diff options
| author | gikidy <gikidy@6f19259b-4bc3-4df7-8a09-765794883524> | 2009-07-08 09:29:08 +0000 |
|---|---|---|
| committer | gikidy <gikidy@6f19259b-4bc3-4df7-8a09-765794883524> | 2009-07-08 09:29:08 +0000 |
| commit | fa70a2c4cc9607f38e49a389f64ac32c600d47d2 (patch) | |
| tree | 07aa4edd6087ab1ccc6e744dc2b2e6e10d925cd5 /IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/Serial.c | |
| parent | 5b3ea840c44bc5a94c542580af3eac7e28e12f2e (diff) | |
| download | edk2-platforms-fa70a2c4cc9607f38e49a389f64ac32c600d47d2.tar.xz | |
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
Diffstat (limited to 'IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/Serial.c')
| -rw-r--r-- | IntelFrameworkModulePkg/Bus/Isa/IsaSerialDxe/Serial.c | 77 |
1 files changed, 42 insertions, 35 deletions
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));
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