[RFC PATCH 5/6] PCI: designware: Add SiFive FU740 PCIe host controller driver
Rob Herring
robh+dt at kernel.org
Wed Mar 3 23:30:58 GMT 2021
On Tue, Mar 2, 2021 at 4:59 AM Greentime Hu <greentime.hu at sifive.com> wrote:
>
> From: Paul Walmsley <paul.walmsley at sifive.com>
>
> Add driver for the SiFive FU740 PCIe host controller.
> This controller is based on the DesignWare PCIe core.
>
> Co-developed-by: Henry Styles <hes at sifive.com>
> Signed-off-by: Henry Styles <hes at sifive.com>
> Co-developed-by: Erik Danie <erik.danie at sifive.com>
> Signed-off-by: Erik Danie <erik.danie at sifive.com>
> Co-developed-by: Greentime Hu <greentime.hu at sifive.com>
> Signed-off-by: Greentime Hu <greentime.hu at sifive.com>
Your Sob should be last since you are sending the patch.
> Signed-off-by: Paul Walmsley <paul.walmsley at sifive.com>
And Paul's either before yours or first in the list depending on the history.
> ---
> drivers/pci/controller/dwc/Kconfig | 9 +
> drivers/pci/controller/dwc/Makefile | 1 +
> drivers/pci/controller/dwc/pcie-fu740.c | 455 ++++++++++++++++++++++++
> 3 files changed, 465 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..6916eea40ea5
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pcie-fu740.c
> @@ -0,0 +1,455 @@
> +// 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/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/resource.h>
> +#include <linux/signal.h>
> +#include <linux/types.h>
> +#include <linux/interrupt.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;
> + int perstn_gpio;
> + int pwren_gpio;
Use gpio descriptors and the gpiod_* api.
> + 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
I tend to think we should split the phy part to a proper phy driver.
Just because the registers happen to be in the same register space
isn't really a good reason to combine them.
> +
> +/* PCIe Port Logic registers (memory-mapped) */
> +#define PL_OFFSET 0x700
That's all DWC controllers.
> +#define PCIE_PL_GEN2_CTRL_OFF (PL_OFFSET + 0x10c)
Also common. Pretty sure there's a define already.
> +#define PCIE_PL_DIRECTED_SPEED_CHANGE_OFF 0x20000
> +
> +#define PCIE_PHY_MAX_RETRY_CNT 1000
> +
> +static void fu740_pcie_assert_perstn(struct fu740_pcie *afp)
> +{
> + /* PERST_N GPIO */
> + if (gpio_is_valid(afp->perstn_gpio))
> + gpio_direction_output(afp->perstn_gpio, 0);
> +
> + /* Controller PERST_N */
> + __raw_writel(0x0, afp->mgmt_base + PCIEX8MGMT_PERST_N);
writel_relaxed is the preferred variant.
> +}
> +
> +static void fu740_pcie_deassert_perstn(struct fu740_pcie *afp)
> +{
> + /* Controller PERST_N */
> + __raw_writel(0x1, afp->mgmt_base + PCIEX8MGMT_PERST_N);
> + /* PERST_N GPIO */
> + if (gpio_is_valid(afp->perstn_gpio))
> + gpio_direction_output(afp->perstn_gpio, 1);
> +}
> +
> +static void fu740_pcie_power_on(struct fu740_pcie *afp)
> +{
> + if (gpio_is_valid(afp->pwren_gpio)) {
> + gpio_direction_output(afp->pwren_gpio, 1);
> + mdelay(100);
> + }
> +}
> +
> +static void fu740_pcie_drive_perstn(struct fu740_pcie *afp)
> +{
> + fu740_pcie_assert_perstn(afp);
> + fu740_pcie_power_on(afp);
> + fu740_pcie_deassert_perstn(afp);
> +}
> +
> +static void fu740_phyregreadwrite(const uint8_t phy, const uint8_t write,
> + const uint16_t addr,
> + const uint16_t wrdata, uint16_t *rddata,
> + struct fu740_pcie *afp)
I think you should split this into separate read and write functions.
> +{
> + unsigned char ack = 0;
> + unsigned int cnt = 0;
> + struct device *dev = afp->pci->dev;
> +
> + /* setup */
> + __raw_writel(addr,
> + afp->mgmt_base +
> + (phy ? PCIEX8MGMT_PHY1_CR_PARA_ADDR :
> + PCIEX8MGMT_PHY0_CR_PARA_ADDR));
> + if (write)
> + __raw_writel(wrdata,
> + afp->mgmt_base +
> + (phy ? PCIEX8MGMT_PHY1_CR_PARA_WR_DATA :
> + PCIEX8MGMT_PHY0_CR_PARA_WR_DATA));
> + if (write)
> + __raw_writel(1,
> + afp->mgmt_base +
> + (phy ? PCIEX8MGMT_PHY1_CR_PARA_WR_EN :
> + PCIEX8MGMT_PHY0_CR_PARA_WR_EN));
> + else
> + __raw_writel(1,
> + afp->mgmt_base +
> + (phy ? PCIEX8MGMT_PHY1_CR_PARA_RD_EN :
> + PCIEX8MGMT_PHY0_CR_PARA_RD_EN));
> +
> + /* wait for wait_idle */
> + do {
> + if (__raw_readl
> + (afp->mgmt_base +
> + (phy ? PCIEX8MGMT_PHY1_CR_PARA_ACK :
> + PCIEX8MGMT_PHY0_CR_PARA_ACK))) {
> + ack = 1;
> + if (!write)
> + __raw_readl(afp->mgmt_base +
> + (phy ?
> + PCIEX8MGMT_PHY1_CR_PARA_RD_DATA :
> + PCIEX8MGMT_PHY0_CR_PARA_RD_DATA));
> + }
> + } while (!ack);
> +
> + /* clear */
> + if (write)
> + __raw_writel(0,
> + afp->mgmt_base +
> + (phy ? PCIEX8MGMT_PHY1_CR_PARA_WR_EN :
> + PCIEX8MGMT_PHY0_CR_PARA_WR_EN));
> + else
> + __raw_writel(0,
> + afp->mgmt_base +
> + (phy ? PCIEX8MGMT_PHY1_CR_PARA_RD_EN :
> + PCIEX8MGMT_PHY0_CR_PARA_RD_EN));
> +
> + /* wait for ~wait_idle */
> + while (__raw_readl
> + (afp->mgmt_base +
> + (phy ? PCIEX8MGMT_PHY1_CR_PARA_ACK :
> + PCIEX8MGMT_PHY0_CR_PARA_ACK))) {
> + cpu_relax();
> + cnt++;
> + if (cnt > PCIE_PHY_MAX_RETRY_CNT) {
> + dev_err(dev, "PCIE phy doesn't enter idle state.\n");
> + break;
> + }
> + }
We have helpers for this kind of loop.
> +}
> +
> +static void fu740_pcie_init_phy(struct fu740_pcie *afp)
> +{
> + int lane;
> +
> + /* enable phy cr_para_sel interfaces */
> + __raw_writel(0x1, afp->mgmt_base + PCIEX8MGMT_PHY0_CR_PARA_SEL);
> + __raw_writel(0x1, afp->mgmt_base + PCIEX8MGMT_PHY1_CR_PARA_SEL);
> +
> + /* wait 10 cr_para cycles */
> + msleep(1);
> +
> + /* set PHY AC termination mode */
> + for (lane = 0; lane < 4; lane++) {
> + fu740_phyregreadwrite(0, 1,
> + 0x1008 + (0x100 * lane),
> + 0x0e21, NULL, afp);
> + fu740_phyregreadwrite(1, 1,
> + 0x1008 + (0x100 * lane),
> + 0x0e21, NULL, afp);
> + }
> +
> +}
> +
> +static void fu740_pcie_ltssm_enable(struct device *dev)
> +{
> + struct fu740_pcie *afp = dev_get_drvdata(dev);
> +
> + /* Enable LTSSM */
> + __raw_writel(0x1, afp->mgmt_base + PCIEX8MGMT_APP_LTSSM_ENABLE);
> +}
> +
> +static int fu740_pcie_start_link(struct dw_pcie *pci)
> +{
> + struct device *dev = pci->dev;
> + u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
> + u32 tmp;
> + int ret;
> +
> + /*
> + * Force Gen1 operation when starting the link. In case the link is
> + * started in Gen2 mode, there is a possibility the devices on the
> + * bus will not be detected at all. This happens with PCIe switches.
> + */
> + dw_pcie_dbi_ro_wr_en(pci);
> + tmp = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCAP);
> + tmp &= ~PCI_EXP_LNKCAP_SLS;
> + tmp |= PCI_EXP_LNKCAP_SLS_2_5GB;
> + dw_pcie_writel_dbi(pci, offset + PCI_EXP_LNKCAP, tmp);
> + dw_pcie_dbi_ro_wr_dis(pci);
> +
> + /* Start LTSSM. */
> + fu740_pcie_ltssm_enable(dev);
> +
> + ret = dw_pcie_wait_for_link(pci);
> + if (ret)
> + goto err_reset_phy;
> +
> + /* Now set it to operate in Gen3 */
> + dw_pcie_dbi_ro_wr_en(pci);
> + tmp = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCAP);
> + tmp &= ~PCI_EXP_LNKCAP_SLS;
> + tmp |= PCI_EXP_LNKCAP_SLS_8_0GB;
You don't support slower speeds?
We have some common DWC handling of this too, that doesn't work?
> + dw_pcie_writel_dbi(pci, offset + PCI_EXP_LNKCAP, tmp);
> + /* Enable DIRECTED SPEED CHANGE bit of GEN2_CTRL_OFF register */
> + tmp = dw_pcie_readl_dbi(pci, PCIE_PL_GEN2_CTRL_OFF);
> + tmp |= PCIE_PL_DIRECTED_SPEED_CHANGE_OFF;
> + dw_pcie_writel_dbi(pci, PCIE_PL_GEN2_CTRL_OFF, tmp);
> + dw_pcie_dbi_ro_wr_dis(pci);
> +
> + ret = dw_pcie_wait_for_link(pci);
> + if (ret)
> + goto err_reset_phy;
> +
> + /*
> + * Reenable DIRECTED SPEED CHANGE.
> + *
> + * You need to set this bit after each speed change, but after
> + * reaching G1, setting it once doesn't seem to work (it reaches G3
> + * equalization states and then times out, falls back to G1). But
> + * If after that, you set it again, it then reaches G3 perfectly
> + * fine.
> + */
> + dw_pcie_dbi_ro_wr_en(pci);
> + tmp = dw_pcie_readl_dbi(pci, PCIE_PL_GEN2_CTRL_OFF);
> + tmp |= PCIE_PL_DIRECTED_SPEED_CHANGE_OFF;
> + dw_pcie_writel_dbi(pci, PCIE_PL_GEN2_CTRL_OFF, tmp);
> + dw_pcie_dbi_ro_wr_dis(pci);
> +
> + ret = dw_pcie_wait_for_link(pci);
The DWC core does this after start_link() now.
> + if (ret)
> + goto err_reset_phy;
> +
> + tmp = dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKSTA);
> + dev_info(dev, "Link up, Gen%i\n", tmp & PCI_EXP_LNKSTA_CLS);
If we want this, it should be common.
> + return 0;
> +
> + err_reset_phy:
> + dev_err(dev, "Failed to bring link up!\n"
> + "PHY DEBUG_R0=0x%08x DEBUG_R1=0x%08x\n",
> + dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG0),
> + dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG1));
> + return ret;
> +}
> +
> +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 = 0;
> +
> + /* power on reset */
> + fu740_pcie_drive_perstn(afp);
> +
> + /* enable pcieauxclk */
> + ret = clk_prepare_enable(afp->pcie_aux);
> + if (ret)
> + dev_err(dev, "unable to enable pcie_aux clock\n");
> +
> + /*
> + * assert hold_phy_rst (hold the controller LTSSM in reset after
> + * power_up_rst_n
> + * for register programming with cr_para)
> + */
> + __raw_writel(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");
> +
> + fu740_pcie_init_phy(afp);
> +
> + /* disable pcieauxclk */
> + clk_disable_unprepare(afp->pcie_aux);
> + /* clear hold_phy_rst */
> + __raw_writel(0x0, afp->mgmt_base + PCIEX8MGMT_APP_HOLD_PHY_RST);
> + /* enable pcieauxclk */
> + ret = clk_prepare_enable(afp->pcie_aux);
> + /* set RC mode */
> + __raw_writel(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 const struct dev_pm_ops fu740_pcie_pm_ops = {
> + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(fu740_pcie_suspend_noirq,
> + fu740_pcie_resume_noirq)
> +};
> +
> +static int fu740_pcie_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct dw_pcie *pci;
> + struct fu740_pcie *afp;
> + struct resource *mgmt_res;
> + struct device_node *node = dev->of_node;
> + int ret;
> + u16 val;
> +
> + afp = devm_kzalloc(dev, sizeof(*afp), GFP_KERNEL);
> + if (!afp)
> + return -ENOMEM;
> +
> + pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
Embed dw_pcie in fu740_pcie and do 1 alloc.
> + if (!pci)
> + return -ENOMEM;
> +
> + pci->dev = dev;
> + pci->ops = &dw_pcie_ops;
> + pci->pp.ops = &fu740_pcie_host_ops;
> +
> + afp->pci = pci;
> +
> + mgmt_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mgmt");
> + if (!mgmt_res) {
> + dev_warn(dev, "missing required mgmt address range");
> + return -ENOENT;
> + }
> + afp->mgmt_base = devm_ioremap_resource(dev, mgmt_res);
Use devm_platform_ioremap_resource_byname
> + if (IS_ERR(afp->mgmt_base))
> + return PTR_ERR(afp->mgmt_base);
> +
> + /* Fetch GPIOs */
> + afp->perstn_gpio = of_get_named_gpio(node, "perstn-gpios", 0);
> + if (gpio_is_valid(afp->perstn_gpio)) {
> + ret = devm_gpio_request_one(dev, afp->perstn_gpio,
> + GPIOF_OUT_INIT_LOW, "perstn-gpios");
> + if (ret) {
> + dev_err(dev, "unable to get perstn gpio\n");
> + return ret;
> + }
> + } else if (afp->perstn_gpio == -EPROBE_DEFER) {
> + dev_err(dev, "perst-gpios EPROBE_DEFER\n");
> + return afp->perstn_gpio;
> + }
GPIOs are optional? That's not what the binding says.
> +
> + afp->pwren_gpio = of_get_named_gpio(node, "pwren-gpios", 0);
> + if (gpio_is_valid(afp->pwren_gpio)) {
> + ret = devm_gpio_request_one(dev, afp->pwren_gpio,
> + GPIOF_OUT_INIT_LOW, "pwren-gpios");
> + if (ret) {
> + dev_err(dev, "unable to get pwren gpio\n");
> + return ret;
> + }
> + } else if (afp->pwren_gpio == -EPROBE_DEFER) {
> + dev_err(dev, "pwren-gpios EPROBE_DEFER\n");
> + return afp->pwren_gpio;
> + }
> +
> + /* 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(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;
> +
> + if (pci_msi_enabled()) {
> + u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
> +
> + val = dw_pcie_readw_dbi(pci, offset + PCI_MSI_FLAGS);
> + val |= PCI_MSI_FLAGS_ENABLE;
> + dw_pcie_writew_dbi(pci, offset + PCI_MSI_FLAGS, val);
Are you sure this is needed? It's suspect that only i.MX6 needs it.
> + }
> +
> + 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_perstn(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,
> + .pm = &fu740_pcie_pm_ops,
> + },
> + .probe = fu740_pcie_probe,
> + .shutdown = fu740_pcie_shutdown,
> +};
> +
> +static int __init fu740_pcie_init(void)
> +{
> + return platform_driver_register(&fu740_pcie_driver);
> +}
> +
> +device_initcall(fu740_pcie_init);
Needs to be early? Why?
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