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3a56482590
Bit 7 of UCR3 is described in the i.MX3x/i.MX5x/i.MX6x
reference manuals as follows:
Autobaud Detection Not Improved-. Disables new features of
autobaud detection (See Baud Rate Automatic Detection
Protocol, for more details).
0 Autobaud detection new features selected
1 Keep old autobaud detection mechanism
On at least i.MX6DQ, i.MX6DLS and i.MX53, the "new features"
occasionally cause the receiver to get out of sync and
continuously produce received characters of '\xff'.
This patch disables the "new feature" on all boards, since
there's no support for auto-baud in U-Boot on any of them.
More details are available in this post on i.MX Community:
https://community.freescale.com/message/403254
Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Stefano Babic <sbabic@denx.de>
225 lines
8.1 KiB
C
225 lines
8.1 KiB
C
/*
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* (c) 2007 Sascha Hauer <s.hauer@pengutronix.de>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <watchdog.h>
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#include <asm/arch/imx-regs.h>
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#include <asm/arch/clock.h>
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#include <serial.h>
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#include <linux/compiler.h>
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#define __REG(x) (*((volatile u32 *)(x)))
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#ifndef CONFIG_MXC_UART_BASE
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#error "define CONFIG_MXC_UART_BASE to use the MXC UART driver"
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#endif
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#define UART_PHYS CONFIG_MXC_UART_BASE
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/* Register definitions */
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#define URXD 0x0 /* Receiver Register */
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#define UTXD 0x40 /* Transmitter Register */
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#define UCR1 0x80 /* Control Register 1 */
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#define UCR2 0x84 /* Control Register 2 */
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#define UCR3 0x88 /* Control Register 3 */
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#define UCR4 0x8c /* Control Register 4 */
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#define UFCR 0x90 /* FIFO Control Register */
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#define USR1 0x94 /* Status Register 1 */
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#define USR2 0x98 /* Status Register 2 */
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#define UESC 0x9c /* Escape Character Register */
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#define UTIM 0xa0 /* Escape Timer Register */
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#define UBIR 0xa4 /* BRM Incremental Register */
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#define UBMR 0xa8 /* BRM Modulator Register */
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#define UBRC 0xac /* Baud Rate Count Register */
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#define UTS 0xb4 /* UART Test Register (mx31) */
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/* UART Control Register Bit Fields.*/
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#define URXD_CHARRDY (1<<15)
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#define URXD_ERR (1<<14)
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#define URXD_OVRRUN (1<<13)
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#define URXD_FRMERR (1<<12)
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#define URXD_BRK (1<<11)
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#define URXD_PRERR (1<<10)
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#define URXD_RX_DATA (0xFF)
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#define UCR1_ADEN (1<<15) /* Auto dectect interrupt */
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#define UCR1_ADBR (1<<14) /* Auto detect baud rate */
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#define UCR1_TRDYEN (1<<13) /* Transmitter ready interrupt enable */
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#define UCR1_IDEN (1<<12) /* Idle condition interrupt */
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#define UCR1_RRDYEN (1<<9) /* Recv ready interrupt enable */
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#define UCR1_RDMAEN (1<<8) /* Recv ready DMA enable */
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#define UCR1_IREN (1<<7) /* Infrared interface enable */
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#define UCR1_TXMPTYEN (1<<6) /* Transimitter empty interrupt enable */
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#define UCR1_RTSDEN (1<<5) /* RTS delta interrupt enable */
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#define UCR1_SNDBRK (1<<4) /* Send break */
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#define UCR1_TDMAEN (1<<3) /* Transmitter ready DMA enable */
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#define UCR1_UARTCLKEN (1<<2) /* UART clock enabled */
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#define UCR1_DOZE (1<<1) /* Doze */
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#define UCR1_UARTEN (1<<0) /* UART enabled */
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#define UCR2_ESCI (1<<15) /* Escape seq interrupt enable */
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#define UCR2_IRTS (1<<14) /* Ignore RTS pin */
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#define UCR2_CTSC (1<<13) /* CTS pin control */
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#define UCR2_CTS (1<<12) /* Clear to send */
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#define UCR2_ESCEN (1<<11) /* Escape enable */
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#define UCR2_PREN (1<<8) /* Parity enable */
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#define UCR2_PROE (1<<7) /* Parity odd/even */
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#define UCR2_STPB (1<<6) /* Stop */
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#define UCR2_WS (1<<5) /* Word size */
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#define UCR2_RTSEN (1<<4) /* Request to send interrupt enable */
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#define UCR2_TXEN (1<<2) /* Transmitter enabled */
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#define UCR2_RXEN (1<<1) /* Receiver enabled */
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#define UCR2_SRST (1<<0) /* SW reset */
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#define UCR3_DTREN (1<<13) /* DTR interrupt enable */
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#define UCR3_PARERREN (1<<12) /* Parity enable */
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#define UCR3_FRAERREN (1<<11) /* Frame error interrupt enable */
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#define UCR3_DSR (1<<10) /* Data set ready */
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#define UCR3_DCD (1<<9) /* Data carrier detect */
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#define UCR3_RI (1<<8) /* Ring indicator */
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#define UCR3_ADNIMP (1<<7) /* Autobaud Detection Not Improved */
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#define UCR3_RXDSEN (1<<6) /* Receive status interrupt enable */
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#define UCR3_AIRINTEN (1<<5) /* Async IR wake interrupt enable */
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#define UCR3_AWAKEN (1<<4) /* Async wake interrupt enable */
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#define UCR3_REF25 (1<<3) /* Ref freq 25 MHz */
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#define UCR3_REF30 (1<<2) /* Ref Freq 30 MHz */
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#define UCR3_INVT (1<<1) /* Inverted Infrared transmission */
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#define UCR3_BPEN (1<<0) /* Preset registers enable */
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#define UCR4_CTSTL_32 (32<<10) /* CTS trigger level (32 chars) */
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#define UCR4_INVR (1<<9) /* Inverted infrared reception */
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#define UCR4_ENIRI (1<<8) /* Serial infrared interrupt enable */
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#define UCR4_WKEN (1<<7) /* Wake interrupt enable */
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#define UCR4_REF16 (1<<6) /* Ref freq 16 MHz */
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#define UCR4_IRSC (1<<5) /* IR special case */
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#define UCR4_TCEN (1<<3) /* Transmit complete interrupt enable */
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#define UCR4_BKEN (1<<2) /* Break condition interrupt enable */
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#define UCR4_OREN (1<<1) /* Receiver overrun interrupt enable */
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#define UCR4_DREN (1<<0) /* Recv data ready interrupt enable */
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#define UFCR_RXTL_SHF 0 /* Receiver trigger level shift */
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#define UFCR_RFDIV (7<<7) /* Reference freq divider mask */
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#define UFCR_TXTL_SHF 10 /* Transmitter trigger level shift */
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#define USR1_PARITYERR (1<<15) /* Parity error interrupt flag */
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#define USR1_RTSS (1<<14) /* RTS pin status */
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#define USR1_TRDY (1<<13) /* Transmitter ready interrupt/dma flag */
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#define USR1_RTSD (1<<12) /* RTS delta */
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#define USR1_ESCF (1<<11) /* Escape seq interrupt flag */
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#define USR1_FRAMERR (1<<10) /* Frame error interrupt flag */
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#define USR1_RRDY (1<<9) /* Receiver ready interrupt/dma flag */
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#define USR1_TIMEOUT (1<<7) /* Receive timeout interrupt status */
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#define USR1_RXDS (1<<6) /* Receiver idle interrupt flag */
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#define USR1_AIRINT (1<<5) /* Async IR wake interrupt flag */
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#define USR1_AWAKE (1<<4) /* Aysnc wake interrupt flag */
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#define USR2_ADET (1<<15) /* Auto baud rate detect complete */
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#define USR2_TXFE (1<<14) /* Transmit buffer FIFO empty */
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#define USR2_DTRF (1<<13) /* DTR edge interrupt flag */
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#define USR2_IDLE (1<<12) /* Idle condition */
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#define USR2_IRINT (1<<8) /* Serial infrared interrupt flag */
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#define USR2_WAKE (1<<7) /* Wake */
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#define USR2_RTSF (1<<4) /* RTS edge interrupt flag */
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#define USR2_TXDC (1<<3) /* Transmitter complete */
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#define USR2_BRCD (1<<2) /* Break condition */
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#define USR2_ORE (1<<1) /* Overrun error */
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#define USR2_RDR (1<<0) /* Recv data ready */
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#define UTS_FRCPERR (1<<13) /* Force parity error */
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#define UTS_LOOP (1<<12) /* Loop tx and rx */
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#define UTS_TXEMPTY (1<<6) /* TxFIFO empty */
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#define UTS_RXEMPTY (1<<5) /* RxFIFO empty */
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#define UTS_TXFULL (1<<4) /* TxFIFO full */
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#define UTS_RXFULL (1<<3) /* RxFIFO full */
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#define UTS_SOFTRST (1<<0) /* Software reset */
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DECLARE_GLOBAL_DATA_PTR;
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static void mxc_serial_setbrg(void)
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{
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u32 clk = imx_get_uartclk();
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if (!gd->baudrate)
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gd->baudrate = CONFIG_BAUDRATE;
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__REG(UART_PHYS + UFCR) = 4 << 7; /* divide input clock by 2 */
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__REG(UART_PHYS + UBIR) = 0xf;
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__REG(UART_PHYS + UBMR) = clk / (2 * gd->baudrate);
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}
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static int mxc_serial_getc(void)
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{
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while (__REG(UART_PHYS + UTS) & UTS_RXEMPTY)
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WATCHDOG_RESET();
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return (__REG(UART_PHYS + URXD) & URXD_RX_DATA); /* mask out status from upper word */
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}
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static void mxc_serial_putc(const char c)
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{
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__REG(UART_PHYS + UTXD) = c;
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/* wait for transmitter to be ready */
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while (!(__REG(UART_PHYS + UTS) & UTS_TXEMPTY))
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WATCHDOG_RESET();
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/* If \n, also do \r */
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if (c == '\n')
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serial_putc ('\r');
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}
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/*
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* Test whether a character is in the RX buffer
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*/
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static int mxc_serial_tstc(void)
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{
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/* If receive fifo is empty, return false */
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if (__REG(UART_PHYS + UTS) & UTS_RXEMPTY)
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return 0;
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return 1;
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}
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/*
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* Initialise the serial port with the given baudrate. The settings
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* are always 8 data bits, no parity, 1 stop bit, no start bits.
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*
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*/
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static int mxc_serial_init(void)
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{
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__REG(UART_PHYS + UCR1) = 0x0;
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__REG(UART_PHYS + UCR2) = 0x0;
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while (!(__REG(UART_PHYS + UCR2) & UCR2_SRST));
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__REG(UART_PHYS + UCR3) = 0x0704 | UCR3_ADNIMP;
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__REG(UART_PHYS + UCR4) = 0x8000;
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__REG(UART_PHYS + UESC) = 0x002b;
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__REG(UART_PHYS + UTIM) = 0x0;
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__REG(UART_PHYS + UTS) = 0x0;
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serial_setbrg();
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__REG(UART_PHYS + UCR2) = UCR2_WS | UCR2_IRTS | UCR2_RXEN | UCR2_TXEN | UCR2_SRST;
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__REG(UART_PHYS + UCR1) = UCR1_UARTEN;
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return 0;
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}
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static struct serial_device mxc_serial_drv = {
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.name = "mxc_serial",
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.start = mxc_serial_init,
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.stop = NULL,
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.setbrg = mxc_serial_setbrg,
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.putc = mxc_serial_putc,
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.puts = default_serial_puts,
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.getc = mxc_serial_getc,
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.tstc = mxc_serial_tstc,
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};
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void mxc_serial_initialize(void)
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{
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serial_register(&mxc_serial_drv);
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}
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__weak struct serial_device *default_serial_console(void)
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{
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return &mxc_serial_drv;
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}
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