Before sending PME_TURN_OFF, don't test the LTSSM state. Since it's safe
to send PME_TURN_OFF message regardless of whether the link is up or
down. So, there would be no need to test the LTSSM state before sending
PME_TURN_OFF message.
Only print the message when ltssm_stat is not in DETECT and POLL.
In the other words, there isn't an error message when no endpoint is
connected at all.
Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
---
v5 changes:
- Remove the redundant check "(val > DW_PCIE_LTSSM_DETECT_WAIT)".
v4 changes:
- Keep error return when L2 entry is failed and the endpoint is
connected refer to Krishna' comments. Thanks.
v3 changes:
- Refine the commit message refer to Manivannan's comments.
- Regarding Frank's comments, avoid 10ms wait when no link up.
v2 changes:
- Don't remove L2 poll check.
- Add one 1us delay after L2 entry.
- No error return when L2 entry is timeout
- Don't print message when no link up.
---
.../pci/controller/dwc/pcie-designware-host.c | 38 +++++++++++--------
drivers/pci/controller/dwc/pcie-designware.h | 1 +
2 files changed, 23 insertions(+), 16 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 24e89b66b772..bbd0ee862c12 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -927,25 +927,31 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
if (dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKCTL) & PCI_EXP_LNKCTL_ASPM_L1)
return 0;
- /* Only send out PME_TURN_OFF when PCIE link is up */
- if (dw_pcie_get_ltssm(pci) > DW_PCIE_LTSSM_DETECT_ACT) {
- if (pci->pp.ops->pme_turn_off)
- pci->pp.ops->pme_turn_off(&pci->pp);
- else
- ret = dw_pcie_pme_turn_off(pci);
-
- if (ret)
- return ret;
+ if (pci->pp.ops->pme_turn_off)
+ pci->pp.ops->pme_turn_off(&pci->pp);
+ else
+ ret = dw_pcie_pme_turn_off(pci);
+ if (ret)
+ return ret;
- ret = read_poll_timeout(dw_pcie_get_ltssm, val, val == DW_PCIE_LTSSM_L2_IDLE,
- PCIE_PME_TO_L2_TIMEOUT_US/10,
- PCIE_PME_TO_L2_TIMEOUT_US, false, pci);
- if (ret) {
- dev_err(pci->dev, "Timeout waiting for L2 entry! LTSSM: 0x%x\n", val);
- return ret;
- }
+ ret = read_poll_timeout(dw_pcie_get_ltssm, val,
+ val == DW_PCIE_LTSSM_L2_IDLE ||
+ val <= DW_PCIE_LTSSM_DETECT_WAIT,
+ PCIE_PME_TO_L2_TIMEOUT_US/10,
+ PCIE_PME_TO_L2_TIMEOUT_US, false, pci);
+ if (ret) {
+ /* Only dump message when ltssm_stat isn't in DETECT and POLL */
+ dev_err(pci->dev, "Timeout waiting for L2 entry! LTSSM: 0x%x\n", val);
+ return ret;
}
+ /*
+ * Refer to r6.0, sec 5.3.3.2.1, software should wait at least
+ * 100ns after L2/L3 Ready before turning off refclock and
+ * main power. It's harmless too when no endpoint connected.
+ */
+ udelay(1);
+
dw_pcie_stop_link(pci);
if (pci->pp.ops->deinit)
pci->pp.ops->deinit(&pci->pp);
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 347ab74ac35a..bf036e66717e 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -330,6 +330,7 @@ enum dw_pcie_ltssm {
/* Need to align with PCIE_PORT_DEBUG0 bits 0:5 */
DW_PCIE_LTSSM_DETECT_QUIET = 0x0,
DW_PCIE_LTSSM_DETECT_ACT = 0x1,
+ DW_PCIE_LTSSM_DETECT_WAIT = 0x6,
DW_PCIE_LTSSM_L0 = 0x11,
DW_PCIE_LTSSM_L2_IDLE = 0x15,
--
2.37.1
