[PATCH V6 4/5] PCI/ASPM: save power on values during bridge init

From: Sinan Kaya
Date: Wed Mar 29 2017 - 19:04:54 EST


Now that we added a hook to be called from device_add, save the
default values from the HW registers early in the boot for further
reuse during hot device add/remove operations.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=194895
Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
---
drivers/pci/pcie/aspm.c | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index e33f84b..a38602a 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -505,8 +505,10 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
*/
if (dwreg.support & upreg.support & PCIE_LINK_STATE_L0S)
link->aspm_support |= ASPM_STATE_L0S;
- if (dwreg.enabled & PCIE_LINK_STATE_L0S)
+ if (dwreg.enabled & PCIE_LINK_STATE_L0S) {
link->aspm_enabled |= ASPM_STATE_L0S_UP;
+ link->aspm_default |= ASPM_STATE_L0S_UP;
+ }
if (upreg.enabled & PCIE_LINK_STATE_L0S)
link->aspm_enabled |= ASPM_STATE_L0S_DW;
link->latency_up.l0s = calc_l0s_latency(upreg.latency_encoding_l0s);
@@ -542,9 +544,6 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
if (link->aspm_support & ASPM_STATE_L1SS)
aspm_calc_l1ss_info(link, &upreg, &dwreg);

- /* Save default state */
- link->aspm_default = link->aspm_enabled;
-
/* Setup initial capable state. Will be updated later */
link->aspm_capable = link->aspm_support;
/*
@@ -835,11 +834,26 @@ static int pci_aspm_init_downstream(struct pci_dev *pdev)
static int pci_aspm_init_upstream(struct pci_dev *pdev)
{
struct pcie_link_state *link;
+ struct aspm_register_info upreg;

link = alloc_pcie_link_state(pdev);
if (!link)
return -ENOMEM;

+ pcie_get_aspm_reg(pdev, &upreg);
+ if (upreg.enabled & PCIE_LINK_STATE_L0S)
+ link->aspm_default |= ASPM_STATE_L0S_DW;
+ if (upreg.enabled & PCIE_LINK_STATE_L1)
+ link->aspm_default |= ASPM_STATE_L1;
+ if (upreg.l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_1)
+ link->aspm_default |= ASPM_STATE_L1_1;
+ if (upreg.l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_2)
+ link->aspm_default |= ASPM_STATE_L1_2;
+ if (upreg.l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_1)
+ link->aspm_default |= ASPM_STATE_L1_1_PCIPM;
+ if (upreg.l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_2)
+ link->aspm_default |= ASPM_STATE_L1_2_PCIPM;
+
return 0;
}

--
1.9.1