RE: [EXT] Re: [PATCH v2 1/1] PCI: layerscape: Add power management support

From: Frank Li <frank.li@nxp.com>
To: Rob Herring <robh+dt@kernel.org>
Cc: "bhelgaas@google.com" <bhelgaas@google.com>,
	Leo Li <leoyang.li@nxp.com>, dl-linux-imx <linux-imx@nxp.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"gustavo.pimentel@synopsys.com" <gustavo.pimentel@synopsys.com>,
	"helgaas@kernel.org" <helgaas@kernel.org>,
	"kw@linux.com" <kw@linux.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
	"M.H. Lian" <minghuan.lian@nxp.com>,
	Mingkai Hu <mingkai.hu@nxp.com>, Roy Zang <roy.zang@nxp.com>,
	"shawnguo@kernel.org" <shawnguo@kernel.org>,
	"Z.Q. Hou" <zhiqiang.hou@nxp.com>
Subject: RE: [EXT] Re: [PATCH v2 1/1] PCI: layerscape: Add power management support
Date: Tue, 21 Mar 2023 19:29:15 +0000	[thread overview]
Message-ID: <AM6PR04MB48386CE9A88D962CF473AF3988819@AM6PR04MB4838.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <CAL_JsqLVSWuoexY+pE5K5bKPz7j1GZugcc5cD73sJW5cEipphQ@mail.gmail.com>

> 
> Caution: EXT Email
> 
> On Tue, Mar 21, 2023 at 11:02 AM Frank Li <Frank.Li@nxp.com> wrote:
> >
> > From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
> >
> > Add PME_Turn_Off/PME_TO_Ack handshake sequence to PCIe devices,
> such as
> > NVME or wifi module, and finally put the PCIe controller into D3 state
> > after the L2/L3 ready state transition process completion.
> >
> > However, it's important to note that not all devices may be able to
> > tolerate the PME_Turn_Off command. In general, fixed PCIe devices
> > connected to Layerscape, such as NXP wifi devices, are able to handle
> > this command.
> >
> > Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > ---
> > Change from v1 to v2
> > - fixed Bjorn Helgaas's comments
> > - remove ls1043 and ls1021, which PME is not self cleaned. After check
> > spec, there are PME interrupt to indicate PEM_TO_ACK command. but I
> > have not these platform to debug it.  I just can test ls1028 platform
> > now.
> >
> >  drivers/pci/controller/dwc/pci-layerscape.c  | 219 ++++++++++++++++++-
> >  drivers/pci/controller/dwc/pcie-designware.h |   1 +
> >  2 files changed, 211 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-layerscape.c
> b/drivers/pci/controller/dwc/pci-layerscape.c
> > index ed5fb492fe08..5fbc9151ff82 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>
> > @@ -29,10 +31,40 @@
> >
> >  #define PCIE_IATU_NUM          6
> >
> > +/* PF Message Command Register */
> > +#define LS_PCIE_PF_MCR         0x2c
> > +#define PF_MCR_PTOMR           BIT(0)
> > +#define PF_MCR_EXL2S           BIT(1)
> > +
> > +#define LS_PCIE_IS_L2(v)       \
> > +       (((v) & PORT_LOGIC_LTSSM_STATE_MASK) ==
> PORT_LOGIC_LTSSM_STATE_L2)
> > +
> > +struct ls_pcie;
> > +
> > +struct ls_pcie_host_pm_ops {
> > +       int (*pm_init)(struct ls_pcie *pcie);
> > +       void (*send_turn_off_message)(struct ls_pcie *pcie);
> > +       void (*exit_from_l2)(struct ls_pcie *pcie);
> > +};
> 
> Please don't create your own private layer of ops. Especially since
> there is only 1 implementation.

I removed ls1043 and ls1021 implement, because I have not platform to
test yet now. which required some logic change to detect PME_TO_ACK. 

What do you preferred?  By using if/else to handle ls1043 and ls1021 difference
In future? 

> 
> Almost every driver has some function to set LTSSM states. Usually
> that's in .start_link(). We probably need some more general DWC op
> function control this.
> 
> > +
> > +struct ls_pcie_drvdata {
> > +       const u32 pf_off;
> > +       const u32 lut_off;
> > +       const struct ls_pcie_host_pm_ops *pm_ops;
> > +};
> > +
> >  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 pm_support;
> > +       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 +105,69 @@ 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)
> 
> You set 'big-endian' for the node, but it's only these PF registers
> that are 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 ls_pcie *pcie)
> > +{
> > +       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_warn(pcie->pci->dev, "poll turn off message timeout\n");
> > +}
> > +
> > +static void ls_pcie_exit_from_l2(struct ls_pcie *pcie)
> > +{
> > +       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_warn(pcie->pci->dev, "poll exit L2 state timeout\n");
> > +}
> > +
> > +static int ls_pcie_pm_init(struct ls_pcie *pcie)
> > +{
> > +       return 0;
> > +}
> > +
> > +static void ls_pcie_set_dstate(struct ls_pcie *pcie, u32 dstate)
> > +{
> > +       struct dw_pcie *pci = pcie->pci;
> > +       u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_PM);
> > +       u32 val;
> > +
> > +       val = dw_pcie_readw_dbi(pci, offset + PCI_PM_CTRL);
> > +       val &= ~PCI_PM_CTRL_STATE_MASK;
> > +       val |= dstate;
> > +       dw_pcie_writew_dbi(pci, offset + PCI_PM_CTRL, val);
> > +}
> > +
> >  static int ls_pcie_host_init(struct dw_pcie_rp *pp)
> >  {
> >         struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > @@ -86,23 +181,46 @@ static int ls_pcie_host_init(struct dw_pcie_rp *pp)
> >
> >         ls_pcie_drop_msg_tlp(pcie);
> >
> > +       if (pcie->drvdata->pm_ops && pcie->drvdata->pm_ops->pm_init &&
> > +           !pcie->drvdata->pm_ops->pm_init(pcie))
> > +               pcie->pm_support = true;
> 
> Just define 'pm_support' in the match data.
> 
> > +
> >         return 0;
> >  }
> >
> > +static struct ls_pcie_host_pm_ops ls_pcie_host_pm_ops = {
> > +       .pm_init = &ls_pcie_pm_init,
> > +       .send_turn_off_message = &ls_pcie_send_turnoff_msg,
> > +       .exit_from_l2 = &ls_pcie_exit_from_l2,
> > +};
> > +
> >  static const struct dw_pcie_host_ops ls_pcie_host_ops = {
> >         .host_init = ls_pcie_host_init,
> >  };
> >
> > +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_ops = &ls_pcie_host_pm_ops,
> > +};
> > +
> >  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 +239,8 @@ 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 +251,14 @@ 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 +267,85 @@ static int ls_pcie_probe(struct platform_device
> *pdev)
> >         return dw_pcie_host_init(&pci->pp);
> >  }
> >
> > +static bool ls_pcie_pm_supported(struct ls_pcie *pcie)
> > +{
> > +       if (!dw_pcie_link_up(pcie->pci)) {
> > +               dev_dbg(pcie->pci->dev, "Endpoint isn't present\n");
> > +               return false;
> > +       }
> > +
> > +       return pcie->pm_support;
> > +}
> > +
> > +#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;
> > +       u32 val;
> > +       int ret;
> > +
> > +       if (!ls_pcie_pm_supported(pcie))
> > +               return 0;
> > +
> > +       pcie->drvdata->pm_ops->send_turn_off_message(pcie);
> > +
> > +       /* 10ms timeout to check L2 ready */
> > +       ret = readl_poll_timeout(pci->dbi_base + PCIE_PORT_DEBUG0,
> > +                                val, LS_PCIE_IS_L2(val), 100, 10000);
> > +       if (ret) {
> > +               dev_err(dev, "PCIe link enter L2 timeout! ltssm = 0x%x\n", val);
> > +               return ret;
> > +       }
> > +
> > +       ls_pcie_set_dstate(pcie, 0x3);
> > +
> > +       return 0;
> > +}
> > +
> > +static int ls_pcie_resume_noirq(struct device *dev)
> > +{
> > +       struct ls_pcie *pcie = dev_get_drvdata(dev);
> > +       struct dw_pcie *pci = pcie->pci;
> > +       int ret;
> > +
> > +       if (!ls_pcie_pm_supported(pcie))
> > +               return 0;
> > +
> > +       ls_pcie_set_dstate(pcie, 0x0);
> > +
> > +       pcie->drvdata->pm_ops->exit_from_l2(pcie);
> > +
> > +       ret = ls_pcie_host_init(&pci->pp);
> > +       if (ret) {
> > +               dev_err(dev, "PCIe host init failed! ret = 0x%x\n", ret);
> > +               return ret;
> > +       }
> > +
> > +       dw_pcie_setup_rc(&pci->pp);
> > +
> > +       ret = dw_pcie_wait_for_link(pci);
> > +       if (ret) {
> > +               dev_err(dev, "Wait link up timeout! ret = 0x%x\n", ret);
> > +               return ret;
> > +       }
> > +
> > +       return 0;
> > +}
> > +#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);
> > diff --git a/drivers/pci/controller/dwc/pcie-designware.h
> b/drivers/pci/controller/dwc/pcie-designware.h
> > index 79713ce075cc..7de8409e2433 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware.h
> > +++ b/drivers/pci/controller/dwc/pcie-designware.h
> > @@ -94,6 +94,7 @@
> >  #define PCIE_PORT_DEBUG0               0x728
> >  #define PORT_LOGIC_LTSSM_STATE_MASK    0x1f
> >  #define PORT_LOGIC_LTSSM_STATE_L0      0x11
> > +#define PORT_LOGIC_LTSSM_STATE_L2      0x15
> >  #define PCIE_PORT_DEBUG1               0x72C
> >  #define PCIE_PORT_DEBUG1_LINK_UP               BIT(4)
> >  #define PCIE_PORT_DEBUG1_LINK_IN_TRAINING      BIT(29)
> > --
> > 2.34.1
> >