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Subject: Re: [PATCH v3 2/2] dwc: PCI: intel: Intel PCIe RC controller driver
To:     Dilip Kota <eswara.kota@linux.intel.com>, jingoohan1@gmail.com,
        gustavo.pimentel@synopsys.com, lorenzo.pieralisi@arm.com,
        robh@kernel.org, martin.blumenstingl@googlemail.com,
        linux-pci@vger.kernel.org, hch@infradead.org,
        devicetree@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, andriy.shevchenko@intel.com,
        cheol.yong.kim@intel.com, qi-ming.wu@intel.com
References: <cover.1567585181.git.eswara.kota@linux.intel.com>
 <35316bac59d3bc681e76d33e0345f4ef950c4414.1567585181.git.eswara.kota@linux.intel.com>
From:   "Chuan Hua, Lei" <chuanhua.lei@linux.intel.com>
Message-ID: <b9dcb16f-f7a7-454a-15be-8aefde39934a@linux.intel.com>
Date:   Thu, 5 Sep 2019 10:30:30 +0800
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Hi Dilip,

On 9/4/2019 6:10 PM, Dilip Kota wrote:
> Add support to PCIe RC controller on Intel Universal
> Gateway SoC. PCIe controller is based of Synopsys
> Designware pci core.
>
> Signed-off-by: Dilip Kota <eswara.kota@linux.intel.com>
> ---
> changes on v3:
> 	Rename PCIe app logic registers with PCIE_APP prefix.
> 	PCIE_IOP_CTRL configuration is not required. Remove respective code.
> 	Remove wrapper functions for clk enable/disable APIs.
> 	Use platform_get_resource_byname() instead of
> 	  devm_platform_ioremap_resource() to be similar with DWC framework.
> 	Rename phy name to "pciephy".
> 	Modify debug message in msi_init() callback to be more specific.
> 	Remove map_irq() callback.
> 	Enable the INTx interrupts at the time of PCIe initialization.
> 	Reduce memory fragmentation by using variable "struct dw_pcie pci"
> 	  instead of allocating memory.
> 	Reduce the delay to 100us during enpoint initialization
> 	  intel_pcie_ep_rst_init().
> 	Call  dw_pcie_host_deinit() during remove() instead of directly
> 	  calling PCIe core APIs.
> 	Rename "intel,rst-interval" to "reset-assert-ms".
> 	Remove unused APP logic Interrupt bit macro definitions.
>   	Use dwc framework's dw_pcie_setup_rc() for PCIe host specific
> 	 configuration instead of redefining the same functionality in
> 	 the driver.
> 	Move the whole DT parsing specific code to intel_pcie_get_resources()
>
>   drivers/pci/controller/dwc/Kconfig          |  13 +
>   drivers/pci/controller/dwc/Makefile         |   1 +
>   drivers/pci/controller/dwc/pcie-intel-axi.c | 840 ++++++++++++++++++++++++++++
>   3 files changed, 854 insertions(+)
>   create mode 100644 drivers/pci/controller/dwc/pcie-intel-axi.c
>
> diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> index 6ea778ae4877..e44b9b6a6390 100644
> --- a/drivers/pci/controller/dwc/Kconfig
> +++ b/drivers/pci/controller/dwc/Kconfig
> @@ -82,6 +82,19 @@ config PCIE_DW_PLAT_EP
>   	  order to enable device-specific features PCI_DW_PLAT_EP must be
>   	  selected.
>   
> +config PCIE_INTEL_AXI
> +        bool "Intel AHB/AXI PCIe host controller support"
> +        depends on PCI_MSI
> +        depends on PCI
> +        depends on OF
> +        select PCIE_DW_HOST
> +        help
> +          Say 'Y' here to enable support for Intel AHB/AXI PCIe Host
> +	  controller driver.
> +	  The Intel PCIe controller is based on the Synopsys Designware
> +	  pcie core and therefore uses the Designware core functions to
> +	  implement the driver.
> +
>   config PCI_EXYNOS
>   	bool "Samsung Exynos PCIe controller"
>   	depends on SOC_EXYNOS5440 || COMPILE_TEST
> diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
> index b085dfd4fab7..46e656ebdf90 100644
> --- a/drivers/pci/controller/dwc/Makefile
> +++ b/drivers/pci/controller/dwc/Makefile
> @@ -3,6 +3,7 @@ obj-$(CONFIG_PCIE_DW) += pcie-designware.o
>   obj-$(CONFIG_PCIE_DW_HOST) += pcie-designware-host.o
>   obj-$(CONFIG_PCIE_DW_EP) += pcie-designware-ep.o
>   obj-$(CONFIG_PCIE_DW_PLAT) += pcie-designware-plat.o
> +obj-$(CONFIG_PCIE_INTEL_AXI) += pcie-intel-axi.o
>   obj-$(CONFIG_PCI_DRA7XX) += pci-dra7xx.o
>   obj-$(CONFIG_PCI_EXYNOS) += pci-exynos.o
>   obj-$(CONFIG_PCI_IMX6) += pci-imx6.o
> diff --git a/drivers/pci/controller/dwc/pcie-intel-axi.c b/drivers/pci/controller/dwc/pcie-intel-axi.c
> new file mode 100644
> index 000000000000..75607ce03ebf
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pcie-intel-axi.c
> @@ -0,0 +1,840 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PCIe host controller driver for Intel AXI PCIe Bridge
> + *
> + * Copyright (c) 2019 Intel Corporation.
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/interrupt.h>
> +#include <linux/iopoll.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_pci.h>
> +#include <linux/of_platform.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +
> +#include "../../pci.h"
> +#include "pcie-designware.h"
> +
> +#define PCIE_CCRID				0x8
> +
> +#define PCIE_LCAP				0x7C
> +#define PCIE_LCAP_MAX_LINK_SPEED		GENMASK(3, 0)
> +#define PCIE_LCAP_MAX_LENGTH_WIDTH		GENMASK(9, 4)
> +
> +/* Link Control and Status Register */
> +#define PCIE_LCTLSTS				0x80
> +#define PCIE_LCTLSTS_ASPM_ENABLE		GENMASK(1, 0)
> +#define PCIE_LCTLSTS_RCB128			BIT(3)
> +#define PCIE_LCTLSTS_LINK_DISABLE		BIT(4)
> +#define PCIE_LCTLSTS_COM_CLK_CFG		BIT(6)
> +#define PCIE_LCTLSTS_HW_AW_DIS			BIT(9)
> +#define PCIE_LCTLSTS_LINK_SPEED			GENMASK(19, 16)
> +#define PCIE_LCTLSTS_NEGOTIATED_LINK_WIDTH	GENMASK(25, 20)
> +#define PCIE_LCTLSTS_SLOT_CLK_CFG		BIT(28)
> +
> +#define PCIE_LCTLSTS2				0xA0
> +#define PCIE_LCTLSTS2_TGT_LINK_SPEED		GENMASK(3, 0)
> +#define PCIE_LCTLSTS2_TGT_LINK_SPEED_25GT	0x1
> +#define PCIE_LCTLSTS2_TGT_LINK_SPEED_5GT	0x2
> +#define PCIE_LCTLSTS2_TGT_LINK_SPEED_8GT	0x3
> +#define PCIE_LCTLSTS2_TGT_LINK_SPEED_16GT	0x4
> +#define PCIE_LCTLSTS2_HW_AUTO_DIS		BIT(5)
> +
> +/* Ack Frequency Register */
> +#define PCIE_AFR				0x70C
> +#define PCIE_AFR_FTS_NUM			GENMASK(15, 8)
> +#define PCIE_AFR_COM_FTS_NUM			GENMASK(23, 16)
> +#define PCIE_AFR_GEN12_FTS_NUM_DFT		(SZ_128 - 1)
> +#define PCIE_AFR_GEN3_FTS_NUM_DFT		180
> +#define PCIE_AFR_GEN4_FTS_NUM_DFT		196
> +
> +#define PCIE_PLCR_DLL_LINK_EN			BIT(5)
> +#define PCIE_PORT_LOGIC_FTS			GENMASK(7, 0)
> +#define PCIE_PORT_LOGIC_DFT_FTS_NUM		(SZ_128 - 1)
> +
> +#define PCIE_MISC_CTRL				0x8BC
> +#define PCIE_MISC_CTRL_DBI_RO_WR_EN		BIT(0)
> +
> +#define PCIE_MULTI_LANE_CTRL			0x8C0
> +#define PCIE_UPCONFIG_SUPPORT			BIT(7)
> +#define PCIE_DIRECT_LINK_WIDTH_CHANGE		BIT(6)
> +#define PCIE_TARGET_LINK_WIDTH			GENMASK(5, 0)
> +
> +/* APP RC Core Control Register */
> +#define PCIE_APP_CCR				0x10
> +#define PCIE_APP_CCR_LTSSM_ENABLE		BIT(0)
> +
> +/* PCIe Message Control */
> +#define PCIE_APP_MSG_CR				0x30
> +#define PCIE_APP_MSG_XMT_PM_TURNOFF		BIT(0)
> +
> +/* PCIe Power Management Control */
> +#define PCIE_APP_PMC				0x44
> +#define PCIE_APP_PMC_IN_L2			BIT(20)
> +
> +/* Interrupt Enable Register */
> +#define PCIE_APP_IRNEN				0xF4
> +#define PCIE_APP_IRNCR				0xF8
> +#define PCIE_APP_IRN_AER_REPORT			BIT(0)
> +#define PCIE_APP_IRN_PME			BIT(2)
> +#define PCIE_APP_IRN_RX_VDM_MSG			BIT(4)
> +#define PCIE_APP_IRN_PM_TO_ACK			BIT(9)
> +#define PCIE_APP_IRN_LINK_AUTO_BW_STAT		BIT(11)
> +#define PCIE_APP_IRN_BW_MGT			BIT(12)
> +#define PCIE_APP_IRN_MSG_LTR			BIT(18)
> +#define PCIE_APP_IRN_SYS_ERR_RC			BIT(29)
> +
> +#define PCIE_APP_INTX_OFST	12
> +#define PCIE_APP_IRN_INT	(PCIE_APP_IRN_AER_REPORT | PCIE_APP_IRN_PME | \
> +			PCIE_APP_IRN_RX_VDM_MSG | PCIE_APP_IRN_SYS_ERR_RC | \
> +			PCIE_APP_IRN_PM_TO_ACK | PCIE_APP_IRN_MSG_LTR | \
> +			PCIE_APP_IRN_BW_MGT | PCIE_APP_IRN_LINK_AUTO_BW_STAT | \
> +			(PCIE_APP_INTX_OFST + PCI_INTERRUPT_INTA) | \
> +			(PCIE_APP_INTX_OFST + PCI_INTERRUPT_INTB) | \
> +			(PCIE_APP_INTX_OFST + PCI_INTERRUPT_INTC) | \
> +			(PCIE_APP_INTX_OFST + PCI_INTERRUPT_INTD))
> +
> +#define BUS_IATU_OFFS		SZ_256M
> +#define RST_INTRVL_DFT_MS	100
> +enum {
> +	PCIE_LINK_SPEED_AUTO = 0,
> +	PCIE_LINK_SPEED_GEN1,
> +	PCIE_LINK_SPEED_GEN2,
> +	PCIE_LINK_SPEED_GEN3,
> +	PCIE_LINK_SPEED_GEN4,
> +};
> +
> +struct intel_pcie_soc {
> +	unsigned int pcie_ver;
> +	unsigned int pcie_atu_offset;
> +	u32 num_viewport;
> +};
> +
> +struct intel_pcie_port {
> +	struct dw_pcie		pci;
> +	unsigned int		id; /* Physical RC Index */
> +	void __iomem		*app_base;
> +	struct gpio_desc	*reset_gpio;
> +	u32			rst_interval;
> +	u32			max_speed;
> +	u32			link_gen;
> +	u32			max_width;
> +	u32			lanes;
> +	struct clk		*core_clk;
> +	struct reset_control	*core_rst;
> +	struct phy		*phy;
> +};
> +
> +static void pcie_update_bits(void __iomem *base, u32 mask, u32 val, u32 ofs)
> +{
> +	u32 orig, tmp;
> +
> +	orig = readl(base + ofs);
> +
> +	tmp = (orig & ~mask) | (val & mask);
> +
> +	if (tmp != orig)
> +		writel(tmp, base + ofs);
> +}
> +
> +static inline u32 pcie_app_rd(struct intel_pcie_port *lpp, u32 ofs)
> +{
> +	return readl(lpp->app_base + ofs);
> +}
> +
> +static inline void pcie_app_wr(struct intel_pcie_port *lpp, u32 val, u32 ofs)
> +{
> +	writel(val, lpp->app_base + ofs);
> +}
> +
> +static void pcie_app_wr_mask(struct intel_pcie_port *lpp,
> +			     u32 mask, u32 val, u32 ofs)
> +{
> +	pcie_update_bits(lpp->app_base, mask, val, ofs);
> +}
> +
> +static inline u32 pcie_rc_cfg_rd(struct intel_pcie_port *lpp, u32 ofs)
> +{
> +	return dw_pcie_readl_dbi(&lpp->pci, ofs);
> +}
> +
> +static inline void pcie_rc_cfg_wr(struct intel_pcie_port *lpp, u32 val, u32 ofs)
> +{
> +	dw_pcie_writel_dbi(&lpp->pci, ofs, val);
> +}
> +
> +static void pcie_rc_cfg_wr_mask(struct intel_pcie_port *lpp,
> +				u32 mask, u32 val, u32 ofs)
> +{
> +	pcie_update_bits(lpp->pci.dbi_base, mask, val, ofs);
> +}
> +
> +static void intel_pcie_mem_iatu(struct intel_pcie_port *lpp)
> +{
> +	struct pcie_port *pp = &lpp->pci.pp;
> +	phys_addr_t cpu_addr = pp->mem_base;
> +
> +	dw_pcie_prog_outbound_atu(&lpp->pci, PCIE_ATU_REGION_INDEX0,
> +				  PCIE_ATU_TYPE_MEM, cpu_addr,
> +				  pp->mem_base, pp->mem_size);
> +}
> +
> +static void intel_pcie_ltssm_enable(struct intel_pcie_port *lpp)
> +{
> +	pcie_app_wr_mask(lpp, PCIE_APP_CCR_LTSSM_ENABLE,
> +			 PCIE_APP_CCR_LTSSM_ENABLE, PCIE_APP_CCR);
> +}
> +
> +static void intel_pcie_ltssm_disable(struct intel_pcie_port *lpp)
> +{
> +	pcie_app_wr_mask(lpp, PCIE_APP_CCR_LTSSM_ENABLE, 0, PCIE_APP_CCR);
> +}
> +
> +static const char *pcie_link_gen_to_str(int gen)
> +{
> +	switch (gen) {
> +	case PCIE_LINK_SPEED_GEN1:
> +		return "2.5";
> +	case PCIE_LINK_SPEED_GEN2:
> +		return "5.0";
> +	case PCIE_LINK_SPEED_GEN3:
> +		return "8.0";
> +	case PCIE_LINK_SPEED_GEN4:
> +		return "16.0";
> +	default:
> +		return "???";
> +	}
> +}
> +
> +static void intel_pcie_link_setup(struct intel_pcie_port *lpp)
> +{
> +	u32 val;
> +
> +	val = pcie_rc_cfg_rd(lpp, PCIE_LCAP);
> +	lpp->max_speed = FIELD_GET(PCIE_LCAP_MAX_LINK_SPEED, val);
> +	lpp->max_width = FIELD_GET(PCIE_LCAP_MAX_LENGTH_WIDTH, val);
> +
> +	val = pcie_rc_cfg_rd(lpp, PCIE_LCTLSTS);
> +
> +	val &= ~(PCIE_LCTLSTS_LINK_DISABLE | PCIE_LCTLSTS_ASPM_ENABLE);
> +	val |= (PCIE_LCTLSTS_SLOT_CLK_CFG | PCIE_LCTLSTS_COM_CLK_CFG |
> +		PCIE_LCTLSTS_RCB128);
> +	pcie_rc_cfg_wr(lpp, val, PCIE_LCTLSTS);
> +}
> +
> +static void intel_pcie_max_speed_setup(struct intel_pcie_port *lpp)
> +{
> +	u32 reg, val;
> +
> +	reg = pcie_rc_cfg_rd(lpp, PCIE_LCTLSTS2);
> +	switch (lpp->link_gen) {
> +	case PCIE_LINK_SPEED_GEN1:
> +		reg &= ~PCIE_LCTLSTS2_TGT_LINK_SPEED;
> +		reg |= PCIE_LCTLSTS2_HW_AUTO_DIS |
> +			PCIE_LCTLSTS2_TGT_LINK_SPEED_25GT;
> +		break;
> +	case PCIE_LINK_SPEED_GEN2:
> +		reg &= ~PCIE_LCTLSTS2_TGT_LINK_SPEED;
> +		reg |= PCIE_LCTLSTS2_HW_AUTO_DIS |
> +			PCIE_LCTLSTS2_TGT_LINK_SPEED_5GT;
> +		break;
> +	case PCIE_LINK_SPEED_GEN3:
> +		reg &= ~PCIE_LCTLSTS2_TGT_LINK_SPEED;
> +		reg |= PCIE_LCTLSTS2_HW_AUTO_DIS |
> +			PCIE_LCTLSTS2_TGT_LINK_SPEED_8GT;
> +		break;
> +	case PCIE_LINK_SPEED_GEN4:
> +		reg &= ~PCIE_LCTLSTS2_TGT_LINK_SPEED;
> +		reg |= PCIE_LCTLSTS2_HW_AUTO_DIS |
> +			PCIE_LCTLSTS2_TGT_LINK_SPEED_16GT;
> +		break;
> +	default:
> +		/* Use hardware capability */
> +		val = pcie_rc_cfg_rd(lpp, PCIE_LCAP);
> +		val = FIELD_GET(PCIE_LCAP_MAX_LINK_SPEED, val);
> +		reg &= ~PCIE_LCTLSTS2_HW_AUTO_DIS;
> +		reg |= val;
> +		break;
> +	}
> +	pcie_rc_cfg_wr(lpp, reg, PCIE_LCTLSTS2);
> +}
> +
> +static void intel_pcie_speed_change_enable(struct intel_pcie_port *lpp)
> +{
> +	u32 mask, val;
> +
> +	mask = PORT_LOGIC_SPEED_CHANGE | PCIE_PORT_LOGIC_FTS;
> +	val = PORT_LOGIC_SPEED_CHANGE | PCIE_PORT_LOGIC_DFT_FTS_NUM;
> +
> +	pcie_rc_cfg_wr_mask(lpp, mask, val, PCIE_LINK_WIDTH_SPEED_CONTROL);
> +}
> +
> +static void intel_pcie_speed_change_disable(struct intel_pcie_port *lpp)
> +{
> +	pcie_rc_cfg_wr_mask(lpp, PORT_LOGIC_SPEED_CHANGE, 0,
> +			    PCIE_LINK_WIDTH_SPEED_CONTROL);
> +}
> +
> +static void intel_pcie_max_link_width_setup(struct intel_pcie_port *lpp)
> +{
> +	u32 mask, val;
> +
> +	/* HW auto bandwidth negotiation must be enabled */
> +	pcie_rc_cfg_wr_mask(lpp, PCIE_LCTLSTS_HW_AW_DIS, 0, PCIE_LCTLSTS);
> +
> +	mask = PCIE_DIRECT_LINK_WIDTH_CHANGE | PCIE_TARGET_LINK_WIDTH;
> +	val = PCIE_DIRECT_LINK_WIDTH_CHANGE | lpp->lanes;
> +	pcie_rc_cfg_wr_mask(lpp, mask, val, PCIE_MULTI_LANE_CTRL);
> +}
> +
> +static void intel_pcie_port_logic_setup(struct intel_pcie_port *lpp)
> +{
> +	u32 val, mask, fts;
> +
> +	switch (lpp->max_speed) {
> +	case PCIE_LINK_SPEED_GEN1:
> +	case PCIE_LINK_SPEED_GEN2:
> +		fts = PCIE_AFR_GEN12_FTS_NUM_DFT;
> +		break;
> +	case PCIE_LINK_SPEED_GEN3:
> +		fts = PCIE_AFR_GEN3_FTS_NUM_DFT;
> +		break;
> +	case PCIE_LINK_SPEED_GEN4:
> +		fts = PCIE_AFR_GEN4_FTS_NUM_DFT;
> +		break;
> +	default:
> +		fts = PCIE_AFR_GEN12_FTS_NUM_DFT;
> +		break;
> +	}
> +	mask = PCIE_AFR_FTS_NUM | PCIE_AFR_COM_FTS_NUM;
> +	val = FIELD_PREP(PCIE_AFR_FTS_NUM, fts) |
> +	       FIELD_PREP(PCIE_AFR_COM_FTS_NUM, fts);
> +	pcie_rc_cfg_wr_mask(lpp, mask, val, PCIE_AFR);
> +
> +	/* Port Link Control Register */
> +	pcie_rc_cfg_wr_mask(lpp, PCIE_PLCR_DLL_LINK_EN,
> +			    PCIE_PLCR_DLL_LINK_EN, PCIE_PORT_LINK_CONTROL);
> +}
> +
> +static void intel_pcie_upconfig_setup(struct intel_pcie_port *lpp)
> +{
> +	pcie_rc_cfg_wr_mask(lpp, PCIE_UPCONFIG_SUPPORT,
> +			    PCIE_UPCONFIG_SUPPORT, PCIE_MULTI_LANE_CTRL);
> +}
> +
> +static void intel_pcie_rc_setup(struct intel_pcie_port *lpp)
> +{
> +	intel_pcie_ltssm_disable(lpp);
> +	intel_pcie_link_setup(lpp);
> +	dw_pcie_setup_rc(&lpp->pci.pp);
> +	intel_pcie_upconfig_setup(lpp);
> +
> +	intel_pcie_max_speed_setup(lpp);
> +	intel_pcie_speed_change_enable(lpp);
> +	intel_pcie_port_logic_setup(lpp);
> +	intel_pcie_mem_iatu(lpp);
> +}
> +
> +static int intel_pcie_ep_rst_init(struct intel_pcie_port *lpp)
> +{
> +	struct device *dev = lpp->pci.dev;
> +	int ret;
> +
> +	lpp->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> +	if (IS_ERR(lpp->reset_gpio)) {
> +		ret = PTR_ERR(lpp->reset_gpio);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(dev, "failed to request PCIe GPIO: %d\n", ret);
> +		return ret;
> +	}
> +	/* Make initial reset last for 100us */
> +	usleep_range(100, 200);
> +
> +	return 0;
> +}
> +
> +static void intel_pcie_core_rst_assert(struct intel_pcie_port *lpp)
> +{
> +	reset_control_assert(lpp->core_rst);
> +}
> +
> +static void intel_pcie_core_rst_deassert(struct intel_pcie_port *lpp)
> +{
> +	/*
> +	 * One micro-second delay to make sure the reset pulse
> +	 * wide enough so that core reset is clean.
> +	 */
> +	udelay(1);
> +	reset_control_deassert(lpp->core_rst);
> +
> +	/*
> +	 * Some SoC core reset also reset PHY, more delay needed
> +	 * to make sure the reset process is done.
> +	 */
> +	usleep_range(1000, 2000);
> +}
> +
> +static void intel_pcie_device_rst_assert(struct intel_pcie_port *lpp)
> +{
> +	gpiod_set_value_cansleep(lpp->reset_gpio, 1);
> +}
> +
> +static void intel_pcie_device_rst_deassert(struct intel_pcie_port *lpp)
> +{
> +	msleep(lpp->rst_interval);
> +	gpiod_set_value_cansleep(lpp->reset_gpio, 0);
> +}
> +
> +static int intel_pcie_app_logic_setup(struct intel_pcie_port *lpp)
> +{
> +	intel_pcie_device_rst_deassert(lpp);
> +	intel_pcie_ltssm_enable(lpp);
> +
> +	return dw_pcie_wait_for_link(&lpp->pci);
> +}
> +
> +static irqreturn_t intel_pcie_core_isr(int irq, void *arg)
> +{
> +	struct intel_pcie_port *lpp = arg;
> +	u32 val, reg;
> +
> +	reg = pcie_app_rd(lpp, PCIE_APP_IRNCR);
> +	val = reg & PCIE_APP_IRN_INT;
> +
> +	pcie_app_wr(lpp, val, PCIE_APP_IRNCR);
> +
> +	trace_printk("PCIe misc interrupt status 0x%x\n", reg);
> +	return IRQ_HANDLED;
> +}
> +
> +static int intel_pcie_setup_irq(struct intel_pcie_port *lpp)
> +{
> +	struct device *dev = lpp->pci.dev;
> +	struct platform_device *pdev;
> +	char *irq_name;
> +	int irq, ret;
> +
> +	pdev = to_platform_device(dev);
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0) {
> +		dev_err(dev, "missing sys integrated irq resource\n");
> +		return irq;
> +	}
> +
> +	irq_name = devm_kasprintf(dev, GFP_KERNEL, "pcie_misc%d", lpp->id);
> +	if (!irq_name) {
> +		dev_err(dev, "failed to alloc irq name\n");
> +		return -ENOMEM;
> +	}
> +
> +	ret = devm_request_irq(dev, irq, intel_pcie_core_isr,
> +			       IRQF_SHARED, irq_name, lpp);
> +	if (ret) {
> +		dev_err(dev, "request irq %d failed\n", irq);
> +		return ret;
> +	}
> +	/* Enable integrated interrupts */
> +	pcie_app_wr_mask(lpp, PCIE_APP_IRN_INT,
> +			 PCIE_APP_IRN_INT, PCIE_APP_IRNEN);
> +
> +	return ret;
> +}
> +
> +static void intel_pcie_core_irq_disable(struct intel_pcie_port *lpp)
> +{
> +	pcie_app_wr(lpp, 0, PCIE_APP_IRNEN);
> +	pcie_app_wr(lpp, PCIE_APP_IRN_INT,  PCIE_APP_IRNCR);
> +}
> +
> +static int intel_pcie_get_resources(struct platform_device *pdev)
> +{
> +	struct intel_pcie_port *lpp;
> +	struct resource *res;
> +	struct dw_pcie *pci;
> +	struct device *dev;
> +	int ret;
> +
> +	lpp = platform_get_drvdata(pdev);
> +	pci = &lpp->pci;
> +	dev = pci->dev;
> +
> +	ret = device_property_read_u32(dev, "linux,pci-domain", &lpp->id);
> +	if (ret) {
> +		dev_err(dev, "failed to get domain id, errno %d\n", ret);
> +		return ret;
> +	}
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
> +	if (!res)
> +		return -ENXIO;
> +
> +	pci->dbi_base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(pci->dbi_base))
> +		return PTR_ERR(pci->dbi_base);
> +
> +	lpp->core_clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(lpp->core_clk)) {
> +		ret = PTR_ERR(lpp->core_clk);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(dev, "failed to get clks: %d\n", ret);
> +		return ret;
> +	}
> +
> +	lpp->core_rst = devm_reset_control_get(dev, NULL);
> +	if (IS_ERR(lpp->core_rst)) {
> +		ret = PTR_ERR(lpp->core_rst);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(dev, "failed to get resets: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = device_property_match_string(dev, "device_type", "pci");
> +	if (ret) {
> +		dev_err(dev, "failed to find pci device type: %d\n", ret);
> +		return ret;
> +	}
> +
> +	if (device_property_read_u32(dev, "reset-assert-ms",
> +				     &lpp->rst_interval))
> +		lpp->rst_interval = RST_INTRVL_DFT_MS;
> +
> +	if (device_property_read_u32(dev, "max-link-speed", &lpp->link_gen))
> +		lpp->link_gen = 0; /* Fallback to auto */
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "app");
> +	if (!res)
> +		return -ENXIO;
> +
> +	lpp->app_base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(lpp->app_base))
> +		return PTR_ERR(lpp->app_base);
> +
> +	ret = intel_pcie_ep_rst_init(lpp);
> +	if (ret)
> +		return ret;
> +
> +	lpp->phy = devm_phy_get(dev, "pciephy");
> +	if (IS_ERR(lpp->phy)) {
> +		ret = PTR_ERR(lpp->phy);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(dev, "couldn't get pcie-phy: %d\n", ret);
> +		return ret;
> +	}
> +	return 0;
> +}
> +
> +static void intel_pcie_deinit_phy(struct intel_pcie_port *lpp)
> +{
> +	phy_exit(lpp->phy);
> +}
> +
> +static int intel_pcie_wait_l2(struct intel_pcie_port *lpp)
> +{
> +	u32 value;
> +	int ret;
> +
> +	if (lpp->max_speed < PCIE_LINK_SPEED_GEN3)
> +		return 0;
> +
> +	/* Send PME_TURN_OFF message */
> +	pcie_app_wr_mask(lpp, PCIE_APP_MSG_XMT_PM_TURNOFF,
> +			 PCIE_APP_MSG_XMT_PM_TURNOFF, PCIE_APP_MSG_CR);
> +
> +	/* Read PMC status and wait for falling into L2 link state */
> +	ret = readl_poll_timeout(lpp->app_base + PCIE_APP_PMC, value,
> +				 (value & PCIE_APP_PMC_IN_L2), 20,
> +				 jiffies_to_usecs(5 * HZ));
> +	if (ret)
> +		dev_err(lpp->pci.dev, "PCIe link enter L2 timeout!\n");
> +
> +	return ret;
> +}
> +
> +static void intel_pcie_turn_off(struct intel_pcie_port *lpp)
> +{
> +	if (dw_pcie_link_up(&lpp->pci))
> +		intel_pcie_wait_l2(lpp);
> +
> +	/* Put EP in reset state */
> +	intel_pcie_device_rst_assert(lpp);
> +	pcie_rc_cfg_wr_mask(lpp, PCI_COMMAND_MEMORY, 0, PCI_COMMAND);
> +}
> +
> +static int intel_pcie_host_setup(struct intel_pcie_port *lpp)
> +{
> +	int ret;
> +
> +	intel_pcie_core_rst_assert(lpp);
> +	intel_pcie_device_rst_assert(lpp);
> +
> +	ret = phy_init(lpp->phy);
> +	if (ret)
> +		return ret;
> +
> +	intel_pcie_core_rst_deassert(lpp);
> +
> +	ret = clk_prepare_enable(lpp->core_clk);
> +	if (ret) {
> +		dev_err(lpp->pci.dev, "Core clock enable failed: %d\n", ret);
> +		goto clk_err;
> +	}
> +
> +	intel_pcie_rc_setup(lpp);
> +	ret = intel_pcie_app_logic_setup(lpp);
> +	if (ret)
> +		goto app_init_err;
> +
> +	ret = intel_pcie_setup_irq(lpp);
> +	if (!ret)
> +		return ret;
> +
> +	intel_pcie_turn_off(lpp);
> +app_init_err:
> +	clk_disable_unprepare(lpp->core_clk);
> +clk_err:
> +	intel_pcie_core_rst_assert(lpp);
> +	intel_pcie_deinit_phy(lpp);
> +	return ret;
> +}
> +
> +static ssize_t
> +pcie_link_status_show(struct device *dev, struct device_attribute *attr,
> +		      char *buf)
> +{
> +	u32 reg, width, gen;
> +	struct intel_pcie_port *lpp;
> +
> +	lpp = dev_get_drvdata(dev);
> +
> +	reg = pcie_rc_cfg_rd(lpp, PCIE_LCTLSTS);
> +	width = FIELD_GET(PCIE_LCTLSTS_NEGOTIATED_LINK_WIDTH, reg);
> +	gen = FIELD_GET(PCIE_LCTLSTS_LINK_SPEED, reg);
> +	if (gen > lpp->max_speed)
> +		return -EINVAL;
> +
> +	return sprintf(buf, "Port %2u Width x%u Speed %s GT/s\n", lpp->id,
> +		       width, pcie_link_gen_to_str(gen));
> +}
> +static DEVICE_ATTR_RO(pcie_link_status);
> +
> +static ssize_t pcie_speed_store(struct device *dev,
> +				struct device_attribute *attr,
> +				const char *buf, size_t len)
> +{
> +	struct intel_pcie_port *lpp;
> +	unsigned long val;
> +	int ret;
> +
> +	lpp = dev_get_drvdata(dev);
> +
> +	ret = kstrtoul(buf, 10, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val > lpp->max_speed)
> +		return -EINVAL;
> +
> +	lpp->link_gen = val;
> +	intel_pcie_max_speed_setup(lpp);
> +	intel_pcie_speed_change_disable(lpp);
> +	intel_pcie_speed_change_enable(lpp);
> +
> +	return len;
> +}
> +static DEVICE_ATTR_WO(pcie_speed);
> +
> +/*
> + * Link width change on the fly is not always successful.
> + * It also depends on the partner.
> + */
> +static ssize_t pcie_width_store(struct device *dev,
> +				struct device_attribute *attr,
> +				const char *buf, size_t len)
> +{
> +	struct intel_pcie_port *lpp;
> +	unsigned long val;
> +
> +	lpp = dev_get_drvdata(dev);
> +
> +	if (kstrtoul(buf, 10, &val))
> +		return -EINVAL;
> +
> +	if (val > lpp->max_width)
> +		return -EINVAL;
> +
> +	lpp->lanes = val;
> +	intel_pcie_max_link_width_setup(lpp);
> +
> +	return len;
> +}
> +static DEVICE_ATTR_WO(pcie_width);
> +
> +static struct attribute *pcie_cfg_attrs[] = {
> +	&dev_attr_pcie_link_status.attr,
> +	&dev_attr_pcie_speed.attr,
> +	&dev_attr_pcie_width.attr,
> +	NULL,
> +};
> +ATTRIBUTE_GROUPS(pcie_cfg);
> +
> +static int intel_pcie_sysfs_init(struct intel_pcie_port *lpp)
> +{
> +	return devm_device_add_groups(lpp->pci.dev, pcie_cfg_groups);
> +}
> +
> +static void __intel_pcie_remove(struct intel_pcie_port *lpp)
> +{
> +	pcie_rc_cfg_wr_mask(lpp, PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER,
> +			    0, PCI_COMMAND);
Does DWC handle this?
> +	intel_pcie_core_irq_disable(lpp);
> +	intel_pcie_turn_off(lpp);
> +	clk_disable_unprepare(lpp->core_clk);
> +	intel_pcie_core_rst_assert(lpp);
> +	intel_pcie_deinit_phy(lpp);
> +}
> +
> +static int intel_pcie_remove(struct platform_device *pdev)
> +{
> +	struct intel_pcie_port *lpp = platform_get_drvdata(pdev);
> +	struct pcie_port *pp = &lpp->pci.pp;
> +
> +	dw_pcie_host_deinit(pp);
> +	__intel_pcie_remove(lpp);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused intel_pcie_suspend_noirq(struct device *dev)
> +{
> +	struct intel_pcie_port *lpp = dev_get_drvdata(dev);
> +	int ret;
> +
> +	intel_pcie_core_irq_disable(lpp);
> +	ret = intel_pcie_wait_l2(lpp);
> +	if (ret)
> +		return ret;
> +
> +	intel_pcie_deinit_phy(lpp);
> +	clk_disable_unprepare(lpp->core_clk);
> +	return ret;
> +}
> +
> +static int __maybe_unused intel_pcie_resume_noirq(struct device *dev)
> +{
> +	struct intel_pcie_port *lpp = dev_get_drvdata(dev);
> +
> +	return intel_pcie_host_setup(lpp);
> +}
> +
> +static int intel_pcie_rc_init(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct intel_pcie_port *lpp = dev_get_drvdata(pci->dev);
> +	int ret;
> +
> +	/* RC/host initialization */
Remove this comment
> +	ret = intel_pcie_host_setup(lpp);
> +	if (ret)
> +		return ret;
> +	ret = intel_pcie_sysfs_init(lpp);
> +	if (ret)
> +		__intel_pcie_remove(lpp);
> +	return ret;
> +}
> +
> +int intel_pcie_msi_init(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +
> +	dev_dbg(pci->dev, "PCIe MSI/MSIx is handled by MSI in x86 processor\n");
> +	return 0;
> +}
> +
> +u64 intel_pcie_cpu_addr(struct dw_pcie *pcie, u64 cpu_addr)
> +{
> +	return cpu_addr + BUS_IATU_OFFS;
> +}
> +
> +static const struct dw_pcie_ops intel_pcie_ops = {
> +	.cpu_addr_fixup = intel_pcie_cpu_addr,
> +};
> +
> +static const struct dw_pcie_host_ops intel_pcie_dw_ops = {
> +	.host_init =		intel_pcie_rc_init,
> +	.msi_host_init =	intel_pcie_msi_init,
> +};
> +
> +static const struct intel_pcie_soc pcie_data = {
> +	.pcie_ver =		0x520A,
> +	.pcie_atu_offset =	0xC0000,
> +	.num_viewport =		3,
> +};
>
> +static int intel_pcie_probe(struct platform_device *pdev)
> +{
> +	const struct intel_pcie_soc *data;
> +	struct device *dev = &pdev->dev;
> +	struct intel_pcie_port *lpp;
> +	struct pcie_port *pp;
> +	struct dw_pcie *pci;
> +	int ret;
> +
> +	lpp = devm_kzalloc(dev, sizeof(*lpp), GFP_KERNEL);
> +	if (!lpp)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, lpp);
> +	pci = &lpp->pci;
> +	pci->dev = dev;
> +	pp = &pci->pp;
> +
> +	ret = intel_pcie_get_resources(pdev);
> +	if (ret)
> +		return ret;
> +
> +	data = device_get_match_data(dev);
> +	pci->ops = &intel_pcie_ops;
> +	pci->version = data->pcie_ver;
> +	pci->atu_base = pci->dbi_base + data->pcie_atu_offset;
> +	pp->ops = &intel_pcie_dw_ops;
> +
> +	ret = dw_pcie_host_init(pp);
> +	if (ret) {
> +		dev_err(dev, "cannot initialize host\n");
> +		return ret;
> +	}
> +	/* Intel PCIe doesn't configure IO region, so configure
> +	 * viewport to not to access IO region during register
> +	 * read write operations.
> +	 */
> +	pci->num_viewport = data->num_viewport;
> +	dev_info(dev,
> +		 "Intel AXI PCIe Root Complex Port %d Init Done\n", lpp->id);
> +	return ret;
> +}
> +
> +static const struct dev_pm_ops intel_pcie_pm_ops = {
> +	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(intel_pcie_suspend_noirq,
> +				      intel_pcie_resume_noirq)
> +};
> +
> +static const struct of_device_id of_intel_pcie_match[] = {
> +	{ .compatible = "intel,lgm-pcie", .data = &pcie_data },
> +	{}
> +};
> +
> +static struct platform_driver intel_pcie_driver = {
> +	.probe = intel_pcie_probe,
> +	.remove = intel_pcie_remove,
> +	.driver = {
> +		.name = "intel-lgm-pcie",
> +		.of_match_table = of_intel_pcie_match,
> +		.pm = &intel_pcie_pm_ops,
> +	},
> +};
> +builtin_platform_driver(intel_pcie_driver);