Date:   Fri, 13 Sep 2019 17:20:26 +0800
From:   Dilip Kota <eswara.kota@...ux.intel.com>
To:     Gustavo Pimentel <Gustavo.Pimentel@...opsys.com>,
        Andrew Murray <andrew.murray@....com>
Cc:     "jingoohan1@...il.com" <jingoohan1@...il.com>,
        "lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>,
        "robh@...nel.org" <robh@...nel.org>,
        "martin.blumenstingl@...glemail.com" 
        <martin.blumenstingl@...glemail.com>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "hch@...radead.org" <hch@...radead.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "andriy.shevchenko@...el.com" <andriy.shevchenko@...el.com>,
        "cheol.yong.kim@...el.com" <cheol.yong.kim@...el.com>,
        "chuanhua.lei@...ux.intel.com" <chuanhua.lei@...ux.intel.com>,
        "qi-ming.wu@...el.com" <qi-ming.wu@...el.com>
Subject: Re: [PATCH v3 2/2] dwc: PCI: intel: Intel PCIe RC controller driver


On 9/12/2019 6:49 PM, Gustavo Pimentel wrote:
> On Thu, Sep 12, 2019 at 10:23:31, Dilip Kota
> <eswara.kota@...ux.intel.com> wrote:
>
>> Quoting Andrew Murray:
>> Quoting Gustavo Pimentel:
>>
>> On 9/12/2019 4:25 PM, Andrew Murray wrote:
>>> [...]
>>>>>>>>>>>> +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.
>>>>>>>>> Indeed, but a user may also set num-lanes in the device tree. I'm wondering
>>>>>>>>> if, when set in device-tree, it will have the desired effect. Because I don't
>>>>>>>>> see anything similar to PCIE_LCTLSTS_HW_AW_DIS in dw_pcie_setup which is what
>>>>>>>>> your function does here.
>>>>>>>>>
>>>>>>>>> I guess I'm trying to avoid the suitation where num-lanes doesn't have the
>>>>>>>>> desired effect and the only way to set the num-lanes is throught the sysfs
>>>>>>>>> control.
>>>>>>>> I will check this and get back to you.
>>>>>> intel_pcie_max_link_width_setup() is doing the lane resizing which is
>>>>>> different from the link up/establishment happening during probe. Also
>>>>>> PCIE_LCTLSTS_HW_AW_DIS default value is 0 so not setting during the probe or
>>>>>> dw_pcie_setup.
>>>>>>
>>>>>> intel_pcie_max_link_width_setup() is programming as per the designware PCIe
>>>>>> controller databook instructions for lane resizing.
>>>>>>
>>>>>> Below lines are from Designware PCIe databook for lane resizing.
>>>>>>
>>>>>>     Program the TARGET_LINK_WIDTH[5:0] field of the MULTI_LANE_CONTROL_OFF
>>>>>> register.
>>>>>>     Program the DIRECT_LINK_WIDTH_CHANGE2 field of the MULTI_LANE_CONTROL_OFF
>>>>>> register.
>>>>>> It is assumed that the PCIE_CAP_HW_AUTO_WIDTH_DISABLE field in the
>>>>>> LINK_CONTROL_LINK_STATUS_REG register is 0.
>>>>> OK, so there is a difference between initial training and then resizing
>>>>> of the link. Given that this is not Intel specific, should this function
>>>>> exist within the designware driver for the benefit of others?
>>>> I am ok to add if maintainer agrees with it.
>> Gustavo Pimentel,
>>
>> Could you please let us know your opinion on this.
> Hi, I just return from parental leave, therefore I still trying to get
> the pace in mailing list discussion.
>
> However your suggestion looks good, I agree that can go into DesignWare
> driver to be available to all.
Thanks Gustavo for the confirmation, i will add it in the next patch version
>
> Just a small request, please do in general:
> s/designware/DesignWare

Sorry, i didnt understand this.

Regards,
Dilip

>
> Regards,
> Gustavo
>
>> [...]
>>
>>>>>>>>>>>> +}
>>>>>>>>>>>> +
>>>>>>>>>>>> +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;
>> [...]
>>>>>>>>>>>> +
>>>>>>>>>>>> +	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.
>>>>>> I just remember, earlier we were using  of_pci_get_max_link_speed() itself.
>>>>>> As per reviewer comments changed to device_property_read_u32() to maintain
>>>>>> symmetry in parsing device tree properties from device node.
>>>>>> Let me know your view.
>>>>> I couldn't find an earlier version of this series that used of_pci_get_max_link_speed,
>>>>> have I missed it somewhere?
>>>> It happened in our internal review.
>>>> What's your suggestion please, either to go with symmetry in parsing
>>>> "device_property_read_u32()" or with pci helper function
>>>> "of_pci_get_max_link_speed"?
>>> I'd prefer the helper, the added benefit of this is additional error checking.
>>> It also means users can be confident that max-link-speed will behave in the
>>> same way as other host controllers that use this field.
>> Ok, i will update it in the next patch version.
>>
>>
>> Regards,
>>
>> Dilip
>>
>>> Thanks,
>>>
>>> Andrew Murray
>>>
>>>>>>>>>>>> +
>>>>>>>>>>>> +	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.
>>>>>>>>> Is this not a host bridge controller?
>>>>>>>> It is PERST#, signals hardware reset to the End point .
>>>>>>>>             /* Put EP in reset state */
>>>>>>>>             intel_pcie_device_rst_assert(lpp);
>>>>>>> OK.
>>>>>>>
>>>>>>>>>>>> +	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.
>>>>>>>>> Please ensure that all supporting macros, functions and defines go with that
>>>>>>>>> other patch as well please.
>>>>>>>> Sure.
>>>>>>>>>>>> +
>>>>>>>>>>>> +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.
>>>>>>>>> OK, please also see how other drivers use the COMPILE_TEST Kconfig option.
>>>>>>>> Ok sure.
>>>>>>>>> I'd suggest that the dev_dbg just becomes a code comment.
>>>>>> Ok
>>>>>>>>>>>> +	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.
>>>>>>>>> I'm keen to ensure that it is consistently named. I've seen other comments
>>>>>>>>> regarding what the name should be - I don't have a strong opinion though
>>>>>>>>> I do think that *-axi may be too generic.
>>>>>> This PCIe driver is for the Intel Gateway SoCs. So how about naming it is as
>>>>>> "pcie-intel-gw"; pcie-intel-gw.c and Kconfig as PCIE_INTEL_GW.
>>>>> I don't have a problem with this, though others may have differing views.
>>>> Sure. thank you.
>>>>> Thanks,
>>>>>
>>>>> Andrew Murray
>>>>>
>>>>>> Regards,
>>>>>> Dilip
>>>>>>
>>>>>>>> Ok, i will check and get back to you on this.
>>>>>>>> Regards,
>>>>>>> Thanks,
>>>>>>>
>>>>>>> Andrew Murray
>>>>>>>
>>>>>>>> Dilip
>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>>
>>>>>>>>> Andrew Murray
>>>>>>>>>
>>>>>>>>>>> Thanks,
>>>>>>>>>>>
>>>>>>>>>>> Andrew Murray
>>>>>>>>>>>
>>>>>>>>>>>> +		.of_match_table = of_intel_pcie_match,
>>>>>>>>>>>> +		.pm = &intel_pcie_pm_ops,
>>>>>>>>>>>> +	},
>>>>>>>>>>>> +};
>>>>>>>>>>>> +builtin_platform_driver(intel_pcie_driver);
>>>>>>>>>>>> -- 
>>>>>>>>>>>> 2.11.0
>>>>>>>>>>>>
>

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