Re: [PATCH v8 2/5] ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.

Bjorn Helgaas
2020-09-10T20:20:59Z

On Fri, Jul 24, 2020 at 08:58:53PM -0700, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>
> pcie_ports_native is set only if user requests native handling
> of PCIe capabilities via pcie_port_setup command line option.
> User input takes precedence over _OSC based control negotiation
> result. So consider the _OSC negotiated result only if
> pcie_ports_native is unset.
>
> Also, since struct pci_host_bridge ->native_* members caches the
> ownership status of various PCIe capabilities, use them instead
> of distributed checks for pcie_ports_native.
>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> ---
> drivers/acpi/pci_root.c | 61 ++++++++++++++++++++++++++-----
> drivers/pci/hotplug/pciehp_core.c | 2 +-
> drivers/pci/pci-acpi.c | 3 --
> drivers/pci/pcie/aer.c | 2 +-
> drivers/pci/pcie/portdrv_core.c | 9 ++---
> 5 files changed, 56 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index f90e841c59f5..f8981d4e044d 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -145,6 +145,17 @@ static struct pci_osc_bit_struct pci_osc_control_bit[] = {
> { OSC_PCI_EXPRESS_DPC_CONTROL, "DPC" },
> };
>
> +static char *get_osc_desc(u32 bit)
> +{
> + int i = 0;
> +
> + for (i = 0; i < ARRAY_SIZE(pci_osc_control_bit); i++)
> + if (bit == pci_osc_control_bit[i].bit)
> + return pci_osc_control_bit[i].desc;
> +
> + return NULL;
> +}
> +
> static void decode_osc_bits(struct acpi_pci_root *root, char *msg, u32 word,
> struct pci_osc_bit_struct *table, int size)
> {
> @@ -914,18 +925,48 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
> goto out_release_info;
>
> host_bridge = to_pci_host_bridge(bus->bridge);
> - if (!(root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
> - host_bridge->native_pcie_hotplug = 0;
> + if (!(root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL)) {
> + if (!pcie_ports_native)
> + host_bridge->native_pcie_hotplug = 0;
> + else
> + dev_warn(&bus->dev, "OS overrides %s firmware control",
> + get_osc_desc(OSC_PCI_EXPRESS_NATIVE_HP_CONTROL));

There's got to be a way to write this more concisely. Maybe something
like this?

#define OSC_OWNER(ctrl, bit, flag) \
if (!(ctrl & bit)) \
flag = 0;

if (pcie_ports_native)
decode_osc_control(root, "OS forcibly taking over", ~0);
else {
ctrl = root->osc_control_set;
OSC_OWNER(ctrl, OSC_PCI_EXPRESS_AER_CONTROL, host_bridge->native_aer);
OSC_OWNER(ctrl, OSC_PCI_EXPRESS_PME_CONTROL, host_bridge->native_pme);
...
}

> + }
> +
> if (!(root->osc_control_set & OSC_PCI_SHPC_NATIVE_HP_CONTROL))
> host_bridge->native_shpc_hotplug = 0;
> - if (!(root->osc_control_set & OSC_PCI_EXPRESS_AER_CONTROL))
> - host_bridge->native_aer = 0;
> - if (!(root->osc_control_set & OSC_PCI_EXPRESS_PME_CONTROL))
> - host_bridge->native_pme = 0;
> - if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
> - host_bridge->native_ltr = 0;
> - if (!(root->osc_control_set & OSC_PCI_EXPRESS_DPC_CONTROL))
> - host_bridge->native_dpc = 0;
> +
> + if (!(root->osc_control_set & OSC_PCI_EXPRESS_AER_CONTROL)) {
> + if (!pcie_ports_native)
> + host_bridge->native_aer = 0;
> + else
> + dev_warn(&bus->dev, "OS overrides %s firmware control",
> + get_osc_desc(OSC_PCI_EXPRESS_AER_CONTROL));
> + }
> +
> + if (!(root->osc_control_set & OSC_PCI_EXPRESS_PME_CONTROL)) {
> + if (!pcie_ports_native)
> + host_bridge->native_pme = 0;
> + else
> + dev_warn(&bus->dev, "OS overrides %s firmware control",
> + get_osc_desc(OSC_PCI_EXPRESS_PME_CONTROL));
> + }
> +
> + if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL)) {
> + if (!pcie_ports_native)
> + host_bridge->native_ltr = 0;
> + else
> + dev_warn(&bus->dev, "OS overrides %s firmware control",
> + get_osc_desc(OSC_PCI_EXPRESS_LTR_CONTROL));
> + }
> +
> + if (!(root->osc_control_set & OSC_PCI_EXPRESS_DPC_CONTROL)) {
> + if (!pcie_ports_native)
> + host_bridge->native_dpc = 0;
> + else
> + dev_warn(&bus->dev, "OS overrides %s firmware control",
> + get_osc_desc(OSC_PCI_EXPRESS_DPC_CONTROL));
> + }
>
> /*
> * Evaluate the "PCI Boot Configuration" _DSM Function. If it
> diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
> index bf779f291f15..5fc999bf6f1b 100644
> --- a/drivers/pci/hotplug/pciehp_core.c
> +++ b/drivers/pci/hotplug/pciehp_core.c
> @@ -255,7 +255,7 @@ static bool pme_is_native(struct pcie_device *dev)
> const struct pci_host_bridge *host;
>
> host = pci_find_host_bridge(dev->port->bus);
> - return pcie_ports_native || host->native_pme;
> + return host->native_pme;

I love this part!

> }
>
> static void pciehp_disable_interrupt(struct pcie_device *dev)
> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
> index 7224b1e5f2a8..e09589571a9d 100644
> --- a/drivers/pci/pci-acpi.c
> +++ b/drivers/pci/pci-acpi.c
> @@ -800,9 +800,6 @@ bool pciehp_is_native(struct pci_dev *bridge)
> if (!(slot_cap & PCI_EXP_SLTCAP_HPC))
> return false;
>
> - if (pcie_ports_native)
> - return true;
> -
> host = pci_find_host_bridge(bridge->bus);
> return host->native_pcie_hotplug;
> }
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index 3acf56683915..d663bd9c7257 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -219,7 +219,7 @@ int pcie_aer_is_native(struct pci_dev *dev)
> if (!dev->aer_cap)
> return 0;
>
> - return pcie_ports_native || host->native_aer;
> + return host->native_aer;
> }
>
> int pci_enable_pcie_error_reporting(struct pci_dev *dev)
> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index 50a9522ab07d..ccd5e0ce5605 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -208,8 +208,7 @@ static int get_port_device_capability(struct pci_dev *dev)
> struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
> int services = 0;
>
> - if (dev->is_hotplug_bridge &&
> - (pcie_ports_native || host->native_pcie_hotplug)) {
> + if (dev->is_hotplug_bridge && host->native_pcie_hotplug) {
> services |= PCIE_PORT_SERVICE_HP;
>
> /*
> @@ -221,8 +220,7 @@ static int get_port_device_capability(struct pci_dev *dev)
> }
>
> #ifdef CONFIG_PCIEAER
> - if (dev->aer_cap && pci_aer_available() &&
> - (pcie_ports_native || host->native_aer)) {
> + if (dev->aer_cap && pci_aer_available() && host->native_aer) {
> services |= PCIE_PORT_SERVICE_AER;
>
> /*
> @@ -238,8 +236,7 @@ static int get_port_device_capability(struct pci_dev *dev)
> * Event Collectors can also generate PMEs, but we don't handle
> * those yet.
> */
> - if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT &&
> - (pcie_ports_native || host->native_pme)) {
> + if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT && host->native_pme) {
> services |= PCIE_PORT_SERVICE_PME;
>
> /*
> --
> 2.17.1
>