Introduced helper function dw_pcie_get_ltssm to retrieve SMLH_LTSS_STATE. Added API pme_turn_off and exit_from_l2 for managing L2/L3 state transitions. Typical L2 entry workflow: 1. Transmit PME turn off signal to PCI devices and wait for PME_To_Ack. 2. Await link entering L2_IDLE state. 3. Transition Root complex to D3 state. Typical L2 exit workflow: 1. Transition Root complex to D0 state. 2. Issue exit from L2 command. 3. Reinitialize PCI host. 4. Wait for link to become active. Signed-off-by: Frank Li <Frank.Li@xxxxxxx> --- Change from v4 to v5: - Closes: https://lore.kernel.org/oe-kbuild-all/202307211904.zExw4Q8H-lkp@xxxxxxxxx/ Change from v3 to v4: - change according to Manivannan's comments. I hope I have not missed anything. quite long discuss thread Change from v2 to v3: - Basic rewrite whole patch according rob herry suggestion. put common function into dwc, so more soc can share the same logic. .../pci/controller/dwc/pcie-designware-host.c | 95 +++++++++++++++++++ drivers/pci/controller/dwc/pcie-designware.h | 28 ++++++ 2 files changed, 123 insertions(+) diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c index 9952057c8819..031e1f9c0d0c 100644 --- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c @@ -8,6 +8,7 @@ * Author: Jingoo Han <jg1.han@xxxxxxxxxxx> */ +#include <linux/iopoll.h> #include <linux/irqchip/chained_irq.h> #include <linux/irqdomain.h> #include <linux/msi.h> @@ -807,3 +808,97 @@ int dw_pcie_setup_rc(struct dw_pcie_rp *pp) return 0; } EXPORT_SYMBOL_GPL(dw_pcie_setup_rc); + +/* + * This resemble the pci_set_power_state() interfaces, but these are for + * configuring host controllers, which are bridges *to* PCI devices but + * are not PCI devices themselves. + */ +static void dw_pcie_set_dstate(struct dw_pcie *pci, pci_power_t dstate) +{ + u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_PM); + u16 val; + + val = dw_pcie_readw_dbi(pci, offset + PCI_PM_CTRL); + val &= ~PCI_PM_CTRL_STATE_MASK; + val |= ((u16 __force)dstate) & PCI_PM_CTRL_STATE_MASK; + dw_pcie_writew_dbi(pci, offset + PCI_PM_CTRL, val); +} + +int dw_pcie_suspend_noirq(struct dw_pcie *pci) +{ + u8 offset; + u32 val; + int ret; + + offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); + /* + * If L1.1\L1.2 enable, devices (such as NVME) want short + * resume latency, controller will not enter L2 + */ + if (dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKCTL) & PCI_EXP_LNKCTL_ASPM_L1) + return 0; + + if (dw_pcie_get_ltssm(pci) <= DW_PCIE_LTSSM_DETECT_ACT) + return 0; + + if (!pci->pp.ops->pme_turn_off) + return -EINVAL; + + pci->pp.ops->pme_turn_off(&pci->pp); + + /* + * PCI Express Base Specification Rev 4.0 + * 5.3.3.2.1 PME Synchronization + * Recommand 1ms to 10ms timeout to check L2 ready + */ + ret = read_poll_timeout(dw_pcie_get_ltssm, val, val == DW_PCIE_LTSSM_L2_IDLE, + 100, 10000, false, pci); + if (ret) { + dev_err(pci->dev, "PCIe link enter L2 timeout! ltssm = 0x%x\n", val); + return ret; + } + + dw_pcie_set_dstate(pci, PCI_D3hot); + + pci->suspended = true; + + return ret; +} +EXPORT_SYMBOL_GPL(dw_pcie_suspend_noirq); + +int dw_pcie_resume_noirq(struct dw_pcie *pci) +{ + int ret; + + if (!pci->suspended) + return 0; + + pci->suspended = false; + + dw_pcie_set_dstate(pci, PCI_D0); + + if (!pci->pp.ops->exit_from_l2) + return -EINVAL; + + pci->pp.ops->exit_from_l2(&pci->pp); + + ret = pci->pp.ops->host_init(&pci->pp); + if (ret) { + dev_err(pci->dev, "Host init failed! ret = 0x%x\n", ret); + return ret; + } + + dw_pcie_setup_rc(&pci->pp); + + ret = dw_pcie_start_link(pci); + if (ret) + return ret; + + ret = dw_pcie_wait_for_link(pci); + if (ret) + return ret; + + return ret; +} +EXPORT_SYMBOL_GPL(dw_pcie_resume_noirq); diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h index 79713ce075cc..effb07a506e4 100644 --- a/drivers/pci/controller/dwc/pcie-designware.h +++ b/drivers/pci/controller/dwc/pcie-designware.h @@ -288,10 +288,21 @@ enum dw_pcie_core_rst { DW_PCIE_NUM_CORE_RSTS }; +enum dw_pcie_ltssm { + DW_PCIE_LTSSM_UNKNOWN = 0xFFFFFFFF, + /* Need align PCIE_PORT_DEBUG0 bit0:5 */ + DW_PCIE_LTSSM_DETECT_QUIET = 0x0, + DW_PCIE_LTSSM_DETECT_ACT = 0x1, + DW_PCIE_LTSSM_L0 = 0x11, + DW_PCIE_LTSSM_L2_IDLE = 0x15, +}; + struct dw_pcie_host_ops { int (*host_init)(struct dw_pcie_rp *pp); void (*host_deinit)(struct dw_pcie_rp *pp); int (*msi_host_init)(struct dw_pcie_rp *pp); + void (*pme_turn_off)(struct dw_pcie_rp *pp); + void (*exit_from_l2)(struct dw_pcie_rp *pp); }; struct dw_pcie_rp { @@ -364,6 +375,7 @@ struct dw_pcie_ops { void (*write_dbi2)(struct dw_pcie *pcie, void __iomem *base, u32 reg, size_t size, u32 val); int (*link_up)(struct dw_pcie *pcie); + enum dw_pcie_ltssm (*get_ltssm)(struct dw_pcie *pcie); int (*start_link)(struct dw_pcie *pcie); void (*stop_link)(struct dw_pcie *pcie); }; @@ -393,6 +405,7 @@ struct dw_pcie { struct reset_control_bulk_data app_rsts[DW_PCIE_NUM_APP_RSTS]; struct reset_control_bulk_data core_rsts[DW_PCIE_NUM_CORE_RSTS]; struct gpio_desc *pe_rst; + bool suspended; }; #define to_dw_pcie_from_pp(port) container_of((port), struct dw_pcie, pp) @@ -430,6 +443,9 @@ 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); +int dw_pcie_suspend_noirq(struct dw_pcie *pci); +int dw_pcie_resume_noirq(struct dw_pcie *pci); + static inline void dw_pcie_writel_dbi(struct dw_pcie *pci, u32 reg, u32 val) { dw_pcie_write_dbi(pci, reg, 0x4, val); @@ -501,6 +517,18 @@ static inline void dw_pcie_stop_link(struct dw_pcie *pci) pci->ops->stop_link(pci); } +static inline enum dw_pcie_ltssm dw_pcie_get_ltssm(struct dw_pcie *pci) +{ + u32 val; + + if (pci->ops && pci->ops->get_ltssm) + return pci->ops->get_ltssm(pci); + + val = dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG0); + + return (enum dw_pcie_ltssm)FIELD_GET(PORT_LOGIC_LTSSM_STATE_MASK, val); +} + #ifdef CONFIG_PCIE_DW_HOST irqreturn_t dw_handle_msi_irq(struct dw_pcie_rp *pp); int dw_pcie_setup_rc(struct dw_pcie_rp *pp); -- 2.34.1
