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PCI/ASPM: Add pci_enable_link_state()

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Add pci_enable_link_state() to allow devices to change the default BIOS
configured states. Clears the BIOS default settings then sets the new
states and reconfigures the link under the semaphore. Also add
PCIE_LINK_STATE_ALL macro for convenience for callers that want to enable
all link states.

Link: https://lore.kernel.org/r/20230120031522.2304439-2-david.e.box@linux.intel.com
Signed-off-by: Michael Bottini <michael.a.bottini@linux.intel.com>
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Michael Bottini 2023-01-19 19:15:19 -08:00 committed by Lorenzo Pieralisi
parent 1b929c02af
commit de82f60f9c
2 changed files with 61 additions and 0 deletions
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54
drivers/pci/pcie/aspm.c
View file

@ -1181,6 +1181,60 @@ int pci_disable_link_state(struct pci_dev *pdev, int state)
}
EXPORT_SYMBOL(pci_disable_link_state);
/**
* pci_enable_link_state - Clear and set the default device link state so that
* the link may be allowed to enter the specified states. Note that if the
* BIOS didn't grant ASPM control to the OS, this does nothing because we can't
* touch the LNKCTL register. Also note that this does not enable states
* disabled by pci_disable_link_state(). Return 0 or a negative errno.
*
* @pdev: PCI device
* @state: Mask of ASPM link states to enable
*/
int pci_enable_link_state(struct pci_dev *pdev, int state)
{
struct pcie_link_state *link = pcie_aspm_get_link(pdev);
if (!link)
return -EINVAL;
/*
* A driver requested that ASPM be enabled on this device, but
* if we don't have permission to manage ASPM (e.g., on ACPI
* systems we have to observe the FADT ACPI_FADT_NO_ASPM bit and
* the _OSC method), we can't honor that request.
*/
if (aspm_disabled) {
pci_warn(pdev, "can't override BIOS ASPM; OS doesn't have ASPM control\n");
return -EPERM;
}
down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
link->aspm_default = 0;
if (state & PCIE_LINK_STATE_L0S)
link->aspm_default |= ASPM_STATE_L0S;
if (state & PCIE_LINK_STATE_L1)
/* L1 PM substates require L1 */
link->aspm_default |= ASPM_STATE_L1 | ASPM_STATE_L1SS;
if (state & PCIE_LINK_STATE_L1_1)
link->aspm_default |= ASPM_STATE_L1_1;
if (state & PCIE_LINK_STATE_L1_2)
link->aspm_default |= ASPM_STATE_L1_2;
if (state & PCIE_LINK_STATE_L1_1_PCIPM)
link->aspm_default |= ASPM_STATE_L1_1_PCIPM;
if (state & PCIE_LINK_STATE_L1_2_PCIPM)
link->aspm_default |= ASPM_STATE_L1_2_PCIPM;
pcie_config_aspm_link(link, policy_to_aspm_state(link));
link->clkpm_default = (state & PCIE_LINK_STATE_CLKPM) ? 1 : 0;
pcie_set_clkpm(link, policy_to_clkpm_state(link));
mutex_unlock(&aspm_lock);
up_read(&pci_bus_sem);
return 0;
}
EXPORT_SYMBOL(pci_enable_link_state);
static int pcie_aspm_set_policy(const char *val,
const struct kernel_param *kp)
{

7
include/linux/pci.h
View file

@ -1685,10 +1685,15 @@ extern bool pcie_ports_native;
#define PCIE_LINK_STATE_L1_2 BIT(4)
#define PCIE_LINK_STATE_L1_1_PCIPM BIT(5)
#define PCIE_LINK_STATE_L1_2_PCIPM BIT(6)
#define PCIE_LINK_STATE_ALL (PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1 |\
PCIE_LINK_STATE_CLKPM | PCIE_LINK_STATE_L1_1 |\
PCIE_LINK_STATE_L1_2 | PCIE_LINK_STATE_L1_1_PCIPM |\
PCIE_LINK_STATE_L1_2_PCIPM)
#ifdef CONFIG_PCIEASPM
int pci_disable_link_state(struct pci_dev *pdev, int state);
int pci_disable_link_state_locked(struct pci_dev *pdev, int state);
int pci_enable_link_state(struct pci_dev *pdev, int state);
void pcie_no_aspm(void);
bool pcie_aspm_support_enabled(void);
bool pcie_aspm_enabled(struct pci_dev *pdev);
@ -1697,6 +1702,8 @@ static inline int pci_disable_link_state(struct pci_dev *pdev, int state)
{ return 0; }
static inline int pci_disable_link_state_locked(struct pci_dev *pdev, int state)
{ return 0; }
static inline int pci_enable_link_state(struct pci_dev *pdev, int state)
{ return 0; }
static inline void pcie_no_aspm(void) { }
static inline bool pcie_aspm_support_enabled(void) { return false; }
static inline bool pcie_aspm_enabled(struct pci_dev *pdev) { return false; }