[PATCH v2 7/7] EmbeddedPkg: Fix DwEmmc read/write size in preparing DMA size

["Loh, Tien Hock" <tien.hock.loh@intel.com>]

From: "Tien Hock, Loh" <tien.hock.loh@intel.com>

Add support for reading data that is less than DWEMMC_BLOCK_SIZE,
otherwise it would read bigger data than requested and cause errors

Signed-off-by: "Tien Hock, Loh" <tien.hock.loh@intel.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>

--
v2:
- Fix white space issue
---
 EmbeddedPkg/Drivers/DwEmmcDxe/DwEmmcDxe.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/EmbeddedPkg/Drivers/DwEmmcDxe/DwEmmcDxe.c b/EmbeddedPkg/Drivers/DwEmmcDxe/DwEmmcDxe.c
index b57833458f..ec2fa7923b 100644
--- a/EmbeddedPkg/Drivers/DwEmmcDxe/DwEmmcDxe.c
+++ b/EmbeddedPkg/Drivers/DwEmmcDxe/DwEmmcDxe.c
@@ -493,7 +493,10 @@ PrepareDmaData (
 
   Cnt = (Length + DWEMMC_DMA_BUF_SIZE - 1) / DWEMMC_DMA_BUF_SIZE;
   Blks = (Length + DWEMMC_BLOCK_SIZE - 1) / DWEMMC_BLOCK_SIZE;
-  Length = DWEMMC_BLOCK_SIZE * Blks;
+
+  if(Length >= DWEMMC_BLOCK_SIZE) {
+    Length = DWEMMC_BLOCK_SIZE * Blks;
+  }
 
   for (Idx = 0; Idx < Cnt; Idx++) {
     (IdmacDesc + Idx)->Des0 = DWEMMC_IDMAC_DES0_OWN | DWEMMC_IDMAC_DES0_CH |
@@ -534,8 +537,14 @@ StartDma (
   Data |= DWEMMC_IDMAC_ENABLE | DWEMMC_IDMAC_FB;
   MmioWrite32 (DWEMMC_BMOD, Data);
 
-  MmioWrite32 (DWEMMC_BLKSIZ, DWEMMC_BLOCK_SIZE);
-  MmioWrite32 (DWEMMC_BYTCNT, Length);
+  if(Length < DWEMMC_BLOCK_SIZE) {
+    MmioWrite32 (DWEMMC_BLKSIZ, Length);
+    MmioWrite32 (DWEMMC_BYTCNT, Length);
+  }
+  else {
+    MmioWrite32 (DWEMMC_BLKSIZ, DWEMMC_BLOCK_SIZE);
+    MmioWrite32 (DWEMMC_BYTCNT, Length);
+  }
 }
 
 EFI_STATUS
-- 
2.19.0