCI allocation issues on RK3399 based platforms. Previous postings can be found at [0][1][2]. The updated patch instead of clearing the 64-bit flag for non-prefetchable memory below 4GB does it unconditionally on the basis that PCI allocation logic cannot deal with the 64-bit flag (although it should be able to). The result is a simpler patch that restores the input to the allocation logic to be identical to before 9d57e61bf723. Tested locally on a RockPro64 on top of v5.13-rc6. Please consider merging. Thanks, Punit Changes: v4: * Updated Patch 1 based on Bjorn's suggestion. Also dropped the Tested-by tags due to the change of logic * Dropped patch 2 and 3 from the series as it's not critical to the series * Dropped the device tree changes (Patch 4) as they are already queued in the soc tree v3: * Improved commit log for clarity (Patch 1) * Added Tested-by tags v2: * Check ranges PCI / bus addresses rather than CPU addresses * (new) Restrict 32-bit size warnings on ranges that don't have the 64-bit attribute set * Refactor the 32-bit size warning to the range parsing loop. This change also prints the warnings right after the window mappings are logged. [0] https://lore.kernel.org/linux-arm-kernel/20210527150541.3130505-1-punitagrawal@gmail.com/ (local) [1] https://lore.kernel.org/linux-pci/20210531221057.3406958-1-punitagrawal@gmail.com/ (local) [2] https://lore.kernel.org/linux-pci/20210607112856.3499682-1-punitagrawal@gmail.com/ (local) drivers/pci/of.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/drivers/pci/of.c b/drivers/pci/of.c index 85dcb7097da4..a143b02b2dcd 100644 --- a/drivers/pci/of.c +++ b/drivers/pci/of.c@@ -353,6 +353,8 @@ static int devm_of_pci_get_host_bridge_resources(struct device *dev, dev_warn(dev, "More than one I/O resource converted for %pOF. CPU base address for old range lost!\n", dev_node); *io_base = range.cpu_addr; + } else if (resource_type(res) == IORESOURCE_MEM) { + res->flags &= ~IORESOURCE_MEM_64; } pci_add_resource_offset(resources, res, res->start - range.pci_addr);
_______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel