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