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

 // SPDX-License-Identifier: GPL-2.0
 /*
  * PCIe host controller driver for Amlogic MESON SoCs
  *
  * Copyright (c) 2018 Amlogic, inc.
  * Author: Yue Wang <yue.wang@amlogic.com>
  */

 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>
 #include <linux/of_device.h>
 #include <linux/of_gpio.h>
 #include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/reset.h>
 #include <linux/resource.h>
 #include <linux/types.h>
 #include <linux/phy/phy.h>
 #include <linux/module.h>

 #include "pcie-designware.h"

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

 #define PCIE_CAP_MAX_PAYLOAD_SIZE(x)	((x) << 5)
 #define PCIE_CAP_MAX_READ_REQ_SIZE(x)	((x) << 12)

 /* PCIe specific config registers */
 #define PCIE_CFG0			0x0
 #define APP_LTSSM_ENABLE		BIT(7)

 #define PCIE_CFG_STATUS12		0x30
 #define IS_SMLH_LINK_UP(x)		((x) & (1 << 6))
 #define IS_RDLH_LINK_UP(x)		((x) & (1 << 16))
 #define IS_LTSSM_UP(x)			((((x) >> 10) & 0x1f) == 0x11)

 #define PCIE_CFG_STATUS17		0x44
 #define PM_CURRENT_STATE(x)		(((x) >> 7) & 0x1)

 #define WAIT_LINKUP_TIMEOUT		4000
 #define PORT_CLK_RATE			100000000UL
 #define MAX_PAYLOAD_SIZE		256
 #define MAX_READ_REQ_SIZE		256
 #define PCIE_RESET_DELAY		500
 #define PCIE_SHARED_RESET		1
 #define PCIE_NORMAL_RESET		0

 enum pcie_data_rate {
 	PCIE_GEN1,
 	PCIE_GEN2,
 	PCIE_GEN3,
 	PCIE_GEN4
 };

 struct meson_pcie_clk_res {
 	struct clk *clk;
 	struct clk *port_clk;
 	struct clk *general_clk;
 };

 struct meson_pcie_rc_reset {
 	struct reset_control *port;
 	struct reset_control *apb;
 };

 struct meson_pcie {
 	struct dw_pcie pci;
 	void __iomem *cfg_base;
 	struct meson_pcie_clk_res clk_res;
 	struct meson_pcie_rc_reset mrst;
 	struct gpio_desc *reset_gpio;
 	struct phy *phy;
 };

 static struct reset_control *meson_pcie_get_reset(struct meson_pcie *mp,
 						  const char *id,
 						  u32 reset_type)
 {
 	struct device *dev = mp->pci.dev;
 	struct reset_control *reset;

 	if (reset_type == PCIE_SHARED_RESET)
 		reset = devm_reset_control_get_shared(dev, id);
 	else
 		reset = devm_reset_control_get(dev, id);

 	return reset;
 }

 static int meson_pcie_get_resets(struct meson_pcie *mp)
 {
 	struct meson_pcie_rc_reset *mrst = &mp->mrst;

 	mrst->port = meson_pcie_get_reset(mp, "port", PCIE_NORMAL_RESET);
 	if (IS_ERR(mrst->port))
 		return PTR_ERR(mrst->port);
 	reset_control_deassert(mrst->port);

 	mrst->apb = meson_pcie_get_reset(mp, "apb", PCIE_SHARED_RESET);
 	if (IS_ERR(mrst->apb))
 		return PTR_ERR(mrst->apb);
 	reset_control_deassert(mrst->apb);

 	return 0;
 }

 static int meson_pcie_get_mems(struct platform_device *pdev,
 			       struct meson_pcie *mp)
 {
 	struct dw_pcie *pci = &mp->pci;

 	pci->dbi_base = devm_platform_ioremap_resource_byname(pdev, "elbi");
 	if (IS_ERR(pci->dbi_base))
 		return PTR_ERR(pci->dbi_base);

 	mp->cfg_base = devm_platform_ioremap_resource_byname(pdev, "cfg");
 	if (IS_ERR(mp->cfg_base))
 		return PTR_ERR(mp->cfg_base);

 	return 0;
 }

 static int meson_pcie_power_on(struct meson_pcie *mp)
 {
 	int ret = 0;

 	ret = phy_init(mp->phy);
 	if (ret)
 		return ret;

 	ret = phy_power_on(mp->phy);
 	if (ret) {
 		phy_exit(mp->phy);
 		return ret;
 	}

 	return 0;
 }

 static void meson_pcie_power_off(struct meson_pcie *mp)
 {
 	phy_power_off(mp->phy);
 	phy_exit(mp->phy);
 }

 static int meson_pcie_reset(struct meson_pcie *mp)
 {
 	struct meson_pcie_rc_reset *mrst = &mp->mrst;
 	int ret = 0;

 	ret = phy_reset(mp->phy);
 	if (ret)
 		return ret;

 	reset_control_assert(mrst->port);
 	reset_control_assert(mrst->apb);
 	udelay(PCIE_RESET_DELAY);
 	reset_control_deassert(mrst->port);
 	reset_control_deassert(mrst->apb);
 	udelay(PCIE_RESET_DELAY);

 	return 0;
 }

 static inline struct clk *meson_pcie_probe_clock(struct device *dev,
 						 const char *id, u64 rate)
 {
 	struct clk *clk;
 	int ret;

 	clk = devm_clk_get(dev, id);
 	if (IS_ERR(clk))
 		return clk;

 	if (rate) {
 		ret = clk_set_rate(clk, rate);
 		if (ret) {
 			dev_err(dev, "set clk rate failed, ret = %d\n", ret);
 			return ERR_PTR(ret);
 		}
 	}

 	ret = clk_prepare_enable(clk);
 	if (ret) {
 		dev_err(dev, "couldn't enable clk\n");
 		return ERR_PTR(ret);
 	}

 	devm_add_action_or_reset(dev,
 				 (void (*) (void *))clk_disable_unprepare,
 				 clk);

 	return clk;
 }

 static int meson_pcie_probe_clocks(struct meson_pcie *mp)
 {
 	struct device *dev = mp->pci.dev;
 	struct meson_pcie_clk_res *res = &mp->clk_res;

 	res->port_clk = meson_pcie_probe_clock(dev, "port", PORT_CLK_RATE);
 	if (IS_ERR(res->port_clk))
 		return PTR_ERR(res->port_clk);

 	res->general_clk = meson_pcie_probe_clock(dev, "general", 0);
 	if (IS_ERR(res->general_clk))
 		return PTR_ERR(res->general_clk);

 	res->clk = meson_pcie_probe_clock(dev, "pclk", 0);
 	if (IS_ERR(res->clk))
 		return PTR_ERR(res->clk);

 	return 0;
 }

 static inline u32 meson_cfg_readl(struct meson_pcie *mp, u32 reg)
 {
 	return readl(mp->cfg_base + reg);
 }

 static inline void meson_cfg_writel(struct meson_pcie *mp, u32 val, u32 reg)
 {
 	writel(val, mp->cfg_base + reg);
 }

 static void meson_pcie_assert_reset(struct meson_pcie *mp)
 {
 	gpiod_set_value_cansleep(mp->reset_gpio, 1);
 	udelay(500);
 	gpiod_set_value_cansleep(mp->reset_gpio, 0);
 }

 static void meson_pcie_init_dw(struct meson_pcie *mp)
 {
 	u32 val;

 	val = meson_cfg_readl(mp, PCIE_CFG0);
 	val |= APP_LTSSM_ENABLE;
 	meson_cfg_writel(mp, val, PCIE_CFG0);
 }

 static int meson_size_to_payload(struct meson_pcie *mp, int size)
 {
 	struct device *dev = mp->pci.dev;

 	/*
 	 * dwc supports 2^(val+7) payload size, which val is 0~5 default to 1.
 	 * So if input size is not 2^order alignment or less than 2^7 or bigger
 	 * than 2^12, just set to default size 2^(1+7).
 	 */
 	if (!is_power_of_2(size) || size < 128 || size > 4096) {
 		dev_warn(dev, "payload size %d, set to default 256\n", size);
 		return 1;
 	}

 	return fls(size) - 8;
 }

 static void meson_set_max_payload(struct meson_pcie *mp, int size)
 {
 	struct dw_pcie *pci = &mp->pci;
 	u32 val;
 	u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
 	int max_payload_size = meson_size_to_payload(mp, size);

 	val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
 	val &= ~PCI_EXP_DEVCTL_PAYLOAD;
 	dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);

 	val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
 	val |= PCIE_CAP_MAX_PAYLOAD_SIZE(max_payload_size);
 	dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);
 }

 static void meson_set_max_rd_req_size(struct meson_pcie *mp, int size)
 {
 	struct dw_pcie *pci = &mp->pci;
 	u32 val;
 	u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
 	int max_rd_req_size = meson_size_to_payload(mp, size);

 	val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
 	val &= ~PCI_EXP_DEVCTL_READRQ;
 	dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);

 	val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
 	val |= PCIE_CAP_MAX_READ_REQ_SIZE(max_rd_req_size);
 	dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);
 }

 static int meson_pcie_establish_link(struct meson_pcie *mp)
 {
 	struct dw_pcie *pci = &mp->pci;
 	struct pcie_port *pp = &pci->pp;

 	meson_pcie_init_dw(mp);
 	meson_set_max_payload(mp, MAX_PAYLOAD_SIZE);
 	meson_set_max_rd_req_size(mp, MAX_READ_REQ_SIZE);

 	dw_pcie_setup_rc(pp);

 	meson_pcie_assert_reset(mp);

 	return dw_pcie_wait_for_link(pci);
 }

 static int meson_pcie_rd_own_conf(struct pci_bus *bus, u32 devfn,
 				  int where, int size, u32 *val)
 {
 	int ret;

 	ret = pci_generic_config_read(bus, devfn, where, size, val);
 	if (ret != PCIBIOS_SUCCESSFUL)
 		return ret;

 	/*
 	 * There is a bug in the MESON AXG PCIe controller whereby software
 	 * cannot program the PCI_CLASS_DEVICE register, so we must fabricate
 	 * the return value in the config accessors.
 	 */
 	if (where == PCI_CLASS_REVISION && size == 4)
 		*val = (PCI_CLASS_BRIDGE_PCI << 16) | (*val & 0xffff);
 	else if (where == PCI_CLASS_DEVICE && size == 2)
 		*val = PCI_CLASS_BRIDGE_PCI;
 	else if (where == PCI_CLASS_DEVICE && size == 1)
 		*val = PCI_CLASS_BRIDGE_PCI & 0xff;
 	else if (where == PCI_CLASS_DEVICE + 1 && size == 1)
 		*val = (PCI_CLASS_BRIDGE_PCI >> 8) & 0xff;

 	return PCIBIOS_SUCCESSFUL;
 }

 static struct pci_ops meson_pci_ops = {
 	.map_bus = dw_pcie_own_conf_map_bus,
 	.read = meson_pcie_rd_own_conf,
 	.write = pci_generic_config_write,
 };

 static int meson_pcie_link_up(struct dw_pcie *pci)
 {
 	struct meson_pcie *mp = to_meson_pcie(pci);
 	struct device *dev = pci->dev;
 	u32 speed_okay = 0;
 	u32 cnt = 0;
 	u32 state12, state17, smlh_up, ltssm_up, rdlh_up;

 	do {
 		state12 = meson_cfg_readl(mp, PCIE_CFG_STATUS12);
 		state17 = meson_cfg_readl(mp, PCIE_CFG_STATUS17);
 		smlh_up = IS_SMLH_LINK_UP(state12);
 		rdlh_up = IS_RDLH_LINK_UP(state12);
 		ltssm_up = IS_LTSSM_UP(state12);

 		if (PM_CURRENT_STATE(state17) < PCIE_GEN3)
 			speed_okay = 1;

 		if (smlh_up)
 			dev_dbg(dev, "smlh_link_up is on\n");
 		if (rdlh_up)
 			dev_dbg(dev, "rdlh_link_up is on\n");
 		if (ltssm_up)
 			dev_dbg(dev, "ltssm_up is on\n");
 		if (speed_okay)
 			dev_dbg(dev, "speed_okay\n");

 		if (smlh_up && rdlh_up && ltssm_up && speed_okay)
 			return 1;

 		cnt++;

 		udelay(10);
 	} while (cnt < WAIT_LINKUP_TIMEOUT);

 	dev_err(dev, "error: wait linkup timeout\n");
 	return 0;
 }

 static int meson_pcie_host_init(struct pcie_port *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
 	struct meson_pcie *mp = to_meson_pcie(pci);
 	int ret;

 	pp->bridge->ops = &meson_pci_ops;

 	ret = meson_pcie_establish_link(mp);
 	if (ret)
 		return ret;

 	dw_pcie_msi_init(pp);

 	return 0;
 }

 static const struct dw_pcie_host_ops meson_pcie_host_ops = {
 	.host_init = meson_pcie_host_init,
 };

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

 	if (IS_ENABLED(CONFIG_PCI_MSI)) {
 		pp->msi_irq = platform_get_irq(pdev, 0);
 		if (pp->msi_irq < 0)
 			return pp->msi_irq;
 	}

 	pp->ops = &meson_pcie_host_ops;

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

 	return 0;
 }

 static const struct dw_pcie_ops dw_pcie_ops = {
 	.link_up = meson_pcie_link_up,
 };

 static int meson_pcie_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct dw_pcie *pci;
 	struct meson_pcie *mp;
 	int ret;

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

 	pci = &mp->pci;
 	pci->dev = dev;
 	pci->ops = &dw_pcie_ops;
 	pci->num_lanes = 1;

 	mp->phy = devm_phy_get(dev, "pcie");
 	if (IS_ERR(mp->phy)) {
 		dev_err(dev, "get phy failed, %ld\n", PTR_ERR(mp->phy));
 		return PTR_ERR(mp->phy);
 	}

 	mp->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
 	if (IS_ERR(mp->reset_gpio)) {
 		dev_err(dev, "get reset gpio failed\n");
 		return PTR_ERR(mp->reset_gpio);
 	}

 	ret = meson_pcie_get_resets(mp);
 	if (ret) {
 		dev_err(dev, "get reset resource failed, %d\n", ret);
 		return ret;
 	}

 	ret = meson_pcie_get_mems(pdev, mp);
 	if (ret) {
 		dev_err(dev, "get memory resource failed, %d\n", ret);
 		return ret;
 	}

 	ret = meson_pcie_power_on(mp);
 	if (ret) {
 		dev_err(dev, "phy power on failed, %d\n", ret);
 		return ret;
 	}

 	ret = meson_pcie_reset(mp);
 	if (ret) {
 		dev_err(dev, "reset failed, %d\n", ret);
 		goto err_phy;
 	}

 	ret = meson_pcie_probe_clocks(mp);
 	if (ret) {
 		dev_err(dev, "init clock resources failed, %d\n", ret);
 		goto err_phy;
 	}

 	platform_set_drvdata(pdev, mp);

 	ret = meson_add_pcie_port(mp, pdev);
 	if (ret < 0) {
 		dev_err(dev, "Add PCIe port failed, %d\n", ret);
 		goto err_phy;
 	}

 	return 0;

 err_phy:
 	meson_pcie_power_off(mp);
 	return ret;
 }

 static const struct of_device_id meson_pcie_of_match[] = {
 	{
 		.compatible = "amlogic,axg-pcie",
 	},
 	{
 		.compatible = "amlogic,g12a-pcie",
 	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, meson_pcie_of_match);

 static struct platform_driver meson_pcie_driver = {
 	.probe = meson_pcie_probe,
 	.driver = {
 		.name = "meson-pcie",
 		.of_match_table = meson_pcie_of_match,
 	},
 };

 module_platform_driver(meson_pcie_driver);

 MODULE_AUTHOR("Yue Wang <yue.wang@amlogic.com>");
 MODULE_DESCRIPTION("Amlogic PCIe Controller driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* PCIe host controller driver for Amlogic MESON SoCs
	*
	* Copyright (c) 2018 Amlogic, inc.
	* Author: Yue Wang <yue.wang@amlogic.com>
	*/

	#include <linux/clk.h>
	#include <linux/delay.h>
	#include <linux/gpio/consumer.h>
	#include <linux/of_device.h>
	#include <linux/of_gpio.h>
	#include <linux/pci.h>
	#include <linux/platform_device.h>
	#include <linux/reset.h>
	#include <linux/resource.h>
	#include <linux/types.h>
	#include <linux/phy/phy.h>
	#include <linux/module.h>

	#include "pcie-designware.h"

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

	#define PCIE_CAP_MAX_PAYLOAD_SIZE(x) ((x) << 5)
	#define PCIE_CAP_MAX_READ_REQ_SIZE(x) ((x) << 12)

	/* PCIe specific config registers */
	#define PCIE_CFG0 0x0
	#define APP_LTSSM_ENABLE BIT(7)

	#define PCIE_CFG_STATUS12 0x30
	#define IS_SMLH_LINK_UP(x) ((x) & (1 << 6))
	#define IS_RDLH_LINK_UP(x) ((x) & (1 << 16))
	#define IS_LTSSM_UP(x) ((((x) >> 10) & 0x1f) == 0x11)

	#define PCIE_CFG_STATUS17 0x44
	#define PM_CURRENT_STATE(x) (((x) >> 7) & 0x1)

	#define WAIT_LINKUP_TIMEOUT 4000
	#define PORT_CLK_RATE 100000000UL
	#define MAX_PAYLOAD_SIZE 256
	#define MAX_READ_REQ_SIZE 256
	#define PCIE_RESET_DELAY 500
	#define PCIE_SHARED_RESET 1
	#define PCIE_NORMAL_RESET 0

	enum pcie_data_rate {
	PCIE_GEN1,
	PCIE_GEN2,
	PCIE_GEN3,
	PCIE_GEN4
	};

	struct meson_pcie_clk_res {
	struct clk *clk;
	struct clk *port_clk;
	struct clk *general_clk;
	};

	struct meson_pcie_rc_reset {
	struct reset_control *port;
	struct reset_control *apb;
	};

	struct meson_pcie {
	struct dw_pcie pci;
	void __iomem *cfg_base;
	struct meson_pcie_clk_res clk_res;
	struct meson_pcie_rc_reset mrst;
	struct gpio_desc *reset_gpio;
	struct phy *phy;
	};

	static struct reset_control meson_pcie_get_reset(struct meson_pcie mp,
	const char *id,
	u32 reset_type)
	{
	struct device *dev = mp->pci.dev;
	struct reset_control *reset;

	if (reset_type == PCIE_SHARED_RESET)
	reset = devm_reset_control_get_shared(dev, id);
	else
	reset = devm_reset_control_get(dev, id);

	return reset;
	}

	static int meson_pcie_get_resets(struct meson_pcie *mp)
	{
	struct meson_pcie_rc_reset *mrst = &mp->mrst;

	mrst->port = meson_pcie_get_reset(mp, "port", PCIE_NORMAL_RESET);
	if (IS_ERR(mrst->port))
	return PTR_ERR(mrst->port);
	reset_control_deassert(mrst->port);

	mrst->apb = meson_pcie_get_reset(mp, "apb", PCIE_SHARED_RESET);
	if (IS_ERR(mrst->apb))
	return PTR_ERR(mrst->apb);
	reset_control_deassert(mrst->apb);

	return 0;
	}

	static int meson_pcie_get_mems(struct platform_device *pdev,
	struct meson_pcie *mp)
	{
	struct dw_pcie *pci = &mp->pci;

	pci->dbi_base = devm_platform_ioremap_resource_byname(pdev, "elbi");
	if (IS_ERR(pci->dbi_base))
	return PTR_ERR(pci->dbi_base);

	mp->cfg_base = devm_platform_ioremap_resource_byname(pdev, "cfg");
	if (IS_ERR(mp->cfg_base))
	return PTR_ERR(mp->cfg_base);

	return 0;
	}

	static int meson_pcie_power_on(struct meson_pcie *mp)
	{
	int ret = 0;

	ret = phy_init(mp->phy);
	if (ret)
	return ret;

	ret = phy_power_on(mp->phy);
	if (ret) {
	phy_exit(mp->phy);
	return ret;
	}

	return 0;
	}

	static void meson_pcie_power_off(struct meson_pcie *mp)
	{
	phy_power_off(mp->phy);
	phy_exit(mp->phy);
	}

	static int meson_pcie_reset(struct meson_pcie *mp)
	{
	struct meson_pcie_rc_reset *mrst = &mp->mrst;
	int ret = 0;

	ret = phy_reset(mp->phy);
	if (ret)
	return ret;

	reset_control_assert(mrst->port);
	reset_control_assert(mrst->apb);
	udelay(PCIE_RESET_DELAY);
	reset_control_deassert(mrst->port);
	reset_control_deassert(mrst->apb);
	udelay(PCIE_RESET_DELAY);

	return 0;
	}

	static inline struct clk meson_pcie_probe_clock(struct device dev,
	const char *id, u64 rate)
	{
	struct clk *clk;
	int ret;

	clk = devm_clk_get(dev, id);
	if (IS_ERR(clk))
	return clk;

	if (rate) {
	ret = clk_set_rate(clk, rate);
	if (ret) {
	dev_err(dev, "set clk rate failed, ret = %d\n", ret);
	return ERR_PTR(ret);
	}
	}

	ret = clk_prepare_enable(clk);
	if (ret) {
	dev_err(dev, "couldn't enable clk\n");
	return ERR_PTR(ret);
	}

	devm_add_action_or_reset(dev,
	(void () (void ))clk_disable_unprepare,
	clk);

	return clk;
	}

	static int meson_pcie_probe_clocks(struct meson_pcie *mp)
	{
	struct device *dev = mp->pci.dev;
	struct meson_pcie_clk_res *res = &mp->clk_res;

	res->port_clk = meson_pcie_probe_clock(dev, "port", PORT_CLK_RATE);
	if (IS_ERR(res->port_clk))
	return PTR_ERR(res->port_clk);

	res->general_clk = meson_pcie_probe_clock(dev, "general", 0);
	if (IS_ERR(res->general_clk))
	return PTR_ERR(res->general_clk);

	res->clk = meson_pcie_probe_clock(dev, "pclk", 0);
	if (IS_ERR(res->clk))
	return PTR_ERR(res->clk);

	return 0;
	}

	static inline u32 meson_cfg_readl(struct meson_pcie *mp, u32 reg)
	{
	return readl(mp->cfg_base + reg);
	}

	static inline void meson_cfg_writel(struct meson_pcie *mp, u32 val, u32 reg)
	{
	writel(val, mp->cfg_base + reg);
	}

	static void meson_pcie_assert_reset(struct meson_pcie *mp)
	{
	gpiod_set_value_cansleep(mp->reset_gpio, 1);
	udelay(500);
	gpiod_set_value_cansleep(mp->reset_gpio, 0);
	}

	static void meson_pcie_init_dw(struct meson_pcie *mp)
	{
	u32 val;

	val = meson_cfg_readl(mp, PCIE_CFG0);
	val \|= APP_LTSSM_ENABLE;
	meson_cfg_writel(mp, val, PCIE_CFG0);
	}

	static int meson_size_to_payload(struct meson_pcie *mp, int size)
	{
	struct device *dev = mp->pci.dev;

	/*
	* dwc supports 2^(val+7) payload size, which val is 0~5 default to 1.
	* So if input size is not 2^order alignment or less than 2^7 or bigger
	* than 2^12, just set to default size 2^(1+7).
	*/
	if (!is_power_of_2(size) \|\| size < 128 \|\| size > 4096) {
	dev_warn(dev, "payload size %d, set to default 256\n", size);
	return 1;
	}

	return fls(size) - 8;
	}

	static void meson_set_max_payload(struct meson_pcie *mp, int size)
	{
	struct dw_pcie *pci = &mp->pci;
	u32 val;
	u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
	int max_payload_size = meson_size_to_payload(mp, size);

	val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
	val &= ~PCI_EXP_DEVCTL_PAYLOAD;
	dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);

	val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
	val \|= PCIE_CAP_MAX_PAYLOAD_SIZE(max_payload_size);
	dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);
	}

	static void meson_set_max_rd_req_size(struct meson_pcie *mp, int size)
	{
	struct dw_pcie *pci = &mp->pci;
	u32 val;
	u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
	int max_rd_req_size = meson_size_to_payload(mp, size);

	val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
	val &= ~PCI_EXP_DEVCTL_READRQ;
	dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);

	val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
	val \|= PCIE_CAP_MAX_READ_REQ_SIZE(max_rd_req_size);
	dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);
	}

	static int meson_pcie_establish_link(struct meson_pcie *mp)
	{
	struct dw_pcie *pci = &mp->pci;
	struct pcie_port *pp = &pci->pp;

	meson_pcie_init_dw(mp);
	meson_set_max_payload(mp, MAX_PAYLOAD_SIZE);
	meson_set_max_rd_req_size(mp, MAX_READ_REQ_SIZE);

	dw_pcie_setup_rc(pp);

	meson_pcie_assert_reset(mp);

	return dw_pcie_wait_for_link(pci);
	}

	static int meson_pcie_rd_own_conf(struct pci_bus *bus, u32 devfn,
	int where, int size, u32 *val)
	{
	int ret;

	ret = pci_generic_config_read(bus, devfn, where, size, val);
	if (ret != PCIBIOS_SUCCESSFUL)
	return ret;

	/*
	* There is a bug in the MESON AXG PCIe controller whereby software
	* cannot program the PCI_CLASS_DEVICE register, so we must fabricate
	* the return value in the config accessors.
	*/
	if (where == PCI_CLASS_REVISION && size == 4)
	val = (PCI_CLASS_BRIDGE_PCI << 16) \| (val & 0xffff);
	else if (where == PCI_CLASS_DEVICE && size == 2)
	*val = PCI_CLASS_BRIDGE_PCI;
	else if (where == PCI_CLASS_DEVICE && size == 1)
	*val = PCI_CLASS_BRIDGE_PCI & 0xff;
	else if (where == PCI_CLASS_DEVICE + 1 && size == 1)
	*val = (PCI_CLASS_BRIDGE_PCI >> 8) & 0xff;

	return PCIBIOS_SUCCESSFUL;
	}

	static struct pci_ops meson_pci_ops = {
	.map_bus = dw_pcie_own_conf_map_bus,
	.read = meson_pcie_rd_own_conf,
	.write = pci_generic_config_write,
	};

	static int meson_pcie_link_up(struct dw_pcie *pci)
	{
	struct meson_pcie *mp = to_meson_pcie(pci);
	struct device *dev = pci->dev;
	u32 speed_okay = 0;
	u32 cnt = 0;
	u32 state12, state17, smlh_up, ltssm_up, rdlh_up;

	do {
	state12 = meson_cfg_readl(mp, PCIE_CFG_STATUS12);
	state17 = meson_cfg_readl(mp, PCIE_CFG_STATUS17);
	smlh_up = IS_SMLH_LINK_UP(state12);
	rdlh_up = IS_RDLH_LINK_UP(state12);
	ltssm_up = IS_LTSSM_UP(state12);

	if (PM_CURRENT_STATE(state17) < PCIE_GEN3)
	speed_okay = 1;

	if (smlh_up)
	dev_dbg(dev, "smlh_link_up is on\n");
	if (rdlh_up)
	dev_dbg(dev, "rdlh_link_up is on\n");
	if (ltssm_up)
	dev_dbg(dev, "ltssm_up is on\n");
	if (speed_okay)
	dev_dbg(dev, "speed_okay\n");

	if (smlh_up && rdlh_up && ltssm_up && speed_okay)
	return 1;

	cnt++;

	udelay(10);
	} while (cnt < WAIT_LINKUP_TIMEOUT);

	dev_err(dev, "error: wait linkup timeout\n");
	return 0;
	}

	static int meson_pcie_host_init(struct pcie_port *pp)
	{
	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
	struct meson_pcie *mp = to_meson_pcie(pci);
	int ret;

	pp->bridge->ops = &meson_pci_ops;

	ret = meson_pcie_establish_link(mp);
	if (ret)
	return ret;

	dw_pcie_msi_init(pp);

	return 0;
	}

	static const struct dw_pcie_host_ops meson_pcie_host_ops = {
	.host_init = meson_pcie_host_init,
	};

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

	if (IS_ENABLED(CONFIG_PCI_MSI)) {
	pp->msi_irq = platform_get_irq(pdev, 0);
	if (pp->msi_irq < 0)
	return pp->msi_irq;
	}

	pp->ops = &meson_pcie_host_ops;

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

	return 0;
	}

	static const struct dw_pcie_ops dw_pcie_ops = {
	.link_up = meson_pcie_link_up,
	};

	static int meson_pcie_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct dw_pcie *pci;
	struct meson_pcie *mp;
	int ret;

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

	pci = &mp->pci;
	pci->dev = dev;
	pci->ops = &dw_pcie_ops;
	pci->num_lanes = 1;

	mp->phy = devm_phy_get(dev, "pcie");
	if (IS_ERR(mp->phy)) {
	dev_err(dev, "get phy failed, %ld\n", PTR_ERR(mp->phy));
	return PTR_ERR(mp->phy);
	}

	mp->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
	if (IS_ERR(mp->reset_gpio)) {
	dev_err(dev, "get reset gpio failed\n");
	return PTR_ERR(mp->reset_gpio);
	}

	ret = meson_pcie_get_resets(mp);
	if (ret) {
	dev_err(dev, "get reset resource failed, %d\n", ret);
	return ret;
	}

	ret = meson_pcie_get_mems(pdev, mp);
	if (ret) {
	dev_err(dev, "get memory resource failed, %d\n", ret);
	return ret;
	}

	ret = meson_pcie_power_on(mp);
	if (ret) {
	dev_err(dev, "phy power on failed, %d\n", ret);
	return ret;
	}

	ret = meson_pcie_reset(mp);
	if (ret) {
	dev_err(dev, "reset failed, %d\n", ret);
	goto err_phy;
	}

	ret = meson_pcie_probe_clocks(mp);
	if (ret) {
	dev_err(dev, "init clock resources failed, %d\n", ret);
	goto err_phy;
	}

	platform_set_drvdata(pdev, mp);

	ret = meson_add_pcie_port(mp, pdev);
	if (ret < 0) {
	dev_err(dev, "Add PCIe port failed, %d\n", ret);
	goto err_phy;
	}

	return 0;

	err_phy:
	meson_pcie_power_off(mp);
	return ret;
	}

	static const struct of_device_id meson_pcie_of_match[] = {
	{
	.compatible = "amlogic,axg-pcie",
	},
	{
	.compatible = "amlogic,g12a-pcie",
	},
	{},
	};
	MODULE_DEVICE_TABLE(of, meson_pcie_of_match);

	static struct platform_driver meson_pcie_driver = {
	.probe = meson_pcie_probe,
	.driver = {
	.name = "meson-pcie",
	.of_match_table = meson_pcie_of_match,
	},
	};

	module_platform_driver(meson_pcie_driver);

	MODULE_AUTHOR("Yue Wang <yue.wang@amlogic.com>");
	MODULE_DESCRIPTION("Amlogic PCIe Controller driver");
	MODULE_LICENSE("GPL v2");