[3/4,SRU,OEM-OSP1-B] UBUNTU: SAUCE: PCI/ASPM: add sysfs attribute for controlling ASPM
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Message ID 20190710094014.18416-4-acelan.kao@canonical.com
State New
Headers show
Series
  • enable realtek ethernet device ASPM function
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Commit Message

AceLan Kao July 10, 2019, 9:40 a.m. UTC
From: Heiner Kallweit <hkallweit1@gmail.com>

BugLink: https://bugs.launchpad.net/bugs/1836030

Link: https://www.spinics.net/lists/linux-pci/msg83231.html

Background of this extension is a problem with the r8169 network driver.
Several combinations of board chipsets and network chip versions have
problems if ASPM is enabled, therefore we have to disable ASPM per default.
However especially on notebooks ASPM can provide significant power-saving,
therefore we want to give users the option to enable ASPM. With the new sysfs
attribute users can control which ASPM link-states are enabled/disabled.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: AceLan Kao <acelan.kao@canonical.com>
---
 Documentation/ABI/testing/sysfs-bus-pci |  13 ++
 drivers/pci/pci.h                       |   8 +-
 drivers/pci/pcie/aspm.c                 | 180 +++++++++++++++++++++++-
 3 files changed, 193 insertions(+), 8 deletions(-)

Patch
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diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 8bfee557e50e..38fe358dee12 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -347,3 +347,16 @@  Description:
 		If the device has any Peer-to-Peer memory registered, this
 	        file contains a '1' if the memory has been published for
 		use outside the driver that owns the device.
+
+What:		/sys/bus/pci/devices/.../power/aspm_link_states
+Date:		May 2019
+Contact:	Heiner Kallweit <hkallweit1@gmail.com>
+Description:
+		If ASPM is supported for an endpoint, then this file can be
+		used to enable / disable link states. A link state
+		displayed in brackets is enabled, otherwise it's disabled.
+		To control link states (case insensitive):
+		+state : enables a supported state
+		-state : disables a state
+		none : disables all link states
+		all : enables all supported link states
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 224d88634115..4093b1154006 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -498,17 +498,13 @@  void pcie_aspm_init_link_state(struct pci_dev *pdev);
 void pcie_aspm_exit_link_state(struct pci_dev *pdev);
 void pcie_aspm_pm_state_change(struct pci_dev *pdev);
 void pcie_aspm_powersave_config_link(struct pci_dev *pdev);
+void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev);
+void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev);
 #else
 static inline void pcie_aspm_init_link_state(struct pci_dev *pdev) { }
 static inline void pcie_aspm_exit_link_state(struct pci_dev *pdev) { }
 static inline void pcie_aspm_pm_state_change(struct pci_dev *pdev) { }
 static inline void pcie_aspm_powersave_config_link(struct pci_dev *pdev) { }
-#endif
-
-#ifdef CONFIG_PCIEASPM_DEBUG
-void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev);
-void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev);
-#else
 static inline void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev) { }
 static inline void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev) { }
 #endif
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 93f581dc47df..210a34f75e0d 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -42,6 +42,8 @@ 
 #define ASPM_STATE_ALL		(ASPM_STATE_L0S | ASPM_STATE_L1 |	\
 				 ASPM_STATE_L1SS)
 
+static const char power_group[] = "power";
+
 struct aspm_latency {
 	u32 l0s;			/* L0s latency (nsec) */
 	u32 l1;				/* L1 latency (nsec) */
@@ -1236,38 +1238,212 @@  static ssize_t clk_ctl_store(struct device *dev,
 
 static DEVICE_ATTR_RW(link_state);
 static DEVICE_ATTR_RW(clk_ctl);
+#endif
+
+struct aspm_sysfs_state {
+	const char *name;
+	int mask;
+};
+
+static const struct aspm_sysfs_state aspm_sysfs_states[] = {
+	{ "L0S",	ASPM_STATE_L0S		},
+	{ "L1",		ASPM_STATE_L1		},
+	{ "L1.1",	ASPM_STATE_L1_1_MASK	},
+	{ "L1.2",	ASPM_STATE_L1_2_MASK	},
+};
+
+static struct pcie_link_state *aspm_get_parent_link(struct pci_dev *pdev)
+{
+	struct pci_dev *parent = pdev->bus->self;
+
+	if (pdev->has_secondary_link)
+		parent = pdev;
+
+	return parent ? parent->link_state : NULL;
+}
+
+static bool pcie_check_aspm_endpoint(struct pci_dev *pdev)
+{
+	struct pcie_link_state *link;
+
+	if (pci_pcie_type(pdev) != PCI_EXP_TYPE_ENDPOINT)
+		return false;
+
+	link = aspm_get_parent_link(pdev);
+
+	return link && link->aspm_support;
+}
+
+static ssize_t aspm_link_states_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct pcie_link_state *link;
+	int len = 0, i;
+
+	link = aspm_get_parent_link(pdev);
+	if (!link)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&aspm_lock);
+
+	for (i = 0; i < ARRAY_SIZE(aspm_sysfs_states); i++) {
+		const struct aspm_sysfs_state *st = aspm_sysfs_states + i;
+
+		if (link->aspm_enabled & st->mask)
+			len += scnprintf(buf + len, PAGE_SIZE - len, "[%s] ",
+					 st->name);
+		else
+			len += scnprintf(buf + len, PAGE_SIZE - len, "%s ",
+					 st->name);
+	}
+
+	if (link->clkpm_enabled)
+		len += scnprintf(buf + len, PAGE_SIZE - len, "[CLKPM] ");
+	else
+		len += scnprintf(buf + len, PAGE_SIZE - len, "CLKPM ");
+
+	mutex_unlock(&aspm_lock);
+
+	len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
+
+	return len;
+}
+
+static ssize_t aspm_link_states_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t len)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct pcie_link_state *link;
+	char *buftmp = (char *)buf, *tok;
+	unsigned int disable_aspm, disable_clkpm;
+	bool first = true, add;
+	int err = 0, i;
+
+	if (aspm_disabled)
+		return -EPERM;
+
+	link = aspm_get_parent_link(pdev);
+	if (!link)
+		return -EOPNOTSUPP;
+
+	down_read(&pci_bus_sem);
+	mutex_lock(&aspm_lock);
+
+	disable_aspm = link->aspm_disable;
+	disable_clkpm = link->clkpm_disable;
+
+	while ((tok = strsep(&buftmp, " \n")) != NULL) {
+		bool found = false;
+
+		if (!*tok)
+			continue;
+
+		if (first) {
+			if (!strcasecmp(tok, "none")) {
+				disable_aspm = ASPM_STATE_ALL;
+				disable_clkpm = 1;
+				break;
+			}
+			if (!strcasecmp(tok, "all")) {
+				disable_aspm = 0;
+				disable_clkpm = 0;
+				break;
+			}
+			first = false;
+		}
+
+		if (*tok != '+' && *tok != '-') {
+			err = -EINVAL;
+			goto out;
+		}
+
+		add = *tok++ == '+';
+
+		for (i = 0; i < ARRAY_SIZE(aspm_sysfs_states); i++) {
+			const struct aspm_sysfs_state *st =
+						aspm_sysfs_states + i;
+
+			if (!strcasecmp(tok, st->name)) {
+				if (add)
+					disable_aspm &= ~st->mask;
+				else
+					disable_aspm |= st->mask;
+				found = true;
+				break;
+			}
+		}
+
+		if (!found && !strcasecmp(tok, "clkpm")) {
+			disable_clkpm = add ? 0 : 1;
+			found = true;
+		}
+
+		if (!found) {
+			err = -EINVAL;
+			goto out;
+		}
+	}
+
+	if (disable_aspm & ASPM_STATE_L1)
+		disable_aspm |= ASPM_STATE_L1SS;
+
+	link->aspm_disable = disable_aspm;
+	link->clkpm_disable = disable_clkpm;
+
+	pcie_config_aspm_link(link, policy_to_aspm_state(link));
+	pcie_set_clkpm(link, policy_to_clkpm_state(link));
+out:
+	mutex_unlock(&aspm_lock);
+	up_read(&pci_bus_sem);
+
+	return err ?: len;
+}
+
+static DEVICE_ATTR_RW(aspm_link_states);
 
-static char power_group[] = "power";
 void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev)
 {
 	struct pcie_link_state *link_state = pdev->link_state;
 
+	if (pcie_check_aspm_endpoint(pdev))
+		sysfs_add_file_to_group(&pdev->dev.kobj,
+			&dev_attr_aspm_link_states.attr, power_group);
+
 	if (!link_state)
 		return;
 
+#ifdef CONFIG_PCIEASPM_DEBUG
 	if (link_state->aspm_support)
 		sysfs_add_file_to_group(&pdev->dev.kobj,
 			&dev_attr_link_state.attr, power_group);
 	if (link_state->clkpm_capable)
 		sysfs_add_file_to_group(&pdev->dev.kobj,
 			&dev_attr_clk_ctl.attr, power_group);
+#endif
 }
 
 void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev)
 {
 	struct pcie_link_state *link_state = pdev->link_state;
 
+	if (pcie_check_aspm_endpoint(pdev))
+		sysfs_remove_file_from_group(&pdev->dev.kobj,
+			&dev_attr_aspm_link_states.attr, power_group);
+
 	if (!link_state)
 		return;
 
+#ifdef CONFIG_PCIEASPM_DEBUG
 	if (link_state->aspm_support)
 		sysfs_remove_file_from_group(&pdev->dev.kobj,
 			&dev_attr_link_state.attr, power_group);
 	if (link_state->clkpm_capable)
 		sysfs_remove_file_from_group(&pdev->dev.kobj,
 			&dev_attr_clk_ctl.attr, power_group);
-}
 #endif
+}
 
 static int __init pcie_aspm_disable(char *str)
 {