[PATCH 1/3] PCI/ASPM: Factor out L1 PM Substates configuration

From: Bjorn Helgaas
Date: Tue Oct 04 2022 - 22:58:31 EST


From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

Move L1 PM Substates configuration from pcie_aspm_cap_init() to a new
aspm_l1ss_init() function. No functional change intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
drivers/pci/pcie/aspm.c | 103 +++++++++++++++++++++-------------------
1 file changed, 55 insertions(+), 48 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 016d222b07c7..4535228e4a64 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -554,13 +554,65 @@ static void aspm_calc_l1ss_info(struct pcie_link_state *link,
aspm_program_l1ss(child, cctl1, ctl2);
}

+static void aspm_l1ss_init(struct pcie_link_state *link)
+{
+ struct pci_dev *child = link->downstream, *parent = link->pdev;
+ u32 parent_l1ss_cap, child_l1ss_cap;
+ u32 parent_l1ss_ctl1 = 0, child_l1ss_ctl1 = 0;
+
+ /* Setup L1 substate */
+ pci_read_config_dword(parent, parent->l1ss + PCI_L1SS_CAP,
+ &parent_l1ss_cap);
+ pci_read_config_dword(child, child->l1ss + PCI_L1SS_CAP,
+ &child_l1ss_cap);
+
+ if (!(parent_l1ss_cap & PCI_L1SS_CAP_L1_PM_SS))
+ parent_l1ss_cap = 0;
+ if (!(child_l1ss_cap & PCI_L1SS_CAP_L1_PM_SS))
+ child_l1ss_cap = 0;
+
+ /*
+ * If we don't have LTR for the entire path from the Root Complex
+ * to this device, we can't use ASPM L1.2 because it relies on the
+ * LTR_L1.2_THRESHOLD. See PCIe r4.0, secs 5.5.4, 6.18.
+ */
+ if (!child->ltr_path)
+ child_l1ss_cap &= ~PCI_L1SS_CAP_ASPM_L1_2;
+
+ if (parent_l1ss_cap & child_l1ss_cap & PCI_L1SS_CAP_ASPM_L1_1)
+ link->aspm_support |= ASPM_STATE_L1_1;
+ if (parent_l1ss_cap & child_l1ss_cap & PCI_L1SS_CAP_ASPM_L1_2)
+ link->aspm_support |= ASPM_STATE_L1_2;
+ if (parent_l1ss_cap & child_l1ss_cap & PCI_L1SS_CAP_PCIPM_L1_1)
+ link->aspm_support |= ASPM_STATE_L1_1_PCIPM;
+ if (parent_l1ss_cap & child_l1ss_cap & PCI_L1SS_CAP_PCIPM_L1_2)
+ link->aspm_support |= ASPM_STATE_L1_2_PCIPM;
+
+ if (parent_l1ss_cap)
+ pci_read_config_dword(parent, parent->l1ss + PCI_L1SS_CTL1,
+ &parent_l1ss_ctl1);
+ if (child_l1ss_cap)
+ pci_read_config_dword(child, child->l1ss + PCI_L1SS_CTL1,
+ &child_l1ss_ctl1);
+
+ if (parent_l1ss_ctl1 & child_l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_1)
+ link->aspm_enabled |= ASPM_STATE_L1_1;
+ if (parent_l1ss_ctl1 & child_l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_2)
+ link->aspm_enabled |= ASPM_STATE_L1_2;
+ if (parent_l1ss_ctl1 & child_l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_1)
+ link->aspm_enabled |= ASPM_STATE_L1_1_PCIPM;
+ if (parent_l1ss_ctl1 & child_l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_2)
+ link->aspm_enabled |= ASPM_STATE_L1_2_PCIPM;
+
+ if (link->aspm_support & ASPM_STATE_L1SS)
+ aspm_calc_l1ss_info(link, parent_l1ss_cap, child_l1ss_cap);
+}
+
static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
{
struct pci_dev *child = link->downstream, *parent = link->pdev;
u32 parent_lnkcap, child_lnkcap;
u16 parent_lnkctl, child_lnkctl;
- u32 parent_l1ss_cap, child_l1ss_cap;
- u32 parent_l1ss_ctl1 = 0, child_l1ss_ctl1 = 0;
struct pci_bus *linkbus = parent->subordinate;

if (blacklist) {
@@ -615,52 +667,7 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
if (parent_lnkctl & child_lnkctl & PCI_EXP_LNKCTL_ASPM_L1)
link->aspm_enabled |= ASPM_STATE_L1;

- /* Setup L1 substate */
- pci_read_config_dword(parent, parent->l1ss + PCI_L1SS_CAP,
- &parent_l1ss_cap);
- pci_read_config_dword(child, child->l1ss + PCI_L1SS_CAP,
- &child_l1ss_cap);
-
- if (!(parent_l1ss_cap & PCI_L1SS_CAP_L1_PM_SS))
- parent_l1ss_cap = 0;
- if (!(child_l1ss_cap & PCI_L1SS_CAP_L1_PM_SS))
- child_l1ss_cap = 0;
-
- /*
- * If we don't have LTR for the entire path from the Root Complex
- * to this device, we can't use ASPM L1.2 because it relies on the
- * LTR_L1.2_THRESHOLD. See PCIe r4.0, secs 5.5.4, 6.18.
- */
- if (!child->ltr_path)
- child_l1ss_cap &= ~PCI_L1SS_CAP_ASPM_L1_2;
-
- if (parent_l1ss_cap & child_l1ss_cap & PCI_L1SS_CAP_ASPM_L1_1)
- link->aspm_support |= ASPM_STATE_L1_1;
- if (parent_l1ss_cap & child_l1ss_cap & PCI_L1SS_CAP_ASPM_L1_2)
- link->aspm_support |= ASPM_STATE_L1_2;
- if (parent_l1ss_cap & child_l1ss_cap & PCI_L1SS_CAP_PCIPM_L1_1)
- link->aspm_support |= ASPM_STATE_L1_1_PCIPM;
- if (parent_l1ss_cap & child_l1ss_cap & PCI_L1SS_CAP_PCIPM_L1_2)
- link->aspm_support |= ASPM_STATE_L1_2_PCIPM;
-
- if (parent_l1ss_cap)
- pci_read_config_dword(parent, parent->l1ss + PCI_L1SS_CTL1,
- &parent_l1ss_ctl1);
- if (child_l1ss_cap)
- pci_read_config_dword(child, child->l1ss + PCI_L1SS_CTL1,
- &child_l1ss_ctl1);
-
- if (parent_l1ss_ctl1 & child_l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_1)
- link->aspm_enabled |= ASPM_STATE_L1_1;
- if (parent_l1ss_ctl1 & child_l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_2)
- link->aspm_enabled |= ASPM_STATE_L1_2;
- if (parent_l1ss_ctl1 & child_l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_1)
- link->aspm_enabled |= ASPM_STATE_L1_1_PCIPM;
- if (parent_l1ss_ctl1 & child_l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_2)
- link->aspm_enabled |= ASPM_STATE_L1_2_PCIPM;
-
- if (link->aspm_support & ASPM_STATE_L1SS)
- aspm_calc_l1ss_info(link, parent_l1ss_cap, child_l1ss_cap);
+ aspm_l1ss_init(link);

/* Save default state */
link->aspm_default = link->aspm_enabled;
--
2.25.1