PCI: fu740: Add SiFive FU740 PCIe host controller driver

Add driver for the SiFive FU740 PCIe host controller.
This controller is based on the DesignWare PCIe core.

Co-developed-by: Henry Styles <hes@sifive.com>
Co-developed-by: Erik Danie <erik.danie@sifive.com>
Co-developed-by: Greentime Hu <greentime.hu@sifive.com>
Link: https://lore.kernel.org/r/20210504105940.100004-6-greentime.hu@sifive.com
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Henry Styles <hes@sifive.com>
Signed-off-by: Erik Danie <erik.danie@sifive.com>
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Author: paul-walmsley-sifive

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

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

drivers/pci/controller/dwc/pcie-fu740.c

@@ -0,0 +1,309 @@
+// 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/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/resource.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/iopoll.h>
+#include <linux/reset.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_warn(dev, "Wait for wait_idle state failed!\n");
+
+	/* 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_warn(dev, "Wait for !wait_idle state failed!\n");
+}
+
+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 int fu740_pcie_start_link(struct dw_pcie *pci)
+{
+	struct device *dev = pci->dev;
+	struct fu740_pcie *afp = dev_get_drvdata(dev);
+
+	/* Enable LTSSM */
+	writel_relaxed(0x1, afp->mgmt_base + PCIEX8MGMT_APP_LTSSM_ENABLE);
+	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");
+		return ret;
+	}
+
+	/*
+	 * 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");
+		return ret;
+	}
+
+	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;
+
+	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))
+		return dev_err_probe(dev, PTR_ERR(afp->reset), "unable to get reset-gpios\n");
+
+	afp->pwren = devm_gpiod_get_optional(dev, "pwren-gpios", GPIOD_OUT_LOW);
+	if (IS_ERR(afp->pwren))
+		return dev_err_probe(dev, PTR_ERR(afp->pwren), "unable to get pwren-gpios\n");
+
+	/* 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);
+
+	return dw_pcie_host_init(&pci->pp);
+}
+
+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);