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PCI ASPM: cleanup calc_Lx_latency

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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>
This commit is contained in:
Kenji Kaneshige 2009-05-13 12:21:48 +09:00 committed by Jesse Barnes
parent 7ab7099103
commit 5e0eaa7d36
1 changed files with 35 additions and 40 deletions
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75
drivers/pci/pcie/aspm.c
View file

@ -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 (latency_encoding == 0x7) {
if (ac)
ns = -1U;
else
ns = 5*1000; /* > 4us */
} else
ns *= (1 << latency_encoding);
return ns;
if (encoding == 0x7)
return (5 * 1000); /* > 4us */
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 L0s acceptable latency encoding to ns */
static u32 calc_l0s_acceptable(u32 encoding)
{
unsigned int ns = 1000;
if (encoding == 0x7)
return -1U;
return (64 << encoding);
}
if (latency_encoding == 0x7) {
if (ac)
ns = -1U;
else
ns = 65*1000; /* > 64us */
} else
ns *= (1 << latency_encoding);
return ns;
/* Convert L1 latency encoding to ns */
static u32 calc_l1_latency(u32 encoding)
{
if (encoding == 0x7)
return (65 * 1000); /* > 64us */
return (1000 << encoding);
}
/* 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);
}
}
}