diff mbox

[edk2,v5,7/9] MmcDxe: set iospeed and bus width in SD stack

Message ID 1479019678-12621-8-git-send-email-haojian.zhuang@linaro.org
State New
Headers show

Commit Message

Haojian Zhuang Nov. 13, 2016, 6:47 a.m. UTC 
Add more SD commands to support 4-bit bus width & iospeed. It's not
formal code. And it needs to be updated later.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>

Tested-by: Ryan Harkin <ryan.harkin@linaro.org>

---
 EmbeddedPkg/Include/Protocol/MmcHost.h           |   3 +
 EmbeddedPkg/Universal/MmcDxe/Mmc.h               |  17 +++
 EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c | 138 ++++++++++++++++++++---
 3 files changed, 142 insertions(+), 16 deletions(-)

-- 
2.7.4

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Comments

Leif Lindholm Nov. 14, 2016, 5:08 p.m. UTC | #1 
On Sun, Nov 13, 2016 at 02:47:56PM +0800, Haojian Zhuang wrote:
> Add more SD commands to support 4-bit bus width & iospeed. It's not

> formal code. And it needs to be updated later.


Little bit concerned about this statement. Is it outdated information?
If so, can you update commit message.

If not, can you specify which bits are missing?

> 

> Contributed-under: TianoCore Contribution Agreement 1.0

> Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>

> Tested-by: Ryan Harkin <ryan.harkin@linaro.org>

> ---

>  EmbeddedPkg/Include/Protocol/MmcHost.h           |   3 +

>  EmbeddedPkg/Universal/MmcDxe/Mmc.h               |  17 +++

>  EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c | 138 ++++++++++++++++++++---

>  3 files changed, 142 insertions(+), 16 deletions(-)

> 

> diff --git a/EmbeddedPkg/Include/Protocol/MmcHost.h b/EmbeddedPkg/Include/Protocol/MmcHost.h

> index 01c0bf4..5028045 100644

> --- a/EmbeddedPkg/Include/Protocol/MmcHost.h

> +++ b/EmbeddedPkg/Include/Protocol/MmcHost.h

> @@ -64,11 +64,14 @@ typedef UINT32 MMC_CMD;

>  #define MMC_CMD24             (MMC_INDX(24) | MMC_CMD_WAIT_RESPONSE)

>  #define MMC_CMD55             (MMC_INDX(55) | MMC_CMD_WAIT_RESPONSE)

>  #define MMC_ACMD41            (MMC_INDX(41) | MMC_CMD_WAIT_RESPONSE | MMC_CMD_NO_CRC_RESPONSE)

> +#define MMC_ACMD51            (MMC_INDX(51) | MMC_CMD_WAIT_RESPONSE)

>  

>  // Valid responses for CMD1 in eMMC

>  #define EMMC_CMD1_CAPACITY_LESS_THAN_2GB 0x00FF8080 // Capacity <= 2GB, byte addressing used

>  #define EMMC_CMD1_CAPACITY_GREATER_THAN_2GB 0x40FF8080 // Capacity > 2GB, 512-byte sector addressing used

>  

> +#define MMC_STATUS_APP_CMD    (1 << 5)

> +

>  typedef enum _MMC_STATE {

>      MmcInvalidState = 0,

>      MmcHwInitializationState,

> diff --git a/EmbeddedPkg/Universal/MmcDxe/Mmc.h b/EmbeddedPkg/Universal/MmcDxe/Mmc.h

> index 67f449c..f054bb2 100644

> --- a/EmbeddedPkg/Universal/MmcDxe/Mmc.h

> +++ b/EmbeddedPkg/Universal/MmcDxe/Mmc.h

> @@ -75,6 +75,23 @@ typedef struct {

>    UINT32  PowerUp:     1; // This bit is set to LOW if the card has not finished the power up routine

>  } OCR;

>  

> +/* For little endian CPU */


All formally supported architectures are little-endian, so I guess
this is OK for now. Don't know if we have a good portable macro to
use for detection anyway.

> +typedef struct {

> +  UINT8   SD_SPEC:               4; // SD Memory Card - Spec. Version [59:56]

> +  UINT8   SCR_STRUCTURE:         4; // SCR Structure [63:60]

> +  UINT8   SD_BUS_WIDTHS:         4; // DAT Bus widths supported [51:48]

> +  UINT8   DATA_STAT_AFTER_ERASE: 1; // Data Status after erases [55]

> +  UINT8   SD_SECURITY:           3; // CPRM Security Support [54:52]

> +  UINT8   EX_SECURITY_1:         1; // Extended Security Support [43]

> +  UINT8   SD_SPEC4:              1; // Spec. Version 4.00 or higher [42]

> +  UINT8   RESERVED_1:            2; // Reserved [41:40]

> +  UINT8   SD_SPEC3:              1; // Spec. Version 3.00 or higher [47]

> +  UINT8   EX_SECURITY_2:         3; // Extended Security Support [46:44]

> +  UINT8   CMD_SUPPORT:           4; // Command Support bits [35:32]

> +  UINT8   RESERVED_2:            4; // Reserved [39:36]

> +  UINT32  RESERVED_3;               // Manufacturer Usage [31:0]

> +} SCR;

> +

>  typedef struct {

>    UINT32  NOT_USED;   // 1 [0:0]

>    UINT32  CRC;        // CRC7 checksum [7:1]

> diff --git a/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c b/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c

> index 9a79767..c469dda 100644

> --- a/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c

> +++ b/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c

> @@ -12,6 +12,9 @@

>  *

>  **/

>  

> +#include <Library/BaseMemoryLib.h>

> +#include <Library/TimerLib.h>

> +

>  #include "Mmc.h"

>  

>  typedef union {

> @@ -41,6 +44,11 @@ typedef union {

>  

>  #define EMMC_SWITCH_ERROR       (1 << 7)

>  

> +#define SD_BUS_WIDTH_1BIT       (1 << 0)

> +#define SD_BUS_WIDTH_4BIT       (1 << 2)

> +

> +#define SD_CCC_SWITCH           (1 << 10)

> +

>  #define DEVICE_STATE(x)         (((x) >> 9) & 0xf)

>  typedef enum _EMMC_DEVICE_STATE {

>    EMMC_IDLE_STATE = 0,

> @@ -68,28 +76,30 @@ EmmcGetDeviceState (

>  {

>    EFI_MMC_HOST_PROTOCOL *Host;

>    EFI_STATUS Status;

> -  UINT32     Data, RCA;

> +  UINT32     Rsp[4], RCA;

>  

>    if (State == NULL)

>      return EFI_INVALID_PARAMETER;

>  

>    Host  = MmcHostInstance->MmcHost;

>    RCA = MmcHostInstance->CardInfo.RCA << RCA_SHIFT_OFFSET;

> -  Status = Host->SendCommand (Host, MMC_CMD13, RCA);

> -  if (EFI_ERROR (Status)) {

> -    DEBUG ((EFI_D_ERROR, "EmmcGetDeviceState(): Failed to get card status, Status=%r.\n", Status));

> -    return Status;

> -  }

> -  Status = Host->ReceiveResponse (Host, MMC_RESPONSE_TYPE_R1, &Data);

> -  if (EFI_ERROR (Status)) {

> -    DEBUG ((EFI_D_ERROR, "EmmcGetDeviceState(): Failed to get response of CMD13, Status=%r.\n", Status));

> -    return Status;

> -  }

> -  if (Data & EMMC_SWITCH_ERROR) {

> -    DEBUG ((EFI_D_ERROR, "EmmcGetDeviceState(): Failed to switch expected mode, Status=%r.\n", Status));

> -    return EFI_DEVICE_ERROR;

> -  }

> -  *State = DEVICE_STATE(Data);

> +  do {

> +    Status = Host->SendCommand (Host, MMC_CMD13, RCA);

> +    if (EFI_ERROR (Status)) {

> +      DEBUG ((EFI_D_ERROR, "EmmcGetDeviceState(): Failed to get card status, Status=%r.\n", Status));

> +      return Status;

> +    }

> +    Status = Host->ReceiveResponse (Host, MMC_RESPONSE_TYPE_R1, Rsp);

> +    if (EFI_ERROR (Status)) {

> +      DEBUG ((EFI_D_ERROR, "EmmcGetDeviceState(): Failed to get response of CMD13, Status=%r.\n", Status));

> +      return Status;

> +    }

> +    if (Rsp[0] & EMMC_SWITCH_ERROR) {

> +      DEBUG ((EFI_D_ERROR, "EmmcGetDeviceState(): Failed to switch expected mode, Status=%r.\n", Status));

> +      return EFI_DEVICE_ERROR;

> +    }

> +  } while (!(Rsp[0] & MMC_R0_READY_FOR_DATA));

> +  *State = MMC_R0_CURRENTSTATE(Rsp);


These changes do not look directly related to the stated purpose of
the patch? Should it be a separate one?

>    return EFI_SUCCESS;

>  }

>  

> @@ -300,9 +310,12 @@ InitializeSdMmcDevice (

>  {

>    UINT32        CmdArg;

>    UINT32        Response[4];

> +  UINT32        Buffer[128];

>    UINTN         BlockSize;

>    UINTN         CardSize;

>    UINTN         NumBlocks;

> +  BOOLEAN       CccSwitch;

> +  SCR           Scr;

>    EFI_STATUS    Status;

>    EFI_MMC_HOST_PROTOCOL     *MmcHost;

>  

> @@ -323,6 +336,10 @@ InitializeSdMmcDevice (

>      return Status;

>    }

>    PrintCSD (Response);

> +  if (MMC_CSD_GET_CCC(Response) & SD_CCC_SWITCH)

> +    CccSwitch = TRUE;

> +  else

> +    CccSwitch = FALSE;

>  

>    if (MmcHostInstance->CardInfo.CardType == SD_CARD_2_HIGH) {

>      CardSize = HC_MMC_CSD_GET_DEVICESIZE (Response);

> @@ -353,6 +370,95 @@ InitializeSdMmcDevice (

>      return Status;

>    }

>  

> +  Status = MmcHost->SendCommand (MmcHost, MMC_CMD55, CmdArg);

> +  if (EFI_ERROR (Status)) {

> +    DEBUG ((EFI_D_ERROR, "%a(MMC_CMD55): Error and Status = %r\n", Status));

> +    return Status;

> +  }

> +  Status = MmcHost->ReceiveResponse (MmcHost, MMC_RESPONSE_TYPE_R1, Response);

> +  if (EFI_ERROR (Status)) {

> +    DEBUG ((EFI_D_ERROR, "%a(MMC_CMD55): Error and Status = %r\n", Status));

> +    return Status;

> +  }

> +  if ((Response[0] & MMC_STATUS_APP_CMD) == 0)

> +    return EFI_SUCCESS;

> +

> +  /* SCR */

> +  Status = MmcHost->SendCommand (MmcHost, MMC_ACMD51, 0);

> +  if (EFI_ERROR (Status)) {

> +    DEBUG ((EFI_D_ERROR, "%a(MMC_ACMD51): Error and Status = %r\n", __func__, Status));

> +    return Status;

> +  } else {

> +    Status = MmcHost->ReadBlockData (MmcHost, 0, 8, Buffer);

> +    if (EFI_ERROR (Status)) {

> +      DEBUG ((EFI_D_ERROR, "%a(MMC_ACMD51): ReadBlockData Error and Status = %r\n", __func__, Status));

> +      return Status;

> +    }

> +    CopyMem (&Scr, Buffer, 8);

> +    if (Scr.SD_SPEC == 2) {

> +      if (Scr.SD_SPEC3 == 1) {

> +	if (Scr.SD_SPEC4 == 1) {

> +          DEBUG ((EFI_D_INFO, "Found SD Card for Spec Version 4.xx\n"));

> +	} else {

> +          DEBUG ((EFI_D_INFO, "Found SD Card for Spec Version 3.0x\n"));

> +	}

> +      } else {

> +	if (Scr.SD_SPEC4 == 0) {

> +          DEBUG ((EFI_D_INFO, "Found SD Card for Spec Version 2.0\n"));

> +	} else {

> +	  DEBUG ((EFI_D_ERROR, "Found invalid SD Card\n"));

> +	}

> +      }

> +    } else {

> +      if ((Scr.SD_SPEC3 == 0) && (Scr.SD_SPEC4 == 0)) {

> +        if (Scr.SD_SPEC == 1) {

> +	  DEBUG ((EFI_D_INFO, "Found SD Card for Spec Version 1.10\n"));

> +	} else {

> +	  DEBUG ((EFI_D_INFO, "Found SD Card for Spec Version 1.0\n"));

> +	}

> +      } else {

> +        DEBUG ((EFI_D_ERROR, "Found invalid SD Card\n"));

> +      }

> +    }

> +  }

> +  if (CccSwitch) {

> +    /* SD Switch, Mode:1, Group:0, Value:1 */

> +    CmdArg = 1 << 31 | 0x00FFFFFF;

> +    CmdArg &= ~(0xF << (0 * 4));

> +    CmdArg |= 1 << (0 * 4);


Can we have some defines to clean the above up?

> +    Status = MmcHost->SendCommand (MmcHost, MMC_CMD6, CmdArg);

> +    if (EFI_ERROR (Status)) {

> +      DEBUG ((EFI_D_ERROR, "%a(MMC_CMD6): Error and Status = %r\n", Status));

> +       return Status;

> +    } else {

> +      Status = MmcHost->ReadBlockData (MmcHost, 0, 64, Buffer);

> +      if (EFI_ERROR (Status)) {

> +        DEBUG ((EFI_D_ERROR, "%a(MMC_CMD6): ReadBlockData Error and Status = %r\n", Status));

> +        return Status;

> +      }

> +    }

> +  }

> +  if (Scr.SD_BUS_WIDTHS & SD_BUS_WIDTH_4BIT) {

> +    CmdArg = MmcHostInstance->CardInfo.RCA << 16;

> +    Status = MmcHost->SendCommand (MmcHost, MMC_CMD55, CmdArg);

> +    if (EFI_ERROR (Status)) {

> +      DEBUG ((EFI_D_ERROR, "%a(MMC_CMD55): Error and Status = %r\n", Status));

> +      return Status;

> +    }

> +    /* Width: 4 */

> +    Status = MmcHost->SendCommand (MmcHost, MMC_CMD6, 2);

> +    if (EFI_ERROR (Status)) {

> +      DEBUG ((EFI_D_ERROR, "%a(MMC_CMD6): Error and Status = %r\n", Status));

> +      return Status;

> +    }

> +  }

> +  if (MmcHost->SetIos) {

> +    Status = MmcHost->SetIos (MmcHost, 24 * 1000 * 1000, 4, EMMCBACKWARD);

> +    if (EFI_ERROR (Status)) {

> +      DEBUG ((EFI_D_ERROR, "%a(SetIos): Error and Status = %r\n", Status));

> +      return Status;

> +    }

> +  }

>    return EFI_SUCCESS;

>  }

>  

> -- 

> 2.7.4

> 

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diff mbox

Patch

diff --git a/EmbeddedPkg/Include/Protocol/MmcHost.h b/EmbeddedPkg/Include/Protocol/MmcHost.h
index 01c0bf4..5028045 100644
--- a/EmbeddedPkg/Include/Protocol/MmcHost.h
+++ b/EmbeddedPkg/Include/Protocol/MmcHost.h
@@ -64,11 +64,14 @@  typedef UINT32 MMC_CMD;
 #define MMC_CMD24             (MMC_INDX(24) | MMC_CMD_WAIT_RESPONSE)
 #define MMC_CMD55             (MMC_INDX(55) | MMC_CMD_WAIT_RESPONSE)
 #define MMC_ACMD41            (MMC_INDX(41) | MMC_CMD_WAIT_RESPONSE | MMC_CMD_NO_CRC_RESPONSE)
+#define MMC_ACMD51            (MMC_INDX(51) | MMC_CMD_WAIT_RESPONSE)
 
 // Valid responses for CMD1 in eMMC
 #define EMMC_CMD1_CAPACITY_LESS_THAN_2GB 0x00FF8080 // Capacity <= 2GB, byte addressing used
 #define EMMC_CMD1_CAPACITY_GREATER_THAN_2GB 0x40FF8080 // Capacity > 2GB, 512-byte sector addressing used
 
+#define MMC_STATUS_APP_CMD    (1 << 5)
+
 typedef enum _MMC_STATE {
     MmcInvalidState = 0,
     MmcHwInitializationState,
diff --git a/EmbeddedPkg/Universal/MmcDxe/Mmc.h b/EmbeddedPkg/Universal/MmcDxe/Mmc.h
index 67f449c..f054bb2 100644
--- a/EmbeddedPkg/Universal/MmcDxe/Mmc.h
+++ b/EmbeddedPkg/Universal/MmcDxe/Mmc.h
@@ -75,6 +75,23 @@  typedef struct {
   UINT32  PowerUp:     1; // This bit is set to LOW if the card has not finished the power up routine
 } OCR;
 
+/* For little endian CPU */
+typedef struct {
+  UINT8   SD_SPEC:               4; // SD Memory Card - Spec. Version [59:56]
+  UINT8   SCR_STRUCTURE:         4; // SCR Structure [63:60]
+  UINT8   SD_BUS_WIDTHS:         4; // DAT Bus widths supported [51:48]
+  UINT8   DATA_STAT_AFTER_ERASE: 1; // Data Status after erases [55]
+  UINT8   SD_SECURITY:           3; // CPRM Security Support [54:52]
+  UINT8   EX_SECURITY_1:         1; // Extended Security Support [43]
+  UINT8   SD_SPEC4:              1; // Spec. Version 4.00 or higher [42]
+  UINT8   RESERVED_1:            2; // Reserved [41:40]
+  UINT8   SD_SPEC3:              1; // Spec. Version 3.00 or higher [47]
+  UINT8   EX_SECURITY_2:         3; // Extended Security Support [46:44]
+  UINT8   CMD_SUPPORT:           4; // Command Support bits [35:32]
+  UINT8   RESERVED_2:            4; // Reserved [39:36]
+  UINT32  RESERVED_3;               // Manufacturer Usage [31:0]
+} SCR;
+
 typedef struct {
   UINT32  NOT_USED;   // 1 [0:0]
   UINT32  CRC;        // CRC7 checksum [7:1]
diff --git a/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c b/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
index 9a79767..c469dda 100644
--- a/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
+++ b/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
@@ -12,6 +12,9 @@ 
 *
 **/
 
+#include <Library/BaseMemoryLib.h>
+#include <Library/TimerLib.h>
+
 #include "Mmc.h"
 
 typedef union {
@@ -41,6 +44,11 @@  typedef union {
 
 #define EMMC_SWITCH_ERROR       (1 << 7)
 
+#define SD_BUS_WIDTH_1BIT       (1 << 0)
+#define SD_BUS_WIDTH_4BIT       (1 << 2)
+
+#define SD_CCC_SWITCH           (1 << 10)
+
 #define DEVICE_STATE(x)         (((x) >> 9) & 0xf)
 typedef enum _EMMC_DEVICE_STATE {
   EMMC_IDLE_STATE = 0,
@@ -68,28 +76,30 @@  EmmcGetDeviceState (
 {
   EFI_MMC_HOST_PROTOCOL *Host;
   EFI_STATUS Status;
-  UINT32     Data, RCA;
+  UINT32     Rsp[4], RCA;
 
   if (State == NULL)
     return EFI_INVALID_PARAMETER;
 
   Host  = MmcHostInstance->MmcHost;
   RCA = MmcHostInstance->CardInfo.RCA << RCA_SHIFT_OFFSET;
-  Status = Host->SendCommand (Host, MMC_CMD13, RCA);
-  if (EFI_ERROR (Status)) {
-    DEBUG ((EFI_D_ERROR, "EmmcGetDeviceState(): Failed to get card status, Status=%r.\n", Status));
-    return Status;
-  }
-  Status = Host->ReceiveResponse (Host, MMC_RESPONSE_TYPE_R1, &Data);
-  if (EFI_ERROR (Status)) {
-    DEBUG ((EFI_D_ERROR, "EmmcGetDeviceState(): Failed to get response of CMD13, Status=%r.\n", Status));
-    return Status;
-  }
-  if (Data & EMMC_SWITCH_ERROR) {
-    DEBUG ((EFI_D_ERROR, "EmmcGetDeviceState(): Failed to switch expected mode, Status=%r.\n", Status));
-    return EFI_DEVICE_ERROR;
-  }
-  *State = DEVICE_STATE(Data);
+  do {
+    Status = Host->SendCommand (Host, MMC_CMD13, RCA);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((EFI_D_ERROR, "EmmcGetDeviceState(): Failed to get card status, Status=%r.\n", Status));
+      return Status;
+    }
+    Status = Host->ReceiveResponse (Host, MMC_RESPONSE_TYPE_R1, Rsp);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((EFI_D_ERROR, "EmmcGetDeviceState(): Failed to get response of CMD13, Status=%r.\n", Status));
+      return Status;
+    }
+    if (Rsp[0] & EMMC_SWITCH_ERROR) {
+      DEBUG ((EFI_D_ERROR, "EmmcGetDeviceState(): Failed to switch expected mode, Status=%r.\n", Status));
+      return EFI_DEVICE_ERROR;
+    }
+  } while (!(Rsp[0] & MMC_R0_READY_FOR_DATA));
+  *State = MMC_R0_CURRENTSTATE(Rsp);
   return EFI_SUCCESS;
 }
 
@@ -300,9 +310,12 @@  InitializeSdMmcDevice (
 {
   UINT32        CmdArg;
   UINT32        Response[4];
+  UINT32        Buffer[128];
   UINTN         BlockSize;
   UINTN         CardSize;
   UINTN         NumBlocks;
+  BOOLEAN       CccSwitch;
+  SCR           Scr;
   EFI_STATUS    Status;
   EFI_MMC_HOST_PROTOCOL     *MmcHost;
 
@@ -323,6 +336,10 @@  InitializeSdMmcDevice (
     return Status;
   }
   PrintCSD (Response);
+  if (MMC_CSD_GET_CCC(Response) & SD_CCC_SWITCH)
+    CccSwitch = TRUE;
+  else
+    CccSwitch = FALSE;
 
   if (MmcHostInstance->CardInfo.CardType == SD_CARD_2_HIGH) {
     CardSize = HC_MMC_CSD_GET_DEVICESIZE (Response);
@@ -353,6 +370,95 @@  InitializeSdMmcDevice (
     return Status;
   }
 
+  Status = MmcHost->SendCommand (MmcHost, MMC_CMD55, CmdArg);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((EFI_D_ERROR, "%a(MMC_CMD55): Error and Status = %r\n", Status));
+    return Status;
+  }
+  Status = MmcHost->ReceiveResponse (MmcHost, MMC_RESPONSE_TYPE_R1, Response);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((EFI_D_ERROR, "%a(MMC_CMD55): Error and Status = %r\n", Status));
+    return Status;
+  }
+  if ((Response[0] & MMC_STATUS_APP_CMD) == 0)
+    return EFI_SUCCESS;
+
+  /* SCR */
+  Status = MmcHost->SendCommand (MmcHost, MMC_ACMD51, 0);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((EFI_D_ERROR, "%a(MMC_ACMD51): Error and Status = %r\n", __func__, Status));
+    return Status;
+  } else {
+    Status = MmcHost->ReadBlockData (MmcHost, 0, 8, Buffer);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((EFI_D_ERROR, "%a(MMC_ACMD51): ReadBlockData Error and Status = %r\n", __func__, Status));
+      return Status;
+    }
+    CopyMem (&Scr, Buffer, 8);
+    if (Scr.SD_SPEC == 2) {
+      if (Scr.SD_SPEC3 == 1) {
+	if (Scr.SD_SPEC4 == 1) {
+          DEBUG ((EFI_D_INFO, "Found SD Card for Spec Version 4.xx\n"));
+	} else {
+          DEBUG ((EFI_D_INFO, "Found SD Card for Spec Version 3.0x\n"));
+	}
+      } else {
+	if (Scr.SD_SPEC4 == 0) {
+          DEBUG ((EFI_D_INFO, "Found SD Card for Spec Version 2.0\n"));
+	} else {
+	  DEBUG ((EFI_D_ERROR, "Found invalid SD Card\n"));
+	}
+      }
+    } else {
+      if ((Scr.SD_SPEC3 == 0) && (Scr.SD_SPEC4 == 0)) {
+        if (Scr.SD_SPEC == 1) {
+	  DEBUG ((EFI_D_INFO, "Found SD Card for Spec Version 1.10\n"));
+	} else {
+	  DEBUG ((EFI_D_INFO, "Found SD Card for Spec Version 1.0\n"));
+	}
+      } else {
+        DEBUG ((EFI_D_ERROR, "Found invalid SD Card\n"));
+      }
+    }
+  }
+  if (CccSwitch) {
+    /* SD Switch, Mode:1, Group:0, Value:1 */
+    CmdArg = 1 << 31 | 0x00FFFFFF;
+    CmdArg &= ~(0xF << (0 * 4));
+    CmdArg |= 1 << (0 * 4);
+    Status = MmcHost->SendCommand (MmcHost, MMC_CMD6, CmdArg);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((EFI_D_ERROR, "%a(MMC_CMD6): Error and Status = %r\n", Status));
+       return Status;
+    } else {
+      Status = MmcHost->ReadBlockData (MmcHost, 0, 64, Buffer);
+      if (EFI_ERROR (Status)) {
+        DEBUG ((EFI_D_ERROR, "%a(MMC_CMD6): ReadBlockData Error and Status = %r\n", Status));
+        return Status;
+      }
+    }
+  }
+  if (Scr.SD_BUS_WIDTHS & SD_BUS_WIDTH_4BIT) {
+    CmdArg = MmcHostInstance->CardInfo.RCA << 16;
+    Status = MmcHost->SendCommand (MmcHost, MMC_CMD55, CmdArg);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((EFI_D_ERROR, "%a(MMC_CMD55): Error and Status = %r\n", Status));
+      return Status;
+    }
+    /* Width: 4 */
+    Status = MmcHost->SendCommand (MmcHost, MMC_CMD6, 2);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((EFI_D_ERROR, "%a(MMC_CMD6): Error and Status = %r\n", Status));
+      return Status;
+    }
+  }
+  if (MmcHost->SetIos) {
+    Status = MmcHost->SetIos (MmcHost, 24 * 1000 * 1000, 4, EMMCBACKWARD);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((EFI_D_ERROR, "%a(SetIos): Error and Status = %r\n", Status));
+      return Status;
+    }
+  }
   return EFI_SUCCESS;
 }