[PATCH v7 3/4] PCI/ASPM: Introduce aspm_get_l1ss_cap()

Jian-Hong Pan
2024-06-26T09:40:14Z

Introduce aspm_get_l1ss_cap() which is extracted from aspm_l1ss_init() to
get the PCIe's L1SS capability. This does not change any behavior, but
aspm_get_l1ss_cap() can be reused later.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=218394
Signed-off-by: Jian-Hong Pan <jhp@endlessos.org>
Reviewed-by: David E. Box <david.e.box@linux.intel.com>
---
v6:
- Skipped

v7:
- Pick back

drivers/pci/pcie/aspm.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index bd0a8a05647e..5db1044c9895 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -611,6 +611,18 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint)
}
}

+static u32 aspm_get_l1ss_cap(struct pci_dev *pdev)
+{
+ u32 l1ss_cap;
+
+ pci_read_config_dword(pdev, pdev->l1ss + PCI_L1SS_CAP, &l1ss_cap);
+
+ if (!(l1ss_cap & PCI_L1SS_CAP_L1_PM_SS))
+ l1ss_cap = 0;
+
+ return l1ss_cap;
+}
+
/* Calculate L1.2 PM substate timing parameters */
static void aspm_calc_l12_info(struct pcie_link_state *link,
u32 parent_l1ss_cap, u32 child_l1ss_cap)
@@ -721,15 +733,8 @@ static void aspm_l1ss_init(struct pcie_link_state *link)
return;

/* 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;
+ parent_l1ss_cap = aspm_get_l1ss_cap(parent);
+ child_l1ss_cap = aspm_get_l1ss_cap(child);

/*
* If we don't have LTR for the entire path from the Root Complex
--
2.45.2