diff options
| author | Richard Zhu <hongxing.zhu@nxp.com> | 2022-12-08 14:05:34 +0800 |
|---|---|---|
| committer | Lorenzo Pieralisi <lpieralisi@kernel.org> | 2023-06-19 11:16:54 +0200 |
| commit | 3bbc3c72c4b8982ecb719df6685dc7067def0904 (patch) | |
| tree | eddc0a2ca4713568681c5122a54f51297f4ff418 /drivers/pci | |
| parent | da56a1bfbab55189595e588f1d984bdfb5cf5924 (diff) | |
PCI: imx6: Save and restore root port MSI control in suspend and resume
The imx6 PCI host controller suffers from a HW integration bug whereby
the MSI enable bit in the root port MSI capability enables/disables MSIs
interrupts for all downstream components in the PCI tree.
This requires, as implemented in
75cb8d20c112 ("PCI: imx: Enable MSI from downstream components")
that the root port MSI enable bit should be set in order for downstream
PCI devices MSIs to function.
The MSI enable bit programming might be lost during the suspend and
should be re-stored during resume.
Save the MSI control during suspend and restore it in resume.
Link: https://lore.kernel.org/r/1670479534-22154-1-git-send-email-hongxing.zhu@nxp.com
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
[lpieralisi@kernel.org: commit log]
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Diffstat (limited to 'drivers/pci')
| -rw-r--r-- | drivers/pci/controller/dwc/pci-imx6.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c index 52906f999f2b..27aaa2a6bf39 100644 --- a/drivers/pci/controller/dwc/pci-imx6.c +++ b/drivers/pci/controller/dwc/pci-imx6.c @@ -80,6 +80,7 @@ struct imx6_pcie { struct clk *pcie; struct clk *pcie_aux; struct regmap *iomuxc_gpr; + u16 msi_ctrl; u32 controller_id; struct reset_control *pciephy_reset; struct reset_control *apps_reset; @@ -1178,6 +1179,26 @@ pm_turnoff_sleep: usleep_range(1000, 10000); } +static void imx6_pcie_msi_save_restore(struct imx6_pcie *imx6_pcie, bool save) +{ + u8 offset; + u16 val; + struct dw_pcie *pci = imx6_pcie->pci; + + if (pci_msi_enabled()) { + offset = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI); + if (save) { + val = dw_pcie_readw_dbi(pci, offset + PCI_MSI_FLAGS); + imx6_pcie->msi_ctrl = val; + } else { + dw_pcie_dbi_ro_wr_en(pci); + val = imx6_pcie->msi_ctrl; + dw_pcie_writew_dbi(pci, offset + PCI_MSI_FLAGS, val); + dw_pcie_dbi_ro_wr_dis(pci); + } + } +} + static int imx6_pcie_suspend_noirq(struct device *dev) { struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev); @@ -1186,6 +1207,7 @@ static int imx6_pcie_suspend_noirq(struct device *dev) if (!(imx6_pcie->drvdata->flags & IMX6_PCIE_FLAG_SUPPORTS_SUSPEND)) return 0; + imx6_pcie_msi_save_restore(imx6_pcie, true); imx6_pcie_pm_turnoff(imx6_pcie); imx6_pcie_stop_link(imx6_pcie->pci); imx6_pcie_host_exit(pp); @@ -1205,6 +1227,7 @@ static int imx6_pcie_resume_noirq(struct device *dev) ret = imx6_pcie_host_init(pp); if (ret) return ret; + imx6_pcie_msi_save_restore(imx6_pcie, false); dw_pcie_setup_rc(pp); if (imx6_pcie->link_is_up) |