Re: [PATCH v11 6/7] ACPI/IORT: Stub out ACS functions when CONFIG_PCI is not set

Lorenzo Pieralisi
2018-12-18T12:00:07Z

On Tue, Dec 18, 2018 at 02:56:05AM +0000, Sinan Kaya wrote:
> Remove PCI dependent code out of iort.c when CONFIG_PCI is not defined.
> A quick search reveals the following functions:
> 1. pci_request_acs()
> 2. pci_domain_nr()
> 3. pci_is_root_bus()
> 4. to_pci_dev()
>
> Both pci_domain_nr() and pci_is_root_bus() are defined in linux/pci.h.
> pci_domain_nr() is a stub function when CONFIG_PCI is not set and
> pci_is_root_bus() just returns a reference to a structure member which
> is still valid without CONFIG_PCI set.
>
> to_pci_dev() is a macro that expands to container_of.
>
> pci_request_acs() is the only code that gets pulled in from drivers/pci/*.c

I am not a big fan of these assumptions but we can stub all code
relying on those behind the CONFIG_PCI guard later, which would result
in cleaner code too.

>
> Signed-off-by: Sinan Kaya <okaya@kernel.org>
> ---
> drivers/acpi/arm64/iort.c | 21 ++++++++++++++-------
> 1 file changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index 70f4e80b9246..beb7e4c05bf5 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -1435,8 +1435,14 @@ static int __init iort_add_platform_device(struct acpi_iort_node *node,
> return ret;
> }
>
> -static bool __init iort_enable_acs(struct acpi_iort_node *iort_node)
> +#ifdef CONFIG_PCI
> +static void __init iort_enable_acs(struct acpi_iort_node *iort_node)
> {
> + static bool acs_enabled __initdata;
> +
> + if (acs_enabled)
> + return;
> +
> if (iort_node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
> struct acpi_iort_node *parent;
> struct acpi_iort_id_mapping *map;
> @@ -1458,13 +1464,16 @@ static bool __init iort_enable_acs(struct acpi_iort_node *iort_node)
> if ((parent->type == ACPI_IORT_NODE_SMMU) ||
> (parent->type == ACPI_IORT_NODE_SMMU_V3)) {
> pci_request_acs();
> - return true;
> + acs_enabled = true;
> + return;
> }
> }
> }
> -
> - return false;
> + return;

Remove this return;

With that updated:

Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

> }
> +#else
> +static inline void iort_enable_acs(struct acpi_iort_node *iort_node) { }
> +#endif
>
> static void __init iort_init_platform_devices(void)
> {
> @@ -1472,7 +1481,6 @@ static void __init iort_init_platform_devices(void)
> struct acpi_table_iort *iort;
> struct fwnode_handle *fwnode;
> int i, ret;
> - bool acs_enabled = false;
> const struct iort_dev_config *ops;
>
> /*
> @@ -1493,8 +1501,7 @@ static void __init iort_init_platform_devices(void)
> return;
> }
>
> - if (!acs_enabled)
> - acs_enabled = iort_enable_acs(iort_node);
> + iort_enable_acs(iort_node);
>
> ops = iort_get_dev_cfg(iort_node);
> if (ops) {
> --
> 2.19.0
>