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mmc: sdhci-pci: Use ACPI to get max frequency for Intel NI byt sdio

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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>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Zach Brown 2016-11-28 13:16:39 -06:00 committed by Ulf Hansson
parent 42b0649640
commit 3f23df72dc
1 changed files with 32 additions and 0 deletions
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32
drivers/mmc/host/sdhci-pci-core.c
View File

@ -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;