Messages in this thread | | | Date | Fri, 14 Jul 2023 12:06:00 +0300 | From | Andy Shevchenko <> | Subject | Re: [PATCH v4 04/11] PCI/ASPM: Use RMW accessors for changing LNKCTL |
| |
On Thu, Jul 13, 2023 at 03:44:58PM +0300, Ilpo Järvinen wrote: > Don't assume that the device is fully under the control of ASPM and use > RMW capability accessors which do proper locking to avoid losing > concurrent updates to the register values. > > If configuration fails in pcie_aspm_configure_common_clock(), the > function attempts to restore the old PCI_EXP_LNKCTL_CCC settings. Store > only the old PCI_EXP_LNKCTL_CCC bit for the relevant devices rather > than the content of the whole LNKCTL registers. It aligns better with > how pcie_lnkctl_clear_and_set() expects its parameter and makes the > code more obvious to understand.
...
> int same_clock = 1; > - u16 reg16, parent_reg, child_reg[8]; > + u16 reg16, parent_old_ccc, child_old_ccc[8];
u16 ccc;
> struct pci_dev *child, *parent = link->pdev; > struct pci_bus *linkbus = parent->subordinate;
...
ccc = same_clock ? PCI_EXP_LNKCTL_CCC : 0);
> /* Configure downstream component, all functions */ > list_for_each_entry(child, &linkbus->devices, bus_list) { > pcie_capability_read_word(child, PCI_EXP_LNKCTL, ®16); > - child_reg[PCI_FUNC(child->devfn)] = reg16; > - if (same_clock) > - reg16 |= PCI_EXP_LNKCTL_CCC; > - else > - reg16 &= ~PCI_EXP_LNKCTL_CCC; > - pcie_capability_write_word(child, PCI_EXP_LNKCTL, reg16); > + child_old_ccc[PCI_FUNC(child->devfn)] = reg16 & PCI_EXP_LNKCTL_CCC; > + pcie_capability_clear_and_set_word(child, PCI_EXP_LNKCTL, > + PCI_EXP_LNKCTL_CCC, > + same_clock ? PCI_EXP_LNKCTL_CCC : 0);
pcie_capability_clear_and_set_word(child, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_CCC, ccc);
> }
...
> + pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL, > + PCI_EXP_LNKCTL_CCC, > + same_clock ? PCI_EXP_LNKCTL_CCC : 0);
pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_CCC, ccc);
?
-- With Best Regards, Andy Shevchenko
| |