linux-kernel - Re: [PATCH 1/2] hid: intel-ish-hid: ipc: finish power flow for EHL OOB

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Date:   Mon, 04 Jan 2021 07:59:58 -0800
From:   Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To:     Zhang Lixu <lixu.zhang@...el.com>, jikos@...nel.org,
        linux-input@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, benjamin.tissoires@...hat.com,
        Najumon Ba <najumon.ba@...el.com>, Even Xu <even.xu@...el.com>
Subject: Re: [PATCH 1/2] hid: intel-ish-hid: ipc: finish power flow for EHL
 OOB

On Wed, 2020-12-16 at 14:36 +0800, Zhang Lixu wrote:
> The EHL (Elkhart Lake) based platforms provide a OOB (Out of band)
> service, which allows wakup device when the system is in S5 (Soft-Off
> state). This OOB service can be enabled/disabled from BIOS settings.
> When
> enabled, the ISH device gets PME wake capability. To enable PME
> wakeup,
> driver also needs to enable ACPI GPE bit.
> 
> Once wakeup, BIOS will clear the wakeup bit to identify wakeup is
> successful. So driver need to re-enable it in resume function to
> keep the next wakeup capability.
> 
> Since this feature is only present on EHL, we use EHL PCI device id
> to
> enable this feature.
> 
> Co-developed-by: Najumon Ba <najumon.ba@...el.com>
> Signed-off-by: Najumon Ba <najumon.ba@...el.com>
> Signed-off-by: Even Xu <even.xu@...el.com>
> Signed-off-by: Zhang Lixu <lixu.zhang@...el.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>

> ---
>  drivers/hid/intel-ish-hid/ipc/pci-ish.c | 48
> +++++++++++++++++++++++++
>  1 file changed, 48 insertions(+)
> 
> diff --git a/drivers/hid/intel-ish-hid/ipc/pci-ish.c
> b/drivers/hid/intel-ish-hid/ipc/pci-ish.c
> index c6d48a8648b7..c9c5488e44cb 100644
> --- a/drivers/hid/intel-ish-hid/ipc/pci-ish.c
> +++ b/drivers/hid/intel-ish-hid/ipc/pci-ish.c
> @@ -5,6 +5,7 @@
>   * Copyright (c) 2014-2016, Intel Corporation.
>   */
>  
> +#include <linux/acpi.h>
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
>  #include <linux/kernel.h>
> @@ -111,6 +112,42 @@ static inline bool ish_should_leave_d0i3(struct
> pci_dev *pdev)
>         return !pm_resume_via_firmware() || pdev->device ==
> CHV_DEVICE_ID;
>  }
>  
> +static int enable_gpe(struct device *dev)
> +{
> +#ifdef CONFIG_ACPI
> +       acpi_status acpi_sts;
> +       struct acpi_device *adev;
> +       struct acpi_device_wakeup *wakeup;
> +
> +       adev = ACPI_COMPANION(dev);
> +       if (!adev) {
> +               dev_err(dev, "get acpi handle failed\n");
> +               return -ENODEV;
> +       }
> +       wakeup = &adev->wakeup;
> +
> +       acpi_sts = acpi_enable_gpe(wakeup->gpe_device, wakeup-
> >gpe_number);
> +       if (ACPI_FAILURE(acpi_sts)) {
> +               dev_err(dev, "enable ose_gpe failed\n");
> +               return -EIO;
> +       }
> +
> +       return 0;
> +#else
> +       return -ENODEV;
> +#endif
> +}
> +
> +static void enable_pme_wake(struct pci_dev *pdev)
> +{
> +       if ((pci_pme_capable(pdev, PCI_D0) ||
> +            pci_pme_capable(pdev, PCI_D3hot) ||
> +            pci_pme_capable(pdev, PCI_D3cold)) && !enable_gpe(&pdev-
> >dev)) {
> +               pci_pme_active(pdev, true);
> +               dev_dbg(&pdev->dev, "ish ipc driver pme wake
> enabled\n");
> +       }
> +}
> +
>  /**
>   * ish_probe() - PCI driver probe callback
>   * @pdev:      pci device
> @@ -179,6 +216,10 @@ static int ish_probe(struct pci_dev *pdev, const
> struct pci_device_id *ent)
>         init_waitqueue_head(&ishtp->suspend_wait);
>         init_waitqueue_head(&ishtp->resume_wait);
>  
> +       /* Enable PME for EHL */
> +       if (pdev->device == EHL_Ax_DEVICE_ID)
> +               enable_pme_wake(pdev);
> +
>         ret = ish_init(ishtp);
>         if (ret)
>                 return ret;
> @@ -317,6 +358,13 @@ static int __maybe_unused ish_resume(struct
> device *device)
>         struct pci_dev *pdev = to_pci_dev(device);
>         struct ishtp_device *dev = pci_get_drvdata(pdev);
>  
> +       /* add this to finish power flow for EHL */
> +       if (dev->pdev->device == EHL_Ax_DEVICE_ID) {
> +               pci_set_power_state(pdev, PCI_D0);
> +               enable_pme_wake(pdev);
> +               dev_dbg(dev->devc, "set power state to D0 for
> ehl\n");
> +       }
> +
>         ish_resume_device = device;
>         dev->resume_flag = 1;
>