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author | Evan Lloyd <evan.lloyd@arm.com> | 2016-06-15 13:52:38 +0100 |
---|---|---|
committer | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2016-06-15 16:15:08 +0200 |
commit | 9f08a052a3e48295b19da20995a6cab23d31e8cf (patch) | |
tree | 2b89326f19638c477d85412c1a6230521dd07ab2 /ArmPlatformPkg/Drivers | |
parent | 8f88f023fc59961973bb1ef121c7bee7b0a61975 (diff) | |
download | edk2-9f08a052a3e48295b19da20995a6cab23d31e8cf.zip edk2-9f08a052a3e48295b19da20995a6cab23d31e8cf.tar.gz edk2-9f08a052a3e48295b19da20995a6cab23d31e8cf.tar.bz2 |
ArmPlatformPkg: Tidy PL011 UART driver
This cosmetic change only tidies things up in preparation for actual
updates. (This reflects responses to a previously submitted patch,
which has been split into several discrete changes.)
There are no functional changes in this commit.
Changes comprise:
Minor corrections to comment typos.
Minor formatting mods.
Expansion of function comments.
Remove OUT from UartBase parameter.
Addition of #define for "magic mumbers".
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Evan Lloyd <evan.lloyd@arm.com>
Reviewed-by: Ryan Harkin <ryan.harkin@linaro.org>
Diffstat (limited to 'ArmPlatformPkg/Drivers')
-rw-r--r-- | ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c | 101 |
1 files changed, 67 insertions, 34 deletions
diff --git a/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c b/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c index 8b256de..ab00cae 100644 --- a/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c +++ b/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c @@ -2,7 +2,7 @@ Serial I/O Port library functions with no library constructor/destructor
Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
- Copyright (c) 2011 - 2014, ARM Ltd. All rights reserved.<BR>
+ Copyright (c) 2011 - 2016, ARM Ltd. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
@@ -20,24 +20,49 @@ #include <Drivers/PL011Uart.h>
+#define FRACTION_PART_SIZE_IN_BITS 6
+#define FRACTION_PART_MASK ((1 << FRACTION_PART_SIZE_IN_BITS) - 1)
+
//
// EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE is the only
// control bit that is not supported.
//
STATIC CONST UINT32 mInvalidControlBits = EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE;
-/*
+/**
Initialise the serial port to the specified settings.
All unspecified settings will be set to the default values.
- @return Always return EFI_SUCCESS or EFI_INVALID_PARAMETER.
+ @param UartBase The base address of the serial device.
+ @param BaudRate The baud rate of the serial device. If the
+ baud rate is not supported, the speed will be
+ reduced to the nearest supported one and the
+ variable's value will be updated accordingly.
+ @param ReceiveFifoDepth The number of characters the device will
+ buffer on input. Value of 0 will use the
+ device's default FIFO depth.
+ @param Parity If applicable, this is the EFI_PARITY_TYPE
+ that is computed or checked as each character
+ is transmitted or received. If the device
+ does not support parity, the value is the
+ default parity value.
+ @param DataBits The number of data bits in each character.
+ @param StopBits If applicable, the EFI_STOP_BITS_TYPE number
+ of stop bits per character.
+ If the device does not support stop bits, the
+ value is the default stop bit value.
+
+ @retval RETURN_SUCCESS All attributes were set correctly on the
+ serial device.
+ @retval RETURN_INVALID_PARAMETER One or more of the attributes has an
+ unsupported value.
**/
RETURN_STATUS
EFIAPI
PL011UartInitializePort (
- IN OUT UINTN UartBase,
+ IN UINTN UartBase,
IN OUT UINT64 *BaudRate,
IN OUT UINT32 *ReceiveFifoDepth,
IN OUT EFI_PARITY_TYPE *Parity,
@@ -51,9 +76,10 @@ PL011UartInitializePort ( LineControl = 0;
// The PL011 supports a buffer of 1, 16 or 32 chars. Therefore we can accept
- // 1 char buffer as the minimum fifo size. Because everything can be rounded down,
- // there is no maximum fifo size.
+ // 1 char buffer as the minimum FIFO size. Because everything can be rounded
+ // down, there is no maximum FIFO size.
if ((*ReceiveFifoDepth == 0) || (*ReceiveFifoDepth >= 32)) {
+ // Enable FIFO
LineControl |= PL011_UARTLCR_H_FEN;
if (PL011_UARTPID2_VER (MmioRead32 (UartBase + UARTPID2)) > PL011_VER_R1P4)
*ReceiveFifoDepth = 32;
@@ -61,7 +87,7 @@ PL011UartInitializePort ( *ReceiveFifoDepth = 16;
} else {
ASSERT (*ReceiveFifoDepth < 32);
- // Nothing else to do. 1 byte fifo is default.
+ // Nothing else to do. 1 byte FIFO is default.
*ReceiveFifoDepth = 1;
}
@@ -81,7 +107,9 @@ PL011UartInitializePort ( LineControl |= PL011_UARTLCR_H_PEN;
break;
case MarkParity:
- LineControl |= (PL011_UARTLCR_H_PEN | PL011_UARTLCR_H_SPS | PL011_UARTLCR_H_EPS);
+ LineControl |= ( PL011_UARTLCR_H_PEN \
+ | PL011_UARTLCR_H_SPS \
+ | PL011_UARTLCR_H_EPS);
break;
case SpaceParity:
LineControl |= (PL011_UARTLCR_H_PEN | PL011_UARTLCR_H_SPS);
@@ -125,7 +153,7 @@ PL011UartInitializePort ( LineControl |= PL011_UARTLCR_H_STP2;
break;
case OneFiveStopBits:
- // Only 1 or 2 stops bits are supported
+ // Only 1 or 2 stop bits are supported
default:
return RETURN_INVALID_PARAMETER;
}
@@ -139,7 +167,7 @@ PL011UartInitializePort ( // Baud Rate
//
- // If PL011 Integral value has been defined then always ignore the BAUD rate
+ // If PL011 Integer value has been defined then always ignore the BAUD rate
if (PcdGet32 (PL011UartInteger) != 0) {
MmioWrite32 (UartBase + UARTIBRD, PcdGet32 (PL011UartInteger));
MmioWrite32 (UartBase + UARTFBRD, PcdGet32 (PL011UartFractional));
@@ -151,8 +179,8 @@ PL011UartInitializePort ( }
Divisor = (PcdGet32 (PL011UartClkInHz) * 4) / *BaudRate;
- MmioWrite32 (UartBase + UARTIBRD, Divisor >> 6);
- MmioWrite32 (UartBase + UARTFBRD, Divisor & 0x3F);
+ MmioWrite32 (UartBase + UARTIBRD, Divisor >> FRACTION_PART_SIZE_IN_BITS);
+ MmioWrite32 (UartBase + UARTFBRD, Divisor & FRACTION_PART_MASK);
}
// No parity, 1 stop, no fifo, 8 data bits
@@ -161,8 +189,9 @@ PL011UartInitializePort ( // Clear any pending errors
MmioWrite32 (UartBase + UARTECR, 0);
- // Enable tx, rx, and uart overall
- MmioWrite32 (UartBase + UARTCR, PL011_UARTCR_RXE | PL011_UARTCR_TXE | PL011_UARTCR_UARTEN);
+ // Enable Tx, Rx, and UART overall
+ MmioWrite32 (UartBase + UARTCR,
+ PL011_UARTCR_RXE | PL011_UARTCR_TXE | PL011_UARTCR_UARTEN);
return RETURN_SUCCESS;
}
@@ -190,8 +219,8 @@ PL011UartInitializePort ( disable the hardware flow control based on CTS (Clear
To Send) and RTS (Ready To Send) control signals.
- @retval RETURN_SUCCESS The new control bits were set on the serial device.
- @retval RETURN_UNSUPPORTED The serial device does not support this operation.
+ @retval RETURN_SUCCESS The new control bits were set on the device.
+ @retval RETURN_UNSUPPORTED The device does not support this operation.
**/
RETURN_STATUS
@@ -245,24 +274,28 @@ PL011UartSetControl ( @param[in] UartBase UART registers base address
@param[out] Control Status of the control bits on a serial device :
- . EFI_SERIAL_DATA_CLEAR_TO_SEND, EFI_SERIAL_DATA_SET_READY,
- EFI_SERIAL_RING_INDICATE, EFI_SERIAL_CARRIER_DETECT,
- EFI_SERIAL_REQUEST_TO_SEND, EFI_SERIAL_DATA_TERMINAL_READY
- are all related to the DTE (Data Terminal Equipment) and
- DCE (Data Communication Equipment) modes of operation of
- the serial device.
- . EFI_SERIAL_INPUT_BUFFER_EMPTY : equal to one if the receive
- buffer is empty, 0 otherwise.
- . EFI_SERIAL_OUTPUT_BUFFER_EMPTY : equal to one if the transmit
- buffer is empty, 0 otherwise.
- . EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE : equal to one if the
- hardware loopback is enabled (the ouput feeds the receive
- buffer), 0 otherwise.
- . EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE : equal to one if a
- loopback is accomplished by software, 0 otherwise.
- . EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE : equal to one if the
- hardware flow control based on CTS (Clear To Send) and RTS
- (Ready To Send) control signals is enabled, 0 otherwise.
+ . EFI_SERIAL_DATA_CLEAR_TO_SEND,
+ EFI_SERIAL_DATA_SET_READY,
+ EFI_SERIAL_RING_INDICATE,
+ EFI_SERIAL_CARRIER_DETECT,
+ EFI_SERIAL_REQUEST_TO_SEND,
+ EFI_SERIAL_DATA_TERMINAL_READY
+ are all related to the DTE (Data Terminal Equipment)
+ and DCE (Data Communication Equipment) modes of
+ operation of the serial device.
+ . EFI_SERIAL_INPUT_BUFFER_EMPTY : equal to one if the
+ receive buffer is empty, 0 otherwise.
+ . EFI_SERIAL_OUTPUT_BUFFER_EMPTY : equal to one if the
+ transmit buffer is empty, 0 otherwise.
+ . EFI_SERIAL_HARDWARE_LOOPBACK_ENABLE : equal to one if
+ the hardware loopback is enabled (the ouput feeds the
+ receive buffer), 0 otherwise.
+ . EFI_SERIAL_SOFTWARE_LOOPBACK_ENABLE : equal to one if
+ a loopback is accomplished by software, 0 otherwise.
+ . EFI_SERIAL_HARDWARE_FLOW_CONTROL_ENABLE : equal to
+ one if the hardware flow control based on CTS (Clear
+ To Send) and RTS (Ready To Send) control signals is
+ enabled, 0 otherwise.
@retval RETURN_SUCCESS The control bits were read from the serial device.
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