[PATCH v5 1/9] MmcDxe: wait OCR busy bit free

[Haojian Zhuang <haojian.zhuang@linaro.org>]

According to eMMC spec, OCR.PowerUp bit is also busy bit. If the busy
bit is '0', CMD1 should be sent and OCR should be fetched again. And add
a timeout counter on the repeated steps.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Tested-by: Ryan Harkin <ryan.harkin@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
---
 EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c b/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
index 2d8038f..3f72b7f 100644
--- a/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
+++ b/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
@@ -222,14 +222,19 @@ MmcIdentificationMode (
 
   // Send CMD1 to get OCR (MMC)
   // This command only valid for MMC and eMMC
-  Status = MmcHost->SendCommand (MmcHost, MMC_CMD1, EMMC_CMD1_CAPACITY_GREATER_THAN_2GB);
-  if (Status == EFI_SUCCESS) {
+  Timeout = MAX_RETRY_COUNT;
+  do {
+    Status = MmcHost->SendCommand (MmcHost, MMC_CMD1, EMMC_CMD1_CAPACITY_GREATER_THAN_2GB);
+    if (EFI_ERROR (Status))
+      break;
     Status = MmcHost->ReceiveResponse (MmcHost, MMC_RESPONSE_TYPE_OCR, (UINT32 *)&OcrResponse);
     if (EFI_ERROR (Status)) {
       DEBUG ((EFI_D_ERROR, "MmcIdentificationMode() : Failed to receive OCR, Status=%r.\n", Status));
       return Status;
     }
-
+    Timeout--;
+  } while (!OcrResponse.Ocr.PowerUp && (Timeout > 0));
+  if (Status == EFI_SUCCESS) {
     if (!OcrResponse.Ocr.PowerUp) {
       DEBUG ((EFI_D_ERROR, "MmcIdentificationMode(MMC_CMD1): Card initialisation failure, Status=%r.\n", Status));
       return EFI_DEVICE_ERROR;
-- 
2.7.4