2 Serial I/O Port library functions with base address discovered from FDT
4 Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
5 Copyright (c) 2012 - 2013, ARM Ltd. All rights reserved.<BR>
6 Copyright (c) 2014, Linaro Ltd. All rights reserved.<BR>
8 This program and the accompanying materials
9 are licensed and made available under the terms and conditions of the BSD License
10 which accompanies this distribution. The full text of the license may be found at
11 http://opensource.org/licenses/bsd-license.php
13 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
14 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
20 #include <Library/PcdLib.h>
21 #include <Library/SerialPortLib.h>
22 #include <Library/SerialPortExtLib.h>
25 #include <Drivers/PL011Uart.h>
29 SerialPortInitialize (
34 // This SerialPortInitialize() function is completely empty, for a number of
36 // - if we are executing from flash, it is hard to keep state (i.e., store the
37 // discovered base address in a global), and the most robust way to deal
38 // with this is to discover the base address at every Write ();
39 // - calls to the Write() function in this module may be issued before this
40 // initialization function is called: this is not a problem when the base
41 // address of the UART is hardcoded, and only the baud rate may be wrong,
42 // but if we don't know the base address yet, we may be poking into memory
43 // that does not tolerate being poked into;
44 // - SEC and PEI phases produce debug output only, so with debug disabled, no
45 // initialization (or device tree parsing) is performed at all.
47 // Note that this means that on *every* Write () call, the device tree will be
48 // parsed and the UART re-initialized. However, this is a small price to pay
49 // for having serial debug output on a UART with no fixed base address.
51 return RETURN_SUCCESS
;
56 SerialPortGetBaseAddress (
61 UINT32 ReceiveFifoDepth
;
62 EFI_PARITY_TYPE Parity
;
64 EFI_STOP_BITS_TYPE StopBits
;
68 CONST CHAR8
*Compatible
;
69 CONST CHAR8
*CompatibleItem
;
70 CONST UINT64
*RegProperty
;
74 DeviceTreeBase
= (VOID
*)(UINTN
)FixedPcdGet64 (PcdDeviceTreeInitialBaseAddress
);
76 if ((DeviceTreeBase
== NULL
) || (fdt_check_header (DeviceTreeBase
) != 0)) {
81 // Enumerate all FDT nodes looking for a PL011 and capture its base address
83 for (Prev
= 0;; Prev
= Node
) {
84 Node
= fdt_next_node (DeviceTreeBase
, Prev
, NULL
);
89 Compatible
= fdt_getprop (DeviceTreeBase
, Node
, "compatible", &Len
);
90 if (Compatible
== NULL
) {
95 // Iterate over the NULL-separated items in the compatible string
97 for (CompatibleItem
= Compatible
; CompatibleItem
< Compatible
+ Len
;
98 CompatibleItem
+= 1 + AsciiStrLen (CompatibleItem
)) {
100 if (AsciiStrCmp (CompatibleItem
, "arm,pl011") == 0) {
101 RegProperty
= fdt_getprop (DeviceTreeBase
, Node
, "reg", &Len
);
105 UartBase
= (UINTN
)fdt64_to_cpu (ReadUnaligned64 (RegProperty
));
107 BaudRate
= (UINTN
)FixedPcdGet64 (PcdUartDefaultBaudRate
);
108 ReceiveFifoDepth
= 0; // Use the default value for Fifo depth
109 Parity
= (EFI_PARITY_TYPE
)FixedPcdGet8 (PcdUartDefaultParity
);
110 DataBits
= FixedPcdGet8 (PcdUartDefaultDataBits
);
111 StopBits
= (EFI_STOP_BITS_TYPE
) FixedPcdGet8 (PcdUartDefaultStopBits
);
113 Status
= PL011UartInitializePort (
115 &BaudRate
, &ReceiveFifoDepth
, &Parity
, &DataBits
, &StopBits
);
116 if (!EFI_ERROR (Status
)) {
126 Write data to serial device.
128 @param Buffer Point of data buffer which need to be written.
129 @param NumberOfBytes Number of output bytes which are cached in Buffer.
131 @retval 0 Write data failed.
132 @retval !0 Actual number of bytes written to serial device.
139 IN UINTN NumberOfBytes
142 UINT64 SerialRegisterBase
;
144 SerialRegisterBase
= SerialPortGetBaseAddress ();
145 if (SerialRegisterBase
!= 0) {
146 return PL011UartWrite ((UINTN
)SerialRegisterBase
, Buffer
, NumberOfBytes
);
152 Read data from serial device and save the data in buffer.
154 @param Buffer Point of data buffer which need to be written.
155 @param NumberOfBytes Size of Buffer[].
157 @retval 0 Read data failed.
158 @retval !0 Actual number of bytes read from serial device.
165 IN UINTN NumberOfBytes
172 Check to see if any data is available to be read from the debug device.
174 @retval TRUE At least one byte of data is available to be read
175 @retval FALSE No data is available to be read