On Tue, Mar 25, 2025 at 11:39:15PM +0530, Manivannan Sadhasivam wrote: > On Mon, Mar 24, 2025 at 03:04:37PM -0500, Bjorn Helgaas wrote: > > On Mon, Mar 24, 2025 at 11:00:24PM +0530, Manivannan Sadhasivam wrote: > > > On Sat, Mar 15, 2025 at 03:15:41PM -0500, Bjorn Helgaas wrote: > > > > From: Frank Li <Frank.Li@xxxxxxx> > > > > > > > > dw_pcie_parent_bus_offset() looks up the parent bus address of a PCI > > > > controller 'reg' property in devicetree. If implemented, .cpu_addr_fixup() > > > > is a hard-coded way to get the parent bus address corresponding to a CPU > > > > physical address. > > > > > > > > Add debug code to compare the address from .cpu_addr_fixup() with the > > > > address from devicetree. If they match, warn that .cpu_addr_fixup() is > > > > redundant and should be removed; if they differ, warn that something is > > > > wrong with the devicetree. > > > > > > > > If .cpu_addr_fixup() is not implemented, the parent bus address should be > > > > identical to the CPU physical address because we previously ignored the > > > > parent bus address from devicetree. If the devicetree has a different > > > > parent bus address, warn about it being broken. > > > > > > > > [bhelgaas: split debug to separate patch for easier future revert, commit > > > > log] > > > > Link: https://lore.kernel.org/r/20250313-pci_fixup_addr-v11-5-01d2313502ab@xxxxxxx > > > > Signed-off-by: Frank Li <Frank.Li@xxxxxxx> > > > > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > > > --- > > > > drivers/pci/controller/dwc/pcie-designware.c | 26 +++++++++++++++++++- > > > > drivers/pci/controller/dwc/pcie-designware.h | 13 ++++++++++ > > > > 2 files changed, 38 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c > > > > index 0a35e36da703..985264c88b92 100644 > > > > --- a/drivers/pci/controller/dwc/pcie-designware.c > > > > +++ b/drivers/pci/controller/dwc/pcie-designware.c > > > > @@ -1114,7 +1114,8 @@ resource_size_t dw_pcie_parent_bus_offset(struct dw_pcie *pci, > > > > struct device *dev = pci->dev; > > > > struct device_node *np = dev->of_node; > > > > int index; > > > > - u64 reg_addr; > > > > + u64 reg_addr, fixup_addr; > > > > + u64 (*fixup)(struct dw_pcie *pcie, u64 cpu_addr); > > > > > > > > /* Look up reg_name address on parent bus */ > > > > index = of_property_match_string(np, "reg-names", reg_name); > > > > @@ -1126,5 +1127,28 @@ resource_size_t dw_pcie_parent_bus_offset(struct dw_pcie *pci, > > > > > > > > of_property_read_reg(np, index, ®_addr, NULL); > > > > > > > > + fixup = pci->ops->cpu_addr_fixup; > > > > + if (fixup) { > > > > + fixup_addr = fixup(pci, cpu_phy_addr); > > > > + if (reg_addr == fixup_addr) { > > > > + dev_warn(dev, "%#010llx %s reg[%d] == %#010llx; %ps is redundant\n", > > > > + cpu_phy_addr, reg_name, index, > > > > + fixup_addr, fixup); > > > > + } else { > > > > + dev_warn(dev, "%#010llx %s reg[%d] != %#010llx fixed up addr; devicetree is broken\n", > > > > + cpu_phy_addr, reg_name, > > > > + index, fixup_addr); > > > > + reg_addr = fixup_addr; > > > > + } > > > > + } else if (!pci->use_parent_dt_ranges) { > > > > > > Is this check still valid? 'use_parent_dt_ranges' is only used here for > > > validation. Moreover, if the fixup is not available, we should be able to > > > safely return 'cpu_phy_addr - reg_addr' unconditionally. > > > > Yes, that's true IF the devicetree has the correct 'ranges' > > translation. This is to avoid breaking platforms with broken > > devicetrees. > > > > You mean the driver without cpu_addr_fixup() and devicetree with broken 'ranges' > property? So the existing platforms... Not a bad idea though. I worry about some platform without cpu_addr_fixup() use fake translation by ranges property. like bus{ ... ranges = <fake_addr, real_addr, size> pcie { regs = <fake_addr + offset> reg-names = "config". ... } } So add above check, we will remove it if none report it for sometimes. Frank > > > > > + if (reg_addr != cpu_phy_addr) { > > > > + dev_warn(dev, "devicetree has incorrect translation; please check parent \"ranges\" property. CPU physical addr %#010llx, parent bus addr %#010llx\n", > > > > + cpu_phy_addr, reg_addr); > > > > + return 0; > > > > + } > > > > + } > > > > + > > > > + dev_info(dev, "%s parent bus offset is %#010llx\n", > > > > + reg_name, cpu_phy_addr - reg_addr); > > > > > > This info is useless on platforms having no translation between CPU and PCI > > > controller. The offset will always be 0. > > > > You're right. This was probably an overzealous message for any > > possible issues. > > > > What would you think of the below as a replacement? It should emit at > > most one message, and none for platforms where devicetree describes no > > translation and there never was a .cpu_addr_fixup(). > > > > It's still pretty aggressive logging, but I'm just concerned about > > being able to quickly debug and fix any regressions. Ideally we can > > revert the whole thing eventually. > > > > > > diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c > > index 27b464a405a4..4b442d1aa55b 100644 > > --- a/drivers/pci/controller/dwc/pcie-designware.c > > +++ b/drivers/pci/controller/dwc/pcie-designware.c > > @@ -1114,7 +1114,8 @@ resource_size_t dw_pcie_parent_bus_offset(struct dw_pcie *pci, > > struct device *dev = pci->dev; > > struct device_node *np = dev->of_node; > > int index; > > - u64 reg_addr; > > + u64 reg_addr, fixup_addr; > > + u64 (*fixup)(struct dw_pcie *pcie, u64 cpu_addr); > > > > /* Look up reg_name address on parent bus */ > > index = of_property_match_string(np, "reg-names", reg_name); > > @@ -1126,5 +1127,42 @@ resource_size_t dw_pcie_parent_bus_offset(struct dw_pcie *pci, > > > > of_property_read_reg(np, index, ®_addr, NULL); > > > > + fixup = pci->ops ? pci->ops->cpu_addr_fixup : NULL; > > + if (fixup) { > > + fixup_addr = fixup(pci, cpu_phys_addr); > > + if (reg_addr == fixup_addr) { > > + dev_info(dev, "%s reg[%d] %#010llx == %#010llx == fixup(cpu %#010llx); %ps is redundant with this devicetree\n", > > + reg_name, index, reg_addr, fixup_addr, > > + (unsigned long long) cpu_phys_addr, fixup); > > + } else { > > + dev_warn(dev, "%s reg[%d] %#010llx != %#010llx == fixup(cpu %#010llx); devicetree is broken\n", > > + reg_name, index, reg_addr, fixup_addr, > > + (unsigned long long) cpu_phys_addr); > > + reg_addr = fixup_addr; > > + } > > + > > + return cpu_phys_addr - reg_addr; > > + } > > + > > + if (pci->use_parent_dt_ranges) { > > + > > + /* > > + * This platform once had a fixup, presumably because it > > + * translates between CPU and PCI controller addresses. > > + * Log a note if devicetree didn't describe a translation. > > + */ > > + if (reg_addr == cpu_phys_addr) > > + dev_info(dev, "%s reg[%d] %#010llx == cpu %#010llx\n; no fixup was ever needed for this devicetree\n", > > + reg_name, index, reg_addr, > > + (unsigned long long) cpu_phys_addr); > > So this check is to detect the usage of old DTs with new kernel without > cpu_addr_fixup()? If so: > > (1) The log is not accurate > (2) The driver would be broken, so the log should be an error. This condition > should not be met (if we do not remove the fixup for some time). But I think > this check should be moved ahead of cpu_addr_fixup() so that the correct DTs > would be honored first and the fixup would be ignored for them. > > - Mani > > -- > மணிவண்ணன் சதாசிவம்
