Re: [RFC PATCH V2 1/3] PCI: hisi: re-architect Hip05/Hip06 controllers driver to preapare for ACPI

Arnd Bergmann
2016-08-31T11:45:42Z

On Wednesday, August 31, 2016 7:48:12 PM CEST Dongdong Liu wrote:
> +
> +/* HipXX PCIe host only supports 32-bit config access */
> +int hisi_pcie_common_cfg_read(void __iomem *reg_base, int where, int size,
> + u32 *val)
> +{
> + u32 reg;
> + u32 reg_val;
> + void *walker = &reg_val;
> +
> + walker += (where & 0x3);
> + reg = where & ~0x3;
> + reg_val = readl(reg_base + reg);
> +
> + if (size == 1)
> + *val = *(u8 __force *) walker;
> + else if (size == 2)
> + *val = *(u16 __force *) walker;

What is the __force for?

> + else if (size == 4)
> + *val = reg_val;
> + else
> + return PCIBIOS_BAD_REGISTER_NUMBER;
> +
> + return PCIBIOS_SUCCESSFUL;

It looks like you are reimplementing pci_generic_config_read32/pci_generic_config_write32
read here, better use them directly.

Arnd