mmc: sdhci-acpi: Fix voltage switch for some Intel host controllers

Some Intel host controllers use an ACPI device-specific method to ensure
correct voltage switching. Fix voltage switch for those, by adding a call
to the DSM.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c
index 5bb5880..b988997 100644 (file)
--- a/drivers/mmc/host/sdhci-acpi.c
+++ b/drivers/mmc/host/sdhci-acpi.c
@@ -96,6 +96,105 @@ static inline bool sdhci_acpi_flag(struct sdhci_acpi_host *c, unsigned int flag)
        return c->slot && (c->slot->flags & flag);
 }
 
+enum {
+       INTEL_DSM_FNS           =  0,
+       INTEL_DSM_V18_SWITCH    =  3,
+       INTEL_DSM_V33_SWITCH    =  4,
+};
+
+struct intel_host {
+       u32     dsm_fns;
+};
+
+static const guid_t intel_dsm_guid =
+       GUID_INIT(0xF6C13EA5, 0x65CD, 0x461F,
+                 0xAB, 0x7A, 0x29, 0xF7, 0xE8, 0xD5, 0xBD, 0x61);
+
+static int __intel_dsm(struct intel_host *intel_host, struct device *dev,
+                      unsigned int fn, u32 *result)
+{
+       union acpi_object *obj;
+       int err = 0;
+
+       obj = acpi_evaluate_dsm(ACPI_HANDLE(dev), &intel_dsm_guid, 0, fn, NULL);
+       if (!obj)
+               return -EOPNOTSUPP;
+
+       if (obj->type == ACPI_TYPE_INTEGER) {
+               *result = obj->integer.value;
+       } else if (obj->type == ACPI_TYPE_BUFFER && obj->buffer.length > 0) {
+               size_t len = min_t(size_t, obj->buffer.length, 4);
+
+               *result = 0;
+               memcpy(result, obj->buffer.pointer, len);
+       } else {
+               dev_err(dev, "%s DSM fn %u obj->type %d obj->buffer.length %d\n",
+                       __func__, fn, obj->type, obj->buffer.length);
+               err = -EINVAL;
+       }
+
+       ACPI_FREE(obj);
+
+       return err;
+}
+
+static int intel_dsm(struct intel_host *intel_host, struct device *dev,
+                    unsigned int fn, u32 *result)
+{
+       if (fn > 31 || !(intel_host->dsm_fns & (1 << fn)))
+               return -EOPNOTSUPP;
+
+       return __intel_dsm(intel_host, dev, fn, result);
+}
+
+static void intel_dsm_init(struct intel_host *intel_host, struct device *dev,
+                          struct mmc_host *mmc)
+{
+       int err;
+
+       err = __intel_dsm(intel_host, dev, INTEL_DSM_FNS, &intel_host->dsm_fns);
+       if (err) {
+               pr_debug("%s: DSM not supported, error %d\n",
+                        mmc_hostname(mmc), err);
+               return;
+       }
+
+       pr_debug("%s: DSM function mask %#x\n",
+                mmc_hostname(mmc), intel_host->dsm_fns);
+}
+
+static int intel_start_signal_voltage_switch(struct mmc_host *mmc,
+                                            struct mmc_ios *ios)
+{
+       struct device *dev = mmc_dev(mmc);
+       struct sdhci_acpi_host *c = dev_get_drvdata(dev);
+       struct intel_host *intel_host = sdhci_acpi_priv(c);
+       unsigned int fn;
+       u32 result = 0;
+       int err;
+
+       err = sdhci_start_signal_voltage_switch(mmc, ios);
+       if (err)
+               return err;
+
+       switch (ios->signal_voltage) {
+       case MMC_SIGNAL_VOLTAGE_330:
+               fn = INTEL_DSM_V33_SWITCH;
+               break;
+       case MMC_SIGNAL_VOLTAGE_180:
+               fn = INTEL_DSM_V18_SWITCH;
+               break;
+       default:
+               return 0;
+       }
+
+       err = intel_dsm(intel_host, dev, fn, &result);
+       pr_debug("%s: %s DSM fn %u error %d result %u\n",
+                mmc_hostname(mmc), __func__, fn, err, result);
+
+       return 0;
+}
+
 static void sdhci_acpi_int_hw_reset(struct sdhci_host *host)
 {
        u8 reg;
@@ -280,6 +379,7 @@ static int intel_probe_slot(struct platform_device *pdev, const char *hid,
                            const char *uid)
 {
        struct sdhci_acpi_host *c = platform_get_drvdata(pdev);
+       struct intel_host *intel_host = sdhci_acpi_priv(c);
        struct sdhci_host *host = c->host;
 
        if (hid && uid && !strcmp(hid, "80860F14") && !strcmp(uid, "1") &&
@@ -290,6 +390,11 @@ static int intel_probe_slot(struct platform_device *pdev, const char *hid,
        if (hid && !strcmp(hid, "80865ACA"))
                host->mmc_host_ops.get_cd = bxt_get_cd;
 
+       intel_dsm_init(intel_host, &pdev->dev, host->mmc);
+
+       host->mmc_host_ops.start_signal_voltage_switch =
+                                       intel_start_signal_voltage_switch;
+
        return 0;
 }
 
@@ -304,6 +409,7 @@ static const struct sdhci_acpi_slot sdhci_acpi_slot_int_emmc = {
                   SDHCI_QUIRK2_STOP_WITH_TC |
                   SDHCI_QUIRK2_CAPS_BIT63_FOR_HS400,
        .probe_slot     = intel_probe_slot,
+       .priv_size      = sizeof(struct intel_host),
 };
 
 static const struct sdhci_acpi_slot sdhci_acpi_slot_int_sdio = {
@@ -315,6 +421,7 @@ static const struct sdhci_acpi_slot sdhci_acpi_slot_int_sdio = {
        .flags   = SDHCI_ACPI_RUNTIME_PM,
        .pm_caps = MMC_PM_KEEP_POWER,
        .probe_slot     = intel_probe_slot,
+       .priv_size      = sizeof(struct intel_host),
 };
 
 static const struct sdhci_acpi_slot sdhci_acpi_slot_int_sd = {
@@ -325,6 +432,7 @@ static const struct sdhci_acpi_slot sdhci_acpi_slot_int_sd = {
                   SDHCI_QUIRK2_STOP_WITH_TC,
        .caps    = MMC_CAP_WAIT_WHILE_BUSY | MMC_CAP_AGGRESSIVE_PM,
        .probe_slot     = intel_probe_slot,
+       .priv_size      = sizeof(struct intel_host),
 };
 
 static const struct sdhci_acpi_slot sdhci_acpi_slot_qcom_sd_3v = {