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Subject[PATCH V4 1/3] PCI/ASPM: divide ASPM capability init into pre and post init
Date
The ASPM capability initialization is done in one pass where both
the current settings such as capable/enable/supported field are set
and also all children are scanned for latencies.

Divide the init into two so that part of the code that needs
scan finished is obvious.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
drivers/pci/pcie/aspm.c | 76 +++++++++++++++++++++++++++----------------------
1 file changed, 42 insertions(+), 34 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 3dd8bcb..453558d 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -338,11 +338,10 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint)
}
}

-static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
+static void pcie_aspm_cap_post_scan(struct pcie_link_state *link, int blacklist)
{
struct pci_dev *child, *parent = link->pdev;
struct pci_bus *linkbus = parent->subordinate;
- struct aspm_register_info upreg, dwreg;

if (blacklist) {
/* Set enabled/disable so that we will disable ASPM later */
@@ -351,6 +350,45 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
return;
}

+ /*
+ * If the downstream component has pci bridge function, don't
+ * do ASPM for now.
+ */
+ list_for_each_entry(child, &linkbus->devices, bus_list) {
+ if (pci_pcie_type(child) == PCI_EXP_TYPE_PCI_BRIDGE) {
+ link->aspm_disable = ASPM_STATE_ALL;
+ break;
+ }
+ }
+
+ /* Get and check endpoint acceptable latencies */
+ list_for_each_entry(child, &linkbus->devices, bus_list) {
+ u32 reg32, encoding;
+ struct aspm_latency *acceptable =
+ &link->acceptable[PCI_FUNC(child->devfn)];
+
+ if (pci_pcie_type(child) != PCI_EXP_TYPE_ENDPOINT &&
+ pci_pcie_type(child) != PCI_EXP_TYPE_LEG_END)
+ continue;
+
+ pcie_capability_read_dword(child, PCI_EXP_DEVCAP, &reg32);
+ /* Calculate endpoint L0s acceptable latency */
+ encoding = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;
+ acceptable->l0s = calc_l0s_acceptable(encoding);
+ /* Calculate endpoint L1 acceptable latency */
+ encoding = (reg32 & PCI_EXP_DEVCAP_L1) >> 9;
+ acceptable->l1 = calc_l1_acceptable(encoding);
+
+ pcie_aspm_check_latency(child);
+ }
+}
+
+static void pcie_aspm_cap_init(struct pcie_link_state *link)
+{
+ struct pci_dev *child, *parent = link->pdev;
+ struct pci_bus *linkbus = parent->subordinate;
+ struct aspm_register_info upreg, dwreg;
+
/* Get upstream/downstream components' register state */
pcie_get_aspm_reg(parent, &upreg);
child = list_entry(linkbus->devices.next, struct pci_dev, bus_list);
@@ -402,37 +440,6 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)

/* Setup initial capable state. Will be updated later */
link->aspm_capable = link->aspm_support;
- /*
- * If the downstream component has pci bridge function, don't
- * do ASPM for now.
- */
- list_for_each_entry(child, &linkbus->devices, bus_list) {
- if (pci_pcie_type(child) == PCI_EXP_TYPE_PCI_BRIDGE) {
- link->aspm_disable = ASPM_STATE_ALL;
- break;
- }
- }
-
- /* Get and check endpoint acceptable latencies */
- list_for_each_entry(child, &linkbus->devices, bus_list) {
- u32 reg32, encoding;
- struct aspm_latency *acceptable =
- &link->acceptable[PCI_FUNC(child->devfn)];
-
- if (pci_pcie_type(child) != PCI_EXP_TYPE_ENDPOINT &&
- pci_pcie_type(child) != PCI_EXP_TYPE_LEG_END)
- continue;
-
- pcie_capability_read_dword(child, PCI_EXP_DEVCAP, &reg32);
- /* Calculate endpoint L0s acceptable latency */
- encoding = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;
- acceptable->l0s = calc_l0s_acceptable(encoding);
- /* Calculate endpoint L1 acceptable latency */
- encoding = (reg32 & PCI_EXP_DEVCAP_L1) >> 9;
- acceptable->l1 = calc_l1_acceptable(encoding);
-
- pcie_aspm_check_latency(child);
- }
}

static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
@@ -606,7 +613,8 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
* upstream links also because capable state of them can be
* update through pcie_aspm_cap_init().
*/
- pcie_aspm_cap_init(link, blacklist);
+ pcie_aspm_cap_init(link);
+ pcie_aspm_cap_post_scan(link, blacklist);

/* Setup initial Clock PM state */
pcie_clkpm_cap_init(link, blacklist);
--
1.9.1
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