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 X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNWANTED_LANGUAGE_BODY,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2985C433E2 for ; Tue, 8 Sep 2020 16:25:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 80520205CB for ; Tue, 8 Sep 2020 16:25:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731770AbgIHQZQ (ORCPT ); Tue, 8 Sep 2020 12:25:16 -0400 Received: from foss.arm.com ([217.140.110.172]:57366 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731892AbgIHQZH (ORCPT ); Tue, 8 Sep 2020 12:25:07 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5AD1315EC; Tue, 8 Sep 2020 06:33:02 -0700 (PDT) Received: from e121166-lin.cambridge.arm.com (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AB4823F73C; Tue, 8 Sep 2020 06:33:00 -0700 (PDT) Date: Tue, 8 Sep 2020 14:32:58 +0100 From: Lorenzo Pieralisi To: Jim Quinlan Cc: linux-pci@vger.kernel.org, Nicolas Saenz Julienne , Christoph Hellwig , Robin Murphy , bcm-kernel-feedback-list@broadcom.com, Rob Herring , Bjorn Helgaas , Florian Fainelli , Philipp Zabel , "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" , "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" , open list Subject: Re: [PATCH v11 06/11] PCI: brcmstb: Add control of rescal reset Message-ID: <20200908133258.GC22909@e121166-lin.cambridge.arm.com> References: <20200824193036.6033-1-james.quinlan@broadcom.com> <20200824193036.6033-7-james.quinlan@broadcom.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200824193036.6033-7-james.quinlan@broadcom.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, Aug 24, 2020 at 03:30:19PM -0400, Jim Quinlan wrote: > From: Jim Quinlan > > Some STB chips have a special purpose reset controller named RESCAL (reset > calibration). The PCIe HW can now control RESCAL to start and stop its > operation. On probe(), the RESCAL is deasserted and the driver goes > through the sequence of setting registers and reading status in order to > start the internal PHY that is required for the PCIe. > > Signed-off-by: Jim Quinlan > Acked-by: Florian Fainelli > --- > drivers/pci/controller/pcie-brcmstb.c | 82 ++++++++++++++++++++++++++- > 1 file changed, 81 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c > index acf2239b0251..041b8d109563 100644 > --- a/drivers/pci/controller/pcie-brcmstb.c > +++ b/drivers/pci/controller/pcie-brcmstb.c > @@ -23,6 +23,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -158,6 +159,16 @@ > #define DATA_ADDR(pcie) (pcie->reg_offsets[EXT_CFG_DATA]) > #define PCIE_RGR1_SW_INIT_1(pcie) (pcie->reg_offsets[RGR1_SW_INIT_1]) > > +/* Rescal registers */ > +#define PCIE_DVT_PMU_PCIE_PHY_CTRL 0xc700 > +#define PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_NFLDS 0x3 > +#define PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_DIG_RESET_MASK 0x4 > +#define PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_DIG_RESET_SHIFT 0x2 > +#define PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_RESET_MASK 0x2 > +#define PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_RESET_SHIFT 0x1 > +#define PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_PWRDN_MASK 0x1 > +#define PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_PWRDN_SHIFT 0x0 > + > enum { > RGR1_SW_INIT_1, > EXT_CFG_INDEX, > @@ -247,6 +258,7 @@ struct brcm_pcie { > const int *reg_offsets; > const int *reg_field_info; > enum pcie_type type; > + struct reset_control *rescal; > }; > > /* > @@ -965,6 +977,47 @@ static void brcm_pcie_enter_l23(struct brcm_pcie *pcie) > dev_err(pcie->dev, "failed to enter low-power link state\n"); > } > > +static int brcm_phy_cntl(struct brcm_pcie *pcie, const int start) > +{ > + static const u32 shifts[PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_NFLDS] = { > + PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_PWRDN_SHIFT, > + PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_RESET_SHIFT, > + PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_DIG_RESET_SHIFT,}; > + static const u32 masks[PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_NFLDS] = { > + PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_PWRDN_MASK, > + PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_RESET_MASK, > + PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_DIG_RESET_MASK,}; > + const int beg = start ? 0 : PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_NFLDS - 1; > + const int end = start ? PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_NFLDS : -1; > + u32 tmp, combined_mask = 0; > + u32 val = !!start; Quick note: I think it would be nicer to init val within the loop below (IIUC how this works): val = start ? BIT_MASK(shifts[i]) : 0; and then use it in the tmp computation but I leave it up to you. Lorenzo > + void __iomem *base = pcie->base; > + int i; > + > + for (i = beg; i != end; start ? i++ : i--) { > + tmp = readl(base + PCIE_DVT_PMU_PCIE_PHY_CTRL); > + tmp = (tmp & ~masks[i]) | ((val << shifts[i]) & masks[i]); > + writel(tmp, base + PCIE_DVT_PMU_PCIE_PHY_CTRL); > + usleep_range(50, 200); > + combined_mask |= masks[i]; > + } > + > + tmp = readl(base + PCIE_DVT_PMU_PCIE_PHY_CTRL); > + val = start ? combined_mask : 0; > + > + return (tmp & combined_mask) == val ? 0 : -EIO; > +} > + > +static inline int brcm_phy_start(struct brcm_pcie *pcie) > +{ > + return pcie->rescal ? brcm_phy_cntl(pcie, 1) : 0; > +} > + > +static inline int brcm_phy_stop(struct brcm_pcie *pcie) > +{ > + return pcie->rescal ? brcm_phy_cntl(pcie, 0) : 0; > +} > + > static void brcm_pcie_turn_off(struct brcm_pcie *pcie) > { > void __iomem *base = pcie->base; > @@ -992,11 +1045,15 @@ static void brcm_pcie_turn_off(struct brcm_pcie *pcie) > static int brcm_pcie_suspend(struct device *dev) > { > struct brcm_pcie *pcie = dev_get_drvdata(dev); > + int ret; > > brcm_pcie_turn_off(pcie); > + ret = brcm_phy_stop(pcie); > + if (ret) > + dev_err(pcie->dev, "failed to stop phy\n"); > clk_disable_unprepare(pcie->clk); > > - return 0; > + return ret; > } > > static int brcm_pcie_resume(struct device *dev) > @@ -1009,6 +1066,12 @@ static int brcm_pcie_resume(struct device *dev) > base = pcie->base; > clk_prepare_enable(pcie->clk); > > + ret = brcm_phy_start(pcie); > + if (ret) { > + dev_err(pcie->dev, "failed to start phy\n"); > + return ret; > + } > + > /* Take bridge out of reset so we can access the SERDES reg */ > brcm_pcie_bridge_sw_init_set(pcie, 0); > > @@ -1034,6 +1097,9 @@ static void __brcm_pcie_remove(struct brcm_pcie *pcie) > { > brcm_msi_remove(pcie); > brcm_pcie_turn_off(pcie); > + if (brcm_phy_stop(pcie)) > + dev_err(pcie->dev, "failed to stop phy\n"); > + reset_control_assert(pcie->rescal); > clk_disable_unprepare(pcie->clk); > } > > @@ -1112,6 +1178,20 @@ static int brcm_pcie_probe(struct platform_device *pdev) > dev_err(&pdev->dev, "could not enable clock\n"); > return ret; > } > + pcie->rescal = devm_reset_control_get_optional_shared(&pdev->dev, "rescal"); > + if (IS_ERR(pcie->rescal)) > + return PTR_ERR(pcie->rescal); > + > + ret = reset_control_deassert(pcie->rescal); > + if (ret) > + dev_err(&pdev->dev, "failed to deassert 'rescal'\n"); > + > + ret = brcm_phy_start(pcie); > + if (ret) { > + dev_err(pcie->dev, "failed to start phy\n"); > + reset_control_assert(pcie->rescal); > + return ret; > + } > > ret = brcm_pcie_setup(pcie); > if (ret) > -- > 2.17.1 >