[PATCH V6 1/5] PCI/ASPM: introduce pci_aspm_init() and add to pci_init_capabilities()

[PATCH V6 1/5] PCI/ASPM: introduce pci_aspm_init() and add to pci_init_capabilities()

[Sinan Kaya]

We need a callback from pci_init_capabilities function for every
single new PCI device that is currently being added.

pci_aspm_init() will be used to save the power on state of the HW.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=194895
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/pci/pcie/aspm.c | 10 ++++++++++
 drivers/pci/probe.c     |  3 +++
 include/linux/pci.h     |  2 ++
 3 files changed, 15 insertions(+)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 1dfa10c..dc36717 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -827,6 +827,16 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
 }
 
 /*
+ * pci_aspm_init: Initiate PCI express link state.
+ * It is called from device_add for every single pci device.
+ * @pdev: all pci devices
+ */
+int pci_aspm_init(struct pci_dev *pdev)
+{
+	return 0;
+}
+
+/*
  * pcie_aspm_init_link_state: Initiate PCI express link state.
  * It is called after the pcie and its children devices are scanned.
  * @pdev: the root port or switch downstream port
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index dfc9a27..1e19364 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1847,6 +1847,9 @@ static void pci_init_capabilities(struct pci_dev *dev)
 
 	/* Advanced Error Reporting */
 	pci_aer_init(dev);
+
+	/* Active State Power Management */
+	pci_aspm_init(dev);
 }
 
 /*
diff --git a/include/linux/pci.h b/include/linux/pci.h
index eb3da1a..8828dd7 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1396,8 +1396,10 @@ static inline int pci_irq_get_node(struct pci_dev *pdev, int vec)
 
 #ifdef CONFIG_PCIEASPM
 bool pcie_aspm_support_enabled(void);
+int pci_aspm_init(struct pci_dev *pdev);
 #else
 static inline bool pcie_aspm_support_enabled(void) { return false; }
+static inline int pci_aspm_init(struct pci_dev *pdev) { return -ENODEV; }
 #endif
 
 #ifdef CONFIG_PCIEAER
-- 
1.9.1

[PATCH V6 2/5] PCI/ASPM: split pci_aspm_init() into two

[Sinan Kaya]

Split pci_aspm_init() body into pci_aspm_init_upstream()
and pci_aspm_init_downstream() for bridge and endpoint
specific code behavior.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=194895
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/pci/pcie/aspm.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index dc36717..a80d64b 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -826,6 +826,16 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
 	return link;
 }
 
+static int pci_aspm_init_downstream(struct pci_dev *pdev)
+{
+	return 0;
+}
+
+static int pci_aspm_init_upstream(struct pci_dev *pdev)
+{
+	return 0;
+}
+
 /*
  * pci_aspm_init: Initiate PCI express link state.
  * It is called from device_add for every single pci device.
@@ -833,7 +843,10 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
  */
 int pci_aspm_init(struct pci_dev *pdev)
 {
-	return 0;
+	if (!pdev->has_secondary_link)
+		return pci_aspm_init_downstream(pdev);
+
+	return pci_aspm_init_upstream(pdev);
 }
 
 /*
-- 
1.9.1

[PATCH V6 3/5] PCI/ASPM: add init hook to device_add

[Sinan Kaya]

For bridges, have pcie_aspm_init_link_state() allocate a link_state,
regardless of whether it currently has any children.

pcie_aspm_init_link_state(): Called for bridges (upstream end of
link) after all children have been enumerated.  No longer needs to
check aspm_support_enabled or pdev->has_secondary_link or the VIA
quirk: pci_aspm_init() already checked that stuff, so we only need
to check pdev->link_state here.

Now that we are calling alloc_pcie_link_state() from pci_aspm_init()
, get rid of pci_function_0 function and detect downstream link in
pci_aspm_init_upstream() instead when the function number is 0.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=194895
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/pci/pcie/aspm.c | 72 ++++++++++++++++++++++++-------------------------
 1 file changed, 36 insertions(+), 36 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index a80d64b..e33f84b 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -422,20 +422,6 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint)
 	}
 }
 
-/*
- * The L1 PM substate capability is only implemented in function 0 in a
- * multi function device.
- */
-static struct pci_dev *pci_function_0(struct pci_bus *linkbus)
-{
-	struct pci_dev *child;
-
-	list_for_each_entry(child, &linkbus->devices, bus_list)
-		if (PCI_FUNC(child->devfn) == 0)
-			return child;
-	return NULL;
-}
-
 /* Calculate L1.2 PM substate timing parameters */
 static void aspm_calc_l1ss_info(struct pcie_link_state *link,
 				struct aspm_register_info *upreg,
@@ -798,7 +784,6 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
 	INIT_LIST_HEAD(&link->children);
 	INIT_LIST_HEAD(&link->link);
 	link->pdev = pdev;
-	link->downstream = pci_function_0(pdev->subordinate);
 
 	/*
 	 * Root Ports and PCI/PCI-X to PCIe Bridges are roots of PCIe
@@ -828,11 +813,33 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
 
 static int pci_aspm_init_downstream(struct pci_dev *pdev)
 {
+	struct pcie_link_state *link;
+	struct pci_dev *parent;
+
+	/*
+	 * The L1 PM substate capability is only implemented in function 0 in a
+	 * multi function device.
+	 */
+	if (PCI_FUNC(pdev->devfn) != 0)
+		return -EINVAL;
+
+	parent = pdev->bus->self;
+	if (!parent)
+		return -EINVAL;
+
+	link = parent->link_state;
+	link->downstream = pdev;
 	return 0;
 }
 
 static int pci_aspm_init_upstream(struct pci_dev *pdev)
 {
+	struct pcie_link_state *link;
+
+	link = alloc_pcie_link_state(pdev);
+	if (!link)
+		return -ENOMEM;
+
 	return 0;
 }
 
@@ -843,6 +850,17 @@ static int pci_aspm_init_upstream(struct pci_dev *pdev)
  */
 int pci_aspm_init(struct pci_dev *pdev)
 {
+	if (!aspm_support_enabled)
+		return 0;
+
+	if (!pci_is_pcie(pdev))
+		return -EINVAL;
+
+	/* VIA has a strange chipset, root port is under a bridge */
+	if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT &&
+	    pdev->bus->self)
+		return 0;
+
 	if (!pdev->has_secondary_link)
 		return pci_aspm_init_downstream(pdev);
 
@@ -859,33 +877,16 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
 	struct pcie_link_state *link;
 	int blacklist = !!pcie_aspm_sanity_check(pdev);
 
-	if (!aspm_support_enabled)
-		return;
-
-	if (pdev->link_state)
-		return;
-
-	/*
-	 * We allocate pcie_link_state for the component on the upstream
-	 * end of a Link, so there's nothing to do unless this device has a
-	 * Link on its secondary side.
-	 */
-	if (!pdev->has_secondary_link)
-		return;
-
-	/* VIA has a strange chipset, root port is under a bridge */
-	if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT &&
-	    pdev->bus->self)
+	if (!pdev->link_state)
 		return;
 
+	link = pdev->link_state;
 	down_read(&pci_bus_sem);
 	if (list_empty(&pdev->subordinate->devices))
 		goto out;
 
 	mutex_lock(&aspm_lock);
-	link = alloc_pcie_link_state(pdev);
-	if (!link)
-		goto unlock;
+
 	/*
 	 * Setup initial ASPM state. Note that we need to configure
 	 * upstream links also because capable state of them can be
@@ -910,7 +911,6 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
 		pcie_set_clkpm(link, policy_to_clkpm_state(link));
 	}
 
-unlock:
 	mutex_unlock(&aspm_lock);
 out:
 	up_read(&pci_bus_sem);
-- 
1.9.1

[PATCH V6 4/5] PCI/ASPM: save power on values during bridge init

[Sinan Kaya]

Now that we added a hook to be called from device_add, save the
default values from the HW registers early in the boot for further
reuse during hot device add/remove operations.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=194895
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/pci/pcie/aspm.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index e33f84b..a38602a 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -505,8 +505,10 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
 	 */
 	if (dwreg.support & upreg.support & PCIE_LINK_STATE_L0S)
 		link->aspm_support |= ASPM_STATE_L0S;
-	if (dwreg.enabled & PCIE_LINK_STATE_L0S)
+	if (dwreg.enabled & PCIE_LINK_STATE_L0S) {
 		link->aspm_enabled |= ASPM_STATE_L0S_UP;
+		link->aspm_default |= ASPM_STATE_L0S_UP;
+	}
 	if (upreg.enabled & PCIE_LINK_STATE_L0S)
 		link->aspm_enabled |= ASPM_STATE_L0S_DW;
 	link->latency_up.l0s = calc_l0s_latency(upreg.latency_encoding_l0s);
@@ -542,9 +544,6 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
 	if (link->aspm_support & ASPM_STATE_L1SS)
 		aspm_calc_l1ss_info(link, &upreg, &dwreg);
 
-	/* Save default state */
-	link->aspm_default = link->aspm_enabled;
-
 	/* Setup initial capable state. Will be updated later */
 	link->aspm_capable = link->aspm_support;
 	/*
@@ -835,11 +834,26 @@ static int pci_aspm_init_downstream(struct pci_dev *pdev)
 static int pci_aspm_init_upstream(struct pci_dev *pdev)
 {
 	struct pcie_link_state *link;
+	struct aspm_register_info upreg;
 
 	link = alloc_pcie_link_state(pdev);
 	if (!link)
 		return -ENOMEM;
 
+	pcie_get_aspm_reg(pdev, &upreg);
+	if (upreg.enabled & PCIE_LINK_STATE_L0S)
+		link->aspm_default |= ASPM_STATE_L0S_DW;
+	if (upreg.enabled & PCIE_LINK_STATE_L1)
+		link->aspm_default |= ASPM_STATE_L1;
+	if (upreg.l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_1)
+		link->aspm_default |= ASPM_STATE_L1_1;
+	if (upreg.l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_2)
+		link->aspm_default |= ASPM_STATE_L1_2;
+	if (upreg.l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_1)
+		link->aspm_default |= ASPM_STATE_L1_1_PCIPM;
+	if (upreg.l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_2)
+		link->aspm_default |= ASPM_STATE_L1_2_PCIPM;
+
 	return 0;
 }
 
-- 
1.9.1

[PATCH V6 5/5] PCI/ASPM: move link_state cleanup to bridge remove

[Sinan Kaya]

For endpoints, change pcie_aspm_exit_link_state() so it cleans up
the device's own state and disables ASPM if necessary, but doesn't
remove the parent's link_state.

For bridges, change pcie_aspm_exit_link_state() so it frees the
bridge's own link_state.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=194895
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/pci/pcie/aspm.c | 20 +++++++++++++++-----
 drivers/pci/remove.c    |  3 +--
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index a38602a..37ca9b3 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -963,6 +963,21 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev)
 	if (!parent || !parent->link_state)
 		return;
 
+	if (pdev->has_secondary_link) {
+		link = pdev->link_state;
+		down_read(&pci_bus_sem);
+		mutex_lock(&aspm_lock);
+
+		list_del(&link->sibling);
+		list_del(&link->link);
+
+		/* Clock PM is for endpoint device */
+		free_link_state(link);
+		mutex_unlock(&aspm_lock);
+		up_read(&pci_bus_sem);
+		return;
+	}
+
 	down_read(&pci_bus_sem);
 	mutex_lock(&aspm_lock);
 	/*
@@ -978,11 +993,6 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev)
 
 	/* All functions are removed, so just disable ASPM for the link */
 	pcie_config_aspm_link(link, 0);
-	list_del(&link->sibling);
-	list_del(&link->link);
-	/* Clock PM is for endpoint device */
-	free_link_state(link);
-
 	/* Recheck latencies and configure upstream links */
 	if (parent_link) {
 		pcie_update_aspm_capable(root);
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 73a03d3..7e14ebd 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -25,8 +25,7 @@ static void pci_stop_dev(struct pci_dev *dev)
 		dev->is_added = 0;
 	}
 
-	if (dev->bus->self)
-		pcie_aspm_exit_link_state(dev);
+	pcie_aspm_exit_link_state(dev);
 }
 
 static void pci_destroy_dev(struct pci_dev *dev)
-- 
1.9.1

Re: [PATCH V6 5/5] PCI/ASPM: move link_state cleanup to bridge remove

[Sinan Kaya]

On 3/29/2017 7:04 PM, Sinan Kaya wrote:
>  	if (!parent || !parent->link_state)
>  		return;
>  
> +	if (pdev->has_secondary_link) {
> +		link = pdev->link_state;

I think I accidentally moved the parent check above this code
and broke the case where you can actually remove the root port.

I'll post v7 with reverting this change.

-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.