[PATCH 5/7][SRU][Focal] PCI/ASPM: Add sysfs attributes for controlling ASPM link states
AceLan Kao
acelan.kao at canonical.com
Tue Mar 10 01:48:34 UTC 2020
From: Heiner Kallweit <hkallweit1 at gmail.com>
BugLink: https://bugs.launchpad.net/ubuntu/bugs/1836030
Add sysfs attributes to Endpoints and other Upstream Ports to control ASPM,
Clock PM, and L1 PM Substates. The new attributes are:
/sys/devices/pci*/.../link/clkpm
/sys/devices/pci*/.../link/l0s_aspm
/sys/devices/pci*/.../link/l1_aspm
/sys/devices/pci*/.../link/l1_1_aspm
/sys/devices/pci*/.../link/l1_2_aspm
/sys/devices/pci*/.../link/l1_1_pcipm
/sys/devices/pci*/.../link/l1_2_pcipm
An attribute is only visible if both ends of the Link leading to the device
support the state. Writing y/1/on to the file enables the state; n/0/off
disables it.
These attributes can be used to tune the power/performance tradeoff for
individual devices.
[bhelgaas: commit log, rename directory to "link"]
Link: https://lore.kernel.org/r/b1c83f8a-9bf6-eac5-82d0-cf5b90128fbf@gmail.com
Signed-off-by: Heiner Kallweit <hkallweit1 at gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
(cherry picked from commit 72ea91afbfb08619696ccde610ee4d0d29cf4a1d)
Signed-off-by: AceLan Kao <acelan.kao at canonical.com>
---
Documentation/ABI/testing/sysfs-bus-pci | 13 +++
drivers/pci/pci-sysfs.c | 3 +
drivers/pci/pci.h | 4 +
drivers/pci/pcie/aspm.c | 149 ++++++++++++++++++++++++
4 files changed, 169 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 8bfee557e50e..450296cc7948 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/.../link/clkpm
+ /sys/bus/pci/devices/.../link/l0s_aspm
+ /sys/bus/pci/devices/.../link/l1_aspm
+ /sys/bus/pci/devices/.../link/l1_1_aspm
+ /sys/bus/pci/devices/.../link/l1_2_aspm
+ /sys/bus/pci/devices/.../link/l1_1_pcipm
+ /sys/bus/pci/devices/.../link/l1_2_pcipm
+Date: October 2019
+Contact: Heiner Kallweit <hkallweit1 at gmail.com>
+Description: If ASPM is supported for an endpoint, these files can be
+ used to disable or enable the individual power management
+ states. Write y/1/on to enable, n/0/off to disable.
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 793412954529..0e76c02e0b7d 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1587,6 +1587,9 @@ static const struct attribute_group *pci_dev_attr_groups[] = {
&pcie_dev_attr_group,
#ifdef CONFIG_PCIEAER
&aer_stats_attr_group,
+#endif
+#ifdef CONFIG_PCIEASPM
+ &aspm_ctrl_attr_group,
#endif
NULL,
};
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index a5adc2e2c351..317a796a723e 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -671,4 +671,8 @@ static inline int pci_acpi_program_hp_params(struct pci_dev *dev)
}
#endif
+#ifdef CONFIG_PCIEASPM
+extern const struct attribute_group aspm_ctrl_attr_group;
+#endif
+
#endif /* DRIVERS_PCI_H */
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 2d5ecede8fa3..9cd251827a67 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -899,6 +899,14 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
return link;
}
+static void pcie_aspm_update_sysfs_visibility(struct pci_dev *pdev)
+{
+ struct pci_dev *child;
+
+ list_for_each_entry(child, &pdev->subordinate->devices, bus_list)
+ sysfs_update_group(&child->dev.kobj, &aspm_ctrl_attr_group);
+}
+
/*
* pcie_aspm_init_link_state: Initiate PCI express link state.
* It is called after the pcie and its children devices are scanned.
@@ -960,6 +968,8 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
pcie_set_clkpm(link, policy_to_clkpm_state(link));
}
+ pcie_aspm_update_sysfs_visibility(pdev);
+
unlock:
mutex_unlock(&aspm_lock);
out:
@@ -1313,6 +1323,145 @@ void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev)
}
#endif
+static ssize_t aspm_attr_show_common(struct device *dev,
+ struct device_attribute *attr,
+ char *buf, u8 state)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct pcie_link_state *link = pcie_aspm_get_link(pdev);
+
+ return sprintf(buf, "%d\n", (link->aspm_enabled & state) ? 1 : 0);
+}
+
+static ssize_t aspm_attr_store_common(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len, u8 state)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct pcie_link_state *link = pcie_aspm_get_link(pdev);
+ bool state_enable;
+
+ if (strtobool(buf, &state_enable) < 0)
+ return -EINVAL;
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+
+ if (state_enable) {
+ link->aspm_disable &= ~state;
+ /* need to enable L1 for substates */
+ if (state & ASPM_STATE_L1SS)
+ link->aspm_disable &= ~ASPM_STATE_L1;
+ } else {
+ link->aspm_disable |= state;
+ }
+
+ pcie_config_aspm_link(link, policy_to_aspm_state(link));
+
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+
+ return len;
+}
+
+#define ASPM_ATTR(_f, _s) \
+static ssize_t _f##_show(struct device *dev, \
+ struct device_attribute *attr, char *buf) \
+{ return aspm_attr_show_common(dev, attr, buf, ASPM_STATE_##_s); } \
+ \
+static ssize_t _f##_store(struct device *dev, \
+ struct device_attribute *attr, \
+ const char *buf, size_t len) \
+{ return aspm_attr_store_common(dev, attr, buf, len, ASPM_STATE_##_s); }
+
+ASPM_ATTR(l0s_aspm, L0S)
+ASPM_ATTR(l1_aspm, L1)
+ASPM_ATTR(l1_1_aspm, L1_1)
+ASPM_ATTR(l1_2_aspm, L1_2)
+ASPM_ATTR(l1_1_pcipm, L1_1_PCIPM)
+ASPM_ATTR(l1_2_pcipm, L1_2_PCIPM)
+
+static ssize_t clkpm_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct pcie_link_state *link = pcie_aspm_get_link(pdev);
+
+ return sprintf(buf, "%d\n", link->clkpm_enabled);
+}
+
+static ssize_t clkpm_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 = pcie_aspm_get_link(pdev);
+ bool state_enable;
+
+ if (strtobool(buf, &state_enable) < 0)
+ return -EINVAL;
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+
+ link->clkpm_disable = !state_enable;
+ pcie_set_clkpm(link, policy_to_clkpm_state(link));
+
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+
+ return len;
+}
+
+static DEVICE_ATTR_RW(clkpm);
+static DEVICE_ATTR_RW(l0s_aspm);
+static DEVICE_ATTR_RW(l1_aspm);
+static DEVICE_ATTR_RW(l1_1_aspm);
+static DEVICE_ATTR_RW(l1_2_aspm);
+static DEVICE_ATTR_RW(l1_1_pcipm);
+static DEVICE_ATTR_RW(l1_2_pcipm);
+
+static struct attribute *aspm_ctrl_attrs[] = {
+ &dev_attr_clkpm.attr,
+ &dev_attr_l0s_aspm.attr,
+ &dev_attr_l1_aspm.attr,
+ &dev_attr_l1_1_aspm.attr,
+ &dev_attr_l1_2_aspm.attr,
+ &dev_attr_l1_1_pcipm.attr,
+ &dev_attr_l1_2_pcipm.attr,
+ NULL
+};
+
+static umode_t aspm_ctrl_attrs_are_visible(struct kobject *kobj,
+ struct attribute *a, int n)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct pcie_link_state *link = pcie_aspm_get_link(pdev);
+ static const u8 aspm_state_map[] = {
+ ASPM_STATE_L0S,
+ ASPM_STATE_L1,
+ ASPM_STATE_L1_1,
+ ASPM_STATE_L1_2,
+ ASPM_STATE_L1_1_PCIPM,
+ ASPM_STATE_L1_2_PCIPM,
+ };
+
+ if (aspm_disabled || !link)
+ return 0;
+
+ if (n == 0)
+ return link->clkpm_capable ? a->mode : 0;
+
+ return link->aspm_capable & aspm_state_map[n - 1] ? a->mode : 0;
+}
+
+const struct attribute_group aspm_ctrl_attr_group = {
+ .name = "link",
+ .attrs = aspm_ctrl_attrs,
+ .is_visible = aspm_ctrl_attrs_are_visible,
+};
+
static int __init pcie_aspm_disable(char *str)
{
if (!strcmp(str, "off")) {
--
2.17.1
More information about the kernel-team
mailing list