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Merge branch 'pci/aspm' into next
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* pci/aspm:
  PCI/ASPM: Add L1 Substates definitions
  PCI/ASPM: Reformat ASPM register definitions
  PCI/ASPM: Use correct capability pointer to program LTR_L1.2_THRESHOLD
  PCI/ASPM: Account for downstream device's Port Common_Mode_Restore_Time
  PCI/ASPM: Deal with missing root ports in link state handling
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@bjorn-helgaas
bjorn-helgaas committed Nov 14, 2017
2 parents f5b4f7c + a48f3d5 commit 9c42da5
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Showing 2 changed files with 48 additions and 32 deletions.
46 changes: 28 additions & 18 deletions drivers/pci/pcie/aspm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -450,24 +450,25 @@ static void aspm_calc_l1ss_info(struct pcie_link_state *link,
if (!(link->aspm_support & ASPM_STATE_L1_2_MASK))
return;

/* Choose the greater of the two T_cmn_mode_rstr_time */
val1 = (upreg->l1ss_cap >> 8) & 0xFF;
val2 = (upreg->l1ss_cap >> 8) & 0xFF;
/* Choose the greater of the two Port Common_Mode_Restore_Times */
val1 = (upreg->l1ss_cap & PCI_L1SS_CAP_CM_RESTORE_TIME) >> 8;
val2 = (dwreg->l1ss_cap & PCI_L1SS_CAP_CM_RESTORE_TIME) >> 8;
if (val1 > val2)
link->l1ss.ctl1 |= val1 << 8;
else
link->l1ss.ctl1 |= val2 << 8;

/*
* We currently use LTR L1.2 threshold to be fixed constant picked from
* Intel's coreboot.
*/
link->l1ss.ctl1 |= LTR_L1_2_THRESHOLD_BITS;

/* Choose the greater of the two T_pwr_on */
val1 = (upreg->l1ss_cap >> 19) & 0x1F;
scale1 = (upreg->l1ss_cap >> 16) & 0x03;
val2 = (dwreg->l1ss_cap >> 19) & 0x1F;
scale2 = (dwreg->l1ss_cap >> 16) & 0x03;
/* Choose the greater of the two Port T_POWER_ON times */
val1 = (upreg->l1ss_cap & PCI_L1SS_CAP_P_PWR_ON_VALUE) >> 19;
scale1 = (upreg->l1ss_cap & PCI_L1SS_CAP_P_PWR_ON_SCALE) >> 16;
val2 = (dwreg->l1ss_cap & PCI_L1SS_CAP_P_PWR_ON_VALUE) >> 19;
scale2 = (dwreg->l1ss_cap & PCI_L1SS_CAP_P_PWR_ON_SCALE) >> 16;

if (calc_l1ss_pwron(link->pdev, scale1, val1) >
calc_l1ss_pwron(link->downstream, scale2, val2))
Expand Down Expand Up @@ -646,21 +647,26 @@ static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state)

if (enable_req & ASPM_STATE_L1_2_MASK) {

/* Program T_pwr_on in both ports */
/* Program T_POWER_ON times in both ports */
pci_write_config_dword(parent, up_cap_ptr + PCI_L1SS_CTL2,
link->l1ss.ctl2);
pci_write_config_dword(child, dw_cap_ptr + PCI_L1SS_CTL2,
link->l1ss.ctl2);

/* Program T_cmn_mode in parent */
/* Program Common_Mode_Restore_Time in upstream device */
pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
0xFF00, link->l1ss.ctl1);

/* Program LTR L1.2 threshold in both ports */
pci_clear_and_set_dword(parent, dw_cap_ptr + PCI_L1SS_CTL1,
0xE3FF0000, link->l1ss.ctl1);
PCI_L1SS_CTL1_CM_RESTORE_TIME,
link->l1ss.ctl1);

/* Program LTR_L1.2_THRESHOLD time in both ports */
pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
PCI_L1SS_CTL1_LTR_L12_TH_VALUE |
PCI_L1SS_CTL1_LTR_L12_TH_SCALE,
link->l1ss.ctl1);
pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1,
0xE3FF0000, link->l1ss.ctl1);
PCI_L1SS_CTL1_LTR_L12_TH_VALUE |
PCI_L1SS_CTL1_LTR_L12_TH_SCALE,
link->l1ss.ctl1);
}

val = 0;
Expand Down Expand Up @@ -802,10 +808,14 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)

/*
* Root Ports and PCI/PCI-X to PCIe Bridges are roots of PCIe
* hierarchies.
* hierarchies. Note that some PCIe host implementations omit
* the root ports entirely, in which case a downstream port on
* a switch may become the root of the link state chain for all
* its subordinate endpoints.
*/
if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT ||
pci_pcie_type(pdev) == PCI_EXP_TYPE_PCIE_BRIDGE) {
pci_pcie_type(pdev) == PCI_EXP_TYPE_PCIE_BRIDGE ||
!pdev->bus->parent->self) {
link->root = link;
} else {
struct pcie_link_state *parent;
Expand Down
34 changes: 20 additions & 14 deletions include/uapi/linux/pci_regs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -995,19 +995,25 @@
#define PCI_PTM_CTRL_ENABLE 0x00000001 /* PTM enable */
#define PCI_PTM_CTRL_ROOT 0x00000002 /* Root select */

/* L1 PM Substates */
#define PCI_L1SS_CAP 4 /* capability register */
#define PCI_L1SS_CAP_PCIPM_L1_2 1 /* PCI PM L1.2 Support */
#define PCI_L1SS_CAP_PCIPM_L1_1 2 /* PCI PM L1.1 Support */
#define PCI_L1SS_CAP_ASPM_L1_2 4 /* ASPM L1.2 Support */
#define PCI_L1SS_CAP_ASPM_L1_1 8 /* ASPM L1.1 Support */
#define PCI_L1SS_CAP_L1_PM_SS 16 /* L1 PM Substates Support */
#define PCI_L1SS_CTL1 8 /* Control Register 1 */
#define PCI_L1SS_CTL1_PCIPM_L1_2 1 /* PCI PM L1.2 Enable */
#define PCI_L1SS_CTL1_PCIPM_L1_1 2 /* PCI PM L1.1 Support */
#define PCI_L1SS_CTL1_ASPM_L1_2 4 /* ASPM L1.2 Support */
#define PCI_L1SS_CTL1_ASPM_L1_1 8 /* ASPM L1.1 Support */
#define PCI_L1SS_CTL1_L1SS_MASK 0x0000000F
#define PCI_L1SS_CTL2 0xC /* Control Register 2 */
/* ASPM L1 PM Substates */
#define PCI_L1SS_CAP 0x04 /* Capabilities Register */
#define PCI_L1SS_CAP_PCIPM_L1_2 0x00000001 /* PCI-PM L1.2 Supported */
#define PCI_L1SS_CAP_PCIPM_L1_1 0x00000002 /* PCI-PM L1.1 Supported */
#define PCI_L1SS_CAP_ASPM_L1_2 0x00000004 /* ASPM L1.2 Supported */
#define PCI_L1SS_CAP_ASPM_L1_1 0x00000008 /* ASPM L1.1 Supported */
#define PCI_L1SS_CAP_L1_PM_SS 0x00000010 /* L1 PM Substates Supported */
#define PCI_L1SS_CAP_CM_RESTORE_TIME 0x0000ff00 /* Port Common_Mode_Restore_Time */
#define PCI_L1SS_CAP_P_PWR_ON_SCALE 0x00030000 /* Port T_POWER_ON scale */
#define PCI_L1SS_CAP_P_PWR_ON_VALUE 0x00f80000 /* Port T_POWER_ON value */
#define PCI_L1SS_CTL1 0x08 /* Control 1 Register */
#define PCI_L1SS_CTL1_PCIPM_L1_2 0x00000001 /* PCI-PM L1.2 Enable */
#define PCI_L1SS_CTL1_PCIPM_L1_1 0x00000002 /* PCI-PM L1.1 Enable */
#define PCI_L1SS_CTL1_ASPM_L1_2 0x00000004 /* ASPM L1.2 Enable */
#define PCI_L1SS_CTL1_ASPM_L1_1 0x00000008 /* ASPM L1.1 Enable */
#define PCI_L1SS_CTL1_L1SS_MASK 0x0000000f
#define PCI_L1SS_CTL1_CM_RESTORE_TIME 0x0000ff00 /* Common_Mode_Restore_Time */
#define PCI_L1SS_CTL1_LTR_L12_TH_VALUE 0x03ff0000 /* LTR_L1.2_THRESHOLD_Value */
#define PCI_L1SS_CTL1_LTR_L12_TH_SCALE 0xe0000000 /* LTR_L1.2_THRESHOLD_Scale */
#define PCI_L1SS_CTL2 0x0c /* Control 2 Register */

#endif /* LINUX_PCI_REGS_H */

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