Message-ID: <BL0PR04MB65147AFB577E2087BB36414BE77B9@BL0PR04MB6514.namprd04.prod.outlook.com>
Date:   Thu, 1 Apr 2021 08:51:14 +0000
From:   Damien Le Moal <Damien.LeMoal@....com>
To:     Greentime Hu <greentime.hu@...ive.com>,
        "paul.walmsley@...ive.com" <paul.walmsley@...ive.com>,
        "hes@...ive.com" <hes@...ive.com>,
        "erik.danie@...ive.com" <erik.danie@...ive.com>,
        "zong.li@...ive.com" <zong.li@...ive.com>,
        "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "aou@...s.berkeley.edu" <aou@...s.berkeley.edu>,
        "mturquette@...libre.com" <mturquette@...libre.com>,
        "sboyd@...nel.org" <sboyd@...nel.org>,
        "lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>,
        "p.zabel@...gutronix.de" <p.zabel@...gutronix.de>,
        "alex.dewar90@...il.com" <alex.dewar90@...il.com>,
        "khilman@...libre.com" <khilman@...libre.com>,
        "hayashi.kunihiko@...ionext.com" <hayashi.kunihiko@...ionext.com>,
        "vidyas@...dia.com" <vidyas@...dia.com>,
        "jh80.chung@...sung.com" <jh80.chung@...sung.com>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-riscv@...ts.infradead.org" <linux-riscv@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
        "helgaas@...nel.org" <helgaas@...nel.org>
Subject: Re: [PATCH v4 5/6] PCI: fu740: Add SiFive FU740 PCIe host controller
 driver

On 2021/04/01 15:02, Greentime Hu wrote:
> From: Paul Walmsley <paul.walmsley@...ive.com>
> 
> Add driver for the SiFive FU740 PCIe host controller.
> This controller is based on the DesignWare PCIe core.
> 
> Signed-off-by: Paul Walmsley <paul.walmsley@...ive.com>
> Co-developed-by: Henry Styles <hes@...ive.com>
> Signed-off-by: Henry Styles <hes@...ive.com>
> Co-developed-by: Erik Danie <erik.danie@...ive.com>
> Signed-off-by: Erik Danie <erik.danie@...ive.com>
> Co-developed-by: Greentime Hu <greentime.hu@...ive.com>
> Signed-off-by: Greentime Hu <greentime.hu@...ive.com>
> ---
>  drivers/pci/controller/dwc/Kconfig      |   9 +
>  drivers/pci/controller/dwc/Makefile     |   1 +
>  drivers/pci/controller/dwc/pcie-fu740.c | 324 ++++++++++++++++++++++++
>  3 files changed, 334 insertions(+)
>  create mode 100644 drivers/pci/controller/dwc/pcie-fu740.c
> 
> diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> index 22c5529e9a65..0a37d21ed64e 100644
> --- a/drivers/pci/controller/dwc/Kconfig
> +++ b/drivers/pci/controller/dwc/Kconfig
> @@ -318,4 +318,13 @@ config PCIE_AL
>  	  required only for DT-based platforms. ACPI platforms with the
>  	  Annapurna Labs PCIe controller don't need to enable this.
>  
> +config PCIE_FU740
> +	bool "SiFive FU740 PCIe host controller"
> +	depends on PCI_MSI_IRQ_DOMAIN
> +	depends on SOC_SIFIVE || COMPILE_TEST
> +	select PCIE_DW_HOST
> +	help
> +	  Say Y here if you want PCIe controller support for the SiFive
> +	  FU740.
> +
>  endmenu
> diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
> index a751553fa0db..625f6aaeb5b8 100644
> --- a/drivers/pci/controller/dwc/Makefile
> +++ b/drivers/pci/controller/dwc/Makefile
> @@ -5,6 +5,7 @@ obj-$(CONFIG_PCIE_DW_EP) += pcie-designware-ep.o
>  obj-$(CONFIG_PCIE_DW_PLAT) += pcie-designware-plat.o
>  obj-$(CONFIG_PCI_DRA7XX) += pci-dra7xx.o
>  obj-$(CONFIG_PCI_EXYNOS) += pci-exynos.o
> +obj-$(CONFIG_PCIE_FU740) += pcie-fu740.o
>  obj-$(CONFIG_PCI_IMX6) += pci-imx6.o
>  obj-$(CONFIG_PCIE_SPEAR13XX) += pcie-spear13xx.o
>  obj-$(CONFIG_PCI_KEYSTONE) += pci-keystone.o
> diff --git a/drivers/pci/controller/dwc/pcie-fu740.c b/drivers/pci/controller/dwc/pcie-fu740.c
> new file mode 100644
> index 000000000000..ebbcbda97490
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pcie-fu740.c
> @@ -0,0 +1,324 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * FU740 DesignWare PCIe Controller integration
> + * Copyright (C) 2019-2021 SiFive, Inc.
> + * Paul Walmsley
> + * Greentime Hu
> + *
> + * Based in part on the i.MX6 PCIe host controller shim which is:
> + *
> + * Copyright (C) 2013 Kosagi
> + *		https://www.kosagi.com
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/gpio.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of_gpio.h>
> +#include <linux/of_device.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/resource.h>
> +#include <linux/signal.h>
> +#include <linux/types.h>
> +#include <linux/interrupt.h>
> +#include <linux/iopoll.h>
> +#include <linux/reset.h>
> +#include <linux/pm_domain.h>
> +#include <linux/pm_runtime.h>
> +
> +#include "pcie-designware.h"
> +
> +#define to_fu740_pcie(x)	dev_get_drvdata((x)->dev)
> +
> +struct fu740_pcie {
> +	struct dw_pcie pci;
> +	void __iomem *mgmt_base;
> +	struct gpio_desc *reset;
> +	struct gpio_desc *pwren;
> +	struct clk *pcie_aux;
> +	struct reset_control *rst;
> +};
> +
> +#define SIFIVE_DEVICESRESETREG		0x28
> +
> +#define PCIEX8MGMT_PERST_N		0x0
> +#define PCIEX8MGMT_APP_LTSSM_ENABLE	0x10
> +#define PCIEX8MGMT_APP_HOLD_PHY_RST	0x18
> +#define PCIEX8MGMT_DEVICE_TYPE		0x708
> +#define PCIEX8MGMT_PHY0_CR_PARA_ADDR	0x860
> +#define PCIEX8MGMT_PHY0_CR_PARA_RD_EN	0x870
> +#define PCIEX8MGMT_PHY0_CR_PARA_RD_DATA	0x878
> +#define PCIEX8MGMT_PHY0_CR_PARA_SEL	0x880
> +#define PCIEX8MGMT_PHY0_CR_PARA_WR_DATA	0x888
> +#define PCIEX8MGMT_PHY0_CR_PARA_WR_EN	0x890
> +#define PCIEX8MGMT_PHY0_CR_PARA_ACK	0x898
> +#define PCIEX8MGMT_PHY1_CR_PARA_ADDR	0x8a0
> +#define PCIEX8MGMT_PHY1_CR_PARA_RD_EN	0x8b0
> +#define PCIEX8MGMT_PHY1_CR_PARA_RD_DATA	0x8b8
> +#define PCIEX8MGMT_PHY1_CR_PARA_SEL	0x8c0
> +#define PCIEX8MGMT_PHY1_CR_PARA_WR_DATA	0x8c8
> +#define PCIEX8MGMT_PHY1_CR_PARA_WR_EN	0x8d0
> +#define PCIEX8MGMT_PHY1_CR_PARA_ACK	0x8d8
> +
> +#define PCIEX8MGMT_PHY_CDR_TRACK_EN	BIT(0)
> +#define PCIEX8MGMT_PHY_LOS_THRSHLD	BIT(5)
> +#define PCIEX8MGMT_PHY_TERM_EN		BIT(9)
> +#define PCIEX8MGMT_PHY_TERM_ACDC	BIT(10)
> +#define PCIEX8MGMT_PHY_EN		BIT(11)
> +#define PCIEX8MGMT_PHY_INIT_VAL		(PCIEX8MGMT_PHY_CDR_TRACK_EN|\
> +					 PCIEX8MGMT_PHY_LOS_THRSHLD|\
> +					 PCIEX8MGMT_PHY_TERM_EN|\
> +					 PCIEX8MGMT_PHY_TERM_ACDC|\
> +					 PCIEX8MGMT_PHY_EN)
> +
> +#define PCIEX8MGMT_PHY_LANEN_DIG_ASIC_RX_OVRD_IN_3	0x1008
> +#define PCIEX8MGMT_PHY_LANE_OFF		0x100
> +#define PCIEX8MGMT_PHY_LANE0_BASE	(PCIEX8MGMT_PHY_LANEN_DIG_ASIC_RX_OVRD_IN_3 + 0x100 * 0)
> +#define PCIEX8MGMT_PHY_LANE1_BASE	(PCIEX8MGMT_PHY_LANEN_DIG_ASIC_RX_OVRD_IN_3 + 0x100 * 1)
> +#define PCIEX8MGMT_PHY_LANE2_BASE	(PCIEX8MGMT_PHY_LANEN_DIG_ASIC_RX_OVRD_IN_3 + 0x100 * 2)
> +#define PCIEX8MGMT_PHY_LANE3_BASE	(PCIEX8MGMT_PHY_LANEN_DIG_ASIC_RX_OVRD_IN_3 + 0x100 * 3)
> +
> +static void fu740_pcie_assert_reset(struct fu740_pcie *afp)
> +{
> +	/* Assert PERST_N GPIO */
> +	gpiod_set_value_cansleep(afp->reset, 0);
> +	/* Assert controller PERST_N */
> +	writel_relaxed(0x0, afp->mgmt_base + PCIEX8MGMT_PERST_N);
> +}
> +
> +static void fu740_pcie_deassert_reset(struct fu740_pcie *afp)
> +{
> +	/* Deassert controller PERST_N */
> +	writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_PERST_N);
> +	/* Deassert PERST_N GPIO */
> +	gpiod_set_value_cansleep(afp->reset, 1);
> +}
> +
> +static void fu740_pcie_power_on(struct fu740_pcie *afp)
> +{
> +	gpiod_set_value_cansleep(afp->pwren, 1);
> +	/*
> +	 * Ensure that PERST has been asserted for at least 100 ms.
> +	 * Section 2.2 of PCI Express Card Electromechanical Specification
> +	 * Revision 3.0
> +	 */
> +	msleep(100);
> +}
> +
> +static void fu740_pcie_drive_reset(struct fu740_pcie *afp)
> +{
> +	fu740_pcie_assert_reset(afp);
> +	fu740_pcie_power_on(afp);
> +	fu740_pcie_deassert_reset(afp);
> +}
> +
> +static void fu740_phyregwrite(const uint8_t phy, const uint16_t addr,
> +			      const uint16_t wrdata, struct fu740_pcie *afp)
> +{
> +	struct device *dev = afp->pci.dev;
> +	void __iomem *phy_cr_para_addr;
> +	void __iomem *phy_cr_para_wr_data;
> +	void __iomem *phy_cr_para_wr_en;
> +	void __iomem *phy_cr_para_ack;
> +	int ret, val;
> +
> +	/* Setup */
> +	if (phy) {
> +		phy_cr_para_addr = afp->mgmt_base + PCIEX8MGMT_PHY1_CR_PARA_ADDR;
> +		phy_cr_para_wr_data = afp->mgmt_base + PCIEX8MGMT_PHY1_CR_PARA_WR_DATA;
> +		phy_cr_para_wr_en = afp->mgmt_base + PCIEX8MGMT_PHY1_CR_PARA_WR_EN;
> +		phy_cr_para_ack = afp->mgmt_base + PCIEX8MGMT_PHY1_CR_PARA_ACK;
> +	} else {
> +		phy_cr_para_addr = afp->mgmt_base + PCIEX8MGMT_PHY0_CR_PARA_ADDR;
> +		phy_cr_para_wr_data = afp->mgmt_base + PCIEX8MGMT_PHY0_CR_PARA_WR_DATA;
> +		phy_cr_para_wr_en = afp->mgmt_base + PCIEX8MGMT_PHY0_CR_PARA_WR_EN;
> +		phy_cr_para_ack = afp->mgmt_base + PCIEX8MGMT_PHY0_CR_PARA_ACK;
> +	}
> +
> +	writel_relaxed(addr, phy_cr_para_addr);
> +	writel_relaxed(wrdata, phy_cr_para_wr_data);
> +	writel_relaxed(1, phy_cr_para_wr_en);
> +
> +	/* Wait for wait_idle */
> +	ret = readl_poll_timeout(phy_cr_para_ack, val, val, 10, 5000);
> +	if (ret)
> +		dev_err(dev, "Wait for wait_ilde state failed!\n");

This is a void function. What is the point of these dev_err() if you do not
return an error or process the failure in any way ? Change this to dev_warn()
may be ?

> +
> +	/* Clear */
> +	writel_relaxed(0, phy_cr_para_wr_en);
> +
> +	/* Wait for ~wait_idle */
> +	ret = readl_poll_timeout(phy_cr_para_ack, val, !val, 10, 5000);
> +	if (ret)
> +		dev_err(dev, "Wait for !wait_ilde state failed!\n");

Same as above.

> +}
> +
> +static void fu740_pcie_init_phy(struct fu740_pcie *afp)
> +{
> +	/* Enable phy cr_para_sel interfaces */
> +	writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_PHY0_CR_PARA_SEL);
> +	writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_PHY1_CR_PARA_SEL);
> +
> +	/*
> +	 * Wait 10 cr_para cycles to guarantee that the registers are ready
> +	 * to be edited.
> +	 */
> +	ndelay(10);
> +
> +	/* Set PHY AC termination mode */
> +	fu740_phyregwrite(0, PCIEX8MGMT_PHY_LANE0_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
> +	fu740_phyregwrite(0, PCIEX8MGMT_PHY_LANE1_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
> +	fu740_phyregwrite(0, PCIEX8MGMT_PHY_LANE2_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
> +	fu740_phyregwrite(0, PCIEX8MGMT_PHY_LANE3_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
> +	fu740_phyregwrite(1, PCIEX8MGMT_PHY_LANE0_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
> +	fu740_phyregwrite(1, PCIEX8MGMT_PHY_LANE1_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
> +	fu740_phyregwrite(1, PCIEX8MGMT_PHY_LANE2_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
> +	fu740_phyregwrite(1, PCIEX8MGMT_PHY_LANE3_BASE, PCIEX8MGMT_PHY_INIT_VAL, afp);
> +}
> +
> +static void fu740_pcie_ltssm_enable(struct device *dev)
> +{
> +	struct fu740_pcie *afp = dev_get_drvdata(dev);
> +
> +	/* Enable LTSSM */
> +	writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_APP_LTSSM_ENABLE);
> +}
> +
> +static int fu740_pcie_start_link(struct dw_pcie *pci)
> +{
> +	struct device *dev = pci->dev;

No need for this variable.

> +
> +	/* Start LTSSM. */
> +	fu740_pcie_ltssm_enable(dev);
> +	return 0;
> +}
> +
> +static int fu740_pcie_host_init(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct fu740_pcie *afp = to_fu740_pcie(pci);
> +	struct device *dev = pci->dev;
> +	int ret;
> +
> +	/* Power on reset */
> +	fu740_pcie_drive_reset(afp);
> +
> +	/* Enable pcieauxclk */
> +	ret = clk_prepare_enable(afp->pcie_aux);
> +	if (ret)
> +		dev_err(dev, "unable to enable pcie_aux clock\n");

No bailing out ? Without a clock, is this going to work ?
If that is not a problem, then I would suggest a dev_warn() here.

> +
> +	/*
> +	 * Assert hold_phy_rst (hold the controller LTSSM in reset after
> +	 * power_up_rst_n for register programming with cr_para)
> +	 */
> +	writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_APP_HOLD_PHY_RST);
> +
> +	/* Deassert power_up_rst_n */
> +	ret = reset_control_deassert(afp->rst);
> +	if (ret)
> +		dev_err(dev, "unable to deassert pcie_power_up_rst_n\n");

Same as above.

> +
> +	fu740_pcie_init_phy(afp);
> +
> +	/* Disable pcieauxclk */
> +	clk_disable_unprepare(afp->pcie_aux);
> +	/* Clear hold_phy_rst */
> +	writel_relaxed(0x0, afp->mgmt_base + PCIEX8MGMT_APP_HOLD_PHY_RST);
> +	/* Enable pcieauxclk */
> +	ret = clk_prepare_enable(afp->pcie_aux);
> +	/* Set RC mode */
> +	writel_relaxed(0x4, afp->mgmt_base + PCIEX8MGMT_DEVICE_TYPE);
> +
> +	return 0;
> +}
> +
> +static const struct dw_pcie_host_ops fu740_pcie_host_ops = {
> +	.host_init = fu740_pcie_host_init,
> +};
> +
> +static const struct dw_pcie_ops dw_pcie_ops = {
> +	.start_link = fu740_pcie_start_link,
> +};
> +
> +static int fu740_pcie_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct dw_pcie *pci;
> +	struct fu740_pcie *afp;
> +	int ret;
> +
> +	afp = devm_kzalloc(dev, sizeof(*afp), GFP_KERNEL);
> +	if (!afp)
> +		return -ENOMEM;
> +	pci = &afp->pci;
> +	pci->dev = dev;
> +	pci->ops = &dw_pcie_ops;
> +	pci->pp.ops = &fu740_pcie_host_ops;
> +
> +	/* SiFive specific region: mgmt */
> +	afp->mgmt_base = devm_platform_ioremap_resource_byname(pdev, "mgmt");
> +	if (IS_ERR(afp->mgmt_base))
> +		return PTR_ERR(afp->mgmt_base);
> +
> +	/* Fetch GPIOs */
> +	afp->reset = devm_gpiod_get_optional(dev, "reset-gpios", GPIOD_OUT_LOW);
> +	if (IS_ERR(afp->reset)) {
> +		dev_err(dev, "unable to get reset-gpios\n");
> +		return ret;
> +	}
> +	afp->pwren = devm_gpiod_get_optional(dev, "pwren-gpios", GPIOD_OUT_LOW);
> +	if (IS_ERR(afp->pwren)) {
> +		dev_err(dev, "unable to get pwren-gpios\n");
> +		return ret;

Why not return dev_err_probe(...); ? Same for the returns above.

> +	}
> +
> +	/* Fetch clocks */
> +	afp->pcie_aux = devm_clk_get(dev, "pcie_aux");
> +	if (IS_ERR(afp->pcie_aux))
> +		return dev_err_probe(dev, PTR_ERR(afp->pcie_aux),
> +					     "pcie_aux clock source missing or invalid\n");
> +
> +	/* Fetch reset */
> +	afp->rst = devm_reset_control_get_exclusive(dev, NULL);
> +	if (IS_ERR(afp->rst))
> +		return dev_err_probe(dev, PTR_ERR(afp->rst), "unable to get reset\n");
> +
> +	platform_set_drvdata(pdev, afp);
> +
> +	ret = dw_pcie_host_init(&pci->pp);
> +	if (ret < 0)
> +		return ret;

You can simplify this with a simple:

	return dw_pcie_host_init(&pci->pp);

> +
> +	return 0;
> +}
> +
> +static void fu740_pcie_shutdown(struct platform_device *pdev)
> +{
> +	struct fu740_pcie *afp = platform_get_drvdata(pdev);
> +
> +	/* Bring down link, so bootloader gets clean state in case of reboot */
> +	fu740_pcie_assert_reset(afp);
> +}
> +
> +static const struct of_device_id fu740_pcie_of_match[] = {
> +	{ .compatible = "sifive,fu740-pcie", },
> +	{},
> +};
> +
> +static struct platform_driver fu740_pcie_driver = {
> +	.driver = {
> +		   .name = "fu740-pcie",
> +		   .of_match_table = fu740_pcie_of_match,
> +		   .suppress_bind_attrs = true,
> +	},
> +	.probe = fu740_pcie_probe,
> +	.shutdown = fu740_pcie_shutdown,
> +};
> +
> +builtin_platform_driver(fu740_pcie_driver);
> 


-- 
Damien Le Moal
Western Digital Research

Powered by blists - more mailing lists