drivers/pci/host/pcie-spear13xx.c - kernel/msm-4.9 - Gitiles

 /*
  * PCIe host controller driver for ST Microelectronics SPEAr13xx SoCs
  *
  * SPEAr13xx PCIe Glue Layer Source Code
  *
  * Copyright (C) 2010-2014 ST Microelectronics
  * Pratyush Anand <pratyush.anand@gmail.com>
  * Mohit Kumar <mohit.kumar.dhaka@gmail.com>
  *
  * This file is licensed under the terms of the GNU General Public
  * License version 2. This program is licensed "as is" without any
  * warranty of any kind, whether express or implied.
  */

 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/pci.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/resource.h>

 #include "pcie-designware.h"

 struct spear13xx_pcie {
 	void __iomem		*app_base;
 	struct phy		*phy;
 	struct clk		*clk;
 	struct pcie_port	pp;
 	bool			is_gen1;
 };

 struct pcie_app_reg {
 	u32	app_ctrl_0;		/* cr0 */
 	u32	app_ctrl_1;		/* cr1 */
 	u32	app_status_0;		/* cr2 */
 	u32	app_status_1;		/* cr3 */
 	u32	msg_status;		/* cr4 */
 	u32	msg_payload;		/* cr5 */
 	u32	int_sts;		/* cr6 */
 	u32	int_clr;		/* cr7 */
 	u32	int_mask;		/* cr8 */
 	u32	mst_bmisc;		/* cr9 */
 	u32	phy_ctrl;		/* cr10 */
 	u32	phy_status;		/* cr11 */
 	u32	cxpl_debug_info_0;	/* cr12 */
 	u32	cxpl_debug_info_1;	/* cr13 */
 	u32	ven_msg_ctrl_0;		/* cr14 */
 	u32	ven_msg_ctrl_1;		/* cr15 */
 	u32	ven_msg_data_0;		/* cr16 */
 	u32	ven_msg_data_1;		/* cr17 */
 	u32	ven_msi_0;		/* cr18 */
 	u32	ven_msi_1;		/* cr19 */
 	u32	mst_rmisc;		/* cr20 */
 };

 /* CR0 ID */
 #define RX_LANE_FLIP_EN_ID			0
 #define TX_LANE_FLIP_EN_ID			1
 #define SYS_AUX_PWR_DET_ID			2
 #define APP_LTSSM_ENABLE_ID			3
 #define SYS_ATTEN_BUTTON_PRESSED_ID		4
 #define SYS_MRL_SENSOR_STATE_ID			5
 #define SYS_PWR_FAULT_DET_ID			6
 #define SYS_MRL_SENSOR_CHGED_ID			7
 #define SYS_PRE_DET_CHGED_ID			8
 #define SYS_CMD_CPLED_INT_ID			9
 #define APP_INIT_RST_0_ID			11
 #define APP_REQ_ENTR_L1_ID			12
 #define APP_READY_ENTR_L23_ID			13
 #define APP_REQ_EXIT_L1_ID			14
 #define DEVICE_TYPE_EP				(0 << 25)
 #define DEVICE_TYPE_LEP				(1 << 25)
 #define DEVICE_TYPE_RC				(4 << 25)
 #define SYS_INT_ID				29
 #define MISCTRL_EN_ID				30
 #define REG_TRANSLATION_ENABLE			31

 /* CR1 ID */
 #define APPS_PM_XMT_TURNOFF_ID			2
 #define APPS_PM_XMT_PME_ID			5

 /* CR3 ID */
 #define XMLH_LTSSM_STATE_DETECT_QUIET		0x00
 #define XMLH_LTSSM_STATE_DETECT_ACT		0x01
 #define XMLH_LTSSM_STATE_POLL_ACTIVE		0x02
 #define XMLH_LTSSM_STATE_POLL_COMPLIANCE	0x03
 #define XMLH_LTSSM_STATE_POLL_CONFIG		0x04
 #define XMLH_LTSSM_STATE_PRE_DETECT_QUIET	0x05
 #define XMLH_LTSSM_STATE_DETECT_WAIT		0x06
 #define XMLH_LTSSM_STATE_CFG_LINKWD_START	0x07
 #define XMLH_LTSSM_STATE_CFG_LINKWD_ACEPT	0x08
 #define XMLH_LTSSM_STATE_CFG_LANENUM_WAIT	0x09
 #define XMLH_LTSSM_STATE_CFG_LANENUM_ACEPT	0x0A
 #define XMLH_LTSSM_STATE_CFG_COMPLETE		0x0B
 #define XMLH_LTSSM_STATE_CFG_IDLE		0x0C
 #define XMLH_LTSSM_STATE_RCVRY_LOCK		0x0D
 #define XMLH_LTSSM_STATE_RCVRY_SPEED		0x0E
 #define XMLH_LTSSM_STATE_RCVRY_RCVRCFG		0x0F
 #define XMLH_LTSSM_STATE_RCVRY_IDLE		0x10
 #define XMLH_LTSSM_STATE_L0			0x11
 #define XMLH_LTSSM_STATE_L0S			0x12
 #define XMLH_LTSSM_STATE_L123_SEND_EIDLE	0x13
 #define XMLH_LTSSM_STATE_L1_IDLE		0x14
 #define XMLH_LTSSM_STATE_L2_IDLE		0x15
 #define XMLH_LTSSM_STATE_L2_WAKE		0x16
 #define XMLH_LTSSM_STATE_DISABLED_ENTRY		0x17
 #define XMLH_LTSSM_STATE_DISABLED_IDLE		0x18
 #define XMLH_LTSSM_STATE_DISABLED		0x19
 #define XMLH_LTSSM_STATE_LPBK_ENTRY		0x1A
 #define XMLH_LTSSM_STATE_LPBK_ACTIVE		0x1B
 #define XMLH_LTSSM_STATE_LPBK_EXIT		0x1C
 #define XMLH_LTSSM_STATE_LPBK_EXIT_TIMEOUT	0x1D
 #define XMLH_LTSSM_STATE_HOT_RESET_ENTRY	0x1E
 #define XMLH_LTSSM_STATE_HOT_RESET		0x1F
 #define XMLH_LTSSM_STATE_MASK			0x3F
 #define XMLH_LINK_UP				(1 << 6)

 /* CR4 ID */
 #define CFG_MSI_EN_ID				18

 /* CR6 */
 #define INTA_CTRL_INT				(1 << 7)
 #define INTB_CTRL_INT				(1 << 8)
 #define INTC_CTRL_INT				(1 << 9)
 #define INTD_CTRL_INT				(1 << 10)
 #define MSI_CTRL_INT				(1 << 26)

 /* CR19 ID */
 #define VEN_MSI_REQ_ID				11
 #define VEN_MSI_FUN_NUM_ID			8
 #define VEN_MSI_TC_ID				5
 #define VEN_MSI_VECTOR_ID			0
 #define VEN_MSI_REQ_EN		((u32)0x1 << VEN_MSI_REQ_ID)
 #define VEN_MSI_FUN_NUM_MASK	((u32)0x7 << VEN_MSI_FUN_NUM_ID)
 #define VEN_MSI_TC_MASK		((u32)0x7 << VEN_MSI_TC_ID)
 #define VEN_MSI_VECTOR_MASK	((u32)0x1F << VEN_MSI_VECTOR_ID)

 #define EXP_CAP_ID_OFFSET			0x70

 #define to_spear13xx_pcie(x)	container_of(x, struct spear13xx_pcie, pp)

 static int spear13xx_pcie_establish_link(struct pcie_port *pp)
 {
 	u32 val;
 	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
 	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
 	u32 exp_cap_off = EXP_CAP_ID_OFFSET;
 	unsigned int retries;

 	if (dw_pcie_link_up(pp)) {
 		dev_err(pp->dev, "link already up\n");
 		return 0;
 	}

 	dw_pcie_setup_rc(pp);

 	/*
 	 * this controller support only 128 bytes read size, however its
 	 * default value in capability register is 512 bytes. So force
 	 * it to 128 here.
 	 */
 	dw_pcie_cfg_read(pp->dbi_base, exp_cap_off + PCI_EXP_DEVCTL, 4, &val);
 	val &= ~PCI_EXP_DEVCTL_READRQ;
 	dw_pcie_cfg_write(pp->dbi_base, exp_cap_off + PCI_EXP_DEVCTL, 4, val);

 	dw_pcie_cfg_write(pp->dbi_base, PCI_VENDOR_ID, 2, 0x104A);
 	dw_pcie_cfg_write(pp->dbi_base, PCI_DEVICE_ID, 2, 0xCD80);

 	/*
 	 * if is_gen1 is set then handle it, so that some buggy card
 	 * also works
 	 */
 	if (spear13xx_pcie->is_gen1) {
 		dw_pcie_cfg_read(pp->dbi_base, exp_cap_off + PCI_EXP_LNKCAP, 4,
 				 &val);
 		if ((val & PCI_EXP_LNKCAP_SLS) != PCI_EXP_LNKCAP_SLS_2_5GB) {
 			val &= ~((u32)PCI_EXP_LNKCAP_SLS);
 			val |= PCI_EXP_LNKCAP_SLS_2_5GB;
 			dw_pcie_cfg_write(pp->dbi_base, exp_cap_off +
 					  PCI_EXP_LNKCAP, 4, val);
 		}

 		dw_pcie_cfg_read(pp->dbi_base, exp_cap_off + PCI_EXP_LNKCTL2, 4,
 				 &val);
 		if ((val & PCI_EXP_LNKCAP_SLS) != PCI_EXP_LNKCAP_SLS_2_5GB) {
 			val &= ~((u32)PCI_EXP_LNKCAP_SLS);
 			val |= PCI_EXP_LNKCAP_SLS_2_5GB;
 			dw_pcie_cfg_write(pp->dbi_base, exp_cap_off +
 					  PCI_EXP_LNKCTL2, 4, val);
 		}
 	}

 	/* enable ltssm */
 	writel(DEVICE_TYPE_RC | (1 << MISCTRL_EN_ID)
 			| (1 << APP_LTSSM_ENABLE_ID)
 			| ((u32)1 << REG_TRANSLATION_ENABLE),
 			&app_reg->app_ctrl_0);

 	/* check if the link is up or not */
 	for (retries = 0; retries < 10; retries++) {
 		if (dw_pcie_link_up(pp)) {
 			dev_info(pp->dev, "link up\n");
 			return 0;
 		}
 		mdelay(100);
 	}

 	dev_err(pp->dev, "link Fail\n");
 	return -EINVAL;
 }

 static irqreturn_t spear13xx_pcie_irq_handler(int irq, void *arg)
 {
 	struct pcie_port *pp = arg;
 	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
 	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
 	unsigned int status;

 	status = readl(&app_reg->int_sts);

 	if (status & MSI_CTRL_INT) {
 		if (!IS_ENABLED(CONFIG_PCI_MSI))
 			BUG();
 		dw_handle_msi_irq(pp);
 	}

 	writel(status, &app_reg->int_clr);

 	return IRQ_HANDLED;
 }

 static void spear13xx_pcie_enable_interrupts(struct pcie_port *pp)
 {
 	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
 	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;

 	/* Enable MSI interrupt */
 	if (IS_ENABLED(CONFIG_PCI_MSI)) {
 		dw_pcie_msi_init(pp);
 		writel(readl(&app_reg->int_mask) |
 				MSI_CTRL_INT, &app_reg->int_mask);
 	}
 }

 static int spear13xx_pcie_link_up(struct pcie_port *pp)
 {
 	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
 	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;

 	if (readl(&app_reg->app_status_1) & XMLH_LINK_UP)
 		return 1;

 	return 0;
 }

 static void spear13xx_pcie_host_init(struct pcie_port *pp)
 {
 	spear13xx_pcie_establish_link(pp);
 	spear13xx_pcie_enable_interrupts(pp);
 }

 static struct pcie_host_ops spear13xx_pcie_host_ops = {
 	.link_up = spear13xx_pcie_link_up,
 	.host_init = spear13xx_pcie_host_init,
 };

 static int spear13xx_add_pcie_port(struct pcie_port *pp,
 					 struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	int ret;

 	pp->irq = platform_get_irq(pdev, 0);
 	if (!pp->irq) {
 		dev_err(dev, "failed to get irq\n");
 		return -ENODEV;
 	}
 	ret = devm_request_irq(dev, pp->irq, spear13xx_pcie_irq_handler,
 			       IRQF_SHARED, "spear1340-pcie", pp);
 	if (ret) {
 		dev_err(dev, "failed to request irq %d\n", pp->irq);
 		return ret;
 	}

 	pp->root_bus_nr = -1;
 	pp->ops = &spear13xx_pcie_host_ops;

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

 	return 0;
 }

 static int spear13xx_pcie_probe(struct platform_device *pdev)
 {
 	struct spear13xx_pcie *spear13xx_pcie;
 	struct pcie_port *pp;
 	struct device *dev = &pdev->dev;
 	struct device_node *np = pdev->dev.of_node;
 	struct resource *dbi_base;
 	int ret;

 	spear13xx_pcie = devm_kzalloc(dev, sizeof(*spear13xx_pcie), GFP_KERNEL);
 	if (!spear13xx_pcie)
 		return -ENOMEM;

 	spear13xx_pcie->phy = devm_phy_get(dev, "pcie-phy");
 	if (IS_ERR(spear13xx_pcie->phy)) {
 		ret = PTR_ERR(spear13xx_pcie->phy);
 		if (ret == -EPROBE_DEFER)
 			dev_info(dev, "probe deferred\n");
 		else
 			dev_err(dev, "couldn't get pcie-phy\n");
 		return ret;
 	}

 	phy_init(spear13xx_pcie->phy);

 	spear13xx_pcie->clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(spear13xx_pcie->clk)) {
 		dev_err(dev, "couldn't get clk for pcie\n");
 		return PTR_ERR(spear13xx_pcie->clk);
 	}
 	ret = clk_prepare_enable(spear13xx_pcie->clk);
 	if (ret) {
 		dev_err(dev, "couldn't enable clk for pcie\n");
 		return ret;
 	}

 	pp = &spear13xx_pcie->pp;

 	pp->dev = dev;

 	dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
 	pp->dbi_base = devm_ioremap_resource(dev, dbi_base);
 	if (IS_ERR(pp->dbi_base)) {
 		dev_err(dev, "couldn't remap dbi base %p\n", dbi_base);
 		ret = PTR_ERR(pp->dbi_base);
 		goto fail_clk;
 	}
 	spear13xx_pcie->app_base = pp->dbi_base + 0x2000;

 	if (of_property_read_bool(np, "st,pcie-is-gen1"))
 		spear13xx_pcie->is_gen1 = true;

 	ret = spear13xx_add_pcie_port(pp, pdev);
 	if (ret < 0)
 		goto fail_clk;

 	platform_set_drvdata(pdev, spear13xx_pcie);
 	return 0;

 fail_clk:
 	clk_disable_unprepare(spear13xx_pcie->clk);

 	return ret;
 }

 static const struct of_device_id spear13xx_pcie_of_match[] = {
 	{ .compatible = "st,spear1340-pcie", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, spear13xx_pcie_of_match);

 static struct platform_driver spear13xx_pcie_driver = {
 	.probe		= spear13xx_pcie_probe,
 	.driver = {
 		.name	= "spear-pcie",
 		.of_match_table = of_match_ptr(spear13xx_pcie_of_match),
 	},
 };

 /* SPEAr13xx PCIe driver does not allow module unload */

 static int __init spear13xx_pcie_init(void)
 {
 	return platform_driver_register(&spear13xx_pcie_driver);
 }
 module_init(spear13xx_pcie_init);

 MODULE_DESCRIPTION("ST Microelectronics SPEAr13xx PCIe host controller driver");
 MODULE_AUTHOR("Pratyush Anand <pratyush.anand@gmail.com>");
 MODULE_LICENSE("GPL v2");
	/*
	* PCIe host controller driver for ST Microelectronics SPEAr13xx SoCs
	*
	* SPEAr13xx PCIe Glue Layer Source Code
	*
	* Copyright (C) 2010-2014 ST Microelectronics
	* Pratyush Anand <pratyush.anand@gmail.com>
	* Mohit Kumar <mohit.kumar.dhaka@gmail.com>
	*
	* This file is licensed under the terms of the GNU General Public
	* License version 2. This program is licensed "as is" without any
	* warranty of any kind, whether express or implied.
	*/

	#include <linux/clk.h>
	#include <linux/delay.h>
	#include <linux/interrupt.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/pci.h>
	#include <linux/phy/phy.h>
	#include <linux/platform_device.h>
	#include <linux/resource.h>

	#include "pcie-designware.h"

	struct spear13xx_pcie {
	void __iomem *app_base;
	struct phy *phy;
	struct clk *clk;
	struct pcie_port pp;
	bool is_gen1;
	};

	struct pcie_app_reg {
	u32 app_ctrl_0; /* cr0 */
	u32 app_ctrl_1; /* cr1 */
	u32 app_status_0; /* cr2 */
	u32 app_status_1; /* cr3 */
	u32 msg_status; /* cr4 */
	u32 msg_payload; /* cr5 */
	u32 int_sts; /* cr6 */
	u32 int_clr; /* cr7 */
	u32 int_mask; /* cr8 */
	u32 mst_bmisc; /* cr9 */
	u32 phy_ctrl; /* cr10 */
	u32 phy_status; /* cr11 */
	u32 cxpl_debug_info_0; /* cr12 */
	u32 cxpl_debug_info_1; /* cr13 */
	u32 ven_msg_ctrl_0; /* cr14 */
	u32 ven_msg_ctrl_1; /* cr15 */
	u32 ven_msg_data_0; /* cr16 */
	u32 ven_msg_data_1; /* cr17 */
	u32 ven_msi_0; /* cr18 */
	u32 ven_msi_1; /* cr19 */
	u32 mst_rmisc; /* cr20 */
	};

	/* CR0 ID */
	#define RX_LANE_FLIP_EN_ID 0
	#define TX_LANE_FLIP_EN_ID 1
	#define SYS_AUX_PWR_DET_ID 2
	#define APP_LTSSM_ENABLE_ID 3
	#define SYS_ATTEN_BUTTON_PRESSED_ID 4
	#define SYS_MRL_SENSOR_STATE_ID 5
	#define SYS_PWR_FAULT_DET_ID 6
	#define SYS_MRL_SENSOR_CHGED_ID 7
	#define SYS_PRE_DET_CHGED_ID 8
	#define SYS_CMD_CPLED_INT_ID 9
	#define APP_INIT_RST_0_ID 11
	#define APP_REQ_ENTR_L1_ID 12
	#define APP_READY_ENTR_L23_ID 13
	#define APP_REQ_EXIT_L1_ID 14
	#define DEVICE_TYPE_EP (0 << 25)
	#define DEVICE_TYPE_LEP (1 << 25)
	#define DEVICE_TYPE_RC (4 << 25)
	#define SYS_INT_ID 29
	#define MISCTRL_EN_ID 30
	#define REG_TRANSLATION_ENABLE 31

	/* CR1 ID */
	#define APPS_PM_XMT_TURNOFF_ID 2
	#define APPS_PM_XMT_PME_ID 5

	/* CR3 ID */
	#define XMLH_LTSSM_STATE_DETECT_QUIET 0x00
	#define XMLH_LTSSM_STATE_DETECT_ACT 0x01
	#define XMLH_LTSSM_STATE_POLL_ACTIVE 0x02
	#define XMLH_LTSSM_STATE_POLL_COMPLIANCE 0x03
	#define XMLH_LTSSM_STATE_POLL_CONFIG 0x04
	#define XMLH_LTSSM_STATE_PRE_DETECT_QUIET 0x05
	#define XMLH_LTSSM_STATE_DETECT_WAIT 0x06
	#define XMLH_LTSSM_STATE_CFG_LINKWD_START 0x07
	#define XMLH_LTSSM_STATE_CFG_LINKWD_ACEPT 0x08
	#define XMLH_LTSSM_STATE_CFG_LANENUM_WAIT 0x09
	#define XMLH_LTSSM_STATE_CFG_LANENUM_ACEPT 0x0A
	#define XMLH_LTSSM_STATE_CFG_COMPLETE 0x0B
	#define XMLH_LTSSM_STATE_CFG_IDLE 0x0C
	#define XMLH_LTSSM_STATE_RCVRY_LOCK 0x0D
	#define XMLH_LTSSM_STATE_RCVRY_SPEED 0x0E
	#define XMLH_LTSSM_STATE_RCVRY_RCVRCFG 0x0F
	#define XMLH_LTSSM_STATE_RCVRY_IDLE 0x10
	#define XMLH_LTSSM_STATE_L0 0x11
	#define XMLH_LTSSM_STATE_L0S 0x12
	#define XMLH_LTSSM_STATE_L123_SEND_EIDLE 0x13
	#define XMLH_LTSSM_STATE_L1_IDLE 0x14
	#define XMLH_LTSSM_STATE_L2_IDLE 0x15
	#define XMLH_LTSSM_STATE_L2_WAKE 0x16
	#define XMLH_LTSSM_STATE_DISABLED_ENTRY 0x17
	#define XMLH_LTSSM_STATE_DISABLED_IDLE 0x18
	#define XMLH_LTSSM_STATE_DISABLED 0x19
	#define XMLH_LTSSM_STATE_LPBK_ENTRY 0x1A
	#define XMLH_LTSSM_STATE_LPBK_ACTIVE 0x1B
	#define XMLH_LTSSM_STATE_LPBK_EXIT 0x1C
	#define XMLH_LTSSM_STATE_LPBK_EXIT_TIMEOUT 0x1D
	#define XMLH_LTSSM_STATE_HOT_RESET_ENTRY 0x1E
	#define XMLH_LTSSM_STATE_HOT_RESET 0x1F
	#define XMLH_LTSSM_STATE_MASK 0x3F
	#define XMLH_LINK_UP (1 << 6)

	/* CR4 ID */
	#define CFG_MSI_EN_ID 18

	/* CR6 */
	#define INTA_CTRL_INT (1 << 7)
	#define INTB_CTRL_INT (1 << 8)
	#define INTC_CTRL_INT (1 << 9)
	#define INTD_CTRL_INT (1 << 10)
	#define MSI_CTRL_INT (1 << 26)

	/* CR19 ID */
	#define VEN_MSI_REQ_ID 11
	#define VEN_MSI_FUN_NUM_ID 8
	#define VEN_MSI_TC_ID 5
	#define VEN_MSI_VECTOR_ID 0
	#define VEN_MSI_REQ_EN ((u32)0x1 << VEN_MSI_REQ_ID)
	#define VEN_MSI_FUN_NUM_MASK ((u32)0x7 << VEN_MSI_FUN_NUM_ID)
	#define VEN_MSI_TC_MASK ((u32)0x7 << VEN_MSI_TC_ID)
	#define VEN_MSI_VECTOR_MASK ((u32)0x1F << VEN_MSI_VECTOR_ID)

	#define EXP_CAP_ID_OFFSET 0x70

	#define to_spear13xx_pcie(x) container_of(x, struct spear13xx_pcie, pp)

	static int spear13xx_pcie_establish_link(struct pcie_port *pp)
	{
	u32 val;
	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
	u32 exp_cap_off = EXP_CAP_ID_OFFSET;
	unsigned int retries;

	if (dw_pcie_link_up(pp)) {
	dev_err(pp->dev, "link already up\n");
	return 0;
	}

	dw_pcie_setup_rc(pp);

	/*
	* this controller support only 128 bytes read size, however its
	* default value in capability register is 512 bytes. So force
	* it to 128 here.
	*/
	dw_pcie_cfg_read(pp->dbi_base, exp_cap_off + PCI_EXP_DEVCTL, 4, &val);
	val &= ~PCI_EXP_DEVCTL_READRQ;
	dw_pcie_cfg_write(pp->dbi_base, exp_cap_off + PCI_EXP_DEVCTL, 4, val);

	dw_pcie_cfg_write(pp->dbi_base, PCI_VENDOR_ID, 2, 0x104A);
	dw_pcie_cfg_write(pp->dbi_base, PCI_DEVICE_ID, 2, 0xCD80);

	/*
	* if is_gen1 is set then handle it, so that some buggy card
	* also works
	*/
	if (spear13xx_pcie->is_gen1) {
	dw_pcie_cfg_read(pp->dbi_base, exp_cap_off + PCI_EXP_LNKCAP, 4,
	&val);
	if ((val & PCI_EXP_LNKCAP_SLS) != PCI_EXP_LNKCAP_SLS_2_5GB) {
	val &= ~((u32)PCI_EXP_LNKCAP_SLS);
	val \|= PCI_EXP_LNKCAP_SLS_2_5GB;
	dw_pcie_cfg_write(pp->dbi_base, exp_cap_off +
	PCI_EXP_LNKCAP, 4, val);
	}

	dw_pcie_cfg_read(pp->dbi_base, exp_cap_off + PCI_EXP_LNKCTL2, 4,
	&val);
	if ((val & PCI_EXP_LNKCAP_SLS) != PCI_EXP_LNKCAP_SLS_2_5GB) {
	val &= ~((u32)PCI_EXP_LNKCAP_SLS);
	val \|= PCI_EXP_LNKCAP_SLS_2_5GB;
	dw_pcie_cfg_write(pp->dbi_base, exp_cap_off +
	PCI_EXP_LNKCTL2, 4, val);
	}
	}

	/* enable ltssm */
	writel(DEVICE_TYPE_RC \| (1 << MISCTRL_EN_ID)
	\| (1 << APP_LTSSM_ENABLE_ID)
	\| ((u32)1 << REG_TRANSLATION_ENABLE),
	&app_reg->app_ctrl_0);

	/* check if the link is up or not */
	for (retries = 0; retries < 10; retries++) {
	if (dw_pcie_link_up(pp)) {
	dev_info(pp->dev, "link up\n");
	return 0;
	}
	mdelay(100);
	}

	dev_err(pp->dev, "link Fail\n");
	return -EINVAL;
	}

	static irqreturn_t spear13xx_pcie_irq_handler(int irq, void *arg)
	{
	struct pcie_port *pp = arg;
	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
	unsigned int status;

	status = readl(&app_reg->int_sts);

	if (status & MSI_CTRL_INT) {
	if (!IS_ENABLED(CONFIG_PCI_MSI))
	BUG();
	dw_handle_msi_irq(pp);
	}

	writel(status, &app_reg->int_clr);

	return IRQ_HANDLED;
	}

	static void spear13xx_pcie_enable_interrupts(struct pcie_port *pp)
	{
	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;

	/* Enable MSI interrupt */
	if (IS_ENABLED(CONFIG_PCI_MSI)) {
	dw_pcie_msi_init(pp);
	writel(readl(&app_reg->int_mask) \|
	MSI_CTRL_INT, &app_reg->int_mask);
	}
	}

	static int spear13xx_pcie_link_up(struct pcie_port *pp)
	{
	struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
	struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;

	if (readl(&app_reg->app_status_1) & XMLH_LINK_UP)
	return 1;

	return 0;
	}

	static void spear13xx_pcie_host_init(struct pcie_port *pp)
	{
	spear13xx_pcie_establish_link(pp);
	spear13xx_pcie_enable_interrupts(pp);
	}

	static struct pcie_host_ops spear13xx_pcie_host_ops = {
	.link_up = spear13xx_pcie_link_up,
	.host_init = spear13xx_pcie_host_init,
	};

	static int spear13xx_add_pcie_port(struct pcie_port *pp,
	struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	int ret;

	pp->irq = platform_get_irq(pdev, 0);
	if (!pp->irq) {
	dev_err(dev, "failed to get irq\n");
	return -ENODEV;
	}
	ret = devm_request_irq(dev, pp->irq, spear13xx_pcie_irq_handler,
	IRQF_SHARED, "spear1340-pcie", pp);
	if (ret) {
	dev_err(dev, "failed to request irq %d\n", pp->irq);
	return ret;
	}

	pp->root_bus_nr = -1;
	pp->ops = &spear13xx_pcie_host_ops;

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

	return 0;
	}

	static int spear13xx_pcie_probe(struct platform_device *pdev)
	{
	struct spear13xx_pcie *spear13xx_pcie;
	struct pcie_port *pp;
	struct device *dev = &pdev->dev;
	struct device_node *np = pdev->dev.of_node;
	struct resource *dbi_base;
	int ret;

	spear13xx_pcie = devm_kzalloc(dev, sizeof(*spear13xx_pcie), GFP_KERNEL);
	if (!spear13xx_pcie)
	return -ENOMEM;

	spear13xx_pcie->phy = devm_phy_get(dev, "pcie-phy");
	if (IS_ERR(spear13xx_pcie->phy)) {
	ret = PTR_ERR(spear13xx_pcie->phy);
	if (ret == -EPROBE_DEFER)
	dev_info(dev, "probe deferred\n");
	else
	dev_err(dev, "couldn't get pcie-phy\n");
	return ret;
	}

	phy_init(spear13xx_pcie->phy);

	spear13xx_pcie->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(spear13xx_pcie->clk)) {
	dev_err(dev, "couldn't get clk for pcie\n");
	return PTR_ERR(spear13xx_pcie->clk);
	}
	ret = clk_prepare_enable(spear13xx_pcie->clk);
	if (ret) {
	dev_err(dev, "couldn't enable clk for pcie\n");
	return ret;
	}

	pp = &spear13xx_pcie->pp;

	pp->dev = dev;

	dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
	pp->dbi_base = devm_ioremap_resource(dev, dbi_base);
	if (IS_ERR(pp->dbi_base)) {
	dev_err(dev, "couldn't remap dbi base %p\n", dbi_base);
	ret = PTR_ERR(pp->dbi_base);
	goto fail_clk;
	}
	spear13xx_pcie->app_base = pp->dbi_base + 0x2000;

	if (of_property_read_bool(np, "st,pcie-is-gen1"))
	spear13xx_pcie->is_gen1 = true;

	ret = spear13xx_add_pcie_port(pp, pdev);
	if (ret < 0)
	goto fail_clk;

	platform_set_drvdata(pdev, spear13xx_pcie);
	return 0;

	fail_clk:
	clk_disable_unprepare(spear13xx_pcie->clk);

	return ret;
	}

	static const struct of_device_id spear13xx_pcie_of_match[] = {
	{ .compatible = "st,spear1340-pcie", },
	{},
	};
	MODULE_DEVICE_TABLE(of, spear13xx_pcie_of_match);

	static struct platform_driver spear13xx_pcie_driver = {
	.probe = spear13xx_pcie_probe,
	.driver = {
	.name = "spear-pcie",
	.of_match_table = of_match_ptr(spear13xx_pcie_of_match),
	},
	};

	/* SPEAr13xx PCIe driver does not allow module unload */

	static int __init spear13xx_pcie_init(void)
	{
	return platform_driver_register(&spear13xx_pcie_driver);
	}
	module_init(spear13xx_pcie_init);

	MODULE_DESCRIPTION("ST Microelectronics SPEAr13xx PCIe host controller driver");
	MODULE_AUTHOR("Pratyush Anand <pratyush.anand@gmail.com>");
	MODULE_LICENSE("GPL v2");