drivers/pci/controller/dwc/pcie-artpec6.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * PCIe host controller driver for Axis ARTPEC-6 SoC
  *
  * Author: Niklas Cassel <niklas.cassel@axis.com>
  *
  * Based on work done by Phil Edworthy <phil@edworthys.org>
  */

 #include <linux/delay.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/of_device.h>
 #include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/resource.h>
 #include <linux/signal.h>
 #include <linux/types.h>
 #include <linux/interrupt.h>
 #include <linux/mfd/syscon.h>
 #include <linux/regmap.h>

 #include "pcie-designware.h"

 #define to_artpec6_pcie(x)	dev_get_drvdata((x)->dev)

 enum artpec_pcie_variants {
 	ARTPEC6,
 	ARTPEC7,
 };

 struct artpec6_pcie {
 	struct dw_pcie		*pci;
 	struct regmap		*regmap;	/* DT axis,syscon-pcie */
 	void __iomem		*phy_base;	/* DT phy */
 	enum artpec_pcie_variants variant;
 	enum dw_pcie_device_mode mode;
 };

 struct artpec_pcie_of_data {
 	enum artpec_pcie_variants variant;
 	enum dw_pcie_device_mode mode;
 };

 static const struct of_device_id artpec6_pcie_of_match[];

 /* PCIe Port Logic registers (memory-mapped) */
 #define PL_OFFSET			0x700

 #define ACK_F_ASPM_CTRL_OFF		(PL_OFFSET + 0xc)
 #define ACK_N_FTS_MASK			GENMASK(15, 8)
 #define ACK_N_FTS(x)			(((x) << 8) & ACK_N_FTS_MASK)

 #define FAST_TRAINING_SEQ_MASK		GENMASK(7, 0)
 #define FAST_TRAINING_SEQ(x)		(((x) << 0) & FAST_TRAINING_SEQ_MASK)

 /* ARTPEC-6 specific registers */
 #define PCIECFG				0x18
 #define  PCIECFG_DBG_OEN		BIT(24)
 #define  PCIECFG_CORE_RESET_REQ		BIT(21)
 #define  PCIECFG_LTSSM_ENABLE		BIT(20)
 #define  PCIECFG_DEVICE_TYPE_MASK	GENMASK(19, 16)
 #define  PCIECFG_CLKREQ_B		BIT(11)
 #define  PCIECFG_REFCLK_ENABLE		BIT(10)
 #define  PCIECFG_PLL_ENABLE		BIT(9)
 #define  PCIECFG_PCLK_ENABLE		BIT(8)
 #define  PCIECFG_RISRCREN		BIT(4)
 #define  PCIECFG_MODE_TX_DRV_EN		BIT(3)
 #define  PCIECFG_CISRREN		BIT(2)
 #define  PCIECFG_MACRO_ENABLE		BIT(0)
 /* ARTPEC-7 specific fields */
 #define  PCIECFG_REFCLKSEL		BIT(23)
 #define  PCIECFG_NOC_RESET		BIT(3)

 #define PCIESTAT			0x1c
 /* ARTPEC-7 specific fields */
 #define  PCIESTAT_EXTREFCLK		BIT(3)

 #define NOCCFG				0x40
 #define  NOCCFG_ENABLE_CLK_PCIE		BIT(4)
 #define  NOCCFG_POWER_PCIE_IDLEACK	BIT(3)
 #define  NOCCFG_POWER_PCIE_IDLE		BIT(2)
 #define  NOCCFG_POWER_PCIE_IDLEREQ	BIT(1)

 #define PHY_STATUS			0x118
 #define  PHY_COSPLLLOCK			BIT(0)

 #define PHY_TX_ASIC_OUT			0x4040
 #define  PHY_TX_ASIC_OUT_TX_ACK		BIT(0)

 #define PHY_RX_ASIC_OUT			0x405c
 #define  PHY_RX_ASIC_OUT_ACK		BIT(0)

 static u32 artpec6_pcie_readl(struct artpec6_pcie *artpec6_pcie, u32 offset)
 {
 	u32 val;

 	regmap_read(artpec6_pcie->regmap, offset, &val);
 	return val;
 }

 static void artpec6_pcie_writel(struct artpec6_pcie *artpec6_pcie, u32 offset, u32 val)
 {
 	regmap_write(artpec6_pcie->regmap, offset, val);
 }

 static u64 artpec6_pcie_cpu_addr_fixup(struct dw_pcie *pci, u64 pci_addr)
 {
 	struct artpec6_pcie *artpec6_pcie = to_artpec6_pcie(pci);
 	struct pcie_port *pp = &pci->pp;
 	struct dw_pcie_ep *ep = &pci->ep;

 	switch (artpec6_pcie->mode) {
 	case DW_PCIE_RC_TYPE:
 		return pci_addr - pp->cfg0_base;
 	case DW_PCIE_EP_TYPE:
 		return pci_addr - ep->phys_base;
 	default:
 		dev_err(pci->dev, "UNKNOWN device type\n");
 	}
 	return pci_addr;
 }

 static int artpec6_pcie_establish_link(struct dw_pcie *pci)
 {
 	struct artpec6_pcie *artpec6_pcie = to_artpec6_pcie(pci);
 	u32 val;

 	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
 	val |= PCIECFG_LTSSM_ENABLE;
 	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);

 	return 0;
 }

 static void artpec6_pcie_stop_link(struct dw_pcie *pci)
 {
 	struct artpec6_pcie *artpec6_pcie = to_artpec6_pcie(pci);
 	u32 val;

 	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
 	val &= ~PCIECFG_LTSSM_ENABLE;
 	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
 }

 static const struct dw_pcie_ops dw_pcie_ops = {
 	.cpu_addr_fixup = artpec6_pcie_cpu_addr_fixup,
 	.start_link = artpec6_pcie_establish_link,
 	.stop_link = artpec6_pcie_stop_link,
 };

 static void artpec6_pcie_wait_for_phy_a6(struct artpec6_pcie *artpec6_pcie)
 {
 	struct dw_pcie *pci = artpec6_pcie->pci;
 	struct device *dev = pci->dev;
 	u32 val;
 	unsigned int retries;

 	retries = 50;
 	do {
 		usleep_range(1000, 2000);
 		val = artpec6_pcie_readl(artpec6_pcie, NOCCFG);
 		retries--;
 	} while (retries &&
 		(val & (NOCCFG_POWER_PCIE_IDLEACK | NOCCFG_POWER_PCIE_IDLE)));
 	if (!retries)
 		dev_err(dev, "PCIe clock manager did not leave idle state\n");

 	retries = 50;
 	do {
 		usleep_range(1000, 2000);
 		val = readl(artpec6_pcie->phy_base + PHY_STATUS);
 		retries--;
 	} while (retries && !(val & PHY_COSPLLLOCK));
 	if (!retries)
 		dev_err(dev, "PHY PLL did not lock\n");
 }

 static void artpec6_pcie_wait_for_phy_a7(struct artpec6_pcie *artpec6_pcie)
 {
 	struct dw_pcie *pci = artpec6_pcie->pci;
 	struct device *dev = pci->dev;
 	u32 val;
 	u16 phy_status_tx, phy_status_rx;
 	unsigned int retries;

 	retries = 50;
 	do {
 		usleep_range(1000, 2000);
 		val = artpec6_pcie_readl(artpec6_pcie, NOCCFG);
 		retries--;
 	} while (retries &&
 		(val & (NOCCFG_POWER_PCIE_IDLEACK | NOCCFG_POWER_PCIE_IDLE)));
 	if (!retries)
 		dev_err(dev, "PCIe clock manager did not leave idle state\n");

 	retries = 50;
 	do {
 		usleep_range(1000, 2000);
 		phy_status_tx = readw(artpec6_pcie->phy_base + PHY_TX_ASIC_OUT);
 		phy_status_rx = readw(artpec6_pcie->phy_base + PHY_RX_ASIC_OUT);
 		retries--;
 	} while (retries && ((phy_status_tx & PHY_TX_ASIC_OUT_TX_ACK) ||
 				(phy_status_rx & PHY_RX_ASIC_OUT_ACK)));
 	if (!retries)
 		dev_err(dev, "PHY did not enter Pn state\n");
 }

 static void artpec6_pcie_wait_for_phy(struct artpec6_pcie *artpec6_pcie)
 {
 	switch (artpec6_pcie->variant) {
 	case ARTPEC6:
 		artpec6_pcie_wait_for_phy_a6(artpec6_pcie);
 		break;
 	case ARTPEC7:
 		artpec6_pcie_wait_for_phy_a7(artpec6_pcie);
 		break;
 	}
 }

 static void artpec6_pcie_init_phy_a6(struct artpec6_pcie *artpec6_pcie)
 {
 	u32 val;

 	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
 	val |=  PCIECFG_RISRCREN |	/* Receiver term. 50 Ohm */
 		PCIECFG_MODE_TX_DRV_EN |
 		PCIECFG_CISRREN |	/* Reference clock term. 100 Ohm */
 		PCIECFG_MACRO_ENABLE;
 	val |= PCIECFG_REFCLK_ENABLE;
 	val &= ~PCIECFG_DBG_OEN;
 	val &= ~PCIECFG_CLKREQ_B;
 	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
 	usleep_range(5000, 6000);

 	val = artpec6_pcie_readl(artpec6_pcie, NOCCFG);
 	val |= NOCCFG_ENABLE_CLK_PCIE;
 	artpec6_pcie_writel(artpec6_pcie, NOCCFG, val);
 	usleep_range(20, 30);

 	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
 	val |= PCIECFG_PCLK_ENABLE | PCIECFG_PLL_ENABLE;
 	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
 	usleep_range(6000, 7000);

 	val = artpec6_pcie_readl(artpec6_pcie, NOCCFG);
 	val &= ~NOCCFG_POWER_PCIE_IDLEREQ;
 	artpec6_pcie_writel(artpec6_pcie, NOCCFG, val);
 }

 static void artpec6_pcie_init_phy_a7(struct artpec6_pcie *artpec6_pcie)
 {
 	struct dw_pcie *pci = artpec6_pcie->pci;
 	u32 val;
 	bool extrefclk;

 	/* Check if external reference clock is connected */
 	val = artpec6_pcie_readl(artpec6_pcie, PCIESTAT);
 	extrefclk = !!(val & PCIESTAT_EXTREFCLK);
 	dev_dbg(pci->dev, "Using reference clock: %s\n",
 		extrefclk ? "external" : "internal");

 	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
 	val |=  PCIECFG_RISRCREN |	/* Receiver term. 50 Ohm */
 		PCIECFG_PCLK_ENABLE;
 	if (extrefclk)
 		val |= PCIECFG_REFCLKSEL;
 	else
 		val &= ~PCIECFG_REFCLKSEL;
 	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
 	usleep_range(10, 20);

 	val = artpec6_pcie_readl(artpec6_pcie, NOCCFG);
 	val |= NOCCFG_ENABLE_CLK_PCIE;
 	artpec6_pcie_writel(artpec6_pcie, NOCCFG, val);
 	usleep_range(20, 30);

 	val = artpec6_pcie_readl(artpec6_pcie, NOCCFG);
 	val &= ~NOCCFG_POWER_PCIE_IDLEREQ;
 	artpec6_pcie_writel(artpec6_pcie, NOCCFG, val);
 }

 static void artpec6_pcie_init_phy(struct artpec6_pcie *artpec6_pcie)
 {
 	switch (artpec6_pcie->variant) {
 	case ARTPEC6:
 		artpec6_pcie_init_phy_a6(artpec6_pcie);
 		break;
 	case ARTPEC7:
 		artpec6_pcie_init_phy_a7(artpec6_pcie);
 		break;
 	}
 }

 static void artpec6_pcie_set_nfts(struct artpec6_pcie *artpec6_pcie)
 {
 	struct dw_pcie *pci = artpec6_pcie->pci;
 	u32 val;

 	if (artpec6_pcie->variant != ARTPEC7)
 		return;

 	/*
 	 * Increase the N_FTS (Number of Fast Training Sequences)
 	 * to be transmitted when transitioning from L0s to L0.
 	 */
 	val = dw_pcie_readl_dbi(pci, ACK_F_ASPM_CTRL_OFF);
 	val &= ~ACK_N_FTS_MASK;
 	val |= ACK_N_FTS(180);
 	dw_pcie_writel_dbi(pci, ACK_F_ASPM_CTRL_OFF, val);

 	/*
 	 * Set the Number of Fast Training Sequences that the core
 	 * advertises as its N_FTS during Gen2 or Gen3 link training.
 	 */
 	val = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
 	val &= ~FAST_TRAINING_SEQ_MASK;
 	val |= FAST_TRAINING_SEQ(180);
 	dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, val);
 }

 static void artpec6_pcie_assert_core_reset(struct artpec6_pcie *artpec6_pcie)
 {
 	u32 val;

 	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
 	switch (artpec6_pcie->variant) {
 	case ARTPEC6:
 		val |= PCIECFG_CORE_RESET_REQ;
 		break;
 	case ARTPEC7:
 		val &= ~PCIECFG_NOC_RESET;
 		break;
 	}
 	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
 }

 static void artpec6_pcie_deassert_core_reset(struct artpec6_pcie *artpec6_pcie)
 {
 	u32 val;

 	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
 	switch (artpec6_pcie->variant) {
 	case ARTPEC6:
 		val &= ~PCIECFG_CORE_RESET_REQ;
 		break;
 	case ARTPEC7:
 		val |= PCIECFG_NOC_RESET;
 		break;
 	}
 	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
 	usleep_range(100, 200);
 }

 static void artpec6_pcie_enable_interrupts(struct artpec6_pcie *artpec6_pcie)
 {
 	struct dw_pcie *pci = artpec6_pcie->pci;
 	struct pcie_port *pp = &pci->pp;

 	if (IS_ENABLED(CONFIG_PCI_MSI))
 		dw_pcie_msi_init(pp);
 }

 static int artpec6_pcie_host_init(struct pcie_port *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
 	struct artpec6_pcie *artpec6_pcie = to_artpec6_pcie(pci);

 	artpec6_pcie_assert_core_reset(artpec6_pcie);
 	artpec6_pcie_init_phy(artpec6_pcie);
 	artpec6_pcie_deassert_core_reset(artpec6_pcie);
 	artpec6_pcie_wait_for_phy(artpec6_pcie);
 	artpec6_pcie_set_nfts(artpec6_pcie);
 	dw_pcie_setup_rc(pp);
 	artpec6_pcie_establish_link(pci);
 	dw_pcie_wait_for_link(pci);
 	artpec6_pcie_enable_interrupts(artpec6_pcie);

 	return 0;
 }

 static const struct dw_pcie_host_ops artpec6_pcie_host_ops = {
 	.host_init = artpec6_pcie_host_init,
 };

 static int artpec6_add_pcie_port(struct artpec6_pcie *artpec6_pcie,
 				 struct platform_device *pdev)
 {
 	struct dw_pcie *pci = artpec6_pcie->pci;
 	struct pcie_port *pp = &pci->pp;
 	struct device *dev = pci->dev;
 	int ret;

 	if (IS_ENABLED(CONFIG_PCI_MSI)) {
 		pp->msi_irq = platform_get_irq_byname(pdev, "msi");
 		if (pp->msi_irq < 0) {
 			dev_err(dev, "failed to get MSI irq\n");
 			return pp->msi_irq;
 		}
 	}

 	pp->ops = &artpec6_pcie_host_ops;

 	ret = dw_pcie_host_init(pp);
 	if (ret) {
 		dev_err(dev, "failed to initialize host\n");
 		return ret;
 	}

 	return 0;
 }

 static void artpec6_pcie_ep_init(struct dw_pcie_ep *ep)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 	struct artpec6_pcie *artpec6_pcie = to_artpec6_pcie(pci);
 	enum pci_barno bar;

 	artpec6_pcie_assert_core_reset(artpec6_pcie);
 	artpec6_pcie_init_phy(artpec6_pcie);
 	artpec6_pcie_deassert_core_reset(artpec6_pcie);
 	artpec6_pcie_wait_for_phy(artpec6_pcie);
 	artpec6_pcie_set_nfts(artpec6_pcie);

 	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++)
 		dw_pcie_ep_reset_bar(pci, bar);
 }

 static int artpec6_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
 				  enum pci_epc_irq_type type, u16 interrupt_num)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);

 	switch (type) {
 	case PCI_EPC_IRQ_LEGACY:
 		dev_err(pci->dev, "EP cannot trigger legacy IRQs\n");
 		return -EINVAL;
 	case PCI_EPC_IRQ_MSI:
 		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
 	default:
 		dev_err(pci->dev, "UNKNOWN IRQ type\n");
 	}

 	return 0;
 }

 static const struct dw_pcie_ep_ops pcie_ep_ops = {
 	.ep_init = artpec6_pcie_ep_init,
 	.raise_irq = artpec6_pcie_raise_irq,
 };

 static int artpec6_add_pcie_ep(struct artpec6_pcie *artpec6_pcie,
 			       struct platform_device *pdev)
 {
 	int ret;
 	struct dw_pcie_ep *ep;
 	struct resource *res;
 	struct device *dev = &pdev->dev;
 	struct dw_pcie *pci = artpec6_pcie->pci;

 	ep = &pci->ep;
 	ep->ops = &pcie_ep_ops;

 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi2");
 	pci->dbi_base2 = devm_ioremap_resource(dev, res);
 	if (IS_ERR(pci->dbi_base2))
 		return PTR_ERR(pci->dbi_base2);

 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "addr_space");
 	if (!res)
 		return -EINVAL;

 	ep->phys_base = res->start;
 	ep->addr_size = resource_size(res);

 	ret = dw_pcie_ep_init(ep);
 	if (ret) {
 		dev_err(dev, "failed to initialize endpoint\n");
 		return ret;
 	}

 	return 0;
 }

 static int artpec6_pcie_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct dw_pcie *pci;
 	struct artpec6_pcie *artpec6_pcie;
 	struct resource *dbi_base;
 	struct resource *phy_base;
 	int ret;
 	const struct of_device_id *match;
 	const struct artpec_pcie_of_data *data;
 	enum artpec_pcie_variants variant;
 	enum dw_pcie_device_mode mode;

 	match = of_match_device(artpec6_pcie_of_match, dev);
 	if (!match)
 		return -EINVAL;

 	data = (struct artpec_pcie_of_data *)match->data;
 	variant = (enum artpec_pcie_variants)data->variant;
 	mode = (enum dw_pcie_device_mode)data->mode;

 	artpec6_pcie = devm_kzalloc(dev, sizeof(*artpec6_pcie), GFP_KERNEL);
 	if (!artpec6_pcie)
 		return -ENOMEM;

 	pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
 	if (!pci)
 		return -ENOMEM;

 	pci->dev = dev;
 	pci->ops = &dw_pcie_ops;

 	artpec6_pcie->pci = pci;
 	artpec6_pcie->variant = variant;
 	artpec6_pcie->mode = mode;

 	dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
 	pci->dbi_base = devm_ioremap_resource(dev, dbi_base);
 	if (IS_ERR(pci->dbi_base))
 		return PTR_ERR(pci->dbi_base);

 	phy_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "phy");
 	artpec6_pcie->phy_base = devm_ioremap_resource(dev, phy_base);
 	if (IS_ERR(artpec6_pcie->phy_base))
 		return PTR_ERR(artpec6_pcie->phy_base);

 	artpec6_pcie->regmap =
 		syscon_regmap_lookup_by_phandle(dev->of_node,
 						"axis,syscon-pcie");
 	if (IS_ERR(artpec6_pcie->regmap))
 		return PTR_ERR(artpec6_pcie->regmap);

 	platform_set_drvdata(pdev, artpec6_pcie);

 	switch (artpec6_pcie->mode) {
 	case DW_PCIE_RC_TYPE:
 		if (!IS_ENABLED(CONFIG_PCIE_ARTPEC6_HOST))
 			return -ENODEV;

 		ret = artpec6_add_pcie_port(artpec6_pcie, pdev);
 		if (ret < 0)
 			return ret;
 		break;
 	case DW_PCIE_EP_TYPE: {
 		u32 val;

 		if (!IS_ENABLED(CONFIG_PCIE_ARTPEC6_EP))
 			return -ENODEV;

 		val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
 		val &= ~PCIECFG_DEVICE_TYPE_MASK;
 		artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
 		ret = artpec6_add_pcie_ep(artpec6_pcie, pdev);
 		if (ret < 0)
 			return ret;
 		break;
 	}
 	default:
 		dev_err(dev, "INVALID device type %d\n", artpec6_pcie->mode);
 	}

 	return 0;
 }

 static const struct artpec_pcie_of_data artpec6_pcie_rc_of_data = {
 	.variant = ARTPEC6,
 	.mode = DW_PCIE_RC_TYPE,
 };

 static const struct artpec_pcie_of_data artpec6_pcie_ep_of_data = {
 	.variant = ARTPEC6,
 	.mode = DW_PCIE_EP_TYPE,
 };

 static const struct artpec_pcie_of_data artpec7_pcie_rc_of_data = {
 	.variant = ARTPEC7,
 	.mode = DW_PCIE_RC_TYPE,
 };

 static const struct artpec_pcie_of_data artpec7_pcie_ep_of_data = {
 	.variant = ARTPEC7,
 	.mode = DW_PCIE_EP_TYPE,
 };

 static const struct of_device_id artpec6_pcie_of_match[] = {
 	{
 		.compatible = "axis,artpec6-pcie",
 		.data = &artpec6_pcie_rc_of_data,
 	},
 	{
 		.compatible = "axis,artpec6-pcie-ep",
 		.data = &artpec6_pcie_ep_of_data,
 	},
 	{
 		.compatible = "axis,artpec7-pcie",
 		.data = &artpec7_pcie_rc_of_data,
 	},
 	{
 		.compatible = "axis,artpec7-pcie-ep",
 		.data = &artpec7_pcie_ep_of_data,
 	},
 	{},
 };

 static struct platform_driver artpec6_pcie_driver = {
 	.probe = artpec6_pcie_probe,
 	.driver = {
 		.name	= "artpec6-pcie",
 		.of_match_table = artpec6_pcie_of_match,
 		.suppress_bind_attrs = true,
 	},
 };
 builtin_platform_driver(artpec6_pcie_driver);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* PCIe host controller driver for Axis ARTPEC-6 SoC
	*
	* Author: Niklas Cassel <niklas.cassel@axis.com>
	*
	* Based on work done by Phil Edworthy <phil@edworthys.org>
	*/

	#include <linux/delay.h>
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/of_device.h>
	#include <linux/pci.h>
	#include <linux/platform_device.h>
	#include <linux/resource.h>
	#include <linux/signal.h>
	#include <linux/types.h>
	#include <linux/interrupt.h>
	#include <linux/mfd/syscon.h>
	#include <linux/regmap.h>

	#include "pcie-designware.h"

	#define to_artpec6_pcie(x) dev_get_drvdata((x)->dev)

	enum artpec_pcie_variants {
	ARTPEC6,
	ARTPEC7,
	};

	struct artpec6_pcie {
	struct dw_pcie *pci;
	struct regmap regmap; / DT axis,syscon-pcie */
	void __iomem phy_base; / DT phy */
	enum artpec_pcie_variants variant;
	enum dw_pcie_device_mode mode;
	};

	struct artpec_pcie_of_data {
	enum artpec_pcie_variants variant;
	enum dw_pcie_device_mode mode;
	};

	static const struct of_device_id artpec6_pcie_of_match[];

	/* PCIe Port Logic registers (memory-mapped) */
	#define PL_OFFSET 0x700

	#define ACK_F_ASPM_CTRL_OFF (PL_OFFSET + 0xc)
	#define ACK_N_FTS_MASK GENMASK(15, 8)
	#define ACK_N_FTS(x) (((x) << 8) & ACK_N_FTS_MASK)

	#define FAST_TRAINING_SEQ_MASK GENMASK(7, 0)
	#define FAST_TRAINING_SEQ(x) (((x) << 0) & FAST_TRAINING_SEQ_MASK)

	/* ARTPEC-6 specific registers */
	#define PCIECFG 0x18
	#define PCIECFG_DBG_OEN BIT(24)
	#define PCIECFG_CORE_RESET_REQ BIT(21)
	#define PCIECFG_LTSSM_ENABLE BIT(20)
	#define PCIECFG_DEVICE_TYPE_MASK GENMASK(19, 16)
	#define PCIECFG_CLKREQ_B BIT(11)
	#define PCIECFG_REFCLK_ENABLE BIT(10)
	#define PCIECFG_PLL_ENABLE BIT(9)
	#define PCIECFG_PCLK_ENABLE BIT(8)
	#define PCIECFG_RISRCREN BIT(4)
	#define PCIECFG_MODE_TX_DRV_EN BIT(3)
	#define PCIECFG_CISRREN BIT(2)
	#define PCIECFG_MACRO_ENABLE BIT(0)
	/* ARTPEC-7 specific fields */
	#define PCIECFG_REFCLKSEL BIT(23)
	#define PCIECFG_NOC_RESET BIT(3)

	#define PCIESTAT 0x1c
	/* ARTPEC-7 specific fields */
	#define PCIESTAT_EXTREFCLK BIT(3)

	#define NOCCFG 0x40
	#define NOCCFG_ENABLE_CLK_PCIE BIT(4)
	#define NOCCFG_POWER_PCIE_IDLEACK BIT(3)
	#define NOCCFG_POWER_PCIE_IDLE BIT(2)
	#define NOCCFG_POWER_PCIE_IDLEREQ BIT(1)

	#define PHY_STATUS 0x118
	#define PHY_COSPLLLOCK BIT(0)

	#define PHY_TX_ASIC_OUT 0x4040
	#define PHY_TX_ASIC_OUT_TX_ACK BIT(0)

	#define PHY_RX_ASIC_OUT 0x405c
	#define PHY_RX_ASIC_OUT_ACK BIT(0)

	static u32 artpec6_pcie_readl(struct artpec6_pcie *artpec6_pcie, u32 offset)
	{
	u32 val;

	regmap_read(artpec6_pcie->regmap, offset, &val);
	return val;
	}

	static void artpec6_pcie_writel(struct artpec6_pcie *artpec6_pcie, u32 offset, u32 val)
	{
	regmap_write(artpec6_pcie->regmap, offset, val);
	}

	static u64 artpec6_pcie_cpu_addr_fixup(struct dw_pcie *pci, u64 pci_addr)
	{
	struct artpec6_pcie *artpec6_pcie = to_artpec6_pcie(pci);
	struct pcie_port *pp = &pci->pp;
	struct dw_pcie_ep *ep = &pci->ep;

	switch (artpec6_pcie->mode) {
	case DW_PCIE_RC_TYPE:
	return pci_addr - pp->cfg0_base;
	case DW_PCIE_EP_TYPE:
	return pci_addr - ep->phys_base;
	default:
	dev_err(pci->dev, "UNKNOWN device type\n");
	}
	return pci_addr;
	}

	static int artpec6_pcie_establish_link(struct dw_pcie *pci)
	{
	struct artpec6_pcie *artpec6_pcie = to_artpec6_pcie(pci);
	u32 val;

	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
	val \|= PCIECFG_LTSSM_ENABLE;
	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);

	return 0;
	}

	static void artpec6_pcie_stop_link(struct dw_pcie *pci)
	{
	struct artpec6_pcie *artpec6_pcie = to_artpec6_pcie(pci);
	u32 val;

	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
	val &= ~PCIECFG_LTSSM_ENABLE;
	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
	}

	static const struct dw_pcie_ops dw_pcie_ops = {
	.cpu_addr_fixup = artpec6_pcie_cpu_addr_fixup,
	.start_link = artpec6_pcie_establish_link,
	.stop_link = artpec6_pcie_stop_link,
	};

	static void artpec6_pcie_wait_for_phy_a6(struct artpec6_pcie *artpec6_pcie)
	{
	struct dw_pcie *pci = artpec6_pcie->pci;
	struct device *dev = pci->dev;
	u32 val;
	unsigned int retries;

	retries = 50;
	do {
	usleep_range(1000, 2000);
	val = artpec6_pcie_readl(artpec6_pcie, NOCCFG);
	retries--;
	} while (retries &&
	(val & (NOCCFG_POWER_PCIE_IDLEACK \| NOCCFG_POWER_PCIE_IDLE)));
	if (!retries)
	dev_err(dev, "PCIe clock manager did not leave idle state\n");

	retries = 50;
	do {
	usleep_range(1000, 2000);
	val = readl(artpec6_pcie->phy_base + PHY_STATUS);
	retries--;
	} while (retries && !(val & PHY_COSPLLLOCK));
	if (!retries)
	dev_err(dev, "PHY PLL did not lock\n");
	}

	static void artpec6_pcie_wait_for_phy_a7(struct artpec6_pcie *artpec6_pcie)
	{
	struct dw_pcie *pci = artpec6_pcie->pci;
	struct device *dev = pci->dev;
	u32 val;
	u16 phy_status_tx, phy_status_rx;
	unsigned int retries;

	retries = 50;
	do {
	usleep_range(1000, 2000);
	val = artpec6_pcie_readl(artpec6_pcie, NOCCFG);
	retries--;
	} while (retries &&
	(val & (NOCCFG_POWER_PCIE_IDLEACK \| NOCCFG_POWER_PCIE_IDLE)));
	if (!retries)
	dev_err(dev, "PCIe clock manager did not leave idle state\n");

	retries = 50;
	do {
	usleep_range(1000, 2000);
	phy_status_tx = readw(artpec6_pcie->phy_base + PHY_TX_ASIC_OUT);
	phy_status_rx = readw(artpec6_pcie->phy_base + PHY_RX_ASIC_OUT);
	retries--;
	} while (retries && ((phy_status_tx & PHY_TX_ASIC_OUT_TX_ACK) \|\|
	(phy_status_rx & PHY_RX_ASIC_OUT_ACK)));
	if (!retries)
	dev_err(dev, "PHY did not enter Pn state\n");
	}

	static void artpec6_pcie_wait_for_phy(struct artpec6_pcie *artpec6_pcie)
	{
	switch (artpec6_pcie->variant) {
	case ARTPEC6:
	artpec6_pcie_wait_for_phy_a6(artpec6_pcie);
	break;
	case ARTPEC7:
	artpec6_pcie_wait_for_phy_a7(artpec6_pcie);
	break;
	}
	}

	static void artpec6_pcie_init_phy_a6(struct artpec6_pcie *artpec6_pcie)
	{
	u32 val;

	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
	val \|= PCIECFG_RISRCREN \| /* Receiver term. 50 Ohm */
	PCIECFG_MODE_TX_DRV_EN \|
	PCIECFG_CISRREN \| /* Reference clock term. 100 Ohm */
	PCIECFG_MACRO_ENABLE;
	val \|= PCIECFG_REFCLK_ENABLE;
	val &= ~PCIECFG_DBG_OEN;
	val &= ~PCIECFG_CLKREQ_B;
	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
	usleep_range(5000, 6000);

	val = artpec6_pcie_readl(artpec6_pcie, NOCCFG);
	val \|= NOCCFG_ENABLE_CLK_PCIE;
	artpec6_pcie_writel(artpec6_pcie, NOCCFG, val);
	usleep_range(20, 30);

	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
	val \|= PCIECFG_PCLK_ENABLE \| PCIECFG_PLL_ENABLE;
	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
	usleep_range(6000, 7000);

	val = artpec6_pcie_readl(artpec6_pcie, NOCCFG);
	val &= ~NOCCFG_POWER_PCIE_IDLEREQ;
	artpec6_pcie_writel(artpec6_pcie, NOCCFG, val);
	}

	static void artpec6_pcie_init_phy_a7(struct artpec6_pcie *artpec6_pcie)
	{
	struct dw_pcie *pci = artpec6_pcie->pci;
	u32 val;
	bool extrefclk;

	/* Check if external reference clock is connected */
	val = artpec6_pcie_readl(artpec6_pcie, PCIESTAT);
	extrefclk = !!(val & PCIESTAT_EXTREFCLK);
	dev_dbg(pci->dev, "Using reference clock: %s\n",
	extrefclk ? "external" : "internal");

	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
	val \|= PCIECFG_RISRCREN \| /* Receiver term. 50 Ohm */
	PCIECFG_PCLK_ENABLE;
	if (extrefclk)
	val \|= PCIECFG_REFCLKSEL;
	else
	val &= ~PCIECFG_REFCLKSEL;
	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
	usleep_range(10, 20);

	val = artpec6_pcie_readl(artpec6_pcie, NOCCFG);
	val \|= NOCCFG_ENABLE_CLK_PCIE;
	artpec6_pcie_writel(artpec6_pcie, NOCCFG, val);
	usleep_range(20, 30);

	val = artpec6_pcie_readl(artpec6_pcie, NOCCFG);
	val &= ~NOCCFG_POWER_PCIE_IDLEREQ;
	artpec6_pcie_writel(artpec6_pcie, NOCCFG, val);
	}

	static void artpec6_pcie_init_phy(struct artpec6_pcie *artpec6_pcie)
	{
	switch (artpec6_pcie->variant) {
	case ARTPEC6:
	artpec6_pcie_init_phy_a6(artpec6_pcie);
	break;
	case ARTPEC7:
	artpec6_pcie_init_phy_a7(artpec6_pcie);
	break;
	}
	}

	static void artpec6_pcie_set_nfts(struct artpec6_pcie *artpec6_pcie)
	{
	struct dw_pcie *pci = artpec6_pcie->pci;
	u32 val;

	if (artpec6_pcie->variant != ARTPEC7)
	return;

	/*
	* Increase the N_FTS (Number of Fast Training Sequences)
	* to be transmitted when transitioning from L0s to L0.
	*/
	val = dw_pcie_readl_dbi(pci, ACK_F_ASPM_CTRL_OFF);
	val &= ~ACK_N_FTS_MASK;
	val \|= ACK_N_FTS(180);
	dw_pcie_writel_dbi(pci, ACK_F_ASPM_CTRL_OFF, val);

	/*
	* Set the Number of Fast Training Sequences that the core
	* advertises as its N_FTS during Gen2 or Gen3 link training.
	*/
	val = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
	val &= ~FAST_TRAINING_SEQ_MASK;
	val \|= FAST_TRAINING_SEQ(180);
	dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, val);
	}

	static void artpec6_pcie_assert_core_reset(struct artpec6_pcie *artpec6_pcie)
	{
	u32 val;

	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
	switch (artpec6_pcie->variant) {
	case ARTPEC6:
	val \|= PCIECFG_CORE_RESET_REQ;
	break;
	case ARTPEC7:
	val &= ~PCIECFG_NOC_RESET;
	break;
	}
	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
	}

	static void artpec6_pcie_deassert_core_reset(struct artpec6_pcie *artpec6_pcie)
	{
	u32 val;

	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
	switch (artpec6_pcie->variant) {
	case ARTPEC6:
	val &= ~PCIECFG_CORE_RESET_REQ;
	break;
	case ARTPEC7:
	val \|= PCIECFG_NOC_RESET;
	break;
	}
	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
	usleep_range(100, 200);
	}

	static void artpec6_pcie_enable_interrupts(struct artpec6_pcie *artpec6_pcie)
	{
	struct dw_pcie *pci = artpec6_pcie->pci;
	struct pcie_port *pp = &pci->pp;

	if (IS_ENABLED(CONFIG_PCI_MSI))
	dw_pcie_msi_init(pp);
	}

	static int artpec6_pcie_host_init(struct pcie_port *pp)
	{
	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
	struct artpec6_pcie *artpec6_pcie = to_artpec6_pcie(pci);

	artpec6_pcie_assert_core_reset(artpec6_pcie);
	artpec6_pcie_init_phy(artpec6_pcie);
	artpec6_pcie_deassert_core_reset(artpec6_pcie);
	artpec6_pcie_wait_for_phy(artpec6_pcie);
	artpec6_pcie_set_nfts(artpec6_pcie);
	dw_pcie_setup_rc(pp);
	artpec6_pcie_establish_link(pci);
	dw_pcie_wait_for_link(pci);
	artpec6_pcie_enable_interrupts(artpec6_pcie);

	return 0;
	}

	static const struct dw_pcie_host_ops artpec6_pcie_host_ops = {
	.host_init = artpec6_pcie_host_init,
	};

	static int artpec6_add_pcie_port(struct artpec6_pcie *artpec6_pcie,
	struct platform_device *pdev)
	{
	struct dw_pcie *pci = artpec6_pcie->pci;
	struct pcie_port *pp = &pci->pp;
	struct device *dev = pci->dev;
	int ret;

	if (IS_ENABLED(CONFIG_PCI_MSI)) {
	pp->msi_irq = platform_get_irq_byname(pdev, "msi");
	if (pp->msi_irq < 0) {
	dev_err(dev, "failed to get MSI irq\n");
	return pp->msi_irq;
	}
	}

	pp->ops = &artpec6_pcie_host_ops;

	ret = dw_pcie_host_init(pp);
	if (ret) {
	dev_err(dev, "failed to initialize host\n");
	return ret;
	}

	return 0;
	}

	static void artpec6_pcie_ep_init(struct dw_pcie_ep *ep)
	{
	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
	struct artpec6_pcie *artpec6_pcie = to_artpec6_pcie(pci);
	enum pci_barno bar;

	artpec6_pcie_assert_core_reset(artpec6_pcie);
	artpec6_pcie_init_phy(artpec6_pcie);
	artpec6_pcie_deassert_core_reset(artpec6_pcie);
	artpec6_pcie_wait_for_phy(artpec6_pcie);
	artpec6_pcie_set_nfts(artpec6_pcie);

	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++)
	dw_pcie_ep_reset_bar(pci, bar);
	}

	static int artpec6_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
	enum pci_epc_irq_type type, u16 interrupt_num)
	{
	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);

	switch (type) {
	case PCI_EPC_IRQ_LEGACY:
	dev_err(pci->dev, "EP cannot trigger legacy IRQs\n");
	return -EINVAL;
	case PCI_EPC_IRQ_MSI:
	return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
	default:
	dev_err(pci->dev, "UNKNOWN IRQ type\n");
	}

	return 0;
	}

	static const struct dw_pcie_ep_ops pcie_ep_ops = {
	.ep_init = artpec6_pcie_ep_init,
	.raise_irq = artpec6_pcie_raise_irq,
	};

	static int artpec6_add_pcie_ep(struct artpec6_pcie *artpec6_pcie,
	struct platform_device *pdev)
	{
	int ret;
	struct dw_pcie_ep *ep;
	struct resource *res;
	struct device *dev = &pdev->dev;
	struct dw_pcie *pci = artpec6_pcie->pci;

	ep = &pci->ep;
	ep->ops = &pcie_ep_ops;

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi2");
	pci->dbi_base2 = devm_ioremap_resource(dev, res);
	if (IS_ERR(pci->dbi_base2))
	return PTR_ERR(pci->dbi_base2);

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "addr_space");
	if (!res)
	return -EINVAL;

	ep->phys_base = res->start;
	ep->addr_size = resource_size(res);

	ret = dw_pcie_ep_init(ep);
	if (ret) {
	dev_err(dev, "failed to initialize endpoint\n");
	return ret;
	}

	return 0;
	}

	static int artpec6_pcie_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct dw_pcie *pci;
	struct artpec6_pcie *artpec6_pcie;
	struct resource *dbi_base;
	struct resource *phy_base;
	int ret;
	const struct of_device_id *match;
	const struct artpec_pcie_of_data *data;
	enum artpec_pcie_variants variant;
	enum dw_pcie_device_mode mode;

	match = of_match_device(artpec6_pcie_of_match, dev);
	if (!match)
	return -EINVAL;

	data = (struct artpec_pcie_of_data *)match->data;
	variant = (enum artpec_pcie_variants)data->variant;
	mode = (enum dw_pcie_device_mode)data->mode;

	artpec6_pcie = devm_kzalloc(dev, sizeof(*artpec6_pcie), GFP_KERNEL);
	if (!artpec6_pcie)
	return -ENOMEM;

	pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
	if (!pci)
	return -ENOMEM;

	pci->dev = dev;
	pci->ops = &dw_pcie_ops;

	artpec6_pcie->pci = pci;
	artpec6_pcie->variant = variant;
	artpec6_pcie->mode = mode;

	dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
	pci->dbi_base = devm_ioremap_resource(dev, dbi_base);
	if (IS_ERR(pci->dbi_base))
	return PTR_ERR(pci->dbi_base);

	phy_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "phy");
	artpec6_pcie->phy_base = devm_ioremap_resource(dev, phy_base);
	if (IS_ERR(artpec6_pcie->phy_base))
	return PTR_ERR(artpec6_pcie->phy_base);

	artpec6_pcie->regmap =
	syscon_regmap_lookup_by_phandle(dev->of_node,
	"axis,syscon-pcie");
	if (IS_ERR(artpec6_pcie->regmap))
	return PTR_ERR(artpec6_pcie->regmap);

	platform_set_drvdata(pdev, artpec6_pcie);

	switch (artpec6_pcie->mode) {
	case DW_PCIE_RC_TYPE:
	if (!IS_ENABLED(CONFIG_PCIE_ARTPEC6_HOST))
	return -ENODEV;

	ret = artpec6_add_pcie_port(artpec6_pcie, pdev);
	if (ret < 0)
	return ret;
	break;
	case DW_PCIE_EP_TYPE: {
	u32 val;

	if (!IS_ENABLED(CONFIG_PCIE_ARTPEC6_EP))
	return -ENODEV;

	val = artpec6_pcie_readl(artpec6_pcie, PCIECFG);
	val &= ~PCIECFG_DEVICE_TYPE_MASK;
	artpec6_pcie_writel(artpec6_pcie, PCIECFG, val);
	ret = artpec6_add_pcie_ep(artpec6_pcie, pdev);
	if (ret < 0)
	return ret;
	break;
	}
	default:
	dev_err(dev, "INVALID device type %d\n", artpec6_pcie->mode);
	}

	return 0;
	}

	static const struct artpec_pcie_of_data artpec6_pcie_rc_of_data = {
	.variant = ARTPEC6,
	.mode = DW_PCIE_RC_TYPE,
	};

	static const struct artpec_pcie_of_data artpec6_pcie_ep_of_data = {
	.variant = ARTPEC6,
	.mode = DW_PCIE_EP_TYPE,
	};

	static const struct artpec_pcie_of_data artpec7_pcie_rc_of_data = {
	.variant = ARTPEC7,
	.mode = DW_PCIE_RC_TYPE,
	};

	static const struct artpec_pcie_of_data artpec7_pcie_ep_of_data = {
	.variant = ARTPEC7,
	.mode = DW_PCIE_EP_TYPE,
	};

	static const struct of_device_id artpec6_pcie_of_match[] = {
	{
	.compatible = "axis,artpec6-pcie",
	.data = &artpec6_pcie_rc_of_data,
	},
	{
	.compatible = "axis,artpec6-pcie-ep",
	.data = &artpec6_pcie_ep_of_data,
	},
	{
	.compatible = "axis,artpec7-pcie",
	.data = &artpec7_pcie_rc_of_data,
	},
	{
	.compatible = "axis,artpec7-pcie-ep",
	.data = &artpec7_pcie_ep_of_data,
	},
	{},
	};

	static struct platform_driver artpec6_pcie_driver = {
	.probe = artpec6_pcie_probe,
	.driver = {
	.name = "artpec6-pcie",
	.of_match_table = artpec6_pcie_of_match,
	.suppress_bind_attrs = true,
	},
	};
	builtin_platform_driver(artpec6_pcie_driver);