Re: [PATCH v3 2/2] dwc: PCI: intel: Intel PCIe RC controller driver

[Dilip Kota]

Hi Andy,

Thanks for the review comments, please find my response inline.

On 9/4/2019 9:05 PM, Andy Shevchenko 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.
> Thanks for an update. My comments below.
>
> > +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.
> This hunk is full of indentation issues. Please, see how it's done in other
> cases which are already part of upstream kernel.
Sure, I will fix it.
> > +#define PCIE_APP_INTX_OFST	12
> > +#define PCIE_APP_IRN_INT	(PCIE_APP_IRN_AER_REPORT | PCIE_APP_IRN_PME | \
> It would be slightly easier to read if the value starts from the next line.
Agree, i will update it in the next patch revision.
> > +			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))
> > +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);
> Unnecessary parentheses.
Sure, i will fix it.
> > +	pcie_rc_cfg_wr(lpp, val, PCIE_LCTLSTS);
> > +}
> > +	switch (lpp->max_speed) {
> > +	case PCIE_LINK_SPEED_GEN1:
> > +	case PCIE_LINK_SPEED_GEN2:
> > +		fts = PCIE_AFR_GEN12_FTS_NUM_DFT;
> > +		break;
> You may group this with default case, right?
Sure, i am ok to group it with default case. I will update it in the 
next patch revision.
> > +	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;
> > +	}
> > +	trace_printk("PCIe misc interrupt status 0x%x\n", reg);
> Hmm... Doesn't it give you a BIG warning?
>
> kernel/trace/trace.c:trace_printk_init_buffers()
I hope this should be fine as it come in debug builds only.
> > +	return IRQ_HANDLED;
> > +}
> Perhaps the PCI needs some trace points instead.
>
> > +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");
> Redundant since this cycle.
platform_get_irq() is not printing any error message, so kept a error 
message here.

> > +		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");
> Not very useful. initcall_debug shows an error code.
Thanks for pointing it. I will remove this debug print.
> > +		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;
> > +	}
> + blank line.
Agree, will fix it.
> > +	/* Enable integrated interrupts */
> > +	pcie_app_wr_mask(lpp, PCIE_APP_IRN_INT,
> > +			 PCIE_APP_IRN_INT, PCIE_APP_IRNEN);
> At least one parameter can be located on the previous line.
Agree, will fix it.
> > +	return ret;
> > +}
> > +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;
> You may save here and there few LOCs by adding these to corresponding
> definition blocks.
Agree, will fix it.
> > +
> > +	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;
> Redundant. It's done in below call.
Agree, will fix it.
> > +
> > +	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))
> I would rather leave it on one line.
Agree, will fix it.
> > +		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;
> Redundant.
Agree, will fix it.
> > +
> > +	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 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);
> Why not phy_exit()?
intel_pcie_deinit_phy() calls phy_exit().
> > +	return ret;
> > +}
> > +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;
> Why shadowing error code?
Thanks for pointing it, will fix it.
> > +
> > +	if (val > lpp->max_width)
> > +		return -EINVAL;
> > +
> > +	lpp->lanes = val;
> > +	intel_pcie_max_link_width_setup(lpp);
> > +
> > +	return len;
> > +}
> > +	pcie_rc_cfg_wr_mask(lpp, PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER,
> > +			    0, PCI_COMMAND);
> 0 is pretty much fits previous line.
Agree, will fix it.
> You need to fix your editor settings.
>
> > +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");
> Is it useful message?
Yes, it is required because MSI controller can be of PCIe RC or a 
different one.
In this case MSI controller is of x86 processor.
> > +	return 0;
> > +}
> > +	dev_info(dev,
> > +		 "Intel AXI PCIe Root Complex Port %d Init Done\n", lpp->id);
> Same, literal can be placed on previous line.
Agree, will fix it.


Regards,

Dilip

>