[V6,15/24] mmc: sdhci-uhs2: add detect_init() to detect the interface
Commit Message
Sdhci_uhs2_do_detect_init() is a sdhci version of mmc's uhs2_detect_init
operation. After detected, the host's UHS-II capabilities will be set up
here and interrupts will also be enabled.
Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Victor Shih <victor.shih@genesyslogic.com.tw>
---
drivers/mmc/host/sdhci-uhs2.c | 117 ++++++++++++++++++++++++++++++++++
1 file changed, 117 insertions(+)
Comments
On 13/12/22 11:00, Victor Shih wrote:
> Sdhci_uhs2_do_detect_init() is a sdhci version of mmc's uhs2_detect_init
> operation. After detected, the host's UHS-II capabilities will be set up
> here and interrupts will also be enabled.
>
> Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> Signed-off-by: Victor Shih <victor.shih@genesyslogic.com.tw>
> ---
> drivers/mmc/host/sdhci-uhs2.c | 117 ++++++++++++++++++++++++++++++++++
> 1 file changed, 117 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
> index 3d52d35a91a5..52587025d5e3 100644
> --- a/drivers/mmc/host/sdhci-uhs2.c
> +++ b/drivers/mmc/host/sdhci-uhs2.c
> @@ -335,6 +335,123 @@ int sdhci_uhs2_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> * *
> \*****************************************************************************/
>
> +static int sdhci_uhs2_interface_detect(struct sdhci_host *host)
> +{
> + /* 100ms */
> + int timeout = 100000;
> + u32 val;
> +
> + udelay(200); /* wait for 200us before check */
> +
> + if (read_poll_timeout_atomic(sdhci_readl, val, (val & SDHCI_UHS2_IF_DETECT),
> + 100, timeout, true, host, SDHCI_PRESENT_STATE)) {
> + pr_warn("%s: not detect UHS2 interface in 200us.\n", mmc_hostname(host->mmc));
> + sdhci_dumpregs(host);
> + return -EIO;
> + }
> +
> + /* Enable UHS2 error interrupts */
> + sdhci_uhs2_clear_set_irqs(host, SDHCI_INT_ALL_MASK, SDHCI_UHS2_INT_ERROR_MASK);
> +
> + /* 150ms */
> + timeout = 150000;
> + if (read_poll_timeout_atomic(sdhci_readl, val, (val & SDHCI_UHS2_LANE_SYNC),
> + 100, timeout, true, host, SDHCI_PRESENT_STATE)) {
> + pr_warn("%s: UHS2 Lane sync fail in 150ms.\n", mmc_hostname(host->mmc));
> + sdhci_dumpregs(host);
> + return -EIO;
> + }
> +
> + DBG("%s: UHS2 Lane synchronized in UHS2 mode, PHY is initialized.\n",
> + mmc_hostname(host->mmc));
> + return 0;
> +}
> +
> +static int sdhci_uhs2_init(struct sdhci_host *host)
> +{
> + u16 caps_ptr = 0;
> + u32 caps_gen = 0;
> + u32 caps_phy = 0;
> + u32 caps_tran[2] = {0, 0};
> + struct mmc_host *mmc = host->mmc;
> +
> + caps_ptr = sdhci_readw(host, SDHCI_UHS2_CAPS_PTR);
> + if (caps_ptr < 0x100 || caps_ptr > 0x1FF) {
> + pr_err("%s: SDHCI_UHS2_CAPS_PTR(%d) is wrong.\n",
> + mmc_hostname(mmc), caps_ptr);
> + return -ENODEV;
> + }
> + caps_gen = sdhci_readl(host, caps_ptr + SDHCI_UHS2_CAPS_OFFSET);
> + caps_phy = sdhci_readl(host, caps_ptr + SDHCI_UHS2_CAPS_PHY_OFFSET);
> + caps_tran[0] = sdhci_readl(host, caps_ptr + SDHCI_UHS2_CAPS_TRAN_OFFSET);
> + caps_tran[1] = sdhci_readl(host, caps_ptr + SDHCI_UHS2_CAPS_TRAN_1_OFFSET);
> +
> + /* General Caps */
> + mmc->uhs2_caps.dap = caps_gen & SDHCI_UHS2_CAPS_DAP_MASK;
> + mmc->uhs2_caps.gap = FIELD_GET(SDHCI_UHS2_CAPS_GAP_MASK, caps_gen);
> + mmc->uhs2_caps.n_lanes = FIELD_GET(SDHCI_UHS2_CAPS_LANE_MASK, caps_gen);
> + mmc->uhs2_caps.addr64 = (caps_gen & SDHCI_UHS2_CAPS_ADDR_64) ? 1 : 0;
> + mmc->uhs2_caps.card_type = FIELD_GET(SDHCI_UHS2_CAPS_DEV_TYPE_MASK, caps_gen);
> +
> + /* PHY Caps */
> + mmc->uhs2_caps.phy_rev = caps_phy & SDHCI_UHS2_CAPS_PHY_REV_MASK;
> + mmc->uhs2_caps.speed_range = FIELD_GET(SDHCI_UHS2_CAPS_PHY_RANGE_MASK, caps_phy);
> + mmc->uhs2_caps.n_lss_sync = FIELD_GET(SDHCI_UHS2_CAPS_PHY_N_LSS_SYN_MASK, caps_phy);
> + mmc->uhs2_caps.n_lss_dir = FIELD_GET(SDHCI_UHS2_CAPS_PHY_N_LSS_DIR_MASK, caps_phy);
> + if (mmc->uhs2_caps.n_lss_sync == 0)
> + mmc->uhs2_caps.n_lss_sync = 16 << 2;
> + else
> + mmc->uhs2_caps.n_lss_sync <<= 2;
> + if (mmc->uhs2_caps.n_lss_dir == 0)
> + mmc->uhs2_caps.n_lss_dir = 16 << 3;
> + else
> + mmc->uhs2_caps.n_lss_dir <<= 3;
> +
> + /* LINK/TRAN Caps */
> + mmc->uhs2_caps.link_rev = caps_tran[0] & SDHCI_UHS2_CAPS_TRAN_LINK_REV_MASK;
> + mmc->uhs2_caps.n_fcu = FIELD_GET(SDHCI_UHS2_CAPS_TRAN_N_FCU_MASK, caps_tran[0]);
> + if (mmc->uhs2_caps.n_fcu == 0)
> + mmc->uhs2_caps.n_fcu = 256;
> + mmc->uhs2_caps.host_type = FIELD_GET(SDHCI_UHS2_CAPS_TRAN_HOST_TYPE_MASK, caps_tran[0]);
> + mmc->uhs2_caps.maxblk_len = FIELD_GET(SDHCI_UHS2_CAPS_TRAN_BLK_LEN_MASK, caps_tran[0]);
> + mmc->uhs2_caps.n_data_gap = caps_tran[1] & SDHCI_UHS2_CAPS_TRAN_1_N_DATA_GAP_MASK;
> +
> + return 0;
> +}
> +
> +static int sdhci_uhs2_do_detect_init(struct mmc_host *mmc)
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> + int ret = -EIO;
> +
> + DBG("Begin do uhs2 detect init.\n");
> +
> + if (sdhci_uhs2_interface_detect(host)) {
> + pr_warn("%s: cannot detect UHS2 interface.\n",
> + mmc_hostname(host->mmc));
> + goto out;
> + }
> +
> + if (sdhci_uhs2_init(host)) {
> + pr_warn("%s: UHS2 init fail.\n", mmc_hostname(host->mmc));
> + goto out;
> + }
> +
> + /* Init complete, do soft reset and enable UHS2 error irqs. */
> + host->ops->uhs2_reset(host, SDHCI_UHS2_SW_RESET_SD);
host->ops->uhs2_reset -> sdhci_uhs2_reset
> + sdhci_uhs2_clear_set_irqs(host, SDHCI_INT_ALL_MASK, SDHCI_UHS2_INT_ERROR_MASK);
> + /*
> + * N.B SDHCI_INT_ENABLE and SDHCI_SIGNAL_ENABLE was cleared
> + * by SDHCI_UHS2_SW_RESET_SD
> + */
> + sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
> + sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
> +
> + ret = 0;
> +out:
> + return ret;
> +}
> +
> static int sdhci_uhs2_host_ops_init(struct sdhci_host *host)
> {
> host->mmc_host_ops.start_signal_voltage_switch =
Hi, Adrian
On Fri, Jan 6, 2023 at 5:28 AM Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> On 13/12/22 11:00, Victor Shih wrote:
> > Sdhci_uhs2_do_detect_init() is a sdhci version of mmc's uhs2_detect_init
> > operation. After detected, the host's UHS-II capabilities will be set up
> > here and interrupts will also be enabled.
> >
> > Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> > Signed-off-by: Victor Shih <victor.shih@genesyslogic.com.tw>
> > ---
> > drivers/mmc/host/sdhci-uhs2.c | 117 ++++++++++++++++++++++++++++++++++
> > 1 file changed, 117 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
> > index 3d52d35a91a5..52587025d5e3 100644
> > --- a/drivers/mmc/host/sdhci-uhs2.c
> > +++ b/drivers/mmc/host/sdhci-uhs2.c
> > @@ -335,6 +335,123 @@ int sdhci_uhs2_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> > * *
> > \*****************************************************************************/
> >
> > +static int sdhci_uhs2_interface_detect(struct sdhci_host *host)
> > +{
> > + /* 100ms */
> > + int timeout = 100000;
> > + u32 val;
> > +
> > + udelay(200); /* wait for 200us before check */
> > +
> > + if (read_poll_timeout_atomic(sdhci_readl, val, (val & SDHCI_UHS2_IF_DETECT),
> > + 100, timeout, true, host, SDHCI_PRESENT_STATE)) {
> > + pr_warn("%s: not detect UHS2 interface in 200us.\n", mmc_hostname(host->mmc));
> > + sdhci_dumpregs(host);
> > + return -EIO;
> > + }
> > +
> > + /* Enable UHS2 error interrupts */
> > + sdhci_uhs2_clear_set_irqs(host, SDHCI_INT_ALL_MASK, SDHCI_UHS2_INT_ERROR_MASK);
> > +
> > + /* 150ms */
> > + timeout = 150000;
> > + if (read_poll_timeout_atomic(sdhci_readl, val, (val & SDHCI_UHS2_LANE_SYNC),
> > + 100, timeout, true, host, SDHCI_PRESENT_STATE)) {
> > + pr_warn("%s: UHS2 Lane sync fail in 150ms.\n", mmc_hostname(host->mmc));
> > + sdhci_dumpregs(host);
> > + return -EIO;
> > + }
> > +
> > + DBG("%s: UHS2 Lane synchronized in UHS2 mode, PHY is initialized.\n",
> > + mmc_hostname(host->mmc));
> > + return 0;
> > +}
> > +
> > +static int sdhci_uhs2_init(struct sdhci_host *host)
> > +{
> > + u16 caps_ptr = 0;
> > + u32 caps_gen = 0;
> > + u32 caps_phy = 0;
> > + u32 caps_tran[2] = {0, 0};
> > + struct mmc_host *mmc = host->mmc;
> > +
> > + caps_ptr = sdhci_readw(host, SDHCI_UHS2_CAPS_PTR);
> > + if (caps_ptr < 0x100 || caps_ptr > 0x1FF) {
> > + pr_err("%s: SDHCI_UHS2_CAPS_PTR(%d) is wrong.\n",
> > + mmc_hostname(mmc), caps_ptr);
> > + return -ENODEV;
> > + }
> > + caps_gen = sdhci_readl(host, caps_ptr + SDHCI_UHS2_CAPS_OFFSET);
> > + caps_phy = sdhci_readl(host, caps_ptr + SDHCI_UHS2_CAPS_PHY_OFFSET);
> > + caps_tran[0] = sdhci_readl(host, caps_ptr + SDHCI_UHS2_CAPS_TRAN_OFFSET);
> > + caps_tran[1] = sdhci_readl(host, caps_ptr + SDHCI_UHS2_CAPS_TRAN_1_OFFSET);
> > +
> > + /* General Caps */
> > + mmc->uhs2_caps.dap = caps_gen & SDHCI_UHS2_CAPS_DAP_MASK;
> > + mmc->uhs2_caps.gap = FIELD_GET(SDHCI_UHS2_CAPS_GAP_MASK, caps_gen);
> > + mmc->uhs2_caps.n_lanes = FIELD_GET(SDHCI_UHS2_CAPS_LANE_MASK, caps_gen);
> > + mmc->uhs2_caps.addr64 = (caps_gen & SDHCI_UHS2_CAPS_ADDR_64) ? 1 : 0;
> > + mmc->uhs2_caps.card_type = FIELD_GET(SDHCI_UHS2_CAPS_DEV_TYPE_MASK, caps_gen);
> > +
> > + /* PHY Caps */
> > + mmc->uhs2_caps.phy_rev = caps_phy & SDHCI_UHS2_CAPS_PHY_REV_MASK;
> > + mmc->uhs2_caps.speed_range = FIELD_GET(SDHCI_UHS2_CAPS_PHY_RANGE_MASK, caps_phy);
> > + mmc->uhs2_caps.n_lss_sync = FIELD_GET(SDHCI_UHS2_CAPS_PHY_N_LSS_SYN_MASK, caps_phy);
> > + mmc->uhs2_caps.n_lss_dir = FIELD_GET(SDHCI_UHS2_CAPS_PHY_N_LSS_DIR_MASK, caps_phy);
> > + if (mmc->uhs2_caps.n_lss_sync == 0)
> > + mmc->uhs2_caps.n_lss_sync = 16 << 2;
> > + else
> > + mmc->uhs2_caps.n_lss_sync <<= 2;
> > + if (mmc->uhs2_caps.n_lss_dir == 0)
> > + mmc->uhs2_caps.n_lss_dir = 16 << 3;
> > + else
> > + mmc->uhs2_caps.n_lss_dir <<= 3;
> > +
> > + /* LINK/TRAN Caps */
> > + mmc->uhs2_caps.link_rev = caps_tran[0] & SDHCI_UHS2_CAPS_TRAN_LINK_REV_MASK;
> > + mmc->uhs2_caps.n_fcu = FIELD_GET(SDHCI_UHS2_CAPS_TRAN_N_FCU_MASK, caps_tran[0]);
> > + if (mmc->uhs2_caps.n_fcu == 0)
> > + mmc->uhs2_caps.n_fcu = 256;
> > + mmc->uhs2_caps.host_type = FIELD_GET(SDHCI_UHS2_CAPS_TRAN_HOST_TYPE_MASK, caps_tran[0]);
> > + mmc->uhs2_caps.maxblk_len = FIELD_GET(SDHCI_UHS2_CAPS_TRAN_BLK_LEN_MASK, caps_tran[0]);
> > + mmc->uhs2_caps.n_data_gap = caps_tran[1] & SDHCI_UHS2_CAPS_TRAN_1_N_DATA_GAP_MASK;
> > +
> > + return 0;
> > +}
> > +
> > +static int sdhci_uhs2_do_detect_init(struct mmc_host *mmc)
> > +{
> > + struct sdhci_host *host = mmc_priv(mmc);
> > + int ret = -EIO;
> > +
> > + DBG("Begin do uhs2 detect init.\n");
> > +
> > + if (sdhci_uhs2_interface_detect(host)) {
> > + pr_warn("%s: cannot detect UHS2 interface.\n",
> > + mmc_hostname(host->mmc));
> > + goto out;
> > + }
> > +
> > + if (sdhci_uhs2_init(host)) {
> > + pr_warn("%s: UHS2 init fail.\n", mmc_hostname(host->mmc));
> > + goto out;
> > + }
> > +
> > + /* Init complete, do soft reset and enable UHS2 error irqs. */
> > + host->ops->uhs2_reset(host, SDHCI_UHS2_SW_RESET_SD);
>
> host->ops->uhs2_reset -> sdhci_uhs2_reset
>
I will update it in V7 version.
> > + sdhci_uhs2_clear_set_irqs(host, SDHCI_INT_ALL_MASK, SDHCI_UHS2_INT_ERROR_MASK);
> > + /*
> > + * N.B SDHCI_INT_ENABLE and SDHCI_SIGNAL_ENABLE was cleared
> > + * by SDHCI_UHS2_SW_RESET_SD
> > + */
> > + sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
> > + sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
> > +
> > + ret = 0;
> > +out:
> > + return ret;
> > +}
> > +
> > static int sdhci_uhs2_host_ops_init(struct sdhci_host *host)
> > {
> > host->mmc_host_ops.start_signal_voltage_switch =
>
Thanks, Victor Shih
@@ -335,6 +335,123 @@ int sdhci_uhs2_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
* *
\*****************************************************************************/
+static int sdhci_uhs2_interface_detect(struct sdhci_host *host)
+{
+ /* 100ms */
+ int timeout = 100000;
+ u32 val;
+
+ udelay(200); /* wait for 200us before check */
+
+ if (read_poll_timeout_atomic(sdhci_readl, val, (val & SDHCI_UHS2_IF_DETECT),
+ 100, timeout, true, host, SDHCI_PRESENT_STATE)) {
+ pr_warn("%s: not detect UHS2 interface in 200us.\n", mmc_hostname(host->mmc));
+ sdhci_dumpregs(host);
+ return -EIO;
+ }
+
+ /* Enable UHS2 error interrupts */
+ sdhci_uhs2_clear_set_irqs(host, SDHCI_INT_ALL_MASK, SDHCI_UHS2_INT_ERROR_MASK);
+
+ /* 150ms */
+ timeout = 150000;
+ if (read_poll_timeout_atomic(sdhci_readl, val, (val & SDHCI_UHS2_LANE_SYNC),
+ 100, timeout, true, host, SDHCI_PRESENT_STATE)) {
+ pr_warn("%s: UHS2 Lane sync fail in 150ms.\n", mmc_hostname(host->mmc));
+ sdhci_dumpregs(host);
+ return -EIO;
+ }
+
+ DBG("%s: UHS2 Lane synchronized in UHS2 mode, PHY is initialized.\n",
+ mmc_hostname(host->mmc));
+ return 0;
+}
+
+static int sdhci_uhs2_init(struct sdhci_host *host)
+{
+ u16 caps_ptr = 0;
+ u32 caps_gen = 0;
+ u32 caps_phy = 0;
+ u32 caps_tran[2] = {0, 0};
+ struct mmc_host *mmc = host->mmc;
+
+ caps_ptr = sdhci_readw(host, SDHCI_UHS2_CAPS_PTR);
+ if (caps_ptr < 0x100 || caps_ptr > 0x1FF) {
+ pr_err("%s: SDHCI_UHS2_CAPS_PTR(%d) is wrong.\n",
+ mmc_hostname(mmc), caps_ptr);
+ return -ENODEV;
+ }
+ caps_gen = sdhci_readl(host, caps_ptr + SDHCI_UHS2_CAPS_OFFSET);
+ caps_phy = sdhci_readl(host, caps_ptr + SDHCI_UHS2_CAPS_PHY_OFFSET);
+ caps_tran[0] = sdhci_readl(host, caps_ptr + SDHCI_UHS2_CAPS_TRAN_OFFSET);
+ caps_tran[1] = sdhci_readl(host, caps_ptr + SDHCI_UHS2_CAPS_TRAN_1_OFFSET);
+
+ /* General Caps */
+ mmc->uhs2_caps.dap = caps_gen & SDHCI_UHS2_CAPS_DAP_MASK;
+ mmc->uhs2_caps.gap = FIELD_GET(SDHCI_UHS2_CAPS_GAP_MASK, caps_gen);
+ mmc->uhs2_caps.n_lanes = FIELD_GET(SDHCI_UHS2_CAPS_LANE_MASK, caps_gen);
+ mmc->uhs2_caps.addr64 = (caps_gen & SDHCI_UHS2_CAPS_ADDR_64) ? 1 : 0;
+ mmc->uhs2_caps.card_type = FIELD_GET(SDHCI_UHS2_CAPS_DEV_TYPE_MASK, caps_gen);
+
+ /* PHY Caps */
+ mmc->uhs2_caps.phy_rev = caps_phy & SDHCI_UHS2_CAPS_PHY_REV_MASK;
+ mmc->uhs2_caps.speed_range = FIELD_GET(SDHCI_UHS2_CAPS_PHY_RANGE_MASK, caps_phy);
+ mmc->uhs2_caps.n_lss_sync = FIELD_GET(SDHCI_UHS2_CAPS_PHY_N_LSS_SYN_MASK, caps_phy);
+ mmc->uhs2_caps.n_lss_dir = FIELD_GET(SDHCI_UHS2_CAPS_PHY_N_LSS_DIR_MASK, caps_phy);
+ if (mmc->uhs2_caps.n_lss_sync == 0)
+ mmc->uhs2_caps.n_lss_sync = 16 << 2;
+ else
+ mmc->uhs2_caps.n_lss_sync <<= 2;
+ if (mmc->uhs2_caps.n_lss_dir == 0)
+ mmc->uhs2_caps.n_lss_dir = 16 << 3;
+ else
+ mmc->uhs2_caps.n_lss_dir <<= 3;
+
+ /* LINK/TRAN Caps */
+ mmc->uhs2_caps.link_rev = caps_tran[0] & SDHCI_UHS2_CAPS_TRAN_LINK_REV_MASK;
+ mmc->uhs2_caps.n_fcu = FIELD_GET(SDHCI_UHS2_CAPS_TRAN_N_FCU_MASK, caps_tran[0]);
+ if (mmc->uhs2_caps.n_fcu == 0)
+ mmc->uhs2_caps.n_fcu = 256;
+ mmc->uhs2_caps.host_type = FIELD_GET(SDHCI_UHS2_CAPS_TRAN_HOST_TYPE_MASK, caps_tran[0]);
+ mmc->uhs2_caps.maxblk_len = FIELD_GET(SDHCI_UHS2_CAPS_TRAN_BLK_LEN_MASK, caps_tran[0]);
+ mmc->uhs2_caps.n_data_gap = caps_tran[1] & SDHCI_UHS2_CAPS_TRAN_1_N_DATA_GAP_MASK;
+
+ return 0;
+}
+
+static int sdhci_uhs2_do_detect_init(struct mmc_host *mmc)
+{
+ struct sdhci_host *host = mmc_priv(mmc);
+ int ret = -EIO;
+
+ DBG("Begin do uhs2 detect init.\n");
+
+ if (sdhci_uhs2_interface_detect(host)) {
+ pr_warn("%s: cannot detect UHS2 interface.\n",
+ mmc_hostname(host->mmc));
+ goto out;
+ }
+
+ if (sdhci_uhs2_init(host)) {
+ pr_warn("%s: UHS2 init fail.\n", mmc_hostname(host->mmc));
+ goto out;
+ }
+
+ /* Init complete, do soft reset and enable UHS2 error irqs. */
+ host->ops->uhs2_reset(host, SDHCI_UHS2_SW_RESET_SD);
+ sdhci_uhs2_clear_set_irqs(host, SDHCI_INT_ALL_MASK, SDHCI_UHS2_INT_ERROR_MASK);
+ /*
+ * N.B SDHCI_INT_ENABLE and SDHCI_SIGNAL_ENABLE was cleared
+ * by SDHCI_UHS2_SW_RESET_SD
+ */
+ sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
+ sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
+
+ ret = 0;
+out:
+ return ret;
+}
+
static int sdhci_uhs2_host_ops_init(struct sdhci_host *host)
{
host->mmc_host_ops.start_signal_voltage_switch =