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PCI/ASPM: Refactor L1 PM Substates Control Register programming 

Refactor the code to extract the common code to program Control
Registers 1 and 2 of the L1 PM Substates capability to a new function
aspm_program_l1ss() and call it for both parent and child devices.

[bhelgaas: squash in update to preserve fields we're not updating from
https://lore.kernel.org/r/36fa13c5-e0f8-022f-77f7-7908e4df98b8@nvidia.com]
Link: https://lore.kernel.org/r/20220913131822.16557-2-vidyas@nvidia.com
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Vidya Sagar 2022-09-13 18:48:21 +05:30 committed by Bjorn Helgaas
parent 568035b01c
commit 5e85eba6f5
1 changed files with 39 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

72
drivers/pci/pcie/aspm.c
View File

@ -455,6 +455,31 @@ static void pci_clear_and_set_dword(struct pci_dev *pdev, int pos,
pci_write_config_dword(pdev, pos, val);
}
static void aspm_program_l1ss(struct pci_dev *dev, u32 ctl1, u32 ctl2)
{
u16 l1ss = dev->l1ss;
u32 l1_2_enable;
/*
* Per PCIe r6.0, sec 5.5.4, T_POWER_ON in PCI_L1SS_CTL2 must be
* programmed prior to setting the L1.2 enable bits in PCI_L1SS_CTL1.
*/
pci_write_config_dword(dev, l1ss + PCI_L1SS_CTL2, ctl2);
/*
* In addition, Common_Mode_Restore_Time and LTR_L1.2_THRESHOLD in
* PCI_L1SS_CTL1 must be programmed *before* setting the L1.2
* enable bits, even though they're all in PCI_L1SS_CTL1.
*/
l1_2_enable = ctl1 & PCI_L1SS_CTL1_L1_2_MASK;
ctl1 &= ~PCI_L1SS_CTL1_L1_2_MASK;
pci_write_config_dword(dev, l1ss + PCI_L1SS_CTL1, ctl1);
if (l1_2_enable)
pci_write_config_dword(dev, l1ss + PCI_L1SS_CTL1,
ctl1 | l1_2_enable);
}
/* Calculate L1.2 PM substate timing parameters */
static void aspm_calc_l1ss_info(struct pcie_link_state *link,
u32 parent_l1ss_cap, u32 child_l1ss_cap)
@ -464,7 +489,6 @@ static void aspm_calc_l1ss_info(struct pcie_link_state *link,
u32 t_common_mode, t_power_on, l1_2_threshold, scale, value;
u32 ctl1 = 0, ctl2 = 0;
u32 pctl1, pctl2, cctl1, cctl2;
u32 pl1_2_enables, cl1_2_enables;
if (!(link->aspm_support & ASPM_STATE_L1_2_MASK))
return;
@ -513,39 +537,21 @@ static void aspm_calc_l1ss_info(struct pcie_link_state *link,
ctl2 == pctl2 && ctl2 == cctl2)
return;
/* Disable L1.2 while updating. See PCIe r5.0, sec 5.5.4, 7.8.3.3 */
pl1_2_enables = pctl1 & PCI_L1SS_CTL1_L1_2_MASK;
cl1_2_enables = cctl1 & PCI_L1SS_CTL1_L1_2_MASK;
pctl1 &= ~(PCI_L1SS_CTL1_CM_RESTORE_TIME |
PCI_L1SS_CTL1_LTR_L12_TH_VALUE |
PCI_L1SS_CTL1_LTR_L12_TH_SCALE);
pctl1 |= (ctl1 & (PCI_L1SS_CTL1_CM_RESTORE_TIME |
PCI_L1SS_CTL1_LTR_L12_TH_VALUE |
PCI_L1SS_CTL1_LTR_L12_TH_SCALE));
aspm_program_l1ss(parent, pctl1, ctl2);
if (pl1_2_enables || cl1_2_enables) {
pci_clear_and_set_dword(child, child->l1ss + PCI_L1SS_CTL1,
PCI_L1SS_CTL1_L1_2_MASK, 0);
pci_clear_and_set_dword(parent, parent->l1ss + PCI_L1SS_CTL1,
PCI_L1SS_CTL1_L1_2_MASK, 0);
}
/* Program T_POWER_ON times in both ports */
pci_write_config_dword(parent, parent->l1ss + PCI_L1SS_CTL2, ctl2);
pci_write_config_dword(child, child->l1ss + PCI_L1SS_CTL2, ctl2);
/* Program Common_Mode_Restore_Time in upstream device */
pci_clear_and_set_dword(parent, parent->l1ss + PCI_L1SS_CTL1,
PCI_L1SS_CTL1_CM_RESTORE_TIME, ctl1);
/* Program LTR_L1.2_THRESHOLD time in both ports */
pci_clear_and_set_dword(parent, parent->l1ss + PCI_L1SS_CTL1,
PCI_L1SS_CTL1_LTR_L12_TH_VALUE |
PCI_L1SS_CTL1_LTR_L12_TH_SCALE, ctl1);
pci_clear_and_set_dword(child, child->l1ss + PCI_L1SS_CTL1,
PCI_L1SS_CTL1_LTR_L12_TH_VALUE |
PCI_L1SS_CTL1_LTR_L12_TH_SCALE, ctl1);
if (pl1_2_enables || cl1_2_enables) {
pci_clear_and_set_dword(parent, parent->l1ss + PCI_L1SS_CTL1, 0,
pl1_2_enables);
pci_clear_and_set_dword(child, child->l1ss + PCI_L1SS_CTL1, 0,
cl1_2_enables);
}
cctl1 &= ~(PCI_L1SS_CTL1_CM_RESTORE_TIME |
PCI_L1SS_CTL1_LTR_L12_TH_VALUE |
PCI_L1SS_CTL1_LTR_L12_TH_SCALE);
cctl1 |= (ctl1 & (PCI_L1SS_CTL1_CM_RESTORE_TIME |
PCI_L1SS_CTL1_LTR_L12_TH_VALUE |
PCI_L1SS_CTL1_LTR_L12_TH_SCALE));
aspm_program_l1ss(child, cctl1, ctl2);
}
static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)