linux-kernel - [RFC PATCH v1 2/4] PCI/ASPM: Remove struct pcie_link_state.clkpm

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Date:   Wed, 29 Sep 2021 02:43:58 +0200
From:   "Saheed O. Bolarinwa" <refactormyself@...il.com>
To:     helgaas@...nel.org
Cc:     "Bolarinwa O. Saheed" <refactormyself@...il.com>,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH v1 2/4] PCI/ASPM: Remove struct pcie_link_state.clkpm_capable

From: "Bolarinwa O. Saheed" <refactormyself@...il.com>

The clkpm_capable member of the struct pcie_link_state indicates
if the device is Clock PM capable. This can be calculated when
it is needed.

This patch:
  - removes clkpm_capable from struct pcie_link_state
  - moves the calculation of clkpm_capable into
    pcie_is_clkpm_capable()
  - replaces references to clkpm_capable with a call to
    pcie_is_clkpm_capable()

Signed-off-by: Bolarinwa O. Saheed <refactormyself@...il.com>
---
 drivers/pci/pcie/aspm.c | 39 ++++++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 17 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index c23da9a4e2fb..9e65da9a22dd 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -61,7 +61,6 @@ struct pcie_link_state {
 	u32 aspm_disable:7;		/* Disabled ASPM state */
 
 	/* Clock PM state */
-	u32 clkpm_capable:1;		/* Clock PM capable? */
 	u32 clkpm_enabled:1;		/* Current Clock PM state */
 	u32 clkpm_disable:1;		/* Clock PM disabled */
 
@@ -146,6 +145,25 @@ static int pcie_get_clkpm_state(struct pci_dev *pdev)
 	return enabled;
 }
 
+static int pcie_is_clkpm_capable(struct pci_dev *pdev)
+{
+	int capable = 1;
+	u32 reg32;
+	struct pci_dev *child;
+	struct pci_bus *linkbus = pdev->subordinate;
+
+	/* All functions should have the same cap state, take the worst */
+	list_for_each_entry(child, &linkbus->devices, bus_list) {
+		pcie_capability_read_dword(child, PCI_EXP_LNKCAP, &reg32);
+		if (!(reg32 & PCI_EXP_LNKCAP_CLKPM)) {
+			capable = 0;
+			break;
+		}
+	}
+
+	return capable;
+}
+
 static int policy_to_clkpm_state(struct pcie_link_state *link)
 {
 	switch (aspm_policy) {
@@ -177,11 +195,12 @@ static void pcie_set_clkpm_nocheck(struct pcie_link_state *link, int enable)
 
 static void pcie_set_clkpm(struct pcie_link_state *link, int enable)
 {
+	int capable = pcie_is_clkpm_capable(link->pdev);
 	/*
 	 * Don't enable Clock PM if the link is not Clock PM capable
 	 * or Clock PM is disabled
 	 */
-	if (!link->clkpm_capable || link->clkpm_disable)
+	if (!capable || link->clkpm_disable)
 		enable = 0;
 	/* Need nothing if the specified equals to current state */
 	if (link->clkpm_enabled == enable)
@@ -191,21 +210,7 @@ static void pcie_set_clkpm(struct pcie_link_state *link, int enable)
 
 static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
 {
-	int capable = 1;
-	u32 reg32;
-	struct pci_dev *child;
-	struct pci_bus *linkbus = link->pdev->subordinate;
-
-	/* All functions should have the same cap and state, take the worst */
-	list_for_each_entry(child, &linkbus->devices, bus_list) {
-		pcie_capability_read_dword(child, PCI_EXP_LNKCAP, &reg32);
-		if (!(reg32 & PCI_EXP_LNKCAP_CLKPM)) {
-			capable = 0;
-			break;
-		}
-	}
 	link->clkpm_enabled = pcie_get_clkpm_state(link->pdev);
-	link->clkpm_capable = capable;
 	link->clkpm_disable = blacklist ? 1 : 0;
 }
 
@@ -1346,7 +1351,7 @@ static umode_t aspm_ctrl_attrs_are_visible(struct kobject *kobj,
 		return 0;
 
 	if (n == 0)
-		return link->clkpm_capable ? a->mode : 0;
+		return pcie_is_clkpm_capable(link->pdev) ? a->mode : 0;
 
 	return link->aspm_capable & aspm_state_map[n - 1] ? a->mode : 0;
 }
-- 
2.20.1