On 06/07/2022 07:21, Pali Rohár wrote:
> [...]
> Fix this issue and introduce a new option CONFIG_PPC_PCI_DOMAIN_FROM_OF_REG.
> When this option is disabled then powerpc kernel would assign PCI domains
> in the similar way like it is doing kernel for other architectures,
> starting from zero and also how it was done prior that commit.
I found this sentence a bit weird, "in the similar way like it is doing
kernel for other architectures", but other than that:
Reviewed-by: Guilherme G. Piccoli <gpiccoli@xxxxxxxxxx>
Thanks for the improvement!
Cheers,
Guilherme
>
> This option is by default enabled for powernv and pseries platform for which
> was that commit originally intended.
>
> With this change upgrading kernels from LTS 4.4 version does not change PCI
> domain on smaller embedded platforms with fixed number of PCIe controllers.
> And also ensure that PCI domain zero is present as before that commit.
>
> Fixes: 63a72284b159 ("powerpc/pci: Assign fixed PHB number based on device-tree properties")
> Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
> ---
> Changes in v2:
> * Enable CONFIG_PPC_PCI_DOMAIN_FROM_OF_REG by default on powernv and pseries
> ---
> arch/powerpc/Kconfig | 11 +++++++++++
> arch/powerpc/kernel/pci-common.c | 4 ++--
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index f66084bc1dfe..053a88e84049 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -386,6 +386,17 @@ config PPC_OF_PLATFORM_PCI
> depends on PCI
> depends on PPC64 # not supported on 32 bits yet
>
> +config PPC_PCI_DOMAIN_FROM_OF_REG
> + bool "Use OF reg property for PCI domain"
> + depends on PCI
> + default y if PPC_PSERIES || PPC_POWERNV
> + help
> + By default PCI domain for host bridge during its registration is
> + chosen as the lowest unused PCI domain number.
> +
> + When this option is enabled then PCI domain can be determined
> + also from lower bits of the OF / Device Tree 'reg' property.
> +
> config ARCH_SUPPORTS_UPROBES
> def_bool y
>
> diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
> index 068410cd54a3..7f959df34833 100644
> --- a/arch/powerpc/kernel/pci-common.c
> +++ b/arch/powerpc/kernel/pci-common.c
> @@ -74,7 +74,6 @@ void __init set_pci_dma_ops(const struct dma_map_ops *dma_ops)
> static int get_phb_number(struct device_node *dn)
> {
> int ret, phb_id = -1;
> - u32 prop_32;
> u64 prop;
>
> /*
> @@ -83,7 +82,8 @@ static int get_phb_number(struct device_node *dn)
> * reading "ibm,opal-phbid", only present in OPAL environment.
> */
> ret = of_property_read_u64(dn, "ibm,opal-phbid", &prop);
> - if (ret) {
> + if (ret && IS_ENABLED(CONFIG_PPC_PCI_DOMAIN_FROM_OF_REG)) {
> + u32 prop_32;
> ret = of_property_read_u32_index(dn, "reg", 1, &prop_32);
> prop = prop_32;
> }
