PCI ASPM: cleanup latency field in struct pcie_link_state

Clean up latency related data structures for ASPM.

- Introduce struct acpi_latency for exit latency and acceptable
  latency management. With this change, struct endpoint_state is no
  longer needed.

- We don't need to hold both upstream latency and downstream latency
  in the current implementation.

Acked-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 28 insertions, 38 deletions

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index fdb3b7da7383..88351c242a48 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -26,9 +26,9 @@
 #endif
 #define MODULE_PARAM_PREFIX "pcie_aspm."
 
-struct endpoint_state {
-        unsigned int l0s_acceptable_latency;
-        unsigned int l1_acceptable_latency;
+struct aspm_latency {
+        u32 l0s;                        /* L0s latency (nsec) */
+        u32 l1;                         /* L1 latency (nsec) */
 };
 
 struct pcie_link_state {
@@ -45,22 +45,19 @@ struct pcie_link_state {
         u32 aspm_enabled:2;             /* Enabled ASPM state */
         u32 aspm_default:2;             /* Default ASPM state by BIOS */
 
-        /* upstream component */
-        unsigned int l0s_upper_latency;
-        unsigned int l1_upper_latency;
-        /* downstream component */
-        unsigned int l0s_down_latency;
-        unsigned int l1_down_latency;
+        /* Latencies */
+        struct aspm_latency latency;    /* Exit latency */
+
         /* Clock PM state*/
         unsigned int clk_pm_capable;
         unsigned int clk_pm_enabled;
         unsigned int bios_clk_state;
 
         /*
-         * A pcie downstream port only has one slot under it, so at most there
-         * are 8 functions
+         * Endpoint acceptable latencies. A pcie downstream port only
+         * has one slot under it, so at most there are 8 functions.
          */
-        struct endpoint_state endpoints[8];
+        struct aspm_latency acceptable[8];
 };
 
 static int aspm_disabled, aspm_force;
@@ -341,8 +338,8 @@ static void pcie_aspm_cap_init(struct pci_dev *pdev)
         /* upstream component states */
         pcie_aspm_get_cap_device(pdev, &support, &l0s, &l1, &enabled);
         link_state->aspm_support = support;
-        link_state->l0s_upper_latency = l0s;
-        link_state->l1_upper_latency = l1;
+        link_state->latency.l0s = l0s;
+        link_state->latency.l1 = l1;
         link_state->aspm_enabled = enabled;
 
         /* downstream component states, all functions have the same setting */
@@ -350,8 +347,8 @@ static void pcie_aspm_cap_init(struct pci_dev *pdev)
                 bus_list);
         pcie_aspm_get_cap_device(child_dev, &support, &l0s, &l1, &enabled);
         link_state->aspm_support &= support;
-        link_state->l0s_down_latency = l0s;
-        link_state->l1_down_latency = l1;
+        link_state->latency.l0s = max_t(u32, link_state->latency.l0s, l0s);
+        link_state->latency.l1 = max_t(u32, link_state->latency.l1, l1);
 
         if (!link_state->aspm_support)
                 return;
@@ -364,8 +361,8 @@ static void pcie_aspm_cap_init(struct pci_dev *pdev)
                 int pos;
                 u32 reg32;
                 unsigned int latency;
-                struct endpoint_state *ep_state =
-                        &link_state->endpoints[PCI_FUNC(child_dev->devfn)];
+                struct aspm_latency *acceptable =
+                        &link_state->acceptable[PCI_FUNC(child_dev->devfn)];
 
                 if (child_dev->pcie_type != PCI_EXP_TYPE_ENDPOINT &&
                         child_dev->pcie_type != PCI_EXP_TYPE_LEG_END)
@@ -375,11 +372,11 @@ static void pcie_aspm_cap_init(struct pci_dev *pdev)
                 pci_read_config_dword(child_dev, pos + PCI_EXP_DEVCAP, &reg32);
                 latency = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;
                 latency = calc_L0S_latency(latency, 1);
-                ep_state->l0s_acceptable_latency = latency;
+                acceptable->l0s = latency;
                 if (link_state->aspm_support & PCIE_LINK_STATE_L1) {
                         latency = (reg32 & PCI_EXP_DEVCAP_L1) >> 9;
                         latency = calc_L1_latency(latency, 1);
-                        ep_state->l1_acceptable_latency = latency;
+                        acceptable->l1 = latency;
                 }
         }
 }
@@ -388,16 +385,16 @@ static unsigned int __pcie_aspm_check_state_one(struct pci_dev *pdev,
         unsigned int state)
 {
         struct pci_dev *parent_dev, *tmp_dev;
-        unsigned int latency, l1_latency = 0;
+        unsigned int l1_latency = 0;
         struct pcie_link_state *link_state;
-        struct endpoint_state *ep_state;
+        struct aspm_latency *acceptable;
 
         parent_dev = pdev->bus->self;
         link_state = parent_dev->link_state;
         state &= link_state->aspm_support;
         if (state == 0)
                 return 0;
-        ep_state = &link_state->endpoints[PCI_FUNC(pdev->devfn)];
+        acceptable = &link_state->acceptable[PCI_FUNC(pdev->devfn)];
 
         /*
          * Check latency for endpoint device.
@@ -411,21 +408,14 @@ static unsigned int __pcie_aspm_check_state_one(struct pci_dev *pdev,
         while (state & (PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1)) {
                 parent_dev = tmp_dev->bus->self;
                 link_state = parent_dev->link_state;
-                if (state & PCIE_LINK_STATE_L0S) {
-                        latency = max_t(unsigned int,
-                                        link_state->l0s_upper_latency,
-                                        link_state->l0s_down_latency);
-                        if (latency > ep_state->l0s_acceptable_latency)
-                                state &= ~PCIE_LINK_STATE_L0S;
-                }
-                if (state & PCIE_LINK_STATE_L1) {
-                        latency = max_t(unsigned int,
-                                        link_state->l1_upper_latency,
-                                        link_state->l1_down_latency);
-                        if (latency + l1_latency >
-                                        ep_state->l1_acceptable_latency)
-                                state &= ~PCIE_LINK_STATE_L1;
-                }
+                if ((state & PCIE_LINK_STATE_L0S) &&
+                    (link_state->latency.l0s > acceptable->l0s))
+                        state &= ~PCIE_LINK_STATE_L0S;
+
+                if ((state & PCIE_LINK_STATE_L1) &&
+                    (link_state->latency.l1 + l1_latency > acceptable->l1))
+                        state &= ~PCIE_LINK_STATE_L1;
+
                 if (!parent_dev->bus->self) /* parent_dev is a root port */
                         break;
                 else {