Re: [PATCH v11 2/5] ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.

From: Bjorn Helgaas
Date: Wed Nov 25 2020 - 15:13:34 EST

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On Mon, Oct 26, 2020 at 07:57:05PM -0700, Kuppuswamy Sathyanarayanan wrote:
> 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@xxxxxxxxxxxxxxx>
> ---
> drivers/acpi/pci_root.c | 35 ++++++++++++++++++++++---------
> 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 +++-----
> include/linux/acpi.h | 2 ++
> 6 files changed, 32 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index c12b5fb3e8fb..a9e6b782622d 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -41,6 +41,12 @@ static int acpi_pci_root_scan_dependent(struct acpi_device *adev)
> | OSC_PCI_CLOCK_PM_SUPPORT \
> | OSC_PCI_MSI_SUPPORT)
>
> +#define OSC_OWNER(ctrl, bit, flag) \
> + do { \
> + if (!(ctrl & bit)) \
> + flag = 0; \
> + } while (0)
> +
> static const struct acpi_device_id root_device_ids[] = {
> {"PNP0A03", 0},
> {"", 0},
> @@ -887,6 +893,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
> struct pci_bus *bus;
> struct pci_host_bridge *host_bridge;
> union acpi_object *obj;
> + u32 ctrl;
>
> info->root = root;
> info->bridge = device;
> @@ -912,18 +919,26 @@ 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 (pcie_ports_native) {
> + decode_osc_control(root, "OS forcibly taking over",
> + OSC_PCI_EXPRESS_CONTROL_MASKS);

The only place OSC_PCI_EXPRESS_CONTROL_MASKS is used is right here, so
it's kind of pointless.

I think I'd rather have this:

dev_info(&root->device->dev, "Ignoring PCIe-related _OSC results because \"pcie_ports=native\" specified\n");

> + } else {
> + ctrl = root->osc_control_set;
> + OSC_OWNER(ctrl, OSC_PCI_EXPRESS_NATIVE_HP_CONTROL,
> + host_bridge->native_pcie_hotplug);
> + OSC_OWNER(ctrl, OSC_PCI_EXPRESS_AER_CONTROL,
> + host_bridge->native_aer);
> + OSC_OWNER(ctrl, OSC_PCI_EXPRESS_PME_CONTROL,
> + host_bridge->native_pme);
> + OSC_OWNER(ctrl, OSC_PCI_EXPRESS_LTR_CONTROL,
> + host_bridge->native_ltr);
> + OSC_OWNER(ctrl, OSC_PCI_EXPRESS_DPC_CONTROL,
> + host_bridge->native_dpc);
> + }
> +
> 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;

followed by something like this after we're done fiddling with all the
host_bridge->native* bits:

#define FLAG(x) ((x) ? '+' : '-')

dev_info(&root->device->dev, "OS native features: SHPCHotplug%c PCIeCapability%c PCIeHotplug%c PME%c AER%c DPC%c LTR%c\n",
FLAG(host_bridge->native_shpc_hotplug),
?,
FLAG(host_bridge->native_pcie_hotplug),
...);

But I don't know how to handle OSC_PCI_EXPRESS_CAPABILITY_CONTROL
since we don't track it the same way. Maybe we'd have to omit it from
this message for now?

> /*
> * 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 ad3393930ecb..d1831e6bf60a 100644
> --- a/drivers/pci/hotplug/pciehp_core.c
> +++ b/drivers/pci/hotplug/pciehp_core.c
> @@ -256,7 +256,7 @@ 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;
> }
>
> static void pciehp_disable_interrupt(struct pcie_device *dev)
> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
> index bf03648c2072..a84f75ec6df8 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 65dff5f3457a..79bb441139c2 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;
>
> /*
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 39263c6b52e1..35689f4e8e1f 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -569,6 +569,8 @@ extern bool osc_pc_lpi_support_confirmed;
> #define OSC_PCI_EXPRESS_LTR_CONTROL 0x00000020
> #define OSC_PCI_EXPRESS_DPC_CONTROL 0x00000080
> #define OSC_PCI_CONTROL_MASKS 0x000000bf
> +/* Masks specific to PCIe Capabilities */
> +#define OSC_PCI_EXPRESS_CONTROL_MASKS 0x000000bd
>
> #define ACPI_GSB_ACCESS_ATTRIB_QUICK 0x00000002
> #define ACPI_GSB_ACCESS_ATTRIB_SEND_RCV 0x00000004
> --
> 2.17.1
>

Next message: Minchan Kim: "Re: [PATCH 1/4] mm: introduce cma_alloc_bulk API"
Previous message: Palmer Dabbelt: "[PATCH] drivers: clocksource: timer-riscv: Depend on the SBI"
Next in thread: Kuppuswamy, Sathyanarayanan: "Re: [PATCH v11 2/5] ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set."
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