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Subject: Re: [PATCH v3 2/2] dwc: PCI: intel: Intel PCIe RC controller driver
To:     Andrew Murray <andrew.murray@arm.com>
Cc:     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,
        linux-kernel@vger.kernel.org, andriy.shevchenko@intel.com,
        cheol.yong.kim@intel.com, chuanhua.lei@linux.intel.com,
        qi-ming.wu@intel.com
References: <cover.1567585181.git.eswara.kota@linux.intel.com>
 <35316bac59d3bc681e76d33e0345f4ef950c4414.1567585181.git.eswara.kota@linux.intel.com>
 <20190905104517.GX9720@e119886-lin.cambridge.arm.com>
From:   Dilip Kota <eswara.kota@linux.intel.com>
Message-ID: <3a3d040e-e57a-3efd-0337-2c2d0b27ad1a@linux.intel.com>
Date:   Fri, 6 Sep 2019 18:58:11 +0800
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Hi Andrew Murray,

Thanks for the review. Please find my response inline.

On 9/5/2019 6:45 PM, Andrew Murray wrote:
> On Wed, Sep 04, 2019 at 06:10:31PM +0800, 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>
>> ---
> Hi Dilip,
>
> Thanks for the patch, initial feedback below:
>
>> 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
> I don't think the PCI dependency is required here.
>
> I'm also not sure why PCI_MSI is required, we select PCIE_DW_HOST which
> depends on PCI_MSI_IRQ_DOMAIN which depends on PCI_MSI.
Agree, dependency on PCI and PCI_MSI can be removed. I will remove it in 
next patch revision.
>
>> +        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.
> I can see this description is similar to others in the same Kconfig,
> however I'm not sure what value a user gains by knowing implementation
> details - it's helpful to know that PCIE_INTEL_AXI is based on the
> Designware core, but is it helpful to know that the Designware core
> functions are used?
>
>> +
>>   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"
> Please remove this - it isn't needed.
Ok, will remove it in next patch revision.
>
>> +#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)
> These look like the standard PCI Link Capabilities Register,
> can you use the standard ones defined in pci_regs.h? (see
> PCI_EXP_LNKCAP_SLS_*).
>
>> +
>> +/* 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)
> These look like the standard Link Control and Link Status register, can
> you use the standard ones defined in pci_regs.h? (see PCI_EXP_LNKCTL_*
> and PCI_EXP_LNKSTA_*).
>
>> +
>> +#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
> And these look like the standard Link Control Register 2 (see
> PCI_EXP_LNKCTL2_*).
>
> Most of the #defines above and below look just like standard PCI defines
> (for example those found in pci_regs.h) - both in terms of their name and
> what they do. Ideally where the functionality is the same or very similar,
> then we should use the standard PCI defines in (pci_regs.h). This helps
> readability/understanding, helps to identify duplicate code and reduces
> the size of your patch.
>
> Also the capability offsets (e.g. PCIE_LCTLSTS2) are also standard. The
> offsets you define are offset by an additional 0x70. E.g.i
> PCIE_LCTLSTS2 = 0xA0, and PCI_EXP_LNKCTL2 = 0x30. Perhaps abstracting
> this offset will allow you to use the standard pci defines?
>
> I haven't looked in much detail at the remainder of the defines, but
> the same rationale should apply.
Agree, that's a good point. I will define the offset macro and use the 
macros defined in pci_regs.h.
>
>> +#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);
> Is this identical functionality to the writing of PCIE_PORT_LINK_CONTROL
> in dw_pcie_setup?
>
> I ask because if the user sets num-lanes in the DT, will it have the
> desired effect?

intel_pcie_max_link_width_setup() function will be called by sysfs attribute pcie_width_store() to change on the fly.

>
>> +}
>> +
>> +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);
> Doesn't dw_pcie_setup_rc do the same as intel_pcie_mem_iatu?
Thanks for pointing it. dw_pcie_setup_rc() does.
intel_pcie_mem_iatu can be removed.
>
>> +}
>> +
>> +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;
>> +}
> Why do we bother handling this interrupt?
This helps during debugging.
>
>> +
>> +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 */
> Is it possible to use of_pci_get_max_link_speed here instead?
Thanks for pointing it. of_pci_get_max_link_speed() can be used here. I 
will update it in the next patch revision.
>
>> +
>> +	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;
> Given that this is called from a function '..._get_resources' I don't think
> we should be resetting anything here.
Agree. I will move it out of get_resources().
>
>> +
>> +	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 */
> EP?
End point device. I will update it.
>
>> +	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);
> You mentioned that a use-case for changing width/speed on the fly was to
> control power consumption (and this also helps debugging issues). As I
> understand there is no current support for this in the kernel - yet it is
> something that would provide value.
>
> I haven't looked in much detail, however as I understand the PCI spec
> allows an upstream partner to change the link speed and retrain. (I'm not
> sure about link width). Given that we already have
> [current,max]_link_[speed,width] is sysfs for each PCI device, it would
> seem natural to extend this to allow for writing a max width or speed.
>
> So ideally this type of thing would be moved to the core or at least in
> the dwc driver. This way the benefits can be applied to more devices on
> larger PCI fabrics - Though perhaps others here will have a different view
> and I'm keen to hear them.
>
> I'm keen to limit the differences between the DWC controller drivers and
> unify common code - thus it would be helpful to have a justification as to
> why this is only relevant for this controller.
>
> For user-space only control, it is possible to achieve what you have here
> with userspace utilities (something like setpci) (assuming the standard
> looking registers you currently access are exposed in the normal config
> space way - though PCIe capabilities).
>
> My suggestion would be to drop these changes and later add something that
> can benefit more devices. In any case if these changes stay within this
> driver then it would be helpful to move them to a separate patch.
Sure, i will submit these entity in separate patch.
>
>> +
>> +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);
>> +	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 */
>> +	ret = intel_pcie_host_setup(lpp);
>> +	if (ret)
>> +		return ret;
> Insert new line here.
Ok.
>
>> +	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");
> What about other processors? (Noting that this driver doesn't depend on
> any specific ARCH in the KConfig).
Agree. i will mark the dependency in Kconfig.
>
>> +	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;
>> +	}
> Add a new line after the closing brace.
Ok
>
>> +	/* 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",
> Is there a reason why the we use intel-lgm-pcie here and pcie-intel-axi
> elsewhere? What does lgm mean?
lgm is the name of intel SoC.  I will name it to pcie-intel-axi to be 
generic.
>
> Thanks,
>
> Andrew Murray
>
>> +		.of_match_table = of_intel_pcie_match,
>> +		.pm = &intel_pcie_pm_ops,
>> +	},
>> +};
>> +builtin_platform_driver(intel_pcie_driver);
>> -- 
>> 2.11.0
>>