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.

If the link is down during boot, assume that we want to enable L0s
and L1 following hotplug insertion as well as L1SS if supported.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=194895
Signed-off-by: Sinan Kaya <[email protected]>
---
 drivers/pci/pcie/aspm.c | 34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index e33f84b..c7da087 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 +834,38 @@ 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;
+       u16 lnk_status;
+       bool ret;
 
        link = alloc_pcie_link_state(pdev);
        if (!link)
                return -ENOMEM;
 
+       pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
+       ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
+
+       if (ret) {
+               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;
+       } else {
+               if (!pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_L1SS))
+                       link->aspm_default = ASPM_STATE_L0S | ASPM_STATE_L1;
+               else
+                       link->aspm_default = ASPM_STATE_ALL;
+       }
+
        return 0;
 }
 
-- 
1.9.1

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