On Wed, Jul 6, 2022 at 7:13 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > 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. Will remove. > > 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. I have a future commit that will remove all forward declarations. I just wanted to keep this the un-revert patchset simple. > > > 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 don't think so. At this commit, attempting the link-up is still done before the call to pci_host_probe(). Since there is no power there will be no link, the probe will fail and pci_host_probe() will never be invoked. > > 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) Will do. > > > + 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? Yes. Jim Quintlan Broadcom STB > > > }; > > > > 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
Attachment:
smime.p7s
Description: S/MIME Cryptographic Signature
