kernel-5.15/0617-Baikal-M-PCIe-driver-from-SDK-M-4.4.patch

From 1865253e6f0bd9dd35495cf5c5cc0db1c5df071b Mon Sep 17 00:00:00 2001
From: Alexey Sheplyakov <asheplyakov@altlinux.org>
Date: Thu, 14 Jan 2021 12:25:44 +0400
Subject: [PATCH 617/625] Baikal-M: PCIe driver from SDK-M 4.4

Appears to successfully probe the hardware, lspci -vv output
looks good. No other testing has been done yet.
---
 drivers/pci/controller/dwc/Makefile          |   2 +-
 drivers/pci/controller/dwc/pcie-baikal-v44.c | 826 +++++++++++++++++++
 2 files changed, 827 insertions(+), 1 deletion(-)
 create mode 100644 drivers/pci/controller/dwc/pcie-baikal-v44.c

diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
index 85e6ad1954e5..dcd23d7d5430 100644
--- a/drivers/pci/controller/dwc/Makefile
+++ b/drivers/pci/controller/dwc/Makefile
@@ -20,7 +20,7 @@ obj-$(CONFIG_PCI_MESON) += pci-meson.o
 obj-$(CONFIG_PCIE_TEGRA194) += pcie-tegra194.o
 obj-$(CONFIG_PCIE_UNIPHIER) += pcie-uniphier.o
 obj-$(CONFIG_PCIE_UNIPHIER_EP) += pcie-uniphier-ep.o
-obj-$(CONFIG_PCI_BAIKAL) += pcie-baikal.o
+obj-$(CONFIG_PCI_BAIKAL) += pcie-baikal.o pcie-baikal-v44.o
 
 # The following drivers are for devices that use the generic ACPI
 # pci_root.c driver but don't support standard ECAM config access.
diff --git a/drivers/pci/controller/dwc/pcie-baikal-v44.c b/drivers/pci/controller/dwc/pcie-baikal-v44.c
new file mode 100644
index 000000000000..5e5f0a9e59e2
--- /dev/null
+++ b/drivers/pci/controller/dwc/pcie-baikal-v44.c
@@ -0,0 +1,826 @@
+/*
+ * PCIe root complex driver for Baikal SoCs
+ *
+ * Copyright (C) 2019-2020 Baikal Electronics, JSC
+ * Authors: Pavel Parkhomenko <pavel.parkhomenko@baikalelectronics.ru>
+ *          Mikhail Ivanov <michail.ivanov@baikalelectronics.ru>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/irqchip/arm-gic-v3.h>
+#include <linux/mfd/baikal/lcru-pcie.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/pci.h>
+#include <linux/phy/phy.h>
+
+#include "pcie-designware.h"
+
+#ifdef CONFIG_PCI_DEBUG
+#define DEBUG
+#endif
+
+struct baikal_pcie {
+	struct dw_pcie pp;
+	unsigned bus_nr;
+	struct regmap *lcru;
+	struct gpio_desc *reset_gpio;
+	unsigned reset_active_low;
+	char reset_name[32];
+	unsigned retrained;
+	unsigned num_lanes;
+};
+
+#define to_baikal_pcie(x)	container_of((x), struct baikal_pcie, pp)
+
+#define PCIE_DEVICE_CONTROL_DEVICE_STATUS_REG	0x78
+#define PCIE_CAP_CORR_ERR_REPORT_EN		BIT(0)
+#define PCIE_CAP_NON_FATAL_ERR_REPORT_EN	BIT(1)
+#define PCIE_CAP_FATAL_ERR_REPORT_EN		BIT(2)
+#define PCIE_CAP_UNSUPPORT_REQ_REP_EN		BIT(3)
+
+#define PCIE_LINK_CAPABILITIES_REG		0x7c
+#define PCIE_CAP_MAX_LINK_WIDTH_MASK		0x3f0
+#define PCIE_CAP_MAX_LINK_WIDTH_SHIFT		4
+
+#define PCIE_LINK_CONTROL_LINK_STATUS_REG	0x80
+#define PCIE_CAP_LINK_SPEED_MASK		0xf0000
+#define PCIE_CAP_LINK_SPEED_SHIFT		16
+#define PCIE_CAP_NEGO_LINK_WIDTH_MASK		0x3f00000
+#define PCIE_CAP_NEGO_LINK_WIDTH_SHIFT		20
+#define PCIE_CAP_LINK_TRAINING			BIT(27)
+
+#define PCIE_ROOT_CONTROL_ROOT_CAPABILITIES_REG	0x8c
+#define PCIE_CAP_SYS_ERR_ON_CORR_ERR_EN		BIT(0)
+#define PCIE_CAP_SYS_ERR_ON_NON_FATAL_ERR_EN	BIT(1)
+#define PCIE_CAP_SYS_ERR_ON_FATAL_ERR_EN	BIT(2)
+#define PCIE_CAP_PME_INT_EN			BIT(3)
+
+#define PCIE_LINK_CONTROL2_LINK_STATUS2_REG	0xa0
+#define PCIE_CAP_TARGET_LINK_SPEED_MASK		0xf
+
+#define PCIE_UNCORR_ERR_STATUS_REG		0x104
+#define PCIE_CORR_ERR_STATUS_REG		0x110
+
+#define PCIE_ROOT_ERR_CMD_REG			0x12c
+#define PCIE_CORR_ERR_REPORTING_EN		BIT(0)
+#define PCIE_NON_FATAL_ERR_REPORTING_EN		BIT(1)
+#define PCIE_FATAL_ERR_REPORTING_EN		BIT(2)
+
+#define PCIE_ROOT_ERR_STATUS_REG		0x130
+
+#define PCIE_GEN2_CTRL_REG			0x80c
+#define PCIE_DIRECT_SPEED_CHANGE		BIT(17)
+
+#define PCIE_MSI_CTRL_ADDR_LO_REG		0x820
+#define PCIE_MSI_CTRL_ADDR_HI_REG		0x824
+
+#define PCIE_MISC_CONTROL_1_REG			0x8bc
+#define PCIE_DBI_RO_RW_EN			BIT(0)
+
+#define PCIE_IATU_VIEWPORT_REG			0x900
+#define PCIE_IATU_REGION_INBOUND		BIT(31)
+#define PCIE_IATU_REGION_OUTBOUND		0
+#define PCIE_IATU_REGION_CTRL_2_REG		0x908
+
+static const struct of_device_id of_baikal_pcie_match[] = {
+	{ .compatible = "baikal,pcie-m", },
+	{},
+};
+
+static unsigned baikal_pcie_link_is_training(struct dw_pcie *pp)
+{
+	unsigned long reg;
+	reg = dw_pcie_readl_dbi(pp, PCIE_LINK_CONTROL_LINK_STATUS_REG);
+	return reg & PCIE_CAP_LINK_TRAINING;
+}
+
+static bool baikal_wait_pcie_link_training_done(struct dw_pcie *pp)
+{
+	unsigned long start_jiffies = jiffies;
+	while (baikal_pcie_link_is_training(pp)) {
+		if (time_after(jiffies, start_jiffies + HZ)) {
+			pr_err("%s: link retrained for too long, timeout occured\n", __func__);
+			return false;
+		}
+		udelay(100);
+	}
+	return true;
+}
+
+static void baikal_print_link_status(struct dw_pcie *pp)
+{
+	unsigned long reg;
+	unsigned speed, width;
+
+	reg = dw_pcie_readl_dbi(pp, PCIE_LINK_CONTROL_LINK_STATUS_REG);
+	speed = (reg & PCIE_CAP_LINK_SPEED_MASK) >> PCIE_CAP_LINK_SPEED_SHIFT;
+	width = (reg & PCIE_CAP_NEGO_LINK_WIDTH_MASK) >>
+		PCIE_CAP_NEGO_LINK_WIDTH_SHIFT;
+
+	dev_info(pp->dev, "link status is Gen%u, x%u\n", speed, width);
+}
+
+static void baikal_pcie_link_retrain(struct dw_pcie *pp, int target_speed)
+{
+	unsigned long reg;
+	unsigned long start_jiffies;
+
+	dev_info(pp->dev, "retrain link to Gen%u\n", target_speed);
+
+	/* In case link is already training wait for training to complete */
+	baikal_wait_pcie_link_training_done(pp);
+
+	/* Set desired speed */
+	reg = dw_pcie_readl_dbi(pp, PCIE_LINK_CONTROL2_LINK_STATUS2_REG);
+	reg &= ~PCIE_CAP_TARGET_LINK_SPEED_MASK;
+	reg |= target_speed;
+	dw_pcie_writel_dbi(pp, PCIE_LINK_CONTROL2_LINK_STATUS2_REG, reg);
+
+	/* Set DIRECT_SPEED_CHANGE bit */
+	reg = dw_pcie_readl_dbi(pp, PCIE_GEN2_CTRL_REG);
+	reg &= ~PCIE_DIRECT_SPEED_CHANGE;
+	dw_pcie_writel_dbi(pp, PCIE_GEN2_CTRL_REG, reg);
+	reg |= PCIE_DIRECT_SPEED_CHANGE;
+	dw_pcie_writel_dbi(pp, PCIE_GEN2_CTRL_REG, reg);
+
+	/* Wait for link training begin */
+	start_jiffies = jiffies;
+	while (baikal_pcie_link_is_training(pp) == 0) {
+		if (time_after(jiffies, start_jiffies + HZ)) {
+			pr_err("%s: link retrained for too long, timeout occured\n", __func__);
+			break;
+		}
+		udelay(100);
+	}
+
+	/* Wait for link training end */
+	baikal_wait_pcie_link_training_done(pp);
+
+	if (dw_pcie_wait_for_link(pp) == 0) {
+		baikal_print_link_status(pp);
+	}
+}
+
+static void baikal_pcie_link_speed_fixup(struct pci_dev *pdev)
+{
+	struct pcie_port *portp = pdev->bus->sysdata;
+	struct dw_pcie *pp = to_dw_pcie_from_pp(portp);
+	struct baikal_pcie *pcie = to_baikal_pcie(pp);
+	unsigned dev_lnkcap_speed;
+	unsigned dev_lnkcap_width;
+	unsigned rc_lnkcap_speed;
+	unsigned rc_lnksta_speed;
+	unsigned rc_target_speed;
+	u32 reg;
+
+	/* Skip Root Bridge */
+	if (!pdev->bus->self) {
+		return;
+	}
+
+	/* Skip any devices not directly connected to the RC */
+	if (pdev->bus->self->bus->number != portp->bridge->bus->number) {
+		return;
+	}
+
+	/* Skip if the bus has already been retrained */
+	if (pcie->retrained) {
+		return;
+	}
+
+	reg = dw_pcie_readl_dbi(pp, PCIE_LINK_CAPABILITIES_REG);
+	rc_lnkcap_speed = reg & PCI_EXP_LNKCAP_SLS;
+
+	reg = dw_pcie_readl_dbi(pp, PCIE_LINK_CONTROL_LINK_STATUS_REG);
+	rc_lnksta_speed = (reg & PCIE_CAP_LINK_SPEED_MASK) >>
+			  PCIE_CAP_LINK_SPEED_SHIFT;
+
+	rc_target_speed = rc_lnksta_speed < 3? rc_lnksta_speed + 1 : 3;
+
+	pcie_capability_read_dword(pdev, PCI_EXP_LNKCAP, &reg);
+	dev_lnkcap_speed = (reg & PCI_EXP_LNKCAP_SLS);
+	dev_lnkcap_width = (reg & PCI_EXP_LNKCAP_MLW) >> PCI_EXP_LNKSTA_NLW_SHIFT;
+
+	baikal_print_link_status(pp);
+	dev_info(&pdev->dev, "device link capability is Gen%u, x%u\n",
+		 dev_lnkcap_speed, dev_lnkcap_width);
+
+	while (rc_target_speed > rc_lnksta_speed &&
+	       rc_target_speed <= rc_lnkcap_speed &&
+	       rc_target_speed <= dev_lnkcap_speed) {
+		/* Try to change link speed */
+		baikal_pcie_link_retrain(pp, rc_target_speed);
+		reg = dw_pcie_readl_dbi(pp, PCIE_LINK_CONTROL_LINK_STATUS_REG);
+		rc_lnksta_speed = (reg & PCIE_CAP_LINK_SPEED_MASK) >>
+				  PCIE_CAP_LINK_SPEED_SHIFT;
+
+		/* Check if the targeted speed has not been reached */
+		if (rc_lnksta_speed < rc_target_speed) {
+			/* Check if the retraining has led to speed regression */
+			if (rc_lnksta_speed < (rc_target_speed - 1)) {
+				/* Fall back to the previous speed */
+				--rc_target_speed;
+				baikal_pcie_link_retrain(pp, rc_target_speed);
+			}
+
+			break;
+		}
+
+		++rc_target_speed;
+	}
+
+	pcie->retrained = 1;
+}
+
+static void baikal_pcie_retrain_links(const struct pci_bus *bus)
+{
+       struct pci_dev *dev;
+       struct pci_bus *child;
+
+       list_for_each_entry(dev, &bus->devices, bus_list)
+               baikal_pcie_link_speed_fixup(dev);
+
+       list_for_each_entry(dev, &bus->devices, bus_list) {
+               child = dev->subordinate;
+               if (child)
+                       baikal_pcie_retrain_links(child);
+       }
+}
+
+static int baikal_pcie_link_up(struct dw_pcie *pp)
+{
+	struct baikal_pcie *pcie = to_baikal_pcie(pp);
+	unsigned long reg;
+
+	reg = baikal_pcie_lcru_readl(pcie->lcru,
+				     BAIKAL_LCRU_PCIE_GEN_CTL(pcie->bus_nr));
+
+	if ((reg & BAIKAL_PCIE_LTSSM_ENABLE) == 0) {
+		return 0;
+	}
+
+	reg = baikal_pcie_lcru_readl(pcie->lcru,
+				     BAIKAL_LCRU_PCIE_STATUS(pcie->bus_nr));
+
+	return (reg & BAIKAL_PCIE_SMLH_LINKUP) &&
+	       (reg & BAIKAL_PCIE_RDLH_LINKUP);
+}
+
+static int baikal_pcie_get_msi(struct baikal_pcie *pcie,
+			       struct device_node *msi_node,
+			       u64 *msi_addr)
+{
+	struct device *dev = pcie->pp.dev;
+	int ret;
+	struct resource res;
+
+	/*
+	 * Check if 'msi-parent' points to ARM GICv3 ITS, which is the only
+	 * supported MSI controller.
+	 */
+	if (!of_device_is_compatible(msi_node, "arm,gic-v3-its")) {
+		dev_err(dev, "unable to find compatible MSI controller\n");
+		return -ENODEV;
+	}
+
+	/* Derive GITS_TRANSLATER address from GICv3 */
+	ret = of_address_to_resource(msi_node, 0, &res);
+	if (ret < 0) {
+		dev_err(dev, "unable to obtain MSI controller resources\n");
+		return ret;
+	}
+
+	*msi_addr = res.start + GITS_TRANSLATER;
+	return 0;
+}
+
+static int baikal_pcie_msi_steer(struct baikal_pcie *pcie,
+				 struct device_node *msi_node)
+{
+	struct dw_pcie *pp = &pcie->pp;
+	struct device *dev = pp->dev;
+	int ret;
+	u64 msi_addr;
+
+	ret = baikal_pcie_get_msi(pcie, msi_node, &msi_addr);
+	if (ret < 0) {
+		dev_err(dev, "MSI steering failed\n");
+		return ret;
+	}
+
+	/* Program the msi_data */
+	dw_pcie_write(pp->dbi_base + PCIE_MSI_CTRL_ADDR_LO_REG, 4,
+			  lower_32_bits(msi_addr));
+	dw_pcie_write(pp->dbi_base + PCIE_MSI_CTRL_ADDR_HI_REG, 4,
+			  upper_32_bits(msi_addr));
+	return 0;
+}
+
+static int baikal_pcie_msi_enable(struct baikal_pcie *pcie)
+{
+	struct device *dev = pcie->pp.dev;
+	struct device_node *msi_node;
+	int ret;
+
+	/*
+	 * The "msi-parent" phandle needs to exist
+	 * for us to obtain the MSI node.
+	 */
+	msi_node = of_parse_phandle(dev->of_node, "msi-parent", 0);
+	if (!msi_node) {
+		dev_err(dev, "failed to read msi-parent node from FDT\n");
+		return -ENODEV;
+	}
+
+	ret = baikal_pcie_msi_steer(pcie, msi_node);
+	if (ret) {
+		goto out_put_node;
+	}
+
+out_put_node:
+	of_node_put(msi_node);
+	return ret;
+}
+
+static irqreturn_t baikal_pcie_err_irq_handler(int irq, void *priv)
+{
+	struct baikal_pcie *pcie = priv;
+	struct device *dev = pcie->pp.dev;
+	unsigned long corr_err_status;
+	unsigned long dev_ctrl_dev_status;
+	unsigned long root_err_status;
+	unsigned long uncorr_err_status;
+
+	uncorr_err_status   = dw_pcie_readl_dbi(&pcie->pp,
+					       PCIE_UNCORR_ERR_STATUS_REG);
+	corr_err_status	    = dw_pcie_readl_dbi(&pcie->pp,
+					       PCIE_CORR_ERR_STATUS_REG);
+	root_err_status     = dw_pcie_readl_dbi(&pcie->pp,
+					       PCIE_ROOT_ERR_STATUS_REG);
+	dev_ctrl_dev_status = dw_pcie_readl_dbi(&pcie->pp,
+					       PCIE_DEVICE_CONTROL_DEVICE_STATUS_REG);
+	dev_err(dev,
+		"dev_err:0x%lx root_err:0x%lx uncorr_err:0x%lx corr_err:0x%lx\n",
+		(dev_ctrl_dev_status & 0xf0000) >> 16,
+		root_err_status, uncorr_err_status, corr_err_status);
+
+	dw_pcie_writel_dbi(&pcie->pp,
+		PCIE_UNCORR_ERR_STATUS_REG, uncorr_err_status);
+	dw_pcie_writel_dbi(&pcie->pp,
+		PCIE_CORR_ERR_STATUS_REG, corr_err_status);
+	dw_pcie_writel_dbi(&pcie->pp,
+		PCIE_ROOT_ERR_STATUS_REG, root_err_status);
+	dw_pcie_writel_dbi(&pcie->pp,
+		PCIE_DEVICE_CONTROL_DEVICE_STATUS_REG, dev_ctrl_dev_status);
+
+	return IRQ_HANDLED;
+}
+
+static int baikal_pcie_host_init(struct pcie_port *port)
+{
+	struct dw_pcie* pp = to_dw_pcie_from_pp(port);
+	struct device *dev = pp->dev;
+	struct baikal_pcie *pcie = to_baikal_pcie(pp);
+	int err;
+	int linkup;
+	unsigned idx;
+	unsigned long reg;
+
+	/* Disable access to PHY registers and DBI2 mode */
+	reg = baikal_pcie_lcru_readl(pcie->lcru,
+				     BAIKAL_LCRU_PCIE_GEN_CTL(pcie->bus_nr));
+
+	reg &= ~(BAIKAL_PCIE_PHY_MGMT_ENABLE |
+		 BAIKAL_PCIE_DBI2_MODE);
+
+	baikal_pcie_lcru_writel(pcie->lcru,
+				BAIKAL_LCRU_PCIE_GEN_CTL(pcie->bus_nr), reg);
+
+	pcie->retrained = 0;
+	linkup = baikal_pcie_link_up(pp);
+
+	/* If link is not established yet, reset the RC */
+	if (!linkup) {
+		/* Disable link training */
+		reg = baikal_pcie_lcru_readl(pcie->lcru,
+					BAIKAL_LCRU_PCIE_GEN_CTL(pcie->bus_nr));
+
+		reg &= ~BAIKAL_PCIE_LTSSM_ENABLE;
+		baikal_pcie_lcru_writel(pcie->lcru,
+				   BAIKAL_LCRU_PCIE_GEN_CTL(pcie->bus_nr), reg);
+
+		/* Assert PERST pin */
+		if (pcie->reset_gpio != NULL) {
+			unsigned long gpio_flags;
+
+			if (pcie->reset_active_low) {
+				gpio_flags = GPIOF_ACTIVE_LOW |
+					     GPIOF_OUT_INIT_LOW;
+			} else {
+				gpio_flags = GPIOF_OUT_INIT_HIGH;
+			}
+
+			err = devm_gpio_request_one(dev,
+						 desc_to_gpio(pcie->reset_gpio),
+						 gpio_flags, pcie->reset_name);
+
+			if (err) {
+				dev_err(dev, "request GPIO failed (%d)\n", err);
+				return -ENODEV;
+			}
+		}
+
+		/* Reset the RC */
+		reg = baikal_pcie_lcru_readl(pcie->lcru,
+					  BAIKAL_LCRU_PCIE_RESET(pcie->bus_nr));
+
+		reg |= BAIKAL_PCIE_NONSTICKY_RST |
+                       BAIKAL_PCIE_STICKY_RST |
+                       BAIKAL_PCIE_PWR_RST |
+                       BAIKAL_PCIE_CORE_RST |
+                       BAIKAL_PCIE_PHY_RESET;
+
+		/* If the RC is PCIe x8, reset PIPE0 and PIPE1 */
+		if (pcie->bus_nr == 2) {
+			reg |= BAIKAL_PCIE_PIPE0_RESET |
+			       BAIKAL_PCIE_PIPE1_RESET;
+		} else {
+			reg |= BAIKAL_PCIE_PIPE_RESET;
+		}
+
+		baikal_pcie_lcru_writel(pcie->lcru,
+				     BAIKAL_LCRU_PCIE_RESET(pcie->bus_nr), reg);
+
+		usleep_range(20000, 30000);
+
+		if (pcie->reset_gpio != NULL) {
+			/* Deassert PERST pin */
+			gpiod_set_value_cansleep(pcie->reset_gpio, 0);
+		}
+
+		/* Deassert PHY reset */
+		reg = baikal_pcie_lcru_readl(pcie->lcru,
+					  BAIKAL_LCRU_PCIE_RESET(pcie->bus_nr));
+
+		reg &= ~BAIKAL_PCIE_PHY_RESET;
+		baikal_pcie_lcru_writel(pcie->lcru,
+				     BAIKAL_LCRU_PCIE_RESET(pcie->bus_nr), reg);
+
+		/* Deassert all software controlled resets */
+		reg = baikal_pcie_lcru_readl(pcie->lcru,
+					  BAIKAL_LCRU_PCIE_RESET(pcie->bus_nr));
+
+		reg &= ~(BAIKAL_PCIE_ADB_PWRDWN |
+			 BAIKAL_PCIE_HOT_RESET |
+			 BAIKAL_PCIE_NONSTICKY_RST |
+			 BAIKAL_PCIE_STICKY_RST |
+			 BAIKAL_PCIE_PWR_RST |
+			 BAIKAL_PCIE_CORE_RST |
+			 BAIKAL_PCIE_PHY_RESET);
+
+		if (pcie->bus_nr == 2) {
+			reg &= ~(BAIKAL_PCIE_PIPE0_RESET |
+				 BAIKAL_PCIE_PIPE1_RESET);
+		} else {
+			reg &= ~BAIKAL_PCIE_PIPE_RESET;
+		}
+
+		baikal_pcie_lcru_writel(pcie->lcru,
+				     BAIKAL_LCRU_PCIE_RESET(pcie->bus_nr), reg);
+	}
+
+	/* Deinitialise all iATU regions */
+	for (idx = 0; idx < pp->num_viewport; ++idx) {
+		dw_pcie_writel_dbi(pp, PCIE_IATU_VIEWPORT_REG,
+				  PCIE_IATU_REGION_OUTBOUND | idx);
+		dw_pcie_writel_dbi(pp, PCIE_IATU_REGION_CTRL_2_REG, 0);
+	}
+
+	/*
+	 * Enable writing to config regs. This is required as the DW driver
+	 * changes the class code. That register needs DBI write enable.
+	 */
+	reg = dw_pcie_readl_dbi(pp, PCIE_MISC_CONTROL_1_REG);
+	reg |= PCIE_DBI_RO_RW_EN;
+	dw_pcie_writel_dbi(pp, PCIE_MISC_CONTROL_1_REG, reg);
+
+	dw_pcie_setup_rc(port);
+
+	/* Set prog-if = 1 */
+	reg = dw_pcie_readl_dbi(pp, PCI_CLASS_REVISION);
+	reg = (1 << 8) | (reg & 0xffff00ff);
+	dw_pcie_writel_dbi(pp, PCI_CLASS_REVISION, reg);
+
+	/* Set max link width in accordance with 'num-lanes' value */
+	reg = dw_pcie_readl_dbi(pp, PCIE_LINK_CAPABILITIES_REG);
+	reg &= ~PCIE_CAP_MAX_LINK_WIDTH_MASK;
+	reg |= (pcie->num_lanes) << PCIE_CAP_MAX_LINK_WIDTH_SHIFT;
+	dw_pcie_writel_dbi(pp, PCIE_LINK_CAPABILITIES_REG, reg);
+
+	/* Disable writing to config regs */
+	reg = dw_pcie_readl_dbi(pp, PCIE_MISC_CONTROL_1_REG);
+	reg &= ~PCIE_DBI_RO_RW_EN;
+	dw_pcie_writel_dbi(pp, PCIE_MISC_CONTROL_1_REG, reg);
+
+	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+		err = baikal_pcie_msi_enable(pcie);
+		if (err) {
+			dev_err(pp->dev, "failed to initialize MSI\n");
+			return -EIO;
+		}
+	}
+
+	/* Enable error reporting */
+	reg = dw_pcie_readl_dbi(pp, PCIE_ROOT_ERR_CMD_REG);
+	reg |= PCIE_CORR_ERR_REPORTING_EN |
+	       PCIE_NON_FATAL_ERR_REPORTING_EN |
+	       PCIE_FATAL_ERR_REPORTING_EN;
+	dw_pcie_writel_dbi(pp, PCIE_ROOT_ERR_CMD_REG, reg);
+
+	reg = dw_pcie_readl_dbi(pp, PCIE_DEVICE_CONTROL_DEVICE_STATUS_REG);
+	reg |= PCIE_CAP_CORR_ERR_REPORT_EN |
+	       PCIE_CAP_NON_FATAL_ERR_REPORT_EN |
+	       PCIE_CAP_FATAL_ERR_REPORT_EN |
+	       PCIE_CAP_UNSUPPORT_REQ_REP_EN;
+	dw_pcie_writel_dbi(pp, PCIE_DEVICE_CONTROL_DEVICE_STATUS_REG, reg);
+
+	reg = dw_pcie_readl_dbi(pp, PCIE_ROOT_CONTROL_ROOT_CAPABILITIES_REG);
+	reg |= PCIE_CAP_SYS_ERR_ON_CORR_ERR_EN |
+	       PCIE_CAP_SYS_ERR_ON_NON_FATAL_ERR_EN |
+	       PCIE_CAP_SYS_ERR_ON_FATAL_ERR_EN |
+	       PCIE_CAP_PME_INT_EN;
+	dw_pcie_writel_dbi(pp, PCIE_ROOT_CONTROL_ROOT_CAPABILITIES_REG, reg);
+
+	if (linkup) {
+		dev_info(dev, "link is already up\n");
+		return 0;
+	}
+
+	/* Use Gen1 mode for link establishing */
+	reg = dw_pcie_readl_dbi(pp, PCIE_LINK_CONTROL2_LINK_STATUS2_REG);
+	reg &= ~PCIE_CAP_TARGET_LINK_SPEED_MASK;
+	reg |= 1;
+	dw_pcie_writel_dbi(pp, PCIE_LINK_CONTROL2_LINK_STATUS2_REG, reg);
+
+	/*
+	 * Clear DIRECT_SPEED_CHANGE bit. It has been set by dw_pcie_setup_rc.
+	 * This bit causes link retraining. However, link retraining should be
+	 * performed later by calling a speed fixup function.
+	 */
+	reg = dw_pcie_readl_dbi(pp, PCIE_GEN2_CTRL_REG);
+	reg &= ~PCIE_DIRECT_SPEED_CHANGE;
+	dw_pcie_writel_dbi(pp, PCIE_GEN2_CTRL_REG, reg);
+
+	/* Establish link */
+	reg = baikal_pcie_lcru_readl(pcie->lcru,
+				     BAIKAL_LCRU_PCIE_GEN_CTL(pcie->bus_nr));
+
+	reg |= BAIKAL_PCIE_LTSSM_ENABLE;
+	baikal_pcie_lcru_writel(pcie->lcru,
+				BAIKAL_LCRU_PCIE_GEN_CTL(pcie->bus_nr), reg);
+
+	dw_pcie_wait_for_link(pp);
+	/* XXX:
+	 * - return OK even if the link is down
+	 * - on error dw_pcie_wait_for_link prints a warning on its own,
+	 *   there's no need to print more messages here
+	 */
+	return 0;
+}
+
+static int baikal_pcie_msi_host_init(struct pcie_port *pp)
+{
+	struct dw_pcie* pcie = to_dw_pcie_from_pp(pp);
+	struct device *dev = pcie->dev;
+	struct device_node *np = dev->of_node;
+	struct device_node *msi_node;
+
+	/*
+	 * The MSI domain is set by the generic of_msi_configure(). This
+	 * .msi_host_init() function keeps us from doing the default MSI domain
+	 * setup in dw_pcie_host_init() and also enforces the requirement that
+	 * "msi-parent" exists.
+	 */
+	msi_node = of_parse_phandle(np, "msi-parent", 0);
+	if (!msi_node) {
+		dev_err(dev, "failed to find msi-parent\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct dw_pcie_host_ops baikal_pcie_host_ops = {
+	.host_init = baikal_pcie_host_init,
+	.msi_host_init = baikal_pcie_msi_host_init,
+};
+
+static const struct dw_pcie_ops baikal_pcie_ops = {
+	.link_up = baikal_pcie_link_up,
+};
+
+static int baikal_add_pcie_port(struct baikal_pcie *pcie,
+				struct platform_device *pdev)
+{
+	struct dw_pcie *dw_pci = &pcie->pp;
+	struct pcie_port *pp = &dw_pci->pp;
+	struct resource *res;
+	int irq;
+	int ret;
+
+	dw_pci->dev = &pdev->dev;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
+	if (res) {
+		devm_request_resource(dw_pci->dev, &iomem_resource, res);
+		dw_pci->dbi_base = devm_ioremap_resource(dw_pci->dev, res);
+		if (IS_ERR(dw_pci->dbi_base)) {
+			dev_err(dw_pci->dev, "error with ioremap\n");
+			return -ENOMEM;
+		}
+	} else {
+		dev_err(dw_pci->dev, "missing *dbi* reg space\n");
+		return -EINVAL;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(dw_pci->dev, "missing IRQ resource: %d\n", irq);
+		return irq;
+	}
+
+	ret = devm_request_irq(dw_pci->dev, irq, baikal_pcie_err_irq_handler,
+			       IRQF_SHARED | IRQF_NO_THREAD,
+			       "baikal-pcie-error-irq", pcie);
+	if (ret) {
+		dev_err(dw_pci->dev, "failed to request IRQ\n");
+		return ret;
+	}
+
+	pp->ops = &baikal_pcie_host_ops;
+	ret = dw_pcie_host_init(pp);
+	if (ret) {
+		dev_err(dw_pci->dev, "failed to initialize host\n");
+		return ret;
+	}
+	baikal_pcie_retrain_links(pp->bridge->bus);
+
+	return 0;
+}
+
+static bool has_incompat_firmware(void) {
+	bool gotcha = false;
+	struct device_node *np = NULL;
+	np = of_find_node_by_path("/soc");
+	if (np) {
+		of_node_put(np);
+	} else {
+		gotcha = true;
+	}
+	return gotcha;
+}
+
+static int baikal_pcie_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct baikal_pcie *pcie;
+	int err;
+	u32 index[2];
+	enum of_gpio_flags gpio_flags;
+	int reset_gpio;
+
+	if (has_incompat_firmware()) {
+		dev_err(dev, "detected incompatible firmware, bailing out\n");
+		return -EINVAL;
+	}
+	if (!of_match_device(of_baikal_pcie_match, dev)) {
+		return -EINVAL;
+	}
+
+	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
+	if (!pcie) {
+		return -ENOMEM;
+	}
+	pcie->pp.dev = dev;
+	pcie->pp.ops = &baikal_pcie_ops;
+
+	err = of_property_read_u32(dev->of_node, "num-lanes", &pcie->num_lanes);
+	if (err) {
+		dev_err(dev, "property num-lanes isn't found\n");
+		return -EINVAL;
+	}
+	pcie->lcru = syscon_regmap_lookup_by_phandle(dev->of_node,
+						     "baikal,pcie-lcru");
+	if (IS_ERR(pcie->lcru)) {
+		dev_err(dev, "No LCRU phandle specified\n");
+		pcie->lcru = NULL;
+		return -EINVAL;
+	}
+
+	if (of_property_read_u32_array(dev->of_node, "baikal,pcie-lcru", index, 2)) {
+		pcie->lcru = NULL;
+		return -EINVAL;
+	}
+
+	pcie->bus_nr = index[1];
+
+	pm_runtime_enable(dev);
+	err = pm_runtime_get_sync(dev);
+	if (err < 0) {
+		dev_err(dev, "pm_runtime_get_sync failed\n");
+		goto err_pm_disable;
+	}
+
+	reset_gpio = of_get_named_gpio_flags(dev->of_node, "reset-gpios", 0,
+					     &gpio_flags);
+	if (gpio_is_valid(reset_gpio)) {
+		pcie->reset_gpio = gpio_to_desc(reset_gpio);
+		pcie->reset_active_low = gpio_flags & OF_GPIO_ACTIVE_LOW;
+		snprintf(pcie->reset_name, sizeof pcie->reset_name,
+			"pcie%u-reset", pcie->bus_nr);
+	} else {
+		pcie->reset_gpio = NULL;
+	}
+
+	err = baikal_add_pcie_port(pcie, pdev);
+	if (err < 0) {
+		goto err_pm_put;
+	}
+
+	platform_set_drvdata(pdev, pcie);
+	return 0;
+
+err_pm_put:
+	pm_runtime_put(dev);
+
+err_pm_disable:
+	pm_runtime_disable(dev);
+
+	return err;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int baikal_pcie_suspend(struct device *dev)
+{
+	struct baikal_pcie *pcie = dev_get_drvdata(dev);
+	struct dw_pcie *pp = &pcie->pp;
+	u32 val;
+
+	/* Clear Memory Space Enable (MSE) bit */
+	val = dw_pcie_readl_dbi(pp, PCI_COMMAND);
+	val &= ~PCI_COMMAND_MEMORY;
+	dw_pcie_writel_dbi(pp, PCI_COMMAND, val);
+	return 0;
+}
+
+static int baikal_pcie_resume(struct device *dev)
+{
+	struct baikal_pcie *pcie = dev_get_drvdata(dev);
+	struct dw_pcie *pp = &pcie->pp;
+	u32 val;
+
+	/* Set Memory Space Enable (MSE) bit */
+	val = dw_pcie_readl_dbi(pp, PCI_COMMAND);
+	val |= PCI_COMMAND_MEMORY;
+	dw_pcie_writel_dbi(pp, PCI_COMMAND, val);
+	return 0;
+}
+
+static int baikal_pcie_suspend_noirq(struct device *dev)
+{
+	return 0;
+}
+
+static int baikal_pcie_resume_noirq(struct device *dev)
+{
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops baikal_pcie_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(baikal_pcie_suspend, baikal_pcie_resume)
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(baikal_pcie_suspend_noirq,
+				      baikal_pcie_resume_noirq)
+};
+
+static struct platform_driver baikal_pcie_driver = {
+	.driver = {
+		.name	= "baikal-pcie-v2",
+		.of_match_table = of_baikal_pcie_match,
+		.suppress_bind_attrs = true,
+		.pm	= &baikal_pcie_pm_ops,
+	},
+	.probe = baikal_pcie_probe,
+};
+
+MODULE_DEVICE_TABLE(of, of_baikal_pcie_match);
+module_platform_driver(baikal_pcie_driver);
+MODULE_LICENSE("GPL v2");
-- 
2.31.1