On Fri, Jul 28, 2023 at 11:49:28AM -0400, Frank Li wrote: > On Fri, Jul 28, 2023 at 09:02:38PM +0530, Manivannan Sadhasivam wrote: > > On Mon, Jul 24, 2023 at 05:58:29PM -0400, Frank Li wrote: > > > 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 > > > > s/interfaces/API > > s/these are/this is > > > > > + * 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; > > > > Why can't just, > > > > val |= dstate; > > fixed a build warning. > > Closes: https://lore.kernel.org/oe-kbuild-all/202307211904.zExw4Q8H-lkp@xxxxxxxxx/ > Ah ok. Missed this report. But still you can get rid of the mask part. > > > > > + 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); > > > > Just assign this during variable definition itself.. > > Do you means? > u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); Yes! > > > > > + /* > > > + * If L1.1\L1.2 enable, devices (such as NVME) want short > > > + * resume latency, controller will not enter L2 > > > > "If L1SS is supported, then do not put the link into L2 as some devices such as > > NVMe expect low resume latency." > > > > > + */ > > > + 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; > > > > Can you just return 0 instead of failing? As per my comment below, if you move > > the D-state change before this callback, then this won't be a hard requirement. > > > > > + > > > + 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 > > > > "Recommends" > > > > Please use full 80 columns for comments. > > > > > + */ > > > + 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); > > > > "Timeout waiting for L2 entry! LTSSM: 0x%x\n" > > > > > + return ret; > > > + } > > > + > > > + dw_pcie_set_dstate(pci, PCI_D3hot); > > > > This should be done before initiating L2 entry as per > > PCI_Express_Base_Specification 3.0, section 5.2. > > This is for root complex bridge, after PCI device and link to L2, > PCI Host can be enter lower power state, I think it is just > borrow 'D3 state' from PCI. > This is confusing now. What is the behavior if the root complex changes D-state but the device driver expects a different one? For instance, during suspend, the NVMe driver expects the D-state to be D0 only [1] not to be changed by the PCI core. This might apply to other drivers as well. Better to leave the D-state change to PCI core itself. - Mani [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/nvme/host/pci.c#n3218 > > > > > + > > > + 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; > > > > Same comment as above. > > > > > + > > > + pci->pp.ops->exit_from_l2(&pci->pp); > > > + > > > + ret = pci->pp.ops->host_init(&pci->pp); > > > > I don't see matching host_deinit() in suspend. > > > > - Mani > > > > > + 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 */ > > > > "Need to align with PCIE_PORT_DEBUG0 bits 0:5". > > > > - Mani > > > > > + 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 > > > > > > > -- > > மணிவண்ணன் சதாசிவம் -- மணிவண்ணன் சதாசிவம்
