On Mon, Nov 10, 2014 at 04:41:46PM +0000, Lorenzo Pieralisi wrote:
> The current logic used for PCI domain assignment in arm64
> pci_bus_assign_domain_nr() is flawed in that, depending on the host
> controllers configuration for a platform and the respective initialization
> sequence, core code may end up allocating PCI domain numbers from both DT and
> the core code generic domain counter, which would result in PCI domain
> allocation aliases/errors.
>
> This patch fixes the logic behind the PCI domain number assignment and
> moves the resulting code to generic PCI core code so that the same domain
> allocation logic is used on all platforms selecting
>
> CONFIG_PCI_DOMAINS_GENERIC
>
> instead of resorting to an arch specific implementation that might end up
> duplicating the PCI domain assignment logic wrongly.
>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Liviu Dudau <liviu.dudau@xxxxxxx>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Applied with Liviu and Arnd's acks to pci/domain for v3.19, thanks.
It doesn't matter whether I'm in the to: or cc: list. The important thing
is that it appears on the linux-pci list, because I use patchwork as my
to-do list, and patchwork only vacuums up stuff from linux-pci.
> ---
> v1 => v2:
>
> - Moved generic pci_bus_assign_domain_nr() code to PCI core instead of
> adding an OF layer API
> - Updated commit log and code comments
>
> arch/arm64/kernel/pci.c | 22 ----------------------
> drivers/pci/pci.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 50 insertions(+), 22 deletions(-)
>
> diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
> index ce5836c..6f93c24 100644
> --- a/arch/arm64/kernel/pci.c
> +++ b/arch/arm64/kernel/pci.c
> @@ -46,25 +46,3 @@ int pcibios_add_device(struct pci_dev *dev)
>
> return 0;
> }
> -
> -
> -#ifdef CONFIG_PCI_DOMAINS_GENERIC
> -static bool dt_domain_found = false;
> -
> -void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
> -{
> - int domain = of_get_pci_domain_nr(parent->of_node);
> -
> - if (domain >= 0) {
> - dt_domain_found = true;
> - } else if (dt_domain_found == true) {
> - dev_err(parent, "Node %s is missing \"linux,pci-domain\" property in DT\n",
> - parent->of_node->full_name);
> - return;
> - } else {
> - domain = pci_get_new_domain_nr();
> - }
> -
> - bus->domain_nr = domain;
> -}
> -#endif
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 625a4ac..2279414 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -10,6 +10,8 @@
> #include <linux/kernel.h>
> #include <linux/delay.h>
> #include <linux/init.h>
> +#include <linux/of.h>
> +#include <linux/of_pci.h>
> #include <linux/pci.h>
> #include <linux/pm.h>
> #include <linux/slab.h>
> @@ -4447,6 +4449,54 @@ int pci_get_new_domain_nr(void)
> {
> return atomic_inc_return(&__domain_nr);
> }
> +
> +#ifdef CONFIG_PCI_DOMAINS_GENERIC
> +
> +void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
> +{
> + static int use_dt_domains = -1;
> + int domain = of_get_pci_domain_nr(parent->of_node);
> +
> + /*
> + * Check DT domain and use_dt_domains values.
> + *
> + * If DT domain property is valid (domain >= 0) and
> + * use_dt_domains != 0, the DT assignment is valid since this means
> + * we have not previously allocated a domain number by using
> + * pci_get_new_domain_nr(); we should also update use_dt_domains to
> + * 1, to indicate that we have just assigned a domain number from
> + * DT.
> + *
> + * If DT domain property value is not valid (ie domain < 0), and we
> + * have not previously assigned a domain number from DT
> + * (use_dt_domains != 1) we should assign a domain number by
> + * using the:
> + *
> + * pci_get_new_domain_nr()
> + *
> + * API and update the use_dt_domains value to keep track of method we
> + * are using to assign domain numbers (use_dt_domains = 0).
> + *
> + * All other combinations imply we have a platform that is trying
> + * to mix domain numbers obtained from DT and pci_get_new_domain_nr(),
> + * which is a recipe for domain mishandling and it is prevented by
> + * invalidating the domain value (domain = -1) and printing a
> + * corresponding error.
> + */
> + if (domain >= 0 && use_dt_domains) {
> + use_dt_domains = 1;
> + } else if (domain < 0 && use_dt_domains != 1) {
> + use_dt_domains = 0;
> + domain = pci_get_new_domain_nr();
> + } else {
> + dev_err(parent, "Node %s has inconsistent \"linux,pci-domain\" property in DT\n",
> + parent->of_node->full_name);
> + domain = -1;
> + }
> +
> + bus->domain_nr = domain;
> +}
> +#endif
> #endif
>
> /**
> --
> 2.1.2
>
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