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Fri, 19 Nov 2021 14:08:15 -0800 (PST) Received: from stbsrv-and-01.and.broadcom.net ([192.19.11.250]) by smtp.gmail.com with ESMTPSA id t2sm612940pfd.36.2021.11.19.14.08.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Nov 2021 14:08:15 -0800 (PST) From: Jim Quinlan To: linux-pci@vger.kernel.org, Bjorn Helgaas , Nicolas Saenz Julienne , Rob Herring , Mark Brown , bcm-kernel-feedback-list@broadcom.com, jim2101024@gmail.com, james.quinlan@broadcom.com Cc: Florian Fainelli , Lorenzo Pieralisi , =?utf-8?q?Krzysztof_Wilczy?= =?utf-8?q?=C5=84ski?= , Philipp Zabel , linux-rpi-kernel@lists.infradead.org (moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE), linux-arm-kernel@lists.infradead.org (moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE), linux-kernel@vger.kernel.org (open list) Subject: [PATCH v9 6/7] PCI: brcmstb: Add control of subdevice voltage regulators Date: Fri, 19 Nov 2021 17:07:53 -0500 Message-Id: <20211119220756.18628-7-jim2101024@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211119220756.18628-1-jim2101024@gmail.com> References: <20211119220756.18628-1-jim2101024@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211119_140816_938358_853C286A X-CRM114-Status: GOOD ( 27.84 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 mechansim 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 acheive linkup after the voltage regulators are turned on. 2. If, in the case of an unsuccessful linkup, to redirect any PCIe accesses to subdevices, e.g. the scan for DEV/ID. This redirection is needed because the Broadcom PCIe HW wil issue a CPU abort if such an access is made when there is no linkup. Signed-off-by: Jim Quinlan --- drivers/pci/controller/pcie-brcmstb.c | 81 +++++++++++++++++++++++++-- 1 file changed, 77 insertions(+), 4 deletions(-) diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c index 5f373227aad6..9b4df253e79a 100644 --- a/drivers/pci/controller/pcie-brcmstb.c +++ b/drivers/pci/controller/pcie-brcmstb.c @@ -191,6 +191,7 @@ 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_add_bus(struct pci_bus *bus); enum { RGR1_SW_INIT_1, @@ -295,6 +296,8 @@ 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; }; /* @@ -711,6 +714,18 @@ 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); @@ -722,6 +737,8 @@ 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 = brcm_pcie_add_bus, + .remove_bus = pci_subdev_regulators_remove_bus, }; static inline void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie, u32 val) @@ -1169,6 +1186,14 @@ 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; @@ -1186,9 +1211,17 @@ 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) @@ -1220,6 +1253,8 @@ static int brcm_pcie_resume(struct device *dev) err_reset: reset_control_rearm(pcie->rescal); +err_regulator: + regulator_bulk_disable(pcie->sr->num_supplies, pcie->sr->supplies); err_disable_clk: clk_disable_unprepare(pcie->clk); return ret; @@ -1258,6 +1293,34 @@ static const struct of_device_id brcm_pcie_match[] = { {}, }; +static int brcm_pcie_add_bus(struct pci_bus *bus) +{ + struct device *dev = &bus->dev; + struct brcm_pcie *pcie = (struct brcm_pcie *) bus->sysdata; + int ret; + + if (!dev->of_node || !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; + + return 0; +} + static int brcm_pcie_probe(struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node, *msi_np; @@ -1349,7 +1412,17 @@ 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; @@ -1358,8 +1431,8 @@ 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, }; static struct platform_driver brcm_pcie_driver = {