Re: [PATCH v3 2/2] mmc: sdhci-pci: Use ACPI to get max frequency for Intel byt sdio controller sub-vended by NI

[Ulf Hansson <ulf.hansson@linaro.org>]

On 28 November 2016 at 20:16, Zach Brown <zach.brown@ni.com> wrote:
> On NI 9037 boards the max SDIO frequency is limited by trace lengths
> and other layout choices. The max SDIO frequency is stored in an ACPI
> table.
>
> The driver reads the ACPI entry MXFQ during sdio_probe_slot and sets the
> f_max field of the host.
>
> Signed-off-by: Nathan Sullivan <nathan.sullivan@ni.com>
> Reviewed-by: Jaeden Amero <jaeden.amero@ni.com>
> Reviewed-by: Josh Cartwright <joshc@ni.com>
> Signed-off-by: Zach Brown <zach.brown@ni.com>

Thanks, applied for next!

Kind regards
Uffe


> ---
>  drivers/mmc/host/sdhci-pci-core.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
> index 9741505..c9e51b1 100644
> --- a/drivers/mmc/host/sdhci-pci-core.c
> +++ b/drivers/mmc/host/sdhci-pci-core.c
> @@ -27,6 +27,7 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/mmc/slot-gpio.h>
>  #include <linux/mmc/sdhci-pci-data.h>
> +#include <linux/acpi.h>
>
>  #include "sdhci.h"
>  #include "sdhci-pci.h"
> @@ -375,8 +376,39 @@ static int byt_emmc_probe_slot(struct sdhci_pci_slot *slot)
>         return 0;
>  }
>
> +#ifdef CONFIG_ACPI
> +static int ni_set_max_freq(struct sdhci_pci_slot *slot)
> +{
> +       acpi_status status;
> +       unsigned long long max_freq;
> +
> +       status = acpi_evaluate_integer(ACPI_HANDLE(&slot->chip->pdev->dev),
> +                                      "MXFQ", NULL, &max_freq);
> +       if (ACPI_FAILURE(status)) {
> +               dev_err(&slot->chip->pdev->dev,
> +                       "MXFQ not found in acpi table\n");
> +               return -EINVAL;
> +       }
> +
> +       slot->host->mmc->f_max = max_freq * 1000000;
> +
> +       return 0;
> +}
> +#else
> +static inline int ni_set_max_freq(struct sdhci_pci_slot *slot)
> +{
> +       return 0;
> +}
> +#endif
> +
>  static int ni_byt_sdio_probe_slot(struct sdhci_pci_slot *slot)
>  {
> +       int err;
> +
> +       err = ni_set_max_freq(slot);
> +       if (err)
> +               return err;
> +
>         slot->host->mmc->caps |= MMC_CAP_POWER_OFF_CARD | MMC_CAP_NONREMOVABLE |
>                                  MMC_CAP_WAIT_WHILE_BUSY;
>         return 0;
> --
> 2.7.4
>