On 08/11/16 22:07, Zach Brown 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, as MXFQ.
>
> The driver reads the ACPI entry MXFQ during sdio_probe_slot and sets the
> f_max field of the host with it.
>
> Signed-off-by: Nathan Sullivan <nathan.sullivan@xxxxxx>
> Reviewed-by: Jaeden Amero <jaeden.amero@xxxxxx>
> Reviewed-by: Josh Cartwright <joshc@xxxxxx>
> Signed-off-by: Zach Brown <zach.brown@xxxxxx>
> ---
> drivers/mmc/host/sdhci-pci-core.c | 30 ++++++++++++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
> index c333ce2..4ac7f16 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"
> @@ -377,6 +378,35 @@ static int byt_emmc_probe_slot(struct sdhci_pci_slot *slot)
>
> static int ni_byt_sdio_probe_slot(struct sdhci_pci_slot *slot)
> {
> +#ifdef CONFIG_ACPI
> + /* Get max freq from ACPI for NI hardware */
> + acpi_handle acpi_hdl;
> + acpi_status status;
> + struct acpi_buffer acpi_result = {
> + ACPI_ALLOCATE_BUFFER, NULL };
> + union acpi_object *acpi_buffer;
> + int max_freq;
> +
> + status = acpi_get_handle(ACPI_HANDLE(&slot->chip->pdev->dev), "MXFQ",
> + &acpi_hdl);
Is "MXFQ" an object that has already been deployed or are you inventing it
now? In the latter case, did you consider device properties as an alternative?
> + if (ACPI_FAILURE(status))
> + return -ENODEV;
> +
> + status = acpi_evaluate_object(acpi_hdl, NULL,
> + NULL, &acpi_result);
> + if (ACPI_FAILURE(status))
> + return -EINVAL;
> +
> + acpi_buffer = (union acpi_object *)acpi_result.pointer;
> +
> + if (acpi_buffer->type != ACPI_TYPE_INTEGER)
> + return -EINVAL;
> +
> + max_freq = acpi_buffer->integer.value;
> +
> + slot->host->mmc->f_max = max_freq * 1000000;
> +#endif
> +
> slot->host->mmc->caps |= MMC_CAP_POWER_OFF_CARD | MMC_CAP_NONREMOVABLE;
> return 0;
> }
>
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