[v2,1/2] PCI: PCIe: ASPM: Introduce pcie_aspm_enabled_mask()
diff mbox series

Message ID 3714448.mG7dE8Q3Fs@kreacher
State New
Headers show
Series
  • nvme-pci: Allow PCI bus-level PM to be used if ASPM is disabled
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Commit Message

Rafael J. Wysocki Aug. 8, 2019, 10:06 a.m. UTC
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Add a function returning the mask of currently enabled ASPM link
states for a given device.

It will be used by the NVMe driver to decide how to handle the
device during system suspend.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

-> v2:
  * Move the PCI/PCIe ASPM changes to a separate patch.
  * Add the _mask suffix to the new function name.
  * Add EXPORT_SYMBOL_GPL() to the new function.
  * Avoid adding an unnecessary blank line.

---
 drivers/pci/pcie/aspm.c |   20 ++++++++++++++++++++
 include/linux/pci.h     |    3 +++
 2 files changed, 23 insertions(+)

Comments

Bjorn Helgaas Aug. 8, 2019, 1:15 p.m. UTC | #1
On Thu, Aug 08, 2019 at 12:06:52PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> Add a function returning the mask of currently enabled ASPM link
> states for a given device.
> 
> It will be used by the NVMe driver to decide how to handle the
> device during system suspend.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> 
> -> v2:
>   * Move the PCI/PCIe ASPM changes to a separate patch.
>   * Add the _mask suffix to the new function name.
>   * Add EXPORT_SYMBOL_GPL() to the new function.
>   * Avoid adding an unnecessary blank line.
> 
> ---
>  drivers/pci/pcie/aspm.c |   20 ++++++++++++++++++++
>  include/linux/pci.h     |    3 +++
>  2 files changed, 23 insertions(+)
> 
> Index: linux-pm/drivers/pci/pcie/aspm.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/pcie/aspm.c
> +++ linux-pm/drivers/pci/pcie/aspm.c
> @@ -1170,6 +1170,26 @@ static int pcie_aspm_get_policy(char *bu
>  module_param_call(policy, pcie_aspm_set_policy, pcie_aspm_get_policy,
>  	NULL, 0644);
>  
> +/*
> + * pcie_aspm_enabled_mask - Return the mask of enabled ASPM link states.
> + * @pci_device: Target device.
> + */
> +u32 pcie_aspm_enabled_mask(struct pci_dev *pci_device)
> +{
> +	struct pci_dev *bridge = pci_upstream_bridge(pci_device);
> +	u32 ret;
> +
> +	if (!bridge)
> +		return 0;
> +
> +	mutex_lock(&aspm_lock);
> +	ret = bridge->link_state ? bridge->link_state->aspm_enabled : 0;

This returns the "aspm_enabled" mask, but the values of that mask are
combinations of:

  ASPM_STATE_L0S_UP
  ASPM_STATE_L0S_DW
  ASPM_STATE_L1
  ...

which are defined internally in drivers/pci/pcie/aspm.c and not
visible to the caller of pcie_aspm_enabled_mask().  If there's no need
for the actual mask (the current caller doesn't seem to use it), maybe
this could be a boolean?

> +	mutex_unlock(&aspm_lock);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(pcie_aspm_enabled_mask);
> +
>  #ifdef CONFIG_PCIEASPM_DEBUG
>  static ssize_t link_state_show(struct device *dev,
>  		struct device_attribute *attr,
> Index: linux-pm/include/linux/pci.h
> ===================================================================
> --- linux-pm.orig/include/linux/pci.h
> +++ linux-pm/include/linux/pci.h
> @@ -1567,8 +1567,11 @@ extern bool pcie_ports_native;
>  
>  #ifdef CONFIG_PCIEASPM
>  bool pcie_aspm_support_enabled(void);
> +u32 pcie_aspm_enabled_mask(struct pci_dev *pci_device);
>  #else
>  static inline bool pcie_aspm_support_enabled(void) { return false; }
> +static inline u32 pcie_aspm_enabled_mask(struct pci_dev *pci_device)
> +{ return 0; }
>  #endif
>  
>  #ifdef CONFIG_PCIEAER
> 
> 
>
Rafael J. Wysocki Aug. 8, 2019, 2:48 p.m. UTC | #2
On Thu, Aug 8, 2019 at 3:15 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Thu, Aug 08, 2019 at 12:06:52PM +0200, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > Add a function returning the mask of currently enabled ASPM link
> > states for a given device.
> >
> > It will be used by the NVMe driver to decide how to handle the
> > device during system suspend.
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > ---
> >
> > -> v2:
> >   * Move the PCI/PCIe ASPM changes to a separate patch.
> >   * Add the _mask suffix to the new function name.
> >   * Add EXPORT_SYMBOL_GPL() to the new function.
> >   * Avoid adding an unnecessary blank line.
> >
> > ---
> >  drivers/pci/pcie/aspm.c |   20 ++++++++++++++++++++
> >  include/linux/pci.h     |    3 +++
> >  2 files changed, 23 insertions(+)
> >
> > Index: linux-pm/drivers/pci/pcie/aspm.c
> > ===================================================================
> > --- linux-pm.orig/drivers/pci/pcie/aspm.c
> > +++ linux-pm/drivers/pci/pcie/aspm.c
> > @@ -1170,6 +1170,26 @@ static int pcie_aspm_get_policy(char *bu
> >  module_param_call(policy, pcie_aspm_set_policy, pcie_aspm_get_policy,
> >       NULL, 0644);
> >
> > +/*
> > + * pcie_aspm_enabled_mask - Return the mask of enabled ASPM link states.
> > + * @pci_device: Target device.
> > + */
> > +u32 pcie_aspm_enabled_mask(struct pci_dev *pci_device)
> > +{
> > +     struct pci_dev *bridge = pci_upstream_bridge(pci_device);
> > +     u32 ret;
> > +
> > +     if (!bridge)
> > +             return 0;
> > +
> > +     mutex_lock(&aspm_lock);
> > +     ret = bridge->link_state ? bridge->link_state->aspm_enabled : 0;
>
> This returns the "aspm_enabled" mask, but the values of that mask are
> combinations of:
>
>   ASPM_STATE_L0S_UP
>   ASPM_STATE_L0S_DW
>   ASPM_STATE_L1
>   ...
>
> which are defined internally in drivers/pci/pcie/aspm.c and not
> visible to the caller of pcie_aspm_enabled_mask().  If there's no need
> for the actual mask (the current caller doesn't seem to use it), maybe
> this could be a boolean?

Yes, it can be a boolean.

>
> > +     mutex_unlock(&aspm_lock);
> > +
> > +     return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(pcie_aspm_enabled_mask);
> > +
> >  #ifdef CONFIG_PCIEASPM_DEBUG
> >  static ssize_t link_state_show(struct device *dev,
> >               struct device_attribute *attr,
> > Index: linux-pm/include/linux/pci.h
> > ===================================================================
> > --- linux-pm.orig/include/linux/pci.h
> > +++ linux-pm/include/linux/pci.h
> > @@ -1567,8 +1567,11 @@ extern bool pcie_ports_native;
> >
> >  #ifdef CONFIG_PCIEASPM
> >  bool pcie_aspm_support_enabled(void);
> > +u32 pcie_aspm_enabled_mask(struct pci_dev *pci_device);
> >  #else
> >  static inline bool pcie_aspm_support_enabled(void) { return false; }
> > +static inline u32 pcie_aspm_enabled_mask(struct pci_dev *pci_device)
> > +{ return 0; }
> >  #endif
> >
> >  #ifdef CONFIG_PCIEAER
> >
> >
> >

Patch
diff mbox series

Index: linux-pm/drivers/pci/pcie/aspm.c
===================================================================
--- linux-pm.orig/drivers/pci/pcie/aspm.c
+++ linux-pm/drivers/pci/pcie/aspm.c
@@ -1170,6 +1170,26 @@  static int pcie_aspm_get_policy(char *bu
 module_param_call(policy, pcie_aspm_set_policy, pcie_aspm_get_policy,
 	NULL, 0644);
 
+/*
+ * pcie_aspm_enabled_mask - Return the mask of enabled ASPM link states.
+ * @pci_device: Target device.
+ */
+u32 pcie_aspm_enabled_mask(struct pci_dev *pci_device)
+{
+	struct pci_dev *bridge = pci_upstream_bridge(pci_device);
+	u32 ret;
+
+	if (!bridge)
+		return 0;
+
+	mutex_lock(&aspm_lock);
+	ret = bridge->link_state ? bridge->link_state->aspm_enabled : 0;
+	mutex_unlock(&aspm_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pcie_aspm_enabled_mask);
+
 #ifdef CONFIG_PCIEASPM_DEBUG
 static ssize_t link_state_show(struct device *dev,
 		struct device_attribute *attr,
Index: linux-pm/include/linux/pci.h
===================================================================
--- linux-pm.orig/include/linux/pci.h
+++ linux-pm/include/linux/pci.h
@@ -1567,8 +1567,11 @@  extern bool pcie_ports_native;
 
 #ifdef CONFIG_PCIEASPM
 bool pcie_aspm_support_enabled(void);
+u32 pcie_aspm_enabled_mask(struct pci_dev *pci_device);
 #else
 static inline bool pcie_aspm_support_enabled(void) { return false; }
+static inline u32 pcie_aspm_enabled_mask(struct pci_dev *pci_device)
+{ return 0; }
 #endif
 
 #ifdef CONFIG_PCIEAER