Hi Feng,
I think the main difference is who to handle the CRC bits. In the
designware emmc/sd controller, the whole 128-bit value is loaded into
the four response registers. There's no any shift on the 128-bit value
to remove CRC. (Refer to: drivers/mmc/host/dw_mmc.c).
In the eMMC spec, it only mentions R2 response in table.
Bit position [127:1]
Width (bits) 127
Value x
Description CID or CSD register incl.
internal CRC7
It also doesn't mention that we need to shift response value for CSD
register.
So I did this fixing patch. I think that shifting isn't common to
support all eMMC/SD controller IP. Without this patch, the eMMC stack
will only get shifted CSD register value.
It results in parse error.
Best Regards
Haojian
在 07/20/2016 04:14 PM, Tian, Feng 写道:
Correct my words,
According to SD host controller spec, the CRC field is ignored by h/c. user
could only get the data between bit8 and bit127.
Kind of Response | Meaning of Response | ResponseField
| ResponseRegister
------------------------------------------------------------------------------------------------------------------------------
R2 (CID, CSD register) | CID or CSD reg. incl. | R [127:8]
| REP [119:0]
So I don't think your fix is correct. Please correct me if I misunderstand.
Thanks
Feng
-----Original Message-----
From: Tian, Feng
Sent: Wednesday, July 20, 2016 10:13 AM
To: Haojian Zhuang <[email protected]>
Cc: [email protected]; [email protected]; [email protected];
[email protected]; Tian, Feng <[email protected]>
Subject: RE: [edk2] [PATCH] EmmcBlockIo: fix to get CSD data
Hi, Haojian
Why I didn't get the lowest byte data is because it's CRC field. I thought
nobody will care about it. My assumption is incorrect for your usage model?
Thanks
Feng
-----Original Message-----
From: edk2-devel [mailto:[email protected]] On Behalf Of Haojian
Zhuang
Sent: Tuesday, July 19, 2016 3:38 PM
To: Tian, Feng <[email protected]>
Cc: Haojian Zhuang <[email protected]>; [email protected];
[email protected]; [email protected]; [email protected]
Subject: [edk2] [PATCH] EmmcBlockIo: fix to get CSD data
The CSD structure is a 128-bit structure. But EmmcGetCsd() only loads
120 bits with 8-bit offset. Now fix it.
Signed-off-by: Haojian Zhuang <[email protected]>
---
MdeModulePkg/Bus/Sd/EmmcDxe/EmmcBlockIo.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/MdeModulePkg/Bus/Sd/EmmcDxe/EmmcBlockIo.c
b/MdeModulePkg/Bus/Sd/EmmcDxe/EmmcBlockIo.c
index fc705e1..fe85627 100644
--- a/MdeModulePkg/Bus/Sd/EmmcDxe/EmmcBlockIo.c
+++ b/MdeModulePkg/Bus/Sd/EmmcDxe/EmmcBlockIo.c
@@ -191,9 +191,9 @@ EmmcGetCsd (
Status = PassThru->PassThru (PassThru, Device->Slot, &Packet, NULL);
if (!EFI_ERROR (Status)) {
//
- // For details, refer to SD Host Controller Simplified Spec 3.0 Table 2-12.
+ // Copy 128bit data for CSD structure.
//
- CopyMem (((UINT8*)Csd) + 1, &SdMmcStatusBlk.Resp0, sizeof (EMMC_CSD) - 1);
+ CopyMem ((VOID*)Csd, &SdMmcStatusBlk.Resp0, sizeof (EMMC_CSD));
}
return Status;
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