On 15/11/16 18:32, 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.
>
> 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@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 | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
> index 9741505..4c31d16 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 +378,18 @@ 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 */
The comment seems a little redundant.
> + 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))
> + return -EINVAL;
I wonder if you should print an error message to let the user know why the
driver failed to probe.
> +
> + slot->host->mmc->f_max = max_freq * 1000000;
> +#endif
> slot->host->mmc->caps |= MMC_CAP_POWER_OFF_CARD | MMC_CAP_NONREMOVABLE |
> MMC_CAP_WAIT_WHILE_BUSY;
> return 0;
>
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