[PATCH v6 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions

[PATCH v6 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions

[Frank Li]

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.

Typical L2 exit workflow/dw_pcie_resume_noirq()

1. Issue exit from L2 command.
2. Reinitialize PCI host.
3. Wait for link to become active.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Change from v5 to v6:
- refine commit message
  change according to Manivannan's comments.
  - remove reduncate step dw_pcie_set_dstate()
  - return 0 when .pme_turn_off is zero
  - call host_deinit() in suspend
  - check .host_deinit and .host_init point before call.

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 | 78 +++++++++++++++++++
 drivers/pci/controller/dwc/pcie-designware.h  | 28 +++++++
 2 files changed, 106 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 9952057c8819c..1822c04d370b2 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 +808,80 @@ int dw_pcie_setup_rc(struct dw_pcie_rp *pp)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(dw_pcie_setup_rc);
+
+int dw_pcie_suspend_noirq(struct dw_pcie *pci)
+{
+	u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
+	u32 val;
+	int ret;
+
+	/*
+	 * 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 0;
+
+	pci->pp.ops->pme_turn_off(&pci->pp);
+
+	/*
+	 * PCI Express Base Specification Rev 4.0 5.3.3.2.1 PME Synchronization
+	 * Recommands 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, "Timeout waiting for L2 entry! LTSSM: 0x%x\n", val);
+		return ret;
+	}
+
+	if (pci->pp.ops->host_deinit)
+		pci->pp.ops->host_deinit(&pci->pp);
+
+	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;
+
+	if (!pci->pp.ops->exit_from_l2)
+		return 0;
+
+	pci->pp.ops->exit_from_l2(&pci->pp);
+
+	if (pci->pp.ops->host_init) {
+		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 79713ce075cc1..cbba3ed19b3c0 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 to align with PCIE_PORT_DEBUG0 bits 0:5 */
+	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

[PATCH v6 2/2] PCI: layerscape: Add power management support for ls1028a

[Frank Li]

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 v5 to v6
  change to NOIRQ_SYSTEM_SLEEP_PM_OPS to remove #ifdef PM_CONFIG
  
- 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 | 146 ++++++++++++++++++--
 1 file changed, 137 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-layerscape.c b/drivers/pci/controller/dwc/pci-layerscape.c
index ed5fb492fe084..f235c79600277 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 +238,41 @@ static int ls_pcie_probe(struct platform_device *pdev)
 	return dw_pcie_host_init(&pci->pp);
 }
 
+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);
+}
+
+static const struct dev_pm_ops ls_pcie_pm_ops = {
+	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

Re: [PATCH v6 2/2] PCI: layerscape: Add power management support for ls1028a

[Manivannan Sadhasivam]

On Mon, Jul 31, 2023 at 03:40:10PM -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.
> 

This commit message is wrong/outdated. Please describe what _this_ patch does.

> Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
> - Change from v5 to v6
>   change to NOIRQ_SYSTEM_SLEEP_PM_OPS to remove #ifdef PM_CONFIG
>   
> - 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 | 146 ++++++++++++++++++--
>  1 file changed, 137 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-layerscape.c b/drivers/pci/controller/dwc/pci-layerscape.c
> index ed5fb492fe084..f235c79600277 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;
> +

Why do you need foward declaration?

> +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;

Where is this variable used?

> +	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 value of this function is marked as void. So you should not return
anything.

> +
> +	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);

As I mentioned in previous patch, if you intend to use 1ms, please change the
value to 1000.

> +	if (ret)
> +		dev_info(pcie->pci->dev, "poll turn off message timeout\n");

dev_err? Same below.

> +}
> +
> +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");

Same as above.

> +}
> +
>  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;

Where is lut_base being used?

> +
> +	if (pcie->drvdata->pf_off)

No need of this check. In the absence of "pf_off", pf_base is going to be 0
which is anyway wrong if used. So just use "pf_off" directly.

If you really need the check, then you should use "pm_support" as below:

	if (pcie->drvdata->pm_support)
		pcie->pf_base = pci->dbi_base + pcie->drvdata->pf_off;

This makes it clear that "pf_base" is only used if pm_support is enabled.

> +		pcie->pf_base = pci->dbi_base + pcie->drvdata->pf_off;
> +
>  	if (!ls_pcie_is_bridge(pcie))
>  		return -ENODEV;
>  
> @@ -139,12 +238,41 @@ static int ls_pcie_probe(struct platform_device *pdev)
>  	return dw_pcie_host_init(&pci->pp);
>  }
>  
> +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)
> +{
> +

Remove newline.

- Mani

> +	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);
> +}
> +
> +static const struct dev_pm_ops ls_pcie_pm_ops = {
> +	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
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v6 1/2] PCI: dwc: Implement general suspend/resume functionality for L2/L3 transitions

[Manivannan Sadhasivam]

On Mon, Jul 31, 2023 at 03:40:09PM -0400, Frank Li wrote:
> 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.

s/handle/handling

> 
> 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.
> 
> Typical L2 exit workflow/dw_pcie_resume_noirq()
> 
> 1. Issue exit from L2 command.
> 2. Reinitialize PCI host.
> 3. Wait for link to become active.
> 
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
> Change from v5 to v6:
> - refine commit message
>   change according to Manivannan's comments.
>   - remove reduncate step dw_pcie_set_dstate()
>   - return 0 when .pme_turn_off is zero
>   - call host_deinit() in suspend
>   - check .host_deinit and .host_init point before call.
> 
> 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 | 78 +++++++++++++++++++
>  drivers/pci/controller/dwc/pcie-designware.h  | 28 +++++++
>  2 files changed, 106 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 9952057c8819c..1822c04d370b2 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 +808,80 @@ int dw_pcie_setup_rc(struct dw_pcie_rp *pp)
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(dw_pcie_setup_rc);
> +
> +int dw_pcie_suspend_noirq(struct dw_pcie *pci)
> +{
> +	u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
> +	u32 val;
> +	int ret;
> +
> +	/*
> +	 * 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 0;
> +
> +	pci->pp.ops->pme_turn_off(&pci->pp);
> +
> +	/*
> +	 * PCI Express Base Specification Rev 4.0 5.3.3.2.1 PME Synchronization

Rev 4.0 Section 5.3.3.2.1

> +	 * Recommands 1ms to 10ms timeout to check L2 ready

Recommends

Also add a full stop at the end of line.

> +	 */
> +	ret = read_poll_timeout(dw_pcie_get_ltssm, val, val == DW_PCIE_LTSSM_L2_IDLE,
> +				100, 10000, false, pci);

sleep_us value should be 1000 for 1ms.

> +	if (ret) {
> +		dev_err(pci->dev, "Timeout waiting for L2 entry! LTSSM: 0x%x\n", val);
> +		return ret;
> +	}
> +
> +	if (pci->pp.ops->host_deinit)
> +		pci->pp.ops->host_deinit(&pci->pp);
> +
> +	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;
> +
> +	if (!pci->pp.ops->exit_from_l2)
> +		return 0;
> +
> +	pci->pp.ops->exit_from_l2(&pci->pp);
> +
> +	if (pci->pp.ops->host_init) {
> +		ret = pci->pp.ops->host_init(&pci->pp);
> +		if (ret) {
> +			dev_err(pci->dev, "Host init failed! ret = 0x%x\n", ret);

Why do you want to print "ret" in hex?

How about,

dev_err(pci->dev, "Host init failed: %d\n", ret);

Rest looks good!

- Mani

> +			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 79713ce075cc1..cbba3ed19b3c0 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 to align with PCIE_PORT_DEBUG0 bits 0:5 */
> +	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
> 

-- 
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