From da56a1bfbab55189595e588f1d984bdfb5cf5924 Mon Sep 17 00:00:00 2001 From: Ajay Agarwal Date: Wed, 12 Apr 2023 15:04:25 +0530 Subject: [PATCH 1/2] PCI: dwc: Wait for link up only if link is started In dw_pcie_host_init() regardless of whether the link has been started or not, the code waits for the link to come up. Even in cases where start_link() is not defined the code ends up spinning in a loop for 1 second. Since in some systems dw_pcie_host_init() gets called during probe, this one second loop for each pcie interface instance ends up extending the boot time. Wait for the link up in only if the start_link() is defined. Link: https://lore.kernel.org/r/20230412093425.3659088-1-ajayagarwal@google.com Tested-by: Will McVicker Signed-off-by: Sajid Dalvi Signed-off-by: Ajay Agarwal Signed-off-by: Lorenzo Pieralisi --- .../pci/controller/dwc/pcie-designware-host.c | 13 ++++++++---- drivers/pci/controller/dwc/pcie-designware.c | 20 ++++++++++++------- drivers/pci/controller/dwc/pcie-designware.h | 1 + 3 files changed, 23 insertions(+), 11 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c index 9952057c8819..cf61733bf78d 100644 --- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c @@ -485,14 +485,19 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp) if (ret) goto err_remove_edma; - if (!dw_pcie_link_up(pci)) { + if (dw_pcie_link_up(pci)) { + dw_pcie_print_link_status(pci); + } else { ret = dw_pcie_start_link(pci); if (ret) goto err_remove_edma; - } - /* Ignore errors, the link may come up later */ - dw_pcie_wait_for_link(pci); + if (pci->ops && pci->ops->start_link) { + ret = dw_pcie_wait_for_link(pci); + if (ret) + goto err_stop_link; + } + } bridge->sysdata = pp; diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c index 8e33e6e59e68..df092229e97d 100644 --- a/drivers/pci/controller/dwc/pcie-designware.c +++ b/drivers/pci/controller/dwc/pcie-designware.c @@ -644,9 +644,20 @@ void dw_pcie_disable_atu(struct dw_pcie *pci, u32 dir, int index) dw_pcie_writel_atu(pci, dir, index, PCIE_ATU_REGION_CTRL2, 0); } -int dw_pcie_wait_for_link(struct dw_pcie *pci) +void dw_pcie_print_link_status(struct dw_pcie *pci) { u32 offset, val; + + offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); + val = dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKSTA); + + dev_info(pci->dev, "PCIe Gen.%u x%u link up\n", + FIELD_GET(PCI_EXP_LNKSTA_CLS, val), + FIELD_GET(PCI_EXP_LNKSTA_NLW, val)); +} + +int dw_pcie_wait_for_link(struct dw_pcie *pci) +{ int retries; /* Check if the link is up or not */ @@ -662,12 +673,7 @@ int dw_pcie_wait_for_link(struct dw_pcie *pci) return -ETIMEDOUT; } - offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); - val = dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKSTA); - - dev_info(pci->dev, "PCIe Gen.%u x%u link up\n", - FIELD_GET(PCI_EXP_LNKSTA_CLS, val), - FIELD_GET(PCI_EXP_LNKSTA_NLW, val)); + dw_pcie_print_link_status(pci); return 0; } diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h index 79713ce075cc..615660640801 100644 --- a/drivers/pci/controller/dwc/pcie-designware.h +++ b/drivers/pci/controller/dwc/pcie-designware.h @@ -429,6 +429,7 @@ void dw_pcie_setup(struct dw_pcie *pci); void dw_pcie_iatu_detect(struct dw_pcie *pci); int dw_pcie_edma_detect(struct dw_pcie *pci); void dw_pcie_edma_remove(struct dw_pcie *pci); +void dw_pcie_print_link_status(struct dw_pcie *pci); static inline void dw_pcie_writel_dbi(struct dw_pcie *pci, u32 reg, u32 val) { From 3bbc3c72c4b8982ecb719df6685dc7067def0904 Mon Sep 17 00:00:00 2001 From: Richard Zhu Date: Thu, 8 Dec 2022 14:05:34 +0800 Subject: [PATCH 2/2] 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 [lpieralisi@kernel.org: commit log] Signed-off-by: Lorenzo Pieralisi --- drivers/pci/controller/dwc/pci-imx6.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) 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)