* [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions
@ 2023-07-24 21:58 Frank Li
2023-07-24 21:58 ` [PATCH v5 2/2] PCI: layerscape: Add power management support for ls1028a Frank Li
` (2 more replies)
0 siblings, 3 replies; 15+ messages in thread
From: Frank Li @ 2023-07-24 21:58 UTC (permalink / raw)
To: frank.li, lorenzo.pieralisi, manivannan.sadhasivam
Cc: bhelgaas, devicetree, gustavo.pimentel, helgaas, imx, kw,
leoyang.li, linux-arm-kernel, linux-imx, linux-kernel, linux-pci,
mani, minghuan.lian, mingkai.hu, robh+dt, roy.zang, shawnguo,
zhiqiang.hou
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@nxp.com>
---
Change from v4 to v5:
- Closes: https://lore.kernel.org/oe-kbuild-all/202307211904.zExw4Q8H-lkp@intel.com/
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@samsung.com>
*/
+#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
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH v5 2/2] PCI: layerscape: Add power management support for ls1028a
2023-07-24 21:58 [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions Frank Li
@ 2023-07-24 21:58 ` Frank Li
2023-07-25 21:09 ` Bjorn Helgaas
2023-07-28 9:05 ` Lorenzo Pieralisi
2023-07-28 15:32 ` Manivannan Sadhasivam
2 siblings, 1 reply; 15+ messages in thread
From: Frank Li @ 2023-07-24 21:58 UTC (permalink / raw)
To: frank.li, lorenzo.pieralisi, manivannan.sadhasivam
Cc: bhelgaas, devicetree, gustavo.pimentel, helgaas, imx, kw,
leoyang.li, linux-arm-kernel, linux-imx, linux-kernel, linux-pci,
mani, minghuan.lian, mingkai.hu, robh+dt, roy.zang, shawnguo,
zhiqiang.hou
From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Add PME_Turn_Off/PME_TO_Ack handshake sequence, and finally
put the PCIe controller into D3 state after the L2/L3 ready
state transition process completion.
Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
- Change from v3 to v5
none
- change at v3
Basic rewrite whole patch according rob herry suggestion.
put common function into dwc, so more soc can share the same logic.
drivers/pci/controller/dwc/pci-layerscape.c | 148 ++++++++++++++++++--
1 file changed, 139 insertions(+), 9 deletions(-)
diff --git a/drivers/pci/controller/dwc/pci-layerscape.c b/drivers/pci/controller/dwc/pci-layerscape.c
index ed5fb492fe08..32832d74a074 100644
--- a/drivers/pci/controller/dwc/pci-layerscape.c
+++ b/drivers/pci/controller/dwc/pci-layerscape.c
@@ -8,9 +8,11 @@
* Author: Minghuan Lian <Minghuan.Lian@freescale.com>
*/
+#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/init.h>
+#include <linux/iopoll.h>
#include <linux/of_pci.h>
#include <linux/of_platform.h>
#include <linux/of_address.h>
@@ -27,12 +29,33 @@
#define PCIE_ABSERR 0x8d0 /* Bridge Slave Error Response Register */
#define PCIE_ABSERR_SETTING 0x9401 /* Forward error of non-posted request */
+/* PF Message Command Register */
+#define LS_PCIE_PF_MCR 0x2c
+#define PF_MCR_PTOMR BIT(0)
+#define PF_MCR_EXL2S BIT(1)
+
#define PCIE_IATU_NUM 6
+struct ls_pcie;
+
+struct ls_pcie_drvdata {
+ const u32 pf_off;
+ const u32 lut_off;
+ bool pm_support;
+};
+
struct ls_pcie {
struct dw_pcie *pci;
+ const struct ls_pcie_drvdata *drvdata;
+ void __iomem *pf_base;
+ void __iomem *lut_base;
+ bool big_endian;
+ bool ep_presence;
+ struct regmap *scfg;
+ int index;
};
+#define ls_pcie_pf_readl_addr(addr) ls_pcie_pf_readl(pcie, addr)
#define to_ls_pcie(x) dev_get_drvdata((x)->dev)
static bool ls_pcie_is_bridge(struct ls_pcie *pcie)
@@ -73,6 +96,57 @@ static void ls_pcie_fix_error_response(struct ls_pcie *pcie)
iowrite32(PCIE_ABSERR_SETTING, pci->dbi_base + PCIE_ABSERR);
}
+static u32 ls_pcie_pf_readl(struct ls_pcie *pcie, u32 off)
+{
+ if (pcie->big_endian)
+ return ioread32be(pcie->pf_base + off);
+
+ return ioread32(pcie->pf_base + off);
+}
+
+static void ls_pcie_pf_writel(struct ls_pcie *pcie, u32 off, u32 val)
+{
+ if (pcie->big_endian)
+ return iowrite32be(val, pcie->pf_base + off);
+
+ return iowrite32(val, pcie->pf_base + off);
+
+}
+
+static void ls_pcie_send_turnoff_msg(struct dw_pcie_rp *pp)
+{
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ struct ls_pcie *pcie = to_ls_pcie(pci);
+ u32 val;
+ int ret;
+
+ val = ls_pcie_pf_readl(pcie, LS_PCIE_PF_MCR);
+ val |= PF_MCR_PTOMR;
+ ls_pcie_pf_writel(pcie, LS_PCIE_PF_MCR, val);
+
+ ret = readx_poll_timeout(ls_pcie_pf_readl_addr, LS_PCIE_PF_MCR,
+ val, !(val & PF_MCR_PTOMR), 100, 10000);
+ if (ret)
+ dev_info(pcie->pci->dev, "poll turn off message timeout\n");
+}
+
+static void ls_pcie_exit_from_l2(struct dw_pcie_rp *pp)
+{
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ struct ls_pcie *pcie = to_ls_pcie(pci);
+ u32 val;
+ int ret;
+
+ val = ls_pcie_pf_readl(pcie, LS_PCIE_PF_MCR);
+ val |= PF_MCR_EXL2S;
+ ls_pcie_pf_writel(pcie, LS_PCIE_PF_MCR, val);
+
+ ret = readx_poll_timeout(ls_pcie_pf_readl_addr, LS_PCIE_PF_MCR,
+ val, !(val & PF_MCR_EXL2S), 100, 10000);
+ if (ret)
+ dev_info(pcie->pci->dev, "poll exit L2 state timeout\n");
+}
+
static int ls_pcie_host_init(struct dw_pcie_rp *pp)
{
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -91,18 +165,33 @@ static int ls_pcie_host_init(struct dw_pcie_rp *pp)
static const struct dw_pcie_host_ops ls_pcie_host_ops = {
.host_init = ls_pcie_host_init,
+ .pme_turn_off = ls_pcie_send_turnoff_msg,
+ .exit_from_l2 = ls_pcie_exit_from_l2,
+};
+
+static const struct ls_pcie_drvdata ls1021a_drvdata = {
+};
+
+static const struct ls_pcie_drvdata ls1043a_drvdata = {
+ .lut_off = 0x10000,
+};
+
+static const struct ls_pcie_drvdata layerscape_drvdata = {
+ .lut_off = 0x80000,
+ .pf_off = 0xc0000,
+ .pm_support = true,
};
static const struct of_device_id ls_pcie_of_match[] = {
- { .compatible = "fsl,ls1012a-pcie", },
- { .compatible = "fsl,ls1021a-pcie", },
- { .compatible = "fsl,ls1028a-pcie", },
- { .compatible = "fsl,ls1043a-pcie", },
- { .compatible = "fsl,ls1046a-pcie", },
- { .compatible = "fsl,ls2080a-pcie", },
- { .compatible = "fsl,ls2085a-pcie", },
- { .compatible = "fsl,ls2088a-pcie", },
- { .compatible = "fsl,ls1088a-pcie", },
+ { .compatible = "fsl,ls1012a-pcie", .data = &layerscape_drvdata },
+ { .compatible = "fsl,ls1021a-pcie", .data = &ls1021a_drvdata },
+ { .compatible = "fsl,ls1028a-pcie", .data = &layerscape_drvdata },
+ { .compatible = "fsl,ls1043a-pcie", .data = &ls1043a_drvdata },
+ { .compatible = "fsl,ls1046a-pcie", .data = &layerscape_drvdata },
+ { .compatible = "fsl,ls2080a-pcie", .data = &layerscape_drvdata },
+ { .compatible = "fsl,ls2085a-pcie", .data = &layerscape_drvdata },
+ { .compatible = "fsl,ls2088a-pcie", .data = &layerscape_drvdata },
+ { .compatible = "fsl,ls1088a-pcie", .data = &layerscape_drvdata },
{ },
};
@@ -121,6 +210,8 @@ static int ls_pcie_probe(struct platform_device *pdev)
if (!pci)
return -ENOMEM;
+ pcie->drvdata = of_device_get_match_data(dev);
+
pci->dev = dev;
pci->pp.ops = &ls_pcie_host_ops;
@@ -131,6 +222,14 @@ static int ls_pcie_probe(struct platform_device *pdev)
if (IS_ERR(pci->dbi_base))
return PTR_ERR(pci->dbi_base);
+ pcie->big_endian = of_property_read_bool(dev->of_node, "big-endian");
+
+ if (pcie->drvdata->lut_off)
+ pcie->lut_base = pci->dbi_base + pcie->drvdata->lut_off;
+
+ if (pcie->drvdata->pf_off)
+ pcie->pf_base = pci->dbi_base + pcie->drvdata->pf_off;
+
if (!ls_pcie_is_bridge(pcie))
return -ENODEV;
@@ -139,12 +238,43 @@ static int ls_pcie_probe(struct platform_device *pdev)
return dw_pcie_host_init(&pci->pp);
}
+#ifdef CONFIG_PM_SLEEP
+static int ls_pcie_suspend_noirq(struct device *dev)
+{
+ struct ls_pcie *pcie = dev_get_drvdata(dev);
+ struct dw_pcie *pci = pcie->pci;
+
+ if (!pcie->drvdata->pm_support)
+ return 0;
+
+ return dw_pcie_suspend_noirq(pci);
+}
+
+static int ls_pcie_resume_noirq(struct device *dev)
+{
+
+ struct ls_pcie *pcie = dev_get_drvdata(dev);
+ struct dw_pcie *pci = pcie->pci;
+
+ if (!pcie->drvdata->pm_support)
+ return 0;
+
+ return dw_pcie_resume_noirq(pci);
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops ls_pcie_pm_ops = {
+ SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(ls_pcie_suspend_noirq,
+ ls_pcie_resume_noirq)
+};
+
static struct platform_driver ls_pcie_driver = {
.probe = ls_pcie_probe,
.driver = {
.name = "layerscape-pcie",
.of_match_table = ls_pcie_of_match,
.suppress_bind_attrs = true,
+ .pm = &ls_pcie_pm_ops,
},
};
builtin_platform_driver(ls_pcie_driver);
--
2.34.1
^ permalink raw reply related [flat|nested] 15+ messages in thread
* Re: [PATCH v5 2/2] PCI: layerscape: Add power management support for ls1028a
2023-07-24 21:58 ` [PATCH v5 2/2] PCI: layerscape: Add power management support for ls1028a Frank Li
@ 2023-07-25 21:09 ` Bjorn Helgaas
0 siblings, 0 replies; 15+ messages in thread
From: Bjorn Helgaas @ 2023-07-25 21:09 UTC (permalink / raw)
To: Frank Li
Cc: lorenzo.pieralisi, manivannan.sadhasivam, bhelgaas, devicetree,
gustavo.pimentel, imx, kw, leoyang.li, linux-arm-kernel,
linux-imx, linux-kernel, linux-pci, mani, minghuan.lian,
mingkai.hu, robh+dt, roy.zang, shawnguo, zhiqiang.hou
On Mon, Jul 24, 2023 at 05:58:30PM -0400, Frank Li wrote:
> From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
>
> Add PME_Turn_Off/PME_TO_Ack handshake sequence, and finally
> put the PCIe controller into D3 state after the L2/L3 ready
> state transition process completion.
> ...
> +#ifdef CONFIG_PM_SLEEP
> +static int ls_pcie_suspend_noirq(struct device *dev)
> +{
> + struct ls_pcie *pcie = dev_get_drvdata(dev);
> + struct dw_pcie *pci = pcie->pci;
> +
> + if (!pcie->drvdata->pm_support)
> + return 0;
> +
> + return dw_pcie_suspend_noirq(pci);
> +}
> +
> +static int ls_pcie_resume_noirq(struct device *dev)
> +{
> +
> + struct ls_pcie *pcie = dev_get_drvdata(dev);
> + struct dw_pcie *pci = pcie->pci;
> +
> + if (!pcie->drvdata->pm_support)
> + return 0;
> +
> + return dw_pcie_resume_noirq(pci);
> +}
> +#endif /* CONFIG_PM_SLEEP */
You may be able to dispense with some of these #ifdefs as in
https://lore.kernel.org/all/20220720224829.GA1667002@bhelgaas/
> +static const struct dev_pm_ops ls_pcie_pm_ops = {
> + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(ls_pcie_suspend_noirq,
> + ls_pcie_resume_noirq)
> +};
> +
> static struct platform_driver ls_pcie_driver = {
> .probe = ls_pcie_probe,
> .driver = {
> .name = "layerscape-pcie",
> .of_match_table = ls_pcie_of_match,
> .suppress_bind_attrs = true,
> + .pm = &ls_pcie_pm_ops,
> },
> };
> builtin_platform_driver(ls_pcie_driver);
> --
> 2.34.1
>
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions
2023-07-24 21:58 [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions Frank Li
@ 2023-07-28 9:05 ` Lorenzo Pieralisi
2023-07-28 9:05 ` Lorenzo Pieralisi
2023-07-28 15:32 ` Manivannan Sadhasivam
2 siblings, 0 replies; 15+ messages in thread
From: Lorenzo Pieralisi @ 2023-07-28 9:05 UTC (permalink / raw)
To: Frank Li
Cc: lorenzo.pieralisi, manivannan.sadhasivam, bhelgaas, devicetree,
gustavo.pimentel, helgaas, imx, kw, leoyang.li, linux-arm-kernel,
linux-imx, linux-kernel, linux-pci, mani, minghuan.lian,
mingkai.hu, robh+dt, roy.zang, shawnguo, zhiqiang.hou
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.
Commit logs should not use the past tense but the present tense.
eg s/Introduced/Introduce
Furthermore, read this post from Bjorn and follow it to the letter
please:
https://lore.kernel.org/linux-pci/20171026223701.GA25649@bhelgaas-glaptop.roam.corp.google.com
>
> 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.
This does not explain what the patch does and why it does it.
Are you describing the L2 entry/exit as implemented in the code ?
>
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
> Change from v4 to v5:
> - Closes: https://lore.kernel.org/oe-kbuild-all/202307211904.zExw4Q8H-lkp@intel.com/
> Change from v3 to v4:
> - change according to Manivannan's comments.
I shall wait for Mani's comments on this series since he reviewed the
previous one.
Thanks,
Lorenzo
> 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@samsung.com>
> */
>
> +#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
>
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions
@ 2023-07-28 9:05 ` Lorenzo Pieralisi
0 siblings, 0 replies; 15+ messages in thread
From: Lorenzo Pieralisi @ 2023-07-28 9:05 UTC (permalink / raw)
To: Frank Li
Cc: lorenzo.pieralisi, manivannan.sadhasivam, bhelgaas, devicetree,
gustavo.pimentel, helgaas, imx, kw, leoyang.li, linux-arm-kernel,
linux-imx, linux-kernel, linux-pci, mani, minghuan.lian,
mingkai.hu, robh+dt, roy.zang, shawnguo, zhiqiang.hou
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.
Commit logs should not use the past tense but the present tense.
eg s/Introduced/Introduce
Furthermore, read this post from Bjorn and follow it to the letter
please:
https://lore.kernel.org/linux-pci/20171026223701.GA25649@bhelgaas-glaptop.roam.corp.google.com
>
> 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.
This does not explain what the patch does and why it does it.
Are you describing the L2 entry/exit as implemented in the code ?
>
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
> Change from v4 to v5:
> - Closes: https://lore.kernel.org/oe-kbuild-all/202307211904.zExw4Q8H-lkp@intel.com/
> Change from v3 to v4:
> - change according to Manivannan's comments.
I shall wait for Mani's comments on this series since he reviewed the
previous one.
Thanks,
Lorenzo
> 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@samsung.com>
> */
>
> +#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
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions
2023-07-28 9:05 ` Lorenzo Pieralisi
@ 2023-07-28 15:02 ` Frank Li
-1 siblings, 0 replies; 15+ messages in thread
From: Frank Li @ 2023-07-28 15:02 UTC (permalink / raw)
To: Lorenzo Pieralisi
Cc: lorenzo.pieralisi, manivannan.sadhasivam, bhelgaas, devicetree,
gustavo.pimentel, helgaas, imx, kw, leoyang.li, linux-arm-kernel,
linux-imx, linux-kernel, linux-pci, mani, minghuan.lian,
mingkai.hu, robh+dt, roy.zang, shawnguo, zhiqiang.hou
On Fri, Jul 28, 2023 at 11:05:56AM +0200, Lorenzo Pieralisi 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.
>
> Commit logs should not use the past tense but the present tense.
>
> eg s/Introduced/Introduce
>
> Furthermore, read this post from Bjorn and follow it to the letter
> please:
>
> https://lore.kernel.org/linux-pci/20171026223701.GA25649@bhelgaas-glaptop.roam.corp.google.com
>
> >
> > 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.
>
> This does not explain what the patch does and why it does it.
>
> Are you describing the L2 entry/exit as implemented in the code ?
Yes.
How about below commit message:
Introduce helper function dw_pcie_get_ltssm to retrieve SMLH_LTSS_STATE.
Add callback .pme_turn_off and .exit_from_l2 for platform specific PME
handle.
Add common dw_pcie_suspend(resume)_noirq() API to avoid duplicated code
in dwc pci host controller platform driver.
Typical L2 entry workflow/dw_pcie_suspend_noirq()
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/dw_pcie_resume_noirq()
1. Transition Root complex to D0 state.
2. Issue exit from L2 command.
3. Reinitialize PCI host.
4. Wait for link to become active.
Frank
>
> >
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > ---
> > Change from v4 to v5:
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions
@ 2023-07-28 15:02 ` Frank Li
0 siblings, 0 replies; 15+ messages in thread
From: Frank Li @ 2023-07-28 15:02 UTC (permalink / raw)
To: Lorenzo Pieralisi
Cc: lorenzo.pieralisi, manivannan.sadhasivam, bhelgaas, devicetree,
gustavo.pimentel, helgaas, imx, kw, leoyang.li, linux-arm-kernel,
linux-imx, linux-kernel, linux-pci, mani, minghuan.lian,
mingkai.hu, robh+dt, roy.zang, shawnguo, zhiqiang.hou
On Fri, Jul 28, 2023 at 11:05:56AM +0200, Lorenzo Pieralisi 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.
>
> Commit logs should not use the past tense but the present tense.
>
> eg s/Introduced/Introduce
>
> Furthermore, read this post from Bjorn and follow it to the letter
> please:
>
> https://lore.kernel.org/linux-pci/20171026223701.GA25649@bhelgaas-glaptop.roam.corp.google.com
>
> >
> > 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.
>
> This does not explain what the patch does and why it does it.
>
> Are you describing the L2 entry/exit as implemented in the code ?
Yes.
How about below commit message:
Introduce helper function dw_pcie_get_ltssm to retrieve SMLH_LTSS_STATE.
Add callback .pme_turn_off and .exit_from_l2 for platform specific PME
handle.
Add common dw_pcie_suspend(resume)_noirq() API to avoid duplicated code
in dwc pci host controller platform driver.
Typical L2 entry workflow/dw_pcie_suspend_noirq()
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/dw_pcie_resume_noirq()
1. Transition Root complex to D0 state.
2. Issue exit from L2 command.
3. Reinitialize PCI host.
4. Wait for link to become active.
Frank
>
> >
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > ---
> > Change from v4 to v5:
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^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions
2023-07-24 21:58 [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions Frank Li
@ 2023-07-28 15:32 ` Manivannan Sadhasivam
2023-07-28 9:05 ` Lorenzo Pieralisi
2023-07-28 15:32 ` Manivannan Sadhasivam
2 siblings, 0 replies; 15+ messages in thread
From: Manivannan Sadhasivam @ 2023-07-28 15:32 UTC (permalink / raw)
To: Frank Li
Cc: lorenzo.pieralisi, bhelgaas, devicetree, gustavo.pimentel,
helgaas, imx, kw, leoyang.li, linux-arm-kernel, linux-imx,
linux-kernel, linux-pci, mani, minghuan.lian, mingkai.hu,
robh+dt, roy.zang, shawnguo, zhiqiang.hou
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@nxp.com>
> ---
> Change from v4 to v5:
> - Closes: https://lore.kernel.org/oe-kbuild-all/202307211904.zExw4Q8H-lkp@intel.com/
> 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@samsung.com>
> */
>
> +#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;
> + 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..
> + /*
> + * 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.
> +
> + 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
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions
@ 2023-07-28 15:32 ` Manivannan Sadhasivam
0 siblings, 0 replies; 15+ messages in thread
From: Manivannan Sadhasivam @ 2023-07-28 15:32 UTC (permalink / raw)
To: Frank Li
Cc: lorenzo.pieralisi, bhelgaas, devicetree, gustavo.pimentel,
helgaas, imx, kw, leoyang.li, linux-arm-kernel, linux-imx,
linux-kernel, linux-pci, mani, minghuan.lian, mingkai.hu,
robh+dt, roy.zang, shawnguo, zhiqiang.hou
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@nxp.com>
> ---
> Change from v4 to v5:
> - Closes: https://lore.kernel.org/oe-kbuild-all/202307211904.zExw4Q8H-lkp@intel.com/
> 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@samsung.com>
> */
>
> +#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;
> + 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..
> + /*
> + * 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.
> +
> + 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
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^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitionse
2023-07-28 15:32 ` Manivannan Sadhasivam
@ 2023-07-28 15:49 ` Frank Li
-1 siblings, 0 replies; 15+ messages in thread
From: Frank Li @ 2023-07-28 15:49 UTC (permalink / raw)
To: Manivannan Sadhasivam
Cc: lorenzo.pieralisi, bhelgaas, devicetree, gustavo.pimentel,
helgaas, imx, kw, leoyang.li, linux-arm-kernel, linux-imx,
linux-kernel, linux-pci, mani, minghuan.lian, mingkai.hu,
robh+dt, roy.zang, shawnguo, zhiqiang.hou
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@nxp.com>
> > ---
> > Change from v4 to v5:
> > - Closes: https://lore.kernel.org/oe-kbuild-all/202307211904.zExw4Q8H-lkp@intel.com/
> > 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@samsung.com>
> > */
> >
> > +#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@intel.com/
>
> > + 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);
>
> > + /*
> > + * 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.
>
> > +
> > + 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
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitionse
@ 2023-07-28 15:49 ` Frank Li
0 siblings, 0 replies; 15+ messages in thread
From: Frank Li @ 2023-07-28 15:49 UTC (permalink / raw)
To: Manivannan Sadhasivam
Cc: lorenzo.pieralisi, bhelgaas, devicetree, gustavo.pimentel,
helgaas, imx, kw, leoyang.li, linux-arm-kernel, linux-imx,
linux-kernel, linux-pci, mani, minghuan.lian, mingkai.hu,
robh+dt, roy.zang, shawnguo, zhiqiang.hou
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@nxp.com>
> > ---
> > Change from v4 to v5:
> > - Closes: https://lore.kernel.org/oe-kbuild-all/202307211904.zExw4Q8H-lkp@intel.com/
> > 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@samsung.com>
> > */
> >
> > +#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@intel.com/
>
> > + 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);
>
> > + /*
> > + * 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.
>
> > +
> > + 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
_______________________________________________
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linux-arm-kernel@lists.infradead.org
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^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitionse
2023-07-28 15:49 ` Frank Li
@ 2023-07-31 13:36 ` Manivannan Sadhasivam
-1 siblings, 0 replies; 15+ messages in thread
From: Manivannan Sadhasivam @ 2023-07-31 13:36 UTC (permalink / raw)
To: Frank Li
Cc: lorenzo.pieralisi, bhelgaas, devicetree, gustavo.pimentel,
helgaas, imx, kw, leoyang.li, linux-arm-kernel, linux-imx,
linux-kernel, linux-pci, mani, minghuan.lian, mingkai.hu,
robh+dt, roy.zang, shawnguo, zhiqiang.hou
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@nxp.com>
> > > ---
> > > Change from v4 to v5:
> > > - Closes: https://lore.kernel.org/oe-kbuild-all/202307211904.zExw4Q8H-lkp@intel.com/
> > > 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@samsung.com>
> > > */
> > >
> > > +#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@intel.com/
>
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
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitionse
@ 2023-07-31 13:36 ` Manivannan Sadhasivam
0 siblings, 0 replies; 15+ messages in thread
From: Manivannan Sadhasivam @ 2023-07-31 13:36 UTC (permalink / raw)
To: Frank Li
Cc: lorenzo.pieralisi, bhelgaas, devicetree, gustavo.pimentel,
helgaas, imx, kw, leoyang.li, linux-arm-kernel, linux-imx,
linux-kernel, linux-pci, mani, minghuan.lian, mingkai.hu,
robh+dt, roy.zang, shawnguo, zhiqiang.hou
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@nxp.com>
> > > ---
> > > Change from v4 to v5:
> > > - Closes: https://lore.kernel.org/oe-kbuild-all/202307211904.zExw4Q8H-lkp@intel.com/
> > > 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@samsung.com>
> > > */
> > >
> > > +#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@intel.com/
>
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
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^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitionse
2023-07-28 15:49 ` Frank Li
@ 2023-07-31 16:54 ` Bjorn Helgaas
-1 siblings, 0 replies; 15+ messages in thread
From: Bjorn Helgaas @ 2023-07-31 16:54 UTC (permalink / raw)
To: Frank Li
Cc: Manivannan Sadhasivam, lorenzo.pieralisi, bhelgaas, devicetree,
gustavo.pimentel, imx, kw, leoyang.li, linux-arm-kernel,
linux-imx, linux-kernel, linux-pci, mani, minghuan.lian,
mingkai.hu, robh+dt, roy.zang, shawnguo, zhiqiang.hou
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.
> > > ...
> > > +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@intel.com/
This is the sparse warning from the lkp URL:
sparse warnings: (new ones prefixed by >>)
>> drivers/pci/controller/dwc/pcie-designware-host.c:824:13: sparse: sparse: invalid assignment: |=
>> drivers/pci/controller/dwc/pcie-designware-host.c:824:13: sparse: left side has type unsigned int
>> drivers/pci/controller/dwc/pcie-designware-host.c:824:13: sparse: right side has type restricted pci_power_t
We have a zillion of those warnings already (try "make C=2 drivers/pci/").
Personally I think it's better to omit the ugly cast and live with the
warning for now. Someday somebody will figure a better way to use
pci_power_t that will fix all these warnings at once. I'd rather wait
for that fix than clutter all the uses with casts like this.
Bjorn
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitionse
@ 2023-07-31 16:54 ` Bjorn Helgaas
0 siblings, 0 replies; 15+ messages in thread
From: Bjorn Helgaas @ 2023-07-31 16:54 UTC (permalink / raw)
To: Frank Li
Cc: Manivannan Sadhasivam, lorenzo.pieralisi, bhelgaas, devicetree,
gustavo.pimentel, imx, kw, leoyang.li, linux-arm-kernel,
linux-imx, linux-kernel, linux-pci, mani, minghuan.lian,
mingkai.hu, robh+dt, roy.zang, shawnguo, zhiqiang.hou
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.
> > > ...
> > > +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@intel.com/
This is the sparse warning from the lkp URL:
sparse warnings: (new ones prefixed by >>)
>> drivers/pci/controller/dwc/pcie-designware-host.c:824:13: sparse: sparse: invalid assignment: |=
>> drivers/pci/controller/dwc/pcie-designware-host.c:824:13: sparse: left side has type unsigned int
>> drivers/pci/controller/dwc/pcie-designware-host.c:824:13: sparse: right side has type restricted pci_power_t
We have a zillion of those warnings already (try "make C=2 drivers/pci/").
Personally I think it's better to omit the ugly cast and live with the
warning for now. Someday somebody will figure a better way to use
pci_power_t that will fix all these warnings at once. I'd rather wait
for that fix than clutter all the uses with casts like this.
Bjorn
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 15+ messages in thread
end of thread, other threads:[~2023-07-31 16:55 UTC | newest]
Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-07-24 21:58 [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions Frank Li
2023-07-24 21:58 ` [PATCH v5 2/2] PCI: layerscape: Add power management support for ls1028a Frank Li
2023-07-25 21:09 ` Bjorn Helgaas
2023-07-28 9:05 ` [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions Lorenzo Pieralisi
2023-07-28 9:05 ` Lorenzo Pieralisi
2023-07-28 15:02 ` Frank Li
2023-07-28 15:02 ` Frank Li
2023-07-28 15:32 ` Manivannan Sadhasivam
2023-07-28 15:32 ` Manivannan Sadhasivam
2023-07-28 15:49 ` [PATCH v5 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitionse Frank Li
2023-07-28 15:49 ` Frank Li
2023-07-31 13:36 ` Manivannan Sadhasivam
2023-07-31 13:36 ` Manivannan Sadhasivam
2023-07-31 16:54 ` Bjorn Helgaas
2023-07-31 16:54 ` Bjorn Helgaas
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