On Fri, Jul 01, 2022 at 12:27:24PM -0400, Jim Quinlan wrote: > This Broadcom STB PCIe RC driver has one port and connects directly to one > device, be it a switch or an endpoint. We want to be able to leverage the > recently added mechanism that allocates and turns on/off subdevice > regulators. > > All that needs to be done is to put the regulator DT nodes in the bridge > below host and to set the pci_ops methods add_bus and remove_bus. > > Note that the pci_subdev_regulators_add_bus() method is wrapped for two > reasons: > > 1. To achieve link up after the voltage regulators are turned on. > > 2. If, in the case of an unsuccessful link up, to redirect any PCIe > accesses to subdevices, e.g. the scan for DEV/ID. This redirection > is needed because the Broadcom PCIe HW will issue a CPU abort if such > an access is made when the link is down. > > [bhelgaas: fold in > https://lore.kernel.org/r/20220112013100.48029-1-jim2101024@xxxxxxxxx] > Link: https://lore.kernel.org/r/20220106160332.2143-7-jim2101024@xxxxxxxxx > Signed-off-by: Jim Quinlan <jim2101024@xxxxxxxxx> > --- > drivers/pci/controller/pcie-brcmstb.c | 86 ++++++++++++++++++++++++--- > 1 file changed, 77 insertions(+), 9 deletions(-) > > diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c > index 661d3834c6da..a86bf502a265 100644 > --- a/drivers/pci/controller/pcie-brcmstb.c > +++ b/drivers/pci/controller/pcie-brcmstb.c > @@ -196,6 +196,8 @@ static inline void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie, > static inline void brcm_pcie_perst_set_4908(struct brcm_pcie *pcie, u32 val); > static inline void brcm_pcie_perst_set_7278(struct brcm_pcie *pcie, u32 val); > static inline void brcm_pcie_perst_set_generic(struct brcm_pcie *pcie, u32 val); > +static int brcm_pcie_linkup(struct brcm_pcie *pcie); > +static int brcm_pcie_add_bus(struct pci_bus *bus); I think the brcm_pcie_add_bus() declaration is unnecessary. The brcm_pcie_linkup() one is probably unnecessary, too, but would require a lot of reordering that I don't think we should do in this series. > enum { > RGR1_SW_INIT_1, > @@ -329,6 +331,8 @@ struct brcm_pcie { > u32 hw_rev; > void (*perst_set)(struct brcm_pcie *pcie, u32 val); > void (*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val); > + bool refusal_mode; > + struct subdev_regulators *sr; > }; > > static inline bool is_bmips(const struct brcm_pcie *pcie) > @@ -497,6 +501,33 @@ static int pci_subdev_regulators_add_bus(struct pci_bus *bus) > return 0; > } > > +static int brcm_pcie_add_bus(struct pci_bus *bus) > +{ > + struct brcm_pcie *pcie = (struct brcm_pcie *) bus->sysdata; > + int ret; > + > + if (!bus->parent || !pci_is_root_bus(bus->parent)) > + return 0; > + > + ret = pci_subdev_regulators_add_bus(bus); > + if (ret) > + return ret; > + > + /* Grab the regulators for suspend/resume */ > + pcie->sr = bus->dev.driver_data; > + > + /* > + * If we have failed linkup there is no point to return an error as > + * currently it will cause a WARNING() from pci_alloc_child_bus(). > + * We return 0 and turn on the "refusal_mode" so that any further > + * accesses to the pci_dev just get 0xffffffff > + */ > + if (brcm_pcie_linkup(pcie) != 0) > + pcie->refusal_mode = true; Is there a bisection hole between the previous patch and this one? The previous patch sets .add_bus() to pci_subdev_regulators_add_bus(), so we'll turn on the regulators, but we don't know whether the link came up. If it didn't come up, it looks like we might get a CPU abort when enumerating? I think we should split out the refusal_mode patch: - Add refusal mode - Add subdev regulator mechanism - This patch (which would then be clearly about managing regulators in suspend/resume, IIUC) > + return 0; > +} > + > static void pci_subdev_regulators_remove_bus(struct pci_bus *bus) > { > struct device *dev = &bus->dev; > @@ -826,6 +857,18 @@ static void __iomem *brcm_pcie_map_conf(struct pci_bus *bus, unsigned int devfn, > /* Accesses to the RC go right to the RC registers if slot==0 */ > if (pci_is_root_bus(bus)) > return PCI_SLOT(devfn) ? NULL : base + where; > + if (pcie->refusal_mode) { > + /* > + * At this point we do not have link. There will be a CPU > + * abort -- a quirk with this controller --if Linux tries > + * to read any config-space registers besides those > + * targeting the host bridge. To prevent this we hijack > + * the address to point to a safe access that will return > + * 0xffffffff. > + */ > + writel(0xffffffff, base + PCIE_MISC_RC_BAR2_CONFIG_HI); > + return base + PCIE_MISC_RC_BAR2_CONFIG_HI + (where & 0x3); > + } > > /* For devices, write to the config space index register */ > idx = PCIE_ECAM_OFFSET(bus->number, devfn, 0); > @@ -854,7 +897,7 @@ static struct pci_ops brcm_pcie_ops = { > .map_bus = brcm_pcie_map_conf, > .read = pci_generic_config_read, > .write = pci_generic_config_write, > - .add_bus = pci_subdev_regulators_add_bus, > + .add_bus = brcm_pcie_add_bus, > .remove_bus = pci_subdev_regulators_remove_bus, > }; > > @@ -1327,6 +1370,14 @@ static int brcm_pcie_suspend(struct device *dev) > return ret; > } > > + if (pcie->sr) { > + ret = regulator_bulk_disable(pcie->sr->num_supplies, pcie->sr->supplies); > + if (ret) { > + dev_err(dev, "Could not turn off regulators\n"); > + reset_control_reset(pcie->rescal); > + return ret; > + } > + } > clk_disable_unprepare(pcie->clk); > > return 0; > @@ -1344,9 +1395,17 @@ static int brcm_pcie_resume(struct device *dev) > if (ret) > return ret; > > + if (pcie->sr) { > + ret = regulator_bulk_enable(pcie->sr->num_supplies, pcie->sr->supplies); > + if (ret) { > + dev_err(dev, "Could not turn on regulators\n"); > + goto err_disable_clk; > + } > + } > + > ret = reset_control_reset(pcie->rescal); > if (ret) > - goto err_disable_clk; > + goto err_regulator; > > ret = brcm_phy_start(pcie); > if (ret) > @@ -1378,6 +1437,9 @@ static int brcm_pcie_resume(struct device *dev) > > err_reset: > reset_control_rearm(pcie->rescal); > +err_regulator: > + if (pcie->sr) > + regulator_bulk_disable(pcie->sr->num_supplies, pcie->sr->supplies); > err_disable_clk: > clk_disable_unprepare(pcie->clk); > return ret; > @@ -1488,10 +1550,6 @@ static int brcm_pcie_probe(struct platform_device *pdev) > if (ret) > goto fail; > > - ret = brcm_pcie_linkup(pcie); > - if (ret) > - goto fail; > - > pcie->hw_rev = readl(pcie->base + PCIE_MISC_REVISION); > if (pcie->type == BCM4908 && pcie->hw_rev >= BRCM_PCIE_HW_REV_3_20) { > dev_err(pcie->dev, "hardware revision with unsupported PERST# setup\n"); > @@ -1513,7 +1571,17 @@ static int brcm_pcie_probe(struct platform_device *pdev) > > platform_set_drvdata(pdev, pcie); > > - return pci_host_probe(bridge); > + ret = pci_host_probe(bridge); > + if (!ret && !brcm_pcie_link_up(pcie)) > + ret = -ENODEV; > + > + if (ret) { > + brcm_pcie_remove(pdev); > + return ret; > + } > + > + return 0; > + > fail: > __brcm_pcie_remove(pcie); > return ret; > @@ -1522,8 +1590,8 @@ static int brcm_pcie_probe(struct platform_device *pdev) > MODULE_DEVICE_TABLE(of, brcm_pcie_match); > > static const struct dev_pm_ops brcm_pcie_pm_ops = { > - .suspend = brcm_pcie_suspend, > - .resume = brcm_pcie_resume, > + .suspend_noirq = brcm_pcie_suspend, > + .resume_noirq = brcm_pcie_resume, Can you name these brcm_pcie_suspend_noirq() and brcm_pcie_resume_noirq() to match the hook names? > }; > > static struct platform_driver brcm_pcie_driver = { > -- > 2.17.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
