Re: [PATCH v1 2/4] PCI: dwc: Add quirk to fix hang issue when send out PME_Turn_Off Msg TLP
From: Manivannan Sadhasivam <hidden>
Date: 2025-05-31 17:50:23
Also in:
imx, linux-pci, lkml
On Tue, Apr 08, 2025 at 02:52:19PM +0800, Richard Zhu wrote:
When no endpoint is connected on i.MX7D PCIe, chip would be freeze when do the dummy write in dw_pcie_pme_turn_off() to issue a PME_Turn_Off Msg TLP. Add one quirk to issue the PME_Turn_Off only when link is up to avoid this problem on the PME_Turn_Off handshake broken platform, for example the i.MX7D.
Why do we need to send PME_Turn_Off if there is no endpoint connected? We should skip PME_Turn_Off and L2/L3 Ready transitions in that case. - Mani
quoted hunk ↗ jump to hunk
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com> --- .../pci/controller/dwc/pcie-designware-host.c | 16 +++++++++++----- drivers/pci/controller/dwc/pcie-designware.h | 1 + 2 files changed, 12 insertions(+), 5 deletions(-)diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c index 0817df5b8a59..a62bf7e0ade8 100644 --- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c@@ -956,12 +956,18 @@ 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; - if (pci->pp.ops->pme_turn_off) { - pci->pp.ops->pme_turn_off(&pci->pp); + if (dw_pcie_get_ltssm(pci) <= DW_PCIE_LTSSM_DETECT_WAIT && + dwc_check_quirk(pci, QUIRK_NOLINK_NOPME)) { + /* Don't send the PME_TURN_OFF when link is down. */ + ; } 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; + } } if (!dwc_check_quirk(pci, QUIRK_NOL2POLL_IN_PM)) {diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h index 05fe654d7761..d752af660e95 100644 --- a/drivers/pci/controller/dwc/pcie-designware.h +++ b/drivers/pci/controller/dwc/pcie-designware.h@@ -283,6 +283,7 @@ #define DMA_LLP_MEM_SIZE PAGE_SIZE #define QUIRK_NOL2POLL_IN_PM BIT(0) +#define QUIRK_NOLINK_NOPME BIT(1) #define dwc_check_quirk(pci, val) (pci->quirk_flag & val) struct dw_pcie;-- 2.37.1
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