[PATCH] UefiPayloadPkg/SerialPortLib: Enhance multi port behaviour

["Kavya" <k.kavyax.sravanthi@intel.com>]

Add condition to return success if mUartCount is greater
than zero in SerialPortInitialize() to avoid filling mUartInfo
with the same hob data when SerialPortInitialize() is called
multiple times. Also add proper conditions in SerialPortRead
function to read the data properly from multiple UART's.

Cc: Guo Dong <guo.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: James Lu <james.lu@intel.com>
Cc: Gua Guo <gua.guo@intel.com>
Signed-off-by: Kavya <k.kavyax.sravanthi@intel.com>
---
 UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c | 37 ++++++++++++++++++++++++++++++++-----
 1 file changed, 32 insertions(+), 5 deletions(-)

diff --git a/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c b/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c
index 809fa2e9c9..84c56bd24d 100644
--- a/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c
+++ b/UefiPayloadPkg/Library/BaseSerialPortLibHob/BaseSerialPortLibHob.c
@@ -138,6 +138,10 @@ SerialPortInitialize (
   BOOLEAN                             MmioEnable;
   UINT8                               Value;
 
+  if (mUartCount > 0) {
+    return RETURN_SUCCESS;
+  }
+
   GuidHob = GetFirstGuidHob (&gUniversalPayloadSerialPortInfoGuid);
   while (GuidHob != NULL) {
     SerialPortInfo     = (UNIVERSAL_PAYLOAD_SERIAL_PORT_INFO *)GET_GUID_HOB_DATA (GuidHob);
@@ -329,6 +333,7 @@ SerialPortRead (
 {
   UINTN    BaseAddress;
   BOOLEAN  UseMmio;
+  BOOLEAN  IsNextPort;
   UINT8    *DataBuffer;
   UINTN    BytesLeft;
   UINTN    Result;
@@ -353,6 +358,7 @@ SerialPortRead (
 
     DataBuffer = Buffer;
     BytesLeft  = NumberOfBytes;
+    IsNextPort = FALSE;
 
     Mcr = (UINT8)(SerialPortReadRegister (BaseAddress, R_UART_MCR, UseMmio, Stride) & ~B_UART_MCR_RTS);
 
@@ -367,6 +373,12 @@ SerialPortRead (
           //
           SerialPortWriteRegister (BaseAddress, R_UART_MCR, (UINT8)(Mcr | B_UART_MCR_RTS), UseMmio, Stride);
         }
+        IsNextPort = TRUE;
+        break;
+      }
+
+      if (IsNextPort) {
+        break;
       }
 
       if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
@@ -382,6 +394,10 @@ SerialPortRead (
       *DataBuffer = SerialPortReadRegister (BaseAddress, R_UART_RXBUF, UseMmio, Stride);
     }
 
+    if ((!IsNextPort) && (*(--DataBuffer) != '\0')) {
+      return Result;
+    }
+
     Count++;
   }
 
@@ -409,10 +425,9 @@ SerialPortPoll (
   BOOLEAN  UseMmio;
   UINT8    Stride;
   UINT8    Count;
-  BOOLEAN  Status;
+  BOOLEAN  IsDataReady;
 
   Count  = 0;
-  Status = FALSE;
   while (Count < mUartCount) {
     BaseAddress = mUartInfo[Count].BaseAddress;
     UseMmio     = mUartInfo[Count].UseMmio;
@@ -423,7 +438,7 @@ SerialPortPoll (
       continue;
     }
 
-    Status = FALSE;
+    IsDataReady = FALSE;
 
     //
     // Read the serial port status
@@ -436,7 +451,7 @@ SerialPortPoll (
         SerialPortWriteRegister (BaseAddress, R_UART_MCR, (UINT8)(SerialPortReadRegister (BaseAddress, R_UART_MCR, UseMmio, Stride) & ~B_UART_MCR_RTS), UseMmio, Stride);
       }
 
-      Status = TRUE;
+      IsDataReady = TRUE;
     }
 
     if (PcdGetBool (PcdSerialUseHardwareFlowControl)) {
@@ -446,10 +461,14 @@ SerialPortPoll (
       SerialPortWriteRegister (BaseAddress, R_UART_MCR, (UINT8)(SerialPortReadRegister (BaseAddress, R_UART_MCR, UseMmio, Stride) | B_UART_MCR_RTS), UseMmio, Stride);
     }
 
+    if (IsDataReady) {
+      return IsDataReady;
+    }
+
     Count++;
   }
 
-  return Status;
+  return IsDataReady;
 }
 
 /**
@@ -603,6 +622,14 @@ SerialPortGetControl (
       *Control |= EFI_SERIAL_INPUT_BUFFER_EMPTY;
     }
 
+    if ((((*Control & EFI_SERIAL_OUTPUT_BUFFER_EMPTY) == EFI_SERIAL_OUTPUT_BUFFER_EMPTY) &&
+        ((*Control & EFI_SERIAL_INPUT_BUFFER_EMPTY) != EFI_SERIAL_INPUT_BUFFER_EMPTY)) ||
+        ((*Control & (EFI_SERIAL_DATA_SET_READY | EFI_SERIAL_CLEAR_TO_SEND |
+        EFI_SERIAL_CARRIER_DETECT)) == (EFI_SERIAL_DATA_SET_READY | EFI_SERIAL_CLEAR_TO_SEND |
+        EFI_SERIAL_CARRIER_DETECT))) {
+        return RETURN_SUCCESS;
+    }
+
     Count++;
   }
 
-- 
2.30.2.windows.1