Re: [RFC PATCH 1/1] mmc: sdhci-pci-gli: fix x86/S0ix SoCs suspend for GL9767

[Ben Chuang <benchuanggli@gmail.com>]

From: benchuanggli@gmail.com

[Resend email format, Sorry.]

Hi Georg and Christoffer,

On Tue, Oct 15, 2024 at 8:47 PM Georg Gottleuber <g.gottleuber@tuxedocomputers.com> wrote:
>
> Adapt commit 1202d617e3d04c ("mmc: sdhci-pci-gli: fix LPM negotiation
> so x86/S0ix SoCs can suspend") also for GL9767 card reader.
>
> This patch was written without specs or deeper knowledge of PCI sleep
> states. Tests show that S0ix is reached and a lower power consumption
> when suspended (6 watts vs 1.2 watts for TUXEDO InfinityBook Pro Gen9
> Intel).
>
> The function of the card reader appears to be normal.
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=219284
> Co-developed-by: Christoffer Sandberg <cs@tuxedo.de>
> Signed-off-by: Christoffer Sandberg <cs@tuxedo.de>
> Signed-off-by: Georg Gottleuber <ggo@tuxedocomputers.com>
Maybe need a Fixes: f3a5b56c1286 ("mmc: sdhci-pci-gli: Add Genesys Logic GL9767 support")

> ---
>  drivers/mmc/host/sdhci-pci-gli.c | 65 +++++++++++++++++++++++++++++++-
>  1 file changed, 64 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-pci-gli.c
> b/drivers/mmc/host/sdhci-pci-gli.c
> index 0f81586a19df..40f43f5cd5c7 100644
> --- a/drivers/mmc/host/sdhci-pci-gli.c
> +++ b/drivers/mmc/host/sdhci-pci-gli.c
> @@ -1205,6 +1205,32 @@ static void
> gl9763e_set_low_power_negotiation(struct sdhci_pci_slot *slot,
>         pci_write_config_dword(pdev, PCIE_GLI_9763E_VHS, value);
>  }
>
> +static void gl9767_set_low_power_negotiation(struct sdhci_pci_slot *slot,
> +                                            bool enable)
> +{
> +       struct pci_dev *pdev = slot->chip->pdev;
> +       u32 value;
> +
> +       pci_read_config_dword(pdev, PCIE_GLI_9767_VHS, &value);
> +       value &= ~GLI_9767_VHS_REV;
> +       value |= FIELD_PREP(GLI_9767_VHS_REV, GLI_9767_VHS_REV_W);
> +       pci_write_config_dword(pdev, PCIE_GLI_9767_VHS, value);
Maybe replace it with gl9767_vhs_write().
There are two functions gl9767_vhs_write()/gl9767_vhs_read() and they should be
meant to be Vendor Header Space (VHS) writable/readable.

> +
> +       pci_read_config_dword(pdev, PCIE_GLI_9767_CFG, &value);
> +
> +       if (enable)
> +               value &= ~PCIE_GLI_9767_CFG_LOW_PWR_OFF;
> +       else
> +               value |= PCIE_GLI_9767_CFG_LOW_PWR_OFF;
> +
> +       pci_write_config_dword(pdev, PCIE_GLI_9767_CFG, value);
> +
> +       pci_read_config_dword(pdev, PCIE_GLI_9767_VHS, &value);
> +       value &= ~GLI_9767_VHS_REV;
> +       value |= FIELD_PREP(GLI_9767_VHS_REV, GLI_9767_VHS_REV_R);
> +       pci_write_config_dword(pdev, PCIE_GLI_9767_VHS, value);
Maybe replace it with gl9767_vhs_read().


> +}
> +
>  static void sdhci_set_gl9763e_signaling(struct sdhci_host *host,
>                                         unsigned int timing)
>  {
> @@ -1470,6 +1496,42 @@ static int gl9763e_suspend(struct sdhci_pci_chip
> *chip)
>         gl9763e_set_low_power_negotiation(slot, false);
>         return ret;
>  }
> +
> +static int gl9767_resume(struct sdhci_pci_chip *chip)
> +{
> +       struct sdhci_pci_slot *slot = chip->slots[0];
> +       int ret;
> +
> +       ret = sdhci_pci_gli_resume(chip);
> +       if (ret)
> +               return ret;
> +
> +       gl9767_set_low_power_negotiation(slot, false);
> +
> +       return 0;
> +}
> +
> +static int gl9767_suspend(struct sdhci_pci_chip *chip)
> +{
> +       struct sdhci_pci_slot *slot = chip->slots[0];
> +       int ret;
> +
> +       /*
> +        * Certain SoCs can suspend only with the bus in low-
> +        * power state, notably x86 SoCs when using S0ix.
> +        * Re-enable LPM negotiation to allow entering L1 state
> +        * and entering system suspend.
> +        */
> +       gl9767_set_low_power_negotiation(slot, true);
> +
> +       ret = sdhci_suspend_host(slot->host);
> +       if (ret) {
> +               gl9767_set_low_power_negotiation(slot, false);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
>  #endif
>
>  static int gli_probe_slot_gl9763e(struct sdhci_pci_slot *slot)
> @@ -1605,6 +1667,7 @@ const struct sdhci_pci_fixes sdhci_gl9767 = {
>         .probe_slot     = gli_probe_slot_gl9767,
>         .ops            = &sdhci_gl9767_ops,
>  #ifdef CONFIG_PM_SLEEP
> -       .resume         = sdhci_pci_gli_resume,
> +       .resume         = gl9767_resume,
> +       .suspend        = gl9767_suspend,
>  #endif
>  };
> --
> 2.34.1
>
Bugzilla wrote that this issue only happens on Intel models, right? 
How do you confirm the status of L1/L1SS, measuring PCIe link state via hardware or software?
Thanks.

Best regards,
Ben Chuang