Re: [PATCH 2/2] PCI: keembay: Add support for Intel Keem Bay

[Bjorn Helgaas <helgaas@kernel.org>]

On Tue, Oct 27, 2020 at 02:00:11PM +0800, Wan Ahmad Zainie wrote:

> +static int keembay_pcie_link_up(struct dw_pcie *pci)
> +{
> +	struct keembay_pcie *pcie = dev_get_drvdata(pci->dev);
> +	u32 val, mask;
> +
> +	val = keembay_pcie_readl(pcie, PCIE_REGS_PCIE_SII_PM_STATE);
> +	mask = SMLH_LINK_UP | RDLH_LINK_UP;
> +
> +	return !!((val & mask) == mask);

I think the "!!" is redundant since you're applying it to a value
that's a boolean already.  So you should be able to do:

  return (val & mask) == mask;

But it seems like "mask" just obfuscates a little bit, too.
Personally I think it'd be easier to add something like:

  #define PCIE_REGS_PCIE_SII_LINK_UP  (SMLH_LINK_UP | RDLH_LINK_UP)

and then:

  if ((val & PCIE_REGS_PCIE_SII_LINK_UP) == PCIE_REGS_PCIE_SII_LINK_UP)
    return 1;
  return 0;

or even:

  return (val & PCIE_REGS_PCIE_SII_LINK_UP) == PCIE_REGS_PCIE_SII_LINK_UP;

> +static int keembay_pcie_establish_link(struct dw_pcie *pci)
> +{
> +	return 0;
> +}

Are you sure you need this?  I see other cases where the .start_link
pointer is left NULL, e.g., pci-exynos.c, pci-imx6.c,
dw_ls1021_pcie_ops, etc.

> +static int keembay_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
> +				     enum pci_epc_irq_type type,
> +				     u16 interrupt_num)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +
> +	switch (type) {
> +	case PCI_EPC_IRQ_LEGACY:
> +		/* Legacy interrupts are not supported in Keem Bay */
> +		dev_err(pci->dev, "Unsupported IRQ type\n");

Might be nice to mention "legacy" here.

> +		return -EINVAL;
> +	case PCI_EPC_IRQ_MSI:
> +		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
> +	case PCI_EPC_IRQ_MSIX:
> +		return dw_pcie_ep_raise_msix_irq(ep, func_no, interrupt_num);
> +	default:
> +		dev_err(pci->dev, "Unknown IRQ type\n");

And maybe include the %d of "type"?