On Thu, Oct 25, 2018 at 11:01:32AM -0500, Aaron Sierra wrote:
> This patch reorganizes negotiate_os_control() to be less ASPM-centric in
> order to:
>
> 1. allow other features (notably AER) to work without enabling ASPM
> 2. better isolate feature-specific tests for readability/maintenance
I really like this idea; thanks for working it up!
> Each feature (ASPM, PCIe hotplug, SHPC hotplug, and AER) now has its own
> inline function for setting its _OSC control requests.
>
> Part of making this function more generic, required eliminating a test
> for overall success/failure that previously caused two different types
> of messages to be printed. Now, printed messages are streamlined to
> always show requested _OSC control versus what was granted.
>
> Previous output (success):
>
> acpi PNP0A08:00: _OSC: OS now controls [PME AER PCIeCapability LTR]
>
> Previous output (failure):
>
> acpi PNP0A08:00: _OSC: OS requested [PME AER PCIeCapability LTR]
> acpi PNP0A08:00: _OSC: platform willing to grant []
>
> Now:
>
> acpi PNP0A08:00: _OSC: OS requested [PME AER PCIeCapability LTR]
> acpi PNP0A08:00: _OSC: platform granted [PME AER PCIeCapability LTR]
>
> Signed-off-by: Aaron Sierra <asierra@xxxxxxxxxxx>
> ---
> drivers/acpi/pci_root.c | 118 ++++++++++++++++++++++++++++++++++--------------
> 1 file changed, 85 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index eb9f14e..9685aba 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -53,9 +53,10 @@ static int acpi_pci_root_scan_dependent(struct acpi_device *adev)
> }
>
> #define ACPI_PCIE_REQ_SUPPORT (OSC_PCI_EXT_CONFIG_SUPPORT \
> - | OSC_PCI_ASPM_SUPPORT \
> - | OSC_PCI_CLOCK_PM_SUPPORT \
> | OSC_PCI_MSI_SUPPORT)
> +#define ACPI_PCIE_ASPM_SUPPORT (ACPI_PCIE_REQ_SUPPORT \
> + | OSC_PCI_ASPM_SUPPORT \
> + | OSC_PCI_CLOCK_PM_SUPPORT)
>
> static const struct acpi_device_id root_device_ids[] = {
> {"PNP0A03", 0},
> @@ -421,6 +422,72 @@ acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)
> }
> EXPORT_SYMBOL(acpi_pci_osc_control_set);
>
> +static inline bool __osc_have_support(u32 support, u32 required)
> +{
> + return ((support & required) == required);
> +}
I'm not really a fan of function names with leading underscores, except
maybe for "raw" things that don't acquire locks.
> +static inline int __osc_set_aspm_control(struct acpi_pci_root *root,
> + u32 support, u32 *control)
> +{
> + if (!IS_ENABLED(CONFIG_PCIEASPM) ||
> + !__osc_have_support(support, ACPI_PCIE_ASPM_SUPPORT))
> + return -ENODEV;
> +
> + *control |= OSC_PCI_EXPRESS_CAPABILITY_CONTROL |
> + OSC_PCI_EXPRESS_LTR_CONTROL |
> + OSC_PCI_EXPRESS_PME_CONTROL;
I think this would be more readable if we could avoid the double
negatives, e.g.,
if (IS_ENABLED(CONFIG_PCIEASPM) &&
__osc_have_support(support, ACPI_PCIE_ASPM_SUPPORT)) {
*control |= OSC_PCI_EXPRESS_CAPABILITY_CONTROL |
OSC_PCI_EXPRESS_LTR_CONTROL |
OSC_PCI_EXPRESS_PME_CONTROL;
return 0;
}
return -ENODEV;
Since the caller ignores the return values anyway, I wonder if this
could also work by *returning* the new mask bits instead of using
"control" as a reference parameter, e.g.,
if (IS_ENABLED(...))
return OSC_PCI_EXPRESS_CAPABILITY_CONTROL |
OSC_PCI_EXPRESS_LTR_CONTROL |
OSC_PCI_EXPRESS_PME_CONTROL;
return 0;
Then the calls would look like:
control |= __osc_set_pciehp_control(root, support);
control |= __osc_set_shpchp_control(root, support);
...
> + return 0;
> +}
> +
> +static inline bool __osc_have_aspm_control(u32 control)
> +{
> + u32 required = OSC_PCI_EXPRESS_CAPABILITY_CONTROL |
> + OSC_PCI_EXPRESS_LTR_CONTROL |
> + OSC_PCI_EXPRESS_PME_CONTROL;
> +
> + return __osc_have_support(control, required);
> +}
> +
> +static inline void __osc_set_pciehp_control(struct acpi_pci_root *root,
> + u32 support, u32 *control)
> +{
> + if (!IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE) ||
> + !__osc_have_support(support, ACPI_PCIE_REQ_SUPPORT))
> + return;
> +
> + *control |= OSC_PCI_EXPRESS_CAPABILITY_CONTROL |
> + OSC_PCI_EXPRESS_NATIVE_HP_CONTROL;
> +}
> +
> +static inline void __osc_set_shpchp_control(struct acpi_pci_root *root,
> + u32 support, u32 *control)
> +{
> + if (!IS_ENABLED(CONFIG_HOTPLUG_PCI_SHPC) ||
> + !__osc_have_support(support, ACPI_PCIE_REQ_SUPPORT))
> + return;
> +
> + *control |= OSC_PCI_EXPRESS_CAPABILITY_CONTROL |
> + OSC_PCI_SHPC_NATIVE_HP_CONTROL;
> +}
> +
> +static inline void __osc_set_aer_control(struct acpi_pci_root *root,
> + u32 support, u32 *control)
> +{
> + if (!pci_aer_available() ||
> + !__osc_have_support(support, ACPI_PCIE_REQ_SUPPORT))
> + return;
> +
> + if (aer_acpi_firmware_first()) {
> + dev_info(&root->device->dev, "PCIe AER handled by firmware\n");
> + return;
> + }
> +
> + *control |= OSC_PCI_EXPRESS_CAPABILITY_CONTROL |
> + OSC_PCI_EXPRESS_AER_CONTROL;
> +}
> +
> static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
> bool is_pcie)
> {
> @@ -474,37 +541,25 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
> return;
> }
>
> - if ((support & ACPI_PCIE_REQ_SUPPORT) != ACPI_PCIE_REQ_SUPPORT) {
> - decode_osc_support(root, "not requesting OS control; OS requires",
> - ACPI_PCIE_REQ_SUPPORT);
> - return;
> - }
> -
> - control = OSC_PCI_EXPRESS_CAPABILITY_CONTROL
> - | OSC_PCI_EXPRESS_PME_CONTROL;
> -
> - if (IS_ENABLED(CONFIG_PCIEASPM))
> - control |= OSC_PCI_EXPRESS_LTR_CONTROL;
> -
> - if (IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE))
> - control |= OSC_PCI_EXPRESS_NATIVE_HP_CONTROL;
> + control = 0;
> + if (__osc_set_aspm_control(root, support, &control))
> + *no_aspm = 1;
>
> - if (IS_ENABLED(CONFIG_HOTPLUG_PCI_SHPC))
> - control |= OSC_PCI_SHPC_NATIVE_HP_CONTROL;
> + __osc_set_pciehp_control(root, support, &control);
> + __osc_set_shpchp_control(root, support, &control);
> + __osc_set_aer_control(root, support, &control);
>
> - if (pci_aer_available()) {
> - if (aer_acpi_firmware_first())
> - dev_info(&device->dev,
> - "PCIe AER handled by firmware\n");
> - else
> - control |= OSC_PCI_EXPRESS_AER_CONTROL;
> + if (!control) {
> + dev_info(&device->dev, "_OSC: not requesting OS control\n");
> + return;
> }
>
> requested = control;
> - status = acpi_pci_osc_control_set(handle, &control,
> - OSC_PCI_EXPRESS_CAPABILITY_CONTROL);
> - if (ACPI_SUCCESS(status)) {
> - decode_osc_control(root, "OS now controls", control);
> + acpi_pci_osc_control_set(handle, &control, 0);
> + decode_osc_control(root, "OS requested", requested);
> + decode_osc_control(root, "platform granted", control);
> +
> + if (__osc_have_aspm_control(control)) {
> if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
> /*
> * We have ASPM control, but the FADT indicates that
> @@ -514,11 +569,8 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
> dev_info(&device->dev, "FADT indicates ASPM is unsupported, using BIOS configuration\n");
> *no_aspm = 1;
> }
> - } else {
> - decode_osc_control(root, "OS requested", requested);
> - decode_osc_control(root, "platform willing to grant", control);
> - dev_info(&device->dev, "_OSC failed (%s); disabling ASPM\n",
> - acpi_format_exception(status));
> + } else if (!*no_aspm) {
> + dev_info(&device->dev, "_OSC failed; disabling ASPM\n");
>
> /*
> * We want to disable ASPM here, but aspm_disabled
> --
> 2.7.4
>
