Enhanced module to handle half handshake flow control.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@8816 6f19259b-4bc3-4df7-8a09-765794883524

3 files changed, 44 insertions, 35 deletions

diff --git a/IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/IsaSerialDxe.inf b/IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/IsaSerialDxe.inf
index aa7c315e1d..4c8c08fd53 100644
--- a/IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/IsaSerialDxe.inf
+++ b/IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/IsaSerialDxe.inf
@@ -65,3 +65,4 @@
   gEfiMdePkgTokenSpaceGuid.PcdUartDefaultDataBits|8

   gEfiMdePkgTokenSpaceGuid.PcdUartDefaultParity|1

   gEfiMdePkgTokenSpaceGuid.PcdUartDefaultStopBits|1

+  gEfiIntelFrameworkModulePkgTokenSpaceGuid.PcdIsaBusSerialUseHalfHandshake|FALSE

diff --git a/IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/Serial.c b/IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/Serial.c
index f9d08ce3a0..65f072356b 100644
--- a/IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/Serial.c
+++ b/IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/Serial.c
@@ -83,7 +83,8 @@ SERIAL_DEV  gSerialDevTempate = {
   FALSE,

   FALSE,

   Uart16550A,

-  NULL

+  NULL,

+  FixedPcdGetBool (PcdIsaBusSerialUseHalfHandshake)   //UseHalfHandshake

 };

 

 /**

@@ -801,6 +802,18 @@ IsaSerialReceiveTransmit (
     } while (!IsaSerialFifoEmpty (&SerialDevice->Transmit));

   } else {

     ReceiveFifoFull = IsaSerialFifoFull (&SerialDevice->Receive);

+    //

+    // For full handshake flow control, tell the peer to send data

+    // if receive buffer is available.

+    //

+    if (SerialDevice->HardwareFlowControl &&

+        !SerialDevice->UseHalfHandshake   &&

+        !ReceiveFifoFull

+        ) {

+      Mcr.Data     = READ_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress);

+      Mcr.Bits.Rts = 1;

+      WRITE_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress, Mcr.Data);

+    }

     do {

       Lsr.Data = READ_LSR (SerialDevice->IsaIo, SerialDevice->BaseAddress);

 

@@ -821,23 +834,21 @@ IsaSerialReceiveTransmit (
               continue;

             }

           }

-          //

-          // Make sure the receive data will not be missed, Assert DTR

-          //

-          if (SerialDevice->HardwareFlowControl) {

-            Mcr.Data = READ_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress);

-            Mcr.Bits.DtrC &= 0;

-            WRITE_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress, Mcr.Data);

-          }

 

           Data = READ_RBR (SerialDevice->IsaIo, SerialDevice->BaseAddress);

 

+          IsaSerialFifoAdd (&SerialDevice->Receive, Data);

+          

           //

-          // Deassert DTR

+          // For full handshake flow control, if receive buffer full

+          // tell the peer to stop sending data.

           //

-          if (SerialDevice->HardwareFlowControl) {

-            Mcr.Data = READ_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress);

-            Mcr.Bits.DtrC |= 1;

+          if (SerialDevice->HardwareFlowControl &&

+              !SerialDevice->UseHalfHandshake   &&

+              IsaSerialFifoFull (&SerialDevice->Receive)

+              ) {

+            Mcr.Data     = READ_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress);

+            Mcr.Bits.Rts = 0;

             WRITE_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress, Mcr.Data);

           }

 

@@ -861,17 +872,19 @@ IsaSerialReceiveTransmit (
         //

         if (SerialDevice->HardwareFlowControl) {

           //

-          // Send RTS

+          // For half handshake flow control assert RTS before sending.

           //

-          Mcr.Data = READ_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress);

-          Mcr.Bits.Rts |= 1;

-          WRITE_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress, Mcr.Data);

+          if (SerialDevice->UseHalfHandshake) {

+            Mcr.Data     = READ_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress);

+            Mcr.Bits.Rts= 0;

+            WRITE_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress, Mcr.Data);

+          }

           //

           // Wait for CTS

           //

           TimeOut   = 0;

           Msr.Data  = READ_MSR (SerialDevice->IsaIo, SerialDevice->BaseAddress);

-          while (Msr.Bits.Cts == 0) {

+          while (Msr.Bits.Dcd == 1 && (!Msr.Bits.Cts ^ SerialDevice->UseHalfHandshake)) {

             gBS->Stall (TIMEOUT_STALL_INTERVAL);

             TimeOut++;

             if (TimeOut > 5) {

@@ -881,28 +894,22 @@ IsaSerialReceiveTransmit (
             Msr.Data = READ_MSR (SerialDevice->IsaIo, SerialDevice->BaseAddress);

           }

 

-          if (Msr.Bits.Cts == 1) {

+          if (Msr.Bits.Dcd== 0 || (Msr.Bits.Cts ^ SerialDevice->UseHalfHandshake)) {

             IsaSerialFifoRemove (&SerialDevice->Transmit, &Data);

             WRITE_THR (SerialDevice->IsaIo, SerialDevice->BaseAddress, Data);

           }

-        }

-        //

-        // write the data out

-        //

-        if (!SerialDevice->HardwareFlowControl) {

-          IsaSerialFifoRemove (&SerialDevice->Transmit, &Data);

-          WRITE_THR (SerialDevice->IsaIo, SerialDevice->BaseAddress, Data);

-        }

-        //

-        // Make sure the transmit data will not be missed

-        //

-        if (SerialDevice->HardwareFlowControl) {

+

           //

-          // Assert RTS

+          // For half handshake flow control, tell DCE we are done.

           //

-          Mcr.Data = READ_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress);

-          Mcr.Bits.Rts &= 0;

-          WRITE_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress, Mcr.Data);

+          if (SerialDevice->UseHalfHandshake) {

+            Mcr.Data = READ_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress);

+            Mcr.Bits.Rts = 1;

+            WRITE_MCR (SerialDevice->IsaIo, SerialDevice->BaseAddress, Mcr.Data);

+          }

+        } else {

+          IsaSerialFifoRemove (&SerialDevice->Transmit, &Data);

+          WRITE_THR (SerialDevice->IsaIo, SerialDevice->BaseAddress, Data);

         }

       }

     } while (Lsr.Bits.Thre == 1 && !IsaSerialFifoEmpty (&SerialDevice->Transmit));

diff --git a/IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/Serial.h b/IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/Serial.h
index c7f2105f62..8d985a408f 100644
--- a/IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/Serial.h
+++ b/IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/Serial.h
@@ -109,6 +109,7 @@ typedef struct {
   BOOLEAN                                HardwareFlowControl;

   EFI_UART_TYPE                          Type;

   EFI_UNICODE_STRING_TABLE               *ControllerNameTable;

+  BOOLEAN                                UseHalfHandshake;

 } SERIAL_DEV;

 

 #define SERIAL_DEV_FROM_THIS(a) CR (a, SERIAL_DEV, SerialIo, SERIAL_DEV_SIGNATURE)