0d87e62b1b06a81f01721b674a37fa4975582d0b
[mirror_edk2.git] / CorebootPayloadPkg / Library / SerialPortLib / SerialPortLib.c
1 /** @file
2 SerialPortLib instance for UART device upon coreboot
3
4 Copyright (c) 2014, Intel Corporation. All rights reserved.<BR>
5 This program and the accompanying materials
6 are licensed and made available under the terms and conditions of the BSD License
7 which accompanies this distribution. The full text of the license may be found at
8 http://opensource.org/licenses/bsd-license.php
9
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
12
13 **/
14
15 #include <Uefi/UefiBaseType.h>
16 #include <Library/SerialPortLib.h>
17 #include <Library/PcdLib.h>
18 #include <Library/IoLib.h>
19 #include <Library/CbParseLib.h>
20
21 //
22 // 16550 UART register offsets and bitfields
23 //
24 #define R_UART_RXBUF 0
25 #define R_UART_TXBUF 0
26 #define R_UART_BAUD_LOW 0
27 #define R_UART_BAUD_HIGH 1
28 #define R_UART_FCR 2
29 #define B_UART_FCR_FIFOE BIT0
30 #define B_UART_FCR_FIFO64 BIT5
31 #define R_UART_LCR 3
32 #define B_UART_LCR_DLAB BIT7
33 #define R_UART_MCR 4
34 #define B_UART_MCR_RTS BIT1
35 #define R_UART_LSR 5
36 #define B_UART_LSR_RXRDY BIT0
37 #define B_UART_LSR_TXRDY BIT5
38 #define B_UART_LSR_TEMT BIT6
39 #define R_UART_MSR 6
40 #define B_UART_MSR_CTS BIT4
41 #define B_UART_MSR_DSR BIT5
42
43 UINT32 mSerialRegBase = 0;
44 UINT32 mSerialRegAccessType = 0;
45
46 /**
47 Read an 8-bit 16550 register. If PcdSerialUseMmio is TRUE, then the value is read from
48 MMIO space. If PcdSerialUseMmio is FALSE, then the value is read from I/O space. The
49 parameter Offset is added to the base address of the 16550 registers that is specified
50 by PcdSerialRegisterBase.
51
52 @param Offset The offset of the 16550 register to read.
53
54 @return The value read from the 16550 register.
55
56 **/
57 UINT8
58 SerialPortReadRegister (
59 UINTN Offset
60 )
61 {
62 if (mSerialRegAccessType == 2) { //MMIO
63 return MmioRead8 (mSerialRegBase + Offset);
64 } else { //IO
65 return IoRead8 ((UINT16)mSerialRegBase + Offset);
66 }
67 }
68
69 /**
70 Write an 8-bit 16550 register. If PcdSerialUseMmio is TRUE, then the value is written to
71 MMIO space. If PcdSerialUseMmio is FALSE, then the value is written to I/O space. The
72 parameter Offset is added to the base address of the 16550 registers that is specified
73 by PcdSerialRegisterBase.
74
75 @param Offset The offset of the 16550 register to write.
76 @param Value The value to write to the 16550 register specified by Offset.
77
78 @return The value written to the 16550 register.
79
80 **/
81 UINT8
82 SerialPortWriteRegister (
83 UINTN Offset,
84 UINT8 Value
85 )
86 {
87 if (mSerialRegAccessType == 2) { //MMIO
88 return MmioWrite8 (mSerialRegBase + Offset, Value);
89 } else {// IO
90 return IoWrite8 ((UINT16)mSerialRegBase + Offset, Value);
91 }
92 }
93
94 /**
95 Initialize the serial device hardware.
96
97 If no initialization is required, then return RETURN_SUCCESS.
98 If the serial device was successfully initialized, then return RETURN_SUCCESS.
99 If the serial device could not be initialized, then return RETURN_DEVICE_ERROR.
100
101 @retval RETURN_SUCCESS The serial device was initialized.
102 @retval RETURN_DEVICE_ERROR The serial device could not be initialized.
103
104 **/
105 RETURN_STATUS
106 EFIAPI
107 SerialPortInitialize (
108 VOID
109 )
110 {
111 RETURN_STATUS Status;
112 UINTN Divisor;
113 BOOLEAN Initialized;
114
115 Status = CbParseSerialInfo (&mSerialRegBase, &mSerialRegAccessType, NULL);
116 if (RETURN_ERROR (Status)) {
117 return Status;
118 }
119
120 //
121 // See if the serial port is already initialized
122 //
123 Initialized = TRUE;
124 if ((SerialPortReadRegister (R_UART_FCR) & (B_UART_FCR_FIFOE | B_UART_FCR_FIFO64)) !=
125 (PcdGet8 (PcdSerialFifoControl) & (B_UART_FCR_FIFOE | B_UART_FCR_FIFO64)) ) {
126 Initialized = FALSE;
127 }
128
129 if ((SerialPortReadRegister (R_UART_LCR) & 0x3F) != (PcdGet8 (PcdSerialLineControl) & 0x3F)) {
130 Initialized = FALSE;
131 }
132 SerialPortWriteRegister (R_UART_LCR, (UINT8)(SerialPortReadRegister (R_UART_LCR) | B_UART_LCR_DLAB));
133 Divisor = SerialPortReadRegister (R_UART_BAUD_HIGH) << 8;
134 Divisor |= SerialPortReadRegister (R_UART_BAUD_LOW);
135 SerialPortWriteRegister (R_UART_LCR, (UINT8)(SerialPortReadRegister (R_UART_LCR) & ~B_UART_LCR_DLAB));
136 if (Divisor != 115200 / PcdGet32 (PcdSerialBaudRate)) {
137 Initialized = FALSE;
138 }
139 if (Initialized) {
140 return RETURN_SUCCESS;
141 }
142
143 //
144 // Configure baud rate
145 //
146 Divisor = 115200 / PcdGet32 (PcdSerialBaudRate);
147 SerialPortWriteRegister (R_UART_LCR, B_UART_LCR_DLAB);
148 SerialPortWriteRegister (R_UART_BAUD_HIGH, (UINT8) (Divisor >> 8));
149 SerialPortWriteRegister (R_UART_BAUD_LOW, (UINT8) (Divisor & 0xff));
150
151 //
152 // Clear DLAB and configure Data Bits, Parity, and Stop Bits.
153 // Strip reserved bits from PcdSerialLineControl
154 //
155 SerialPortWriteRegister (R_UART_LCR, (UINT8)(PcdGet8 (PcdSerialLineControl) & 0x3F));
156
157 //
158 // Enable and reset FIFOs
159 // Strip reserved bits from PcdSerialFifoControl
160 //
161 SerialPortWriteRegister (R_UART_FCR, (UINT8)(PcdGet8 (PcdSerialFifoControl) & 0x27));
162
163 //
164 // Put Modem Control Register(MCR) into its reset state of 0x00.
165 //
166 SerialPortWriteRegister (R_UART_MCR, 0x00);
167
168 return RETURN_SUCCESS;
169 }
170
171 /**
172 Write data from buffer to serial device.
173
174 Writes NumberOfBytes data bytes from Buffer to the serial device.
175 The number of bytes actually written to the serial device is returned.
176 If the return value is less than NumberOfBytes, then the write operation failed.
177
178 If Buffer is NULL, then ASSERT().
179
180 If NumberOfBytes is zero, then return 0.
181
182 @param Buffer Pointer to the data buffer to be written.
183 @param NumberOfBytes Number of bytes to written to the serial device.
184
185 @retval 0 NumberOfBytes is 0.
186 @retval >0 The number of bytes written to the serial device.
187 If this value is less than NumberOfBytes, then the read operation failed.
188
189 **/
190 UINTN
191 EFIAPI
192 SerialPortWrite (
193 IN UINT8 *Buffer,
194 IN UINTN NumberOfBytes
195 )
196 {
197 UINTN Result;
198 UINTN Index;
199 UINTN FifoSize;
200
201 if (Buffer == NULL) {
202 return 0;
203 }
204
205 if (NumberOfBytes == 0) {
206 //
207 // Flush the hardware
208 //
209
210 //
211 // Wait for both the transmit FIFO and shift register empty.
212 //
213 while ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_TEMT) == 0);
214
215 return 0;
216 }
217
218 //
219 // Compute the maximum size of the Tx FIFO
220 //
221 FifoSize = 1;
222 if ((PcdGet8 (PcdSerialFifoControl) & B_UART_FCR_FIFOE) != 0) {
223 if ((PcdGet8 (PcdSerialFifoControl) & B_UART_FCR_FIFO64) == 0) {
224 FifoSize = 16;
225 } else {
226 FifoSize = 64;
227 }
228 }
229
230 Result = NumberOfBytes;
231 while (NumberOfBytes != 0) {
232 //
233 // Wait for the serial port to be ready, to make sure both the transmit FIFO
234 // and shift register empty.
235 //
236 while ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_TEMT) == 0);
237
238 //
239 // Fill then entire Tx FIFO
240 //
241 for (Index = 0; Index < FifoSize && NumberOfBytes != 0; Index++, NumberOfBytes--, Buffer++) {
242
243 //
244 // Write byte to the transmit buffer.
245 //
246 SerialPortWriteRegister (R_UART_TXBUF, *Buffer);
247 }
248 }
249 return Result;
250 }
251
252 /**
253 Reads data from a serial device into a buffer.
254
255 @param Buffer Pointer to the data buffer to store the data read from the serial device.
256 @param NumberOfBytes Number of bytes to read from the serial device.
257
258 @retval 0 NumberOfBytes is 0.
259 @retval >0 The number of bytes read from the serial device.
260 If this value is less than NumberOfBytes, then the read operation failed.
261
262 **/
263 UINTN
264 EFIAPI
265 SerialPortRead (
266 OUT UINT8 *Buffer,
267 IN UINTN NumberOfBytes
268 )
269 {
270 UINTN Result;
271
272 if (NULL == Buffer) {
273 return 0;
274 }
275
276 for (Result = 0; NumberOfBytes-- != 0; Result++, Buffer++) {
277 //
278 // Wait for the serial port to have some data.
279 //
280 while ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_RXRDY) == 0);
281
282 //
283 // Read byte from the receive buffer.
284 //
285 *Buffer = SerialPortReadRegister (R_UART_RXBUF);
286 }
287
288 return Result;
289 }
290
291 /**
292 Polls a serial device to see if there is any data waiting to be read.
293
294 Polls aserial device to see if there is any data waiting to be read.
295 If there is data waiting to be read from the serial device, then TRUE is returned.
296 If there is no data waiting to be read from the serial device, then FALSE is returned.
297
298 @retval TRUE Data is waiting to be read from the serial device.
299 @retval FALSE There is no data waiting to be read from the serial device.
300
301 **/
302 BOOLEAN
303 EFIAPI
304 SerialPortPoll (
305 VOID
306 )
307 {
308 //
309 // Read the serial port status
310 //
311 if ((SerialPortReadRegister (R_UART_LSR) & B_UART_LSR_RXRDY) != 0) {
312 return TRUE;
313 }
314
315 return FALSE;
316 }