path: root/drivers/pci/controller/pcie-mediatek-gen3.c

// SPDX-License-Identifier: GPL-2.0
/*
 * MediaTek PCIe host controller driver.
 *
 * Copyright (c) 2020 MediaTek Inc.
 * Author: Jianjun Wang <jianjun.wang@mediatek.com>
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>

#include "../pci.h"

#define PCIE_SETTING_REG		0x80
#define PCIE_PCI_IDS_1			0x9c
#define PCI_CLASS(class)		(class << 8)
#define PCIE_RC_MODE			BIT(0)

#define PCIE_CFGNUM_REG			0x140
#define PCIE_CFG_DEVFN(devfn)		((devfn) & GENMASK(7, 0))
#define PCIE_CFG_BUS(bus)		(((bus) << 8) & GENMASK(15, 8))
#define PCIE_CFG_BYTE_EN(bytes)		(((bytes) << 16) & GENMASK(19, 16))
#define PCIE_CFG_FORCE_BYTE_EN		BIT(20)
#define PCIE_CFG_OFFSET_ADDR		0x1000
#define PCIE_CFG_HEADER(bus, devfn) \
	(PCIE_CFG_BUS(bus) | PCIE_CFG_DEVFN(devfn))

#define PCIE_RST_CTRL_REG		0x148
#define PCIE_MAC_RSTB			BIT(0)
#define PCIE_PHY_RSTB			BIT(1)
#define PCIE_BRG_RSTB			BIT(2)
#define PCIE_PE_RSTB			BIT(3)

#define PCIE_LTSSM_STATUS_REG		0x150

#define PCIE_LINK_STATUS_REG		0x154
#define PCIE_PORT_LINKUP		BIT(8)

#define PCIE_TRANS_TABLE_BASE_REG	0x800
#define PCIE_ATR_SRC_ADDR_MSB_OFFSET	0x4
#define PCIE_ATR_TRSL_ADDR_LSB_OFFSET	0x8
#define PCIE_ATR_TRSL_ADDR_MSB_OFFSET	0xc
#define PCIE_ATR_TRSL_PARAM_OFFSET	0x10
#define PCIE_ATR_TLB_SET_OFFSET		0x20

#define PCIE_MAX_TRANS_TABLES		8
#define PCIE_ATR_EN			BIT(0)
#define PCIE_ATR_SIZE(size) \
	(((((size) - 1) << 1) & GENMASK(6, 1)) | PCIE_ATR_EN)
#define PCIE_ATR_ID(id)			((id) & GENMASK(3, 0))
#define PCIE_ATR_TYPE_MEM		PCIE_ATR_ID(0)
#define PCIE_ATR_TYPE_IO		PCIE_ATR_ID(1)
#define PCIE_ATR_TLP_TYPE(type)		(((type) << 16) & GENMASK(18, 16))
#define PCIE_ATR_TLP_TYPE_MEM		PCIE_ATR_TLP_TYPE(0)
#define PCIE_ATR_TLP_TYPE_IO		PCIE_ATR_TLP_TYPE(2)

/**
 * struct mtk_pcie_port - PCIe port information
 * @dev: pointer to PCIe device
 * @base: IO mapped register base
 * @reg_base: physical register base
 * @mac_reset: MAC reset control
 * @phy_reset: PHY reset control
 * @phy: PHY controller block
 * @clks: PCIe clocks
 * @num_clks: PCIe clocks count for this port
 */
struct mtk_pcie_port {
	struct device *dev;
	void __iomem *base;
	phys_addr_t reg_base;
	struct reset_control *mac_reset;
	struct reset_control *phy_reset;
	struct phy *phy;
	struct clk_bulk_data *clks;
	int num_clks;
};

/**
 * mtk_pcie_config_tlp_header() - Configure a configuration TLP header
 * @bus: PCI bus to query
 * @devfn: device/function number
 * @where: offset in config space
 * @size: data size in TLP header
 *
 * Set byte enable field and device information in configuration TLP header.
 */
static void mtk_pcie_config_tlp_header(struct pci_bus *bus, unsigned int devfn,
					int where, int size)
{
	struct mtk_pcie_port *port = bus->sysdata;
	int bytes;
	u32 val;

	bytes = (GENMASK(size - 1, 0) & 0xf) << (where & 0x3);

	val = PCIE_CFG_FORCE_BYTE_EN | PCIE_CFG_BYTE_EN(bytes) |
	      PCIE_CFG_HEADER(bus->number, devfn);

	writel_relaxed(val, port->base + PCIE_CFGNUM_REG);
}

static void __iomem *mtk_pcie_map_bus(struct pci_bus *bus, unsigned int devfn,
				      int where)
{
	struct mtk_pcie_port *port = bus->sysdata;

	return port->base + PCIE_CFG_OFFSET_ADDR + where;
}

static int mtk_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
				int where, int size, u32 *val)
{
	mtk_pcie_config_tlp_header(bus, devfn, where, size);

	return pci_generic_config_read32(bus, devfn, where, size, val);
}

static int mtk_pcie_config_write(struct pci_bus *bus, unsigned int devfn,
				 int where, int size, u32 val)
{
	mtk_pcie_config_tlp_header(bus, devfn, where, size);

	if (size <= 2)
		val <<= (where & 0x3) * 8;

	return pci_generic_config_write32(bus, devfn, where, 4, val);
}

static struct pci_ops mtk_pcie_ops = {
	.map_bus = mtk_pcie_map_bus,
	.read  = mtk_pcie_config_read,
	.write = mtk_pcie_config_write,
};

static int mtk_pcie_set_trans_table(struct mtk_pcie_port *port,
				    resource_size_t cpu_addr,
				    resource_size_t pci_addr,
				    resource_size_t size,
				    unsigned long type, int num)
{
	void __iomem *table;
	u32 val;

	if (num >= PCIE_MAX_TRANS_TABLES) {
		dev_err(port->dev, "not enough translate table for addr: %#llx, limited to [%d]\n",
			(unsigned long long)cpu_addr, PCIE_MAX_TRANS_TABLES);
		return -ENODEV;
	}

	table = port->base + PCIE_TRANS_TABLE_BASE_REG +
		num * PCIE_ATR_TLB_SET_OFFSET;

	writel_relaxed(lower_32_bits(cpu_addr) | PCIE_ATR_SIZE(fls(size) - 1),
		       table);
	writel_relaxed(upper_32_bits(cpu_addr),
		       table + PCIE_ATR_SRC_ADDR_MSB_OFFSET);
	writel_relaxed(lower_32_bits(pci_addr),
		       table + PCIE_ATR_TRSL_ADDR_LSB_OFFSET);
	writel_relaxed(upper_32_bits(pci_addr),
		       table + PCIE_ATR_TRSL_ADDR_MSB_OFFSET);

	if (type == IORESOURCE_IO)
		val = PCIE_ATR_TYPE_IO | PCIE_ATR_TLP_TYPE_IO;
	else
		val = PCIE_ATR_TYPE_MEM | PCIE_ATR_TLP_TYPE_MEM;

	writel_relaxed(val, table + PCIE_ATR_TRSL_PARAM_OFFSET);

	return 0;
}

static int mtk_pcie_startup_port(struct mtk_pcie_port *port)
{
	struct resource_entry *entry;
	struct pci_host_bridge *host = pci_host_bridge_from_priv(port);
	unsigned int table_index = 0;
	int err;
	u32 val;

	/* Set as RC mode */
	val = readl_relaxed(port->base + PCIE_SETTING_REG);
	val |= PCIE_RC_MODE;
	writel_relaxed(val, port->base + PCIE_SETTING_REG);

	/* Set class code */
	val = readl_relaxed(port->base + PCIE_PCI_IDS_1);
	val &= ~GENMASK(31, 8);
	val |= PCI_CLASS(PCI_CLASS_BRIDGE_PCI << 8);
	writel_relaxed(val, port->base + PCIE_PCI_IDS_1);

	/* Assert all reset signals */
	val = readl_relaxed(port->base + PCIE_RST_CTRL_REG);
	val |= PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB | PCIE_PE_RSTB;
	writel_relaxed(val, port->base + PCIE_RST_CTRL_REG);

	/*
	 * Described in PCIe CEM specification setctions 2.2 (PERST# Signal)
	 * and 2.2.1 (Initial Power-Up (G3 to S0)).
	 * The deassertion of PERST# should be delayed 100ms (TPVPERL)
	 * for the power and clock to become stable.
	 */
	msleep(100);

	/* De-assert reset signals */
	val &= ~(PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB | PCIE_PE_RSTB);
	writel_relaxed(val, port->base + PCIE_RST_CTRL_REG);

	/* Check if the link is up or not */
	err = readl_poll_timeout(port->base + PCIE_LINK_STATUS_REG, val,
				 !!(val & PCIE_PORT_LINKUP), 20,
				 PCI_PM_D3COLD_WAIT * USEC_PER_MSEC);
	if (err) {
		val = readl_relaxed(port->base + PCIE_LTSSM_STATUS_REG);
		dev_err(port->dev, "PCIe link down, ltssm reg val: %#x\n", val);
		return err;
	}

	/* Set PCIe translation windows */
	resource_list_for_each_entry(entry, &host->windows) {
		struct resource *res = entry->res;
		unsigned long type = resource_type(res);
		resource_size_t cpu_addr;
		resource_size_t pci_addr;
		resource_size_t size;
		const char *range_type;

		if (type == IORESOURCE_IO) {
			cpu_addr = pci_pio_to_address(res->start);
			range_type = "IO";
		} else if (type == IORESOURCE_MEM) {
			cpu_addr = res->start;
			range_type = "MEM";
		} else {
			continue;
		}

		pci_addr = res->start - entry->offset;
		size = resource_size(res);
		err = mtk_pcie_set_trans_table(port, cpu_addr, pci_addr, size,
					       type, table_index);
		if (err)
			return err;

		dev_dbg(port->dev, "set %s trans window[%d]: cpu_addr = %#llx, pci_addr = %#llx, size = %#llx\n",
			range_type, table_index, (unsigned long long)cpu_addr,
			(unsigned long long)pci_addr, (unsigned long long)size);

		table_index++;
	}

	return 0;
}

static int mtk_pcie_parse_port(struct mtk_pcie_port *port)
{
	struct device *dev = port->dev;
	struct platform_device *pdev = to_platform_device(dev);
	struct resource *regs;
	int ret;

	regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac");
	if (!regs)
		return -EINVAL;
	port->base = devm_ioremap_resource(dev, regs);
	if (IS_ERR(port->base)) {
		dev_err(dev, "failed to map register base\n");
		return PTR_ERR(port->base);
	}

	port->reg_base = regs->start;

	port->phy_reset = devm_reset_control_get_optional_exclusive(dev, "phy");
	if (IS_ERR(port->phy_reset)) {
		ret = PTR_ERR(port->phy_reset);
		if (ret != -EPROBE_DEFER)
			dev_err(dev, "failed to get PHY reset\n");

		return ret;
	}

	port->mac_reset = devm_reset_control_get_optional_exclusive(dev, "mac");
	if (IS_ERR(port->mac_reset)) {
		ret = PTR_ERR(port->mac_reset);
		if (ret != -EPROBE_DEFER)
			dev_err(dev, "failed to get MAC reset\n");

		return ret;
	}

	port->phy = devm_phy_optional_get(dev, "pcie-phy");
	if (IS_ERR(port->phy)) {
		ret = PTR_ERR(port->phy);
		if (ret != -EPROBE_DEFER)
			dev_err(dev, "failed to get PHY\n");

		return ret;
	}

	port->num_clks = devm_clk_bulk_get_all(dev, &port->clks);
	if (port->num_clks < 0) {
		dev_err(dev, "failed to get clocks\n");
		return port->num_clks;
	}

	return 0;
}

static int mtk_pcie_power_up(struct mtk_pcie_port *port)
{
	struct device *dev = port->dev;
	int err;

	/* PHY power on and enable pipe clock */
	reset_control_deassert(port->phy_reset);

	err = phy_init(port->phy);
	if (err) {
		dev_err(dev, "failed to initialize PHY\n");
		goto err_phy_init;
	}

	err = phy_power_on(port->phy);
	if (err) {
		dev_err(dev, "failed to power on PHY\n");
		goto err_phy_on;
	}

	/* MAC power on and enable transaction layer clocks */
	reset_control_deassert(port->mac_reset);

	pm_runtime_enable(dev);
	pm_runtime_get_sync(dev);

	err = clk_bulk_prepare_enable(port->num_clks, port->clks);
	if (err) {
		dev_err(dev, "failed to enable clocks\n");
		goto err_clk_init;
	}

	return 0;

err_clk_init:
	pm_runtime_put_sync(dev);
	pm_runtime_disable(dev);
	reset_control_assert(port->mac_reset);
	phy_power_off(port->phy);
err_phy_on:
	phy_exit(port->phy);
err_phy_init:
	reset_control_assert(port->phy_reset);

	return err;
}

static void mtk_pcie_power_down(struct mtk_pcie_port *port)
{
	clk_bulk_disable_unprepare(port->num_clks, port->clks);

	pm_runtime_put_sync(port->dev);
	pm_runtime_disable(port->dev);
	reset_control_assert(port->mac_reset);

	phy_power_off(port->phy);
	phy_exit(port->phy);
	reset_control_assert(port->phy_reset);
}

static int mtk_pcie_setup(struct mtk_pcie_port *port)
{
	int err;

	err = mtk_pcie_parse_port(port);
	if (err)
		return err;

	/* Don't touch the hardware registers before power up */
	err = mtk_pcie_power_up(port);
	if (err)
		return err;

	/* Try link up */
	err = mtk_pcie_startup_port(port);
	if (err)
		goto err_setup;

	return 0;

err_setup:
	mtk_pcie_power_down(port);

	return err;
}

static int mtk_pcie_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct mtk_pcie_port *port;
	struct pci_host_bridge *host;
	int err;

	host = devm_pci_alloc_host_bridge(dev, sizeof(*port));
	if (!host)
		return -ENOMEM;

	port = pci_host_bridge_priv(host);

	port->dev = dev;
	platform_set_drvdata(pdev, port);

	err = mtk_pcie_setup(port);
	if (err)
		return err;

	host->ops = &mtk_pcie_ops;
	host->sysdata = port;

	err = pci_host_probe(host);
	if (err) {
		mtk_pcie_power_down(port);
		return err;
	}

	return 0;
}

static int mtk_pcie_remove(struct platform_device *pdev)
{
	struct mtk_pcie_port *port = platform_get_drvdata(pdev);
	struct pci_host_bridge *host = pci_host_bridge_from_priv(port);

	pci_lock_rescan_remove();
	pci_stop_root_bus(host->bus);
	pci_remove_root_bus(host->bus);
	pci_unlock_rescan_remove();

	mtk_pcie_power_down(port);

	return 0;
}

static const struct of_device_id mtk_pcie_of_match[] = {
	{ .compatible = "mediatek,mt8192-pcie" },
	{},
};

static struct platform_driver mtk_pcie_driver = {
	.probe = mtk_pcie_probe,
	.remove = mtk_pcie_remove,
	.driver = {
		.name = "mtk-pcie",
		.of_match_table = mtk_pcie_of_match,
	},
};

module_platform_driver(mtk_pcie_driver);
MODULE_LICENSE("GPL v2");