[PATCH v5 3/4] PCI/ASPM: Introduce aspm_get_l1ss_cap()

[Jian-Hong Pan]

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@xxxxxxxxxxxxx>
---
 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 91a8b35b1ae2..c55ac11faa73 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -612,6 +612,18 @@ 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)
@@ -722,15 +734,8 @@ 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
-- 
2.44.0