From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id ED1D5C43334 for ; Wed, 6 Jul 2022 23:14:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:References: List-Owner; bh=8eq2SC/xGvSSWBMFR3dnEdw1sAvckNUHiMj9YKXVTbw=; b=ij/ednkyx+46rO aYWaagO0SE8Bevt28W5NDMyVBcxi1WpIaA3ZmEbT7N+T1VcKsEliO2RMDcZWqnbh/qmW0FFu9cN/M aMSmAiVn78zd/6i0tgjVI+TS33GMYPJKoozrdZgwdpkmauZzMMMPj+9+d4BBH9WUGCfU1urzRnwj3 bwC/VCDpfQrbsgqv1qkpIpHvfQSpj3ksQpfrPkqSkOy4jeJKq5JcVmFYfstqEkRl+zWcLgvvHD1Ri fDPAj7yneOCcCSp8YorDw+RpO7GIX4ujl+Bwq530S1xQ8mtTqNdtyEWWrSnjjUqb5ozeU1bT3h8O5 r0fkb15XavJdh+G+j9VQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o9ED6-00ChbI-PW; Wed, 06 Jul 2022 23:13:32 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1o9ED2-00Cha8-QI; Wed, 06 Jul 2022 23:13:30 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E4FC061E59; Wed, 6 Jul 2022 23:13:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E338C341CA; Wed, 6 Jul 2022 23:13:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1657149205; bh=t5NRaBUfMxchTeFrdnqRAu3a2uP/L9/bkoa+5umIdRc=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=ejH77V8VcSzb3ntMwzTqxcvBZ2lvKt5cd0HMa3isbENM9k4eLmL5UKfmu4IYSe6AR 867ArwZ3Xm8nzQubQ3ihsDrBuf4dOzyt31b+n73r43B1XMZzSx8lZ4LovHMF+VQoEV WD0RpJfclOuf8NYUqdOcFE379X7iZkvxBVnW5ONX6C2dLE2iylQb/gFGmqTcTcGhKB yoiujjq2gI4m/Qz3eN8Mp42lC7fACdA/Llgtuu7B2MuvDTRQvFcmIKYu2v5+AfwxIn ksP20rXfuLhjhE9V1tSnSzYw+1ydIBOHZ4EoQqYhtfk3TvVv0LJYvfFsgX0aHbrQpu Sh185EFya+9hw== Date: Wed, 6 Jul 2022 18:13:23 -0500 From: Bjorn Helgaas To: Jim Quinlan Cc: linux-pci@vger.kernel.org, Nicolas Saenz Julienne , Bjorn Helgaas , Lorenzo Pieralisi , Cyril Brulebois , bcm-kernel-feedback-list@broadcom.com, james.quinlan@broadcom.com, Florian Fainelli , Lorenzo Pieralisi , Rob Herring , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Philipp Zabel , "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" , "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" , open list Subject: Re: [PATCH v1 3/4] PCI: brcmstb: Add control of subdevice voltage regulators Message-ID: <20220706231323.GA237418@bhelgaas> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220701162726.31346-4-jim2101024@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220706_161328_977386_0501C81B X-CRM114-Status: GOOD ( 48.91 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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@gmail.com] > Link: https://lore.kernel.org/r/20220106160332.2143-7-jim2101024@gmail.com > Signed-off-by: Jim Quinlan > --- > 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@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel