PCI ASPM: cleanup calc_Lx_latency

Cleanup for calc_L0S_latency() and calc_L1_latency().

  - Separate exit latency and acceptable latency calculation.
  - Some minor cleanups.

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, 34 insertions, 39 deletions

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index d85f77ff150c..23fabb303e82 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -257,38 +257,36 @@ static void pcie_aspm_configure_common_clock(struct pcie_link_state *link)
         pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, parent_reg);
 }
 
-/*
- * calc_L0S_latency: Convert L0s latency encoding to ns
- */
-static unsigned int calc_L0S_latency(unsigned int latency_encoding, int ac)
+/* Convert L0s latency encoding to ns */
+static u32 calc_l0s_latency(u32 encoding)
 {
-        unsigned int ns = 64;
+        if (encoding == 0x7)
+                return (5 * 1000);      /* > 4us */
+        return (64 << encoding);
+}
 
-        if (latency_encoding == 0x7) {
-                if (ac)
-                        ns = -1U;
-                else
-                        ns = 5*1000; /* > 4us */
-        } else
-                ns *= (1 << latency_encoding);
-        return ns;
+/* Convert L0s acceptable latency encoding to ns */
+static u32 calc_l0s_acceptable(u32 encoding)
+{
+        if (encoding == 0x7)
+                return -1U;
+        return (64 << encoding);
 }
 
-/*
- * calc_L1_latency: Convert L1 latency encoding to ns
- */
-static unsigned int calc_L1_latency(unsigned int latency_encoding, int ac)
+/* Convert L1 latency encoding to ns */
+static u32 calc_l1_latency(u32 encoding)
 {
-        unsigned int ns = 1000;
+        if (encoding == 0x7)
+                return (65 * 1000);     /* > 64us */
+        return (1000 << encoding);
+}
 
-        if (latency_encoding == 0x7) {
-                if (ac)
-                        ns = -1U;
-                else
-                        ns = 65*1000; /* > 64us */
-        } else
-                ns *= (1 << latency_encoding);
-        return ns;
+/* Convert L1 acceptable latency encoding to ns */
+static u32 calc_l1_acceptable(u32 encoding)
+{
+        if (encoding == 0x7)
+                return -1U;
+        return (1000 << encoding);
 }
 
 static void pcie_aspm_get_cap_device(struct pci_dev *pdev, u32 *state,
@@ -296,7 +294,7 @@ static void pcie_aspm_get_cap_device(struct pci_dev *pdev, u32 *state,
 {
         int pos;
         u16 reg16;
-        u32 reg32, latency;
+        u32 reg32, encoding;
 
         *l0s = *l1 = *enabled = 0;
         pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
@@ -308,11 +306,11 @@ static void pcie_aspm_get_cap_device(struct pci_dev *pdev, u32 *state,
         if (*state == 0)
                 return;
 
-        latency = (reg32 & PCI_EXP_LNKCAP_L0SEL) >> 12;
-        *l0s = calc_L0S_latency(latency, 0);
+        encoding = (reg32 & PCI_EXP_LNKCAP_L0SEL) >> 12;
+        *l0s = calc_l0s_latency(encoding);
         if (*state & PCIE_LINK_STATE_L1) {
-                latency = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15;
-                *l1 = calc_L1_latency(latency, 0);
+                encoding = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15;
+                *l1 = calc_l1_latency(encoding);
         }
         pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);
         *enabled = reg16 & (PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1);
@@ -358,8 +356,7 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
         /* ENDPOINT states*/
         list_for_each_entry(child, &linkbus->devices, bus_list) {
                 int pos;
-                u32 reg32;
-                unsigned int latency;
+                u32 reg32, encoding;
                 struct aspm_latency *acceptable =
                         &link->acceptable[PCI_FUNC(child->devfn)];
 
@@ -369,13 +366,11 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
 
                 pos = pci_find_capability(child, PCI_CAP_ID_EXP);
                 pci_read_config_dword(child, pos + PCI_EXP_DEVCAP, &reg32);
-                latency = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;
-                latency = calc_L0S_latency(latency, 1);
-                acceptable->l0s = latency;
+                encoding = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;
+                acceptable->l0s = calc_l0s_acceptable(encoding);
                 if (link->aspm_support & PCIE_LINK_STATE_L1) {
-                        latency = (reg32 & PCI_EXP_DEVCAP_L1) >> 9;
-                        latency = calc_L1_latency(latency, 1);
-                        acceptable->l1 = latency;
+                        encoding = (reg32 & PCI_EXP_DEVCAP_L1) >> 9;
+                        acceptable->l1 = calc_l1_acceptable(encoding);
                 }
         }
 }