drivers/serial/serial_mxc.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * (c) 2007 Sascha Hauer <s.hauer@pengutronix.de>
  */

 #include <common.h>
 #include <dm.h>
 #include <errno.h>
 #include <watchdog.h>
 #include <asm/arch/imx-regs.h>
 #include <asm/arch/clock.h>
 #include <asm/global_data.h>
 #include <dm/platform_data/serial_mxc.h>
 #include <serial.h>
 #include <linux/compiler.h>

 /* UART Control Register Bit Fields.*/
 #define URXD_CHARRDY	(1<<15)
 #define URXD_ERR	(1<<14)
 #define URXD_OVRRUN	(1<<13)
 #define URXD_FRMERR	(1<<12)
 #define URXD_BRK	(1<<11)
 #define URXD_PRERR	(1<<10)
 #define URXD_RX_DATA	(0xFF)
 #define UCR1_ADEN	(1<<15) /* Auto dectect interrupt */
 #define UCR1_ADBR	(1<<14) /* Auto detect baud rate */
 #define UCR1_TRDYEN	(1<<13) /* Transmitter ready interrupt enable */
 #define UCR1_IDEN	(1<<12) /* Idle condition interrupt */
 #define UCR1_RRDYEN	(1<<9)	/* Recv ready interrupt enable */
 #define UCR1_RDMAEN	(1<<8)	/* Recv ready DMA enable */
 #define UCR1_IREN	(1<<7)	/* Infrared interface enable */
 #define UCR1_TXMPTYEN	(1<<6)	/* Transimitter empty interrupt enable */
 #define UCR1_RTSDEN	(1<<5)	/* RTS delta interrupt enable */
 #define UCR1_SNDBRK	(1<<4)	/* Send break */
 #define UCR1_TDMAEN	(1<<3)	/* Transmitter ready DMA enable */
 #define UCR1_UARTCLKEN	(1<<2)	/* UART clock enabled */
 #define UCR1_DOZE	(1<<1)	/* Doze */
 #define UCR1_UARTEN	(1<<0)	/* UART enabled */
 #define UCR2_ESCI	(1<<15) /* Escape seq interrupt enable */
 #define UCR2_IRTS	(1<<14) /* Ignore RTS pin */
 #define UCR2_CTSC	(1<<13) /* CTS pin control */
 #define UCR2_CTS	(1<<12) /* Clear to send */
 #define UCR2_ESCEN	(1<<11) /* Escape enable */
 #define UCR2_PREN	(1<<8)  /* Parity enable */
 #define UCR2_PROE	(1<<7)  /* Parity odd/even */
 #define UCR2_STPB	(1<<6)	/* Stop */
 #define UCR2_WS		(1<<5)	/* Word size */
 #define UCR2_RTSEN	(1<<4)	/* Request to send interrupt enable */
 #define UCR2_TXEN	(1<<2)	/* Transmitter enabled */
 #define UCR2_RXEN	(1<<1)	/* Receiver enabled */
 #define UCR2_SRST	(1<<0)	/* SW reset */
 #define UCR3_DTREN	(1<<13) /* DTR interrupt enable */
 #define UCR3_PARERREN	(1<<12) /* Parity enable */
 #define UCR3_FRAERREN	(1<<11) /* Frame error interrupt enable */
 #define UCR3_DSR	(1<<10) /* Data set ready */
 #define UCR3_DCD	(1<<9)  /* Data carrier detect */
 #define UCR3_RI		(1<<8)  /* Ring indicator */
 #define UCR3_ADNIMP	(1<<7)  /* Autobaud Detection Not Improved */
 #define UCR3_RXDSEN	(1<<6)  /* Receive status interrupt enable */
 #define UCR3_AIRINTEN	(1<<5)  /* Async IR wake interrupt enable */
 #define UCR3_AWAKEN	(1<<4)  /* Async wake interrupt enable */
 #define UCR3_REF25	(1<<3)  /* Ref freq 25 MHz */
 #define UCR3_REF30	(1<<2)  /* Ref Freq 30 MHz */

 /* imx8 names these bitsfields instead: */
 #define UCR3_DTRDEN	BIT(3)  /* bit not used in this chip */
 #define UCR3_RXDMUXSEL	BIT(2)  /* RXD muxed input selected; 'should always be set' */

 #define UCR3_INVT	(1<<1)  /* Inverted Infrared transmission */
 #define UCR3_BPEN	(1<<0)  /* Preset registers enable */
 #define UCR4_CTSTL_32	(32<<10) /* CTS trigger level (32 chars) */
 #define UCR4_INVR	(1<<9)  /* Inverted infrared reception */
 #define UCR4_ENIRI	(1<<8)  /* Serial infrared interrupt enable */
 #define UCR4_WKEN	(1<<7)  /* Wake interrupt enable */
 #define UCR4_REF16	(1<<6)  /* Ref freq 16 MHz */
 #define UCR4_IRSC	(1<<5)  /* IR special case */
 #define UCR4_TCEN	(1<<3)  /* Transmit complete interrupt enable */
 #define UCR4_BKEN	(1<<2)  /* Break condition interrupt enable */
 #define UCR4_OREN	(1<<1)  /* Receiver overrun interrupt enable */
 #define UCR4_DREN	(1<<0)  /* Recv data ready interrupt enable */
 #define UFCR_RXTL_SHF	0       /* Receiver trigger level shift */
 #define UFCR_RFDIV	(7<<7)  /* Reference freq divider mask */
 #define UFCR_RFDIV_SHF	7	/* Reference freq divider shift */
 #define RFDIV		4	/* divide input clock by 2 */
 #define UFCR_DCEDTE	(1<<6)  /* DTE mode select */
 #define UFCR_TXTL_SHF	10      /* Transmitter trigger level shift */
 #define USR1_PARITYERR	(1<<15) /* Parity error interrupt flag */
 #define USR1_RTSS	(1<<14) /* RTS pin status */
 #define USR1_TRDY	(1<<13) /* Transmitter ready interrupt/dma flag */
 #define USR1_RTSD	(1<<12) /* RTS delta */
 #define USR1_ESCF	(1<<11) /* Escape seq interrupt flag */
 #define USR1_FRAMERR	(1<<10) /* Frame error interrupt flag */
 #define USR1_RRDY	(1<<9)	/* Receiver ready interrupt/dma flag */
 #define USR1_TIMEOUT	(1<<7)	/* Receive timeout interrupt status */
 #define USR1_RXDS	(1<<6)	/* Receiver idle interrupt flag */
 #define USR1_AIRINT	(1<<5)	/* Async IR wake interrupt flag */
 #define USR1_AWAKE	(1<<4)	/* Aysnc wake interrupt flag */
 #define USR2_ADET	(1<<15) /* Auto baud rate detect complete */
 #define USR2_TXFE	(1<<14) /* Transmit buffer FIFO empty */
 #define USR2_DTRF	(1<<13) /* DTR edge interrupt flag */
 #define USR2_IDLE	(1<<12) /* Idle condition */
 #define USR2_IRINT	(1<<8)	/* Serial infrared interrupt flag */
 #define USR2_WAKE	(1<<7)	/* Wake */
 #define USR2_RTSF	(1<<4)	/* RTS edge interrupt flag */
 #define USR2_TXDC	(1<<3)	/* Transmitter complete */
 #define USR2_BRCD	(1<<2)	/* Break condition */
 #define USR2_ORE	(1<<1)	/* Overrun error */
 #define USR2_RDR	(1<<0)	/* Recv data ready */
 #define UTS_FRCPERR	(1<<13) /* Force parity error */
 #define UTS_LOOP	(1<<12) /* Loop tx and rx */
 #define UTS_TXEMPTY	(1<<6)	/* TxFIFO empty */
 #define UTS_RXEMPTY	(1<<5)	/* RxFIFO empty */
 #define UTS_TXFULL	(1<<4)	/* TxFIFO full */
 #define UTS_RXFULL	(1<<3)	/* RxFIFO full */
 #define UTS_SOFTRS	(1<<0)	/* Software reset */
 #define TXTL		2  /* reset default */
 #define RXTL		1  /* reset default */

 DECLARE_GLOBAL_DATA_PTR;

 struct mxc_uart {
 	u32 rxd;
 	u32 spare0[15];

 	u32 txd;
 	u32 spare1[15];

 	u32 cr1;
 	u32 cr2;
 	u32 cr3;
 	u32 cr4;

 	u32 fcr;
 	u32 sr1;
 	u32 sr2;
 	u32 esc;

 	u32 tim;
 	u32 bir;
 	u32 bmr;
 	u32 brc;

 	u32 onems;
 	u32 ts;
 };

 static void _mxc_serial_init(struct mxc_uart *base, int use_dte)
 {
 	writel(0, &base->cr1);
 	writel(0, &base->cr2);

 	while (!(readl(&base->cr2) & UCR2_SRST));

 	if (use_dte)
 		writel(0x404 | UCR3_ADNIMP, &base->cr3);
 	else
 		writel(0x704 | UCR3_ADNIMP, &base->cr3);

 	writel(0x704 | UCR3_ADNIMP, &base->cr3);
 	writel(0x8000, &base->cr4);
 	writel(0x2b, &base->esc);
 	writel(0, &base->tim);

 	writel(0, &base->ts);
 }

 static void _mxc_serial_setbrg(struct mxc_uart *base, unsigned long clk,
 			       unsigned long baudrate, bool use_dte)
 {
 	u32 tmp;

 	tmp = RFDIV << UFCR_RFDIV_SHF;
 	if (use_dte)
 		tmp |= UFCR_DCEDTE;
 	else
 		tmp |= (TXTL << UFCR_TXTL_SHF) | (RXTL << UFCR_RXTL_SHF);
 	writel(tmp, &base->fcr);

 	writel(0xf, &base->bir);
 	writel(clk / (2 * baudrate), &base->bmr);

 	writel(UCR2_WS | UCR2_IRTS | UCR2_RXEN | UCR2_TXEN | UCR2_SRST,
 	       &base->cr2);

 	/*
 	 * setting the baudrate triggers a reset, returning cr3 to its
 	 * reset value but UCR3_RXDMUXSEL "should always be set."
 	 * according to the imx8 reference-manual
 	 */
 	writel(readl(&base->cr3) | UCR3_RXDMUXSEL, &base->cr3);

 	writel(UCR1_UARTEN, &base->cr1);
 }

 #if !CONFIG_IS_ENABLED(DM_SERIAL)

 #ifndef CONFIG_MXC_UART_BASE
 #error "define CONFIG_MXC_UART_BASE to use the MXC UART driver"
 #endif

 #define mxc_base	((struct mxc_uart *)CONFIG_MXC_UART_BASE)

 static void mxc_serial_setbrg(void)
 {
 	u32 clk = imx_get_uartclk();

 	if (!gd->baudrate)
 		gd->baudrate = CONFIG_BAUDRATE;

 	_mxc_serial_setbrg(mxc_base, clk, gd->baudrate, false);
 }

 static int mxc_serial_getc(void)
 {
 	while (readl(&mxc_base->ts) & UTS_RXEMPTY)
 		schedule();
 	return (readl(&mxc_base->rxd) & URXD_RX_DATA); /* mask out status from upper word */
 }

 static void mxc_serial_putc(const char c)
 {
 	/* If \n, also do \r */
 	if (c == '\n')
 		serial_putc('\r');

 	writel(c, &mxc_base->txd);

 	/* wait for transmitter to be ready */
 	while (!(readl(&mxc_base->ts) & UTS_TXEMPTY))
 		schedule();
 }

 /* Test whether a character is in the RX buffer */
 static int mxc_serial_tstc(void)
 {
 	/* If receive fifo is empty, return false */
 	if (readl(&mxc_base->ts) & UTS_RXEMPTY)
 		return 0;
 	return 1;
 }

 /*
  * Initialise the serial port with the given baudrate. The settings
  * are always 8 data bits, no parity, 1 stop bit, no start bits.
  */
 static int mxc_serial_init(void)
 {
 	_mxc_serial_init(mxc_base, false);

 	serial_setbrg();

 	return 0;
 }

 static struct serial_device mxc_serial_drv = {
 	.name	= "mxc_serial",
 	.start	= mxc_serial_init,
 	.stop	= NULL,
 	.setbrg	= mxc_serial_setbrg,
 	.putc	= mxc_serial_putc,
 	.puts	= default_serial_puts,
 	.getc	= mxc_serial_getc,
 	.tstc	= mxc_serial_tstc,
 };

 void mxc_serial_initialize(void)
 {
 	serial_register(&mxc_serial_drv);
 }

 __weak struct serial_device *default_serial_console(void)
 {
 	return &mxc_serial_drv;
 }
 #endif

 #if CONFIG_IS_ENABLED(DM_SERIAL)

 int mxc_serial_setbrg(struct udevice *dev, int baudrate)
 {
 	struct mxc_serial_plat *plat = dev_get_plat(dev);
 	u32 clk = imx_get_uartclk();

 	_mxc_serial_setbrg(plat->reg, clk, baudrate, plat->use_dte);

 	return 0;
 }

 static int mxc_serial_probe(struct udevice *dev)
 {
 	struct mxc_serial_plat *plat = dev_get_plat(dev);

 	_mxc_serial_init(plat->reg, plat->use_dte);

 	return 0;
 }

 static int mxc_serial_getc(struct udevice *dev)
 {
 	struct mxc_serial_plat *plat = dev_get_plat(dev);
 	struct mxc_uart *const uart = plat->reg;

 	if (readl(&uart->ts) & UTS_RXEMPTY)
 		return -EAGAIN;

 	return readl(&uart->rxd) & URXD_RX_DATA;
 }

 static int mxc_serial_putc(struct udevice *dev, const char ch)
 {
 	struct mxc_serial_plat *plat = dev_get_plat(dev);
 	struct mxc_uart *const uart = plat->reg;

 	if (readl(&uart->ts) & UTS_TXFULL)
 		return -EAGAIN;

 	writel(ch, &uart->txd);

 	return 0;
 }

 static int mxc_serial_pending(struct udevice *dev, bool input)
 {
 	struct mxc_serial_plat *plat = dev_get_plat(dev);
 	struct mxc_uart *const uart = plat->reg;
 	uint32_t sr2 = readl(&uart->sr2);

 	if (input)
 		return sr2 & USR2_RDR ? 1 : 0;
 	else
 		return sr2 & USR2_TXDC ? 0 : 1;
 }

 static const struct dm_serial_ops mxc_serial_ops = {
 	.putc = mxc_serial_putc,
 	.pending = mxc_serial_pending,
 	.getc = mxc_serial_getc,
 	.setbrg = mxc_serial_setbrg,
 };

 #if CONFIG_IS_ENABLED(OF_CONTROL)
 static int mxc_serial_of_to_plat(struct udevice *dev)
 {
 	struct mxc_serial_plat *plat = dev_get_plat(dev);
 	fdt_addr_t addr;

 	addr = dev_read_addr(dev);
 	if (addr == FDT_ADDR_T_NONE)
 		return -EINVAL;

 	plat->reg = (struct mxc_uart *)addr;

 	plat->use_dte = fdtdec_get_bool(gd->fdt_blob, dev_of_offset(dev),
 					"fsl,dte-mode");
 	return 0;
 }

 static const struct udevice_id mxc_serial_ids[] = {
 	{ .compatible = "fsl,imx21-uart" },
 	{ .compatible = "fsl,imx53-uart" },
 	{ .compatible = "fsl,imx6sx-uart" },
 	{ .compatible = "fsl,imx6ul-uart" },
 	{ .compatible = "fsl,imx7d-uart" },
 	{ .compatible = "fsl,imx6q-uart" },
 	{ }
 };
 #endif

 U_BOOT_DRIVER(serial_mxc) = {
 	.name	= "serial_mxc",
 	.id	= UCLASS_SERIAL,
 #if CONFIG_IS_ENABLED(OF_CONTROL)
 	.of_match = mxc_serial_ids,
 	.of_to_plat = mxc_serial_of_to_plat,
 	.plat_auto	= sizeof(struct mxc_serial_plat),
 #endif
 	.probe = mxc_serial_probe,
 	.ops	= &mxc_serial_ops,
 	.flags = DM_FLAG_PRE_RELOC,
 };
 #endif

 #ifdef CONFIG_DEBUG_UART_MXC
 #include <debug_uart.h>

 static inline void _debug_uart_init(void)
 {
 	struct mxc_uart *base = (struct mxc_uart *)CONFIG_VAL(DEBUG_UART_BASE);

 	_mxc_serial_init(base, false);
 	_mxc_serial_setbrg(base, CONFIG_DEBUG_UART_CLOCK,
 			   CONFIG_BAUDRATE, false);
 }

 static inline void _debug_uart_putc(int ch)
 {
 	struct mxc_uart *base = (struct mxc_uart *)CONFIG_VAL(DEBUG_UART_BASE);

 	while (!(readl(&base->ts) & UTS_TXEMPTY))
 		schedule();

 	writel(ch, &base->txd);
 }

 DEBUG_UART_FUNCS

 #endif
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* (c) 2007 Sascha Hauer <s.hauer@pengutronix.de>
	*/

	#include <common.h>
	#include <dm.h>
	#include <errno.h>
	#include <watchdog.h>
	#include <asm/arch/imx-regs.h>
	#include <asm/arch/clock.h>
	#include <asm/global_data.h>
	#include <dm/platform_data/serial_mxc.h>
	#include <serial.h>
	#include <linux/compiler.h>

	/* UART Control Register Bit Fields.*/
	#define URXD_CHARRDY (1<<15)
	#define URXD_ERR (1<<14)
	#define URXD_OVRRUN (1<<13)
	#define URXD_FRMERR (1<<12)
	#define URXD_BRK (1<<11)
	#define URXD_PRERR (1<<10)
	#define URXD_RX_DATA (0xFF)
	#define UCR1_ADEN (1<<15) /* Auto dectect interrupt */
	#define UCR1_ADBR (1<<14) /* Auto detect baud rate */
	#define UCR1_TRDYEN (1<<13) /* Transmitter ready interrupt enable */
	#define UCR1_IDEN (1<<12) /* Idle condition interrupt */
	#define UCR1_RRDYEN (1<<9) /* Recv ready interrupt enable */
	#define UCR1_RDMAEN (1<<8) /* Recv ready DMA enable */
	#define UCR1_IREN (1<<7) /* Infrared interface enable */
	#define UCR1_TXMPTYEN (1<<6) /* Transimitter empty interrupt enable */
	#define UCR1_RTSDEN (1<<5) /* RTS delta interrupt enable */
	#define UCR1_SNDBRK (1<<4) /* Send break */
	#define UCR1_TDMAEN (1<<3) /* Transmitter ready DMA enable */
	#define UCR1_UARTCLKEN (1<<2) /* UART clock enabled */
	#define UCR1_DOZE (1<<1) /* Doze */
	#define UCR1_UARTEN (1<<0) /* UART enabled */
	#define UCR2_ESCI (1<<15) /* Escape seq interrupt enable */
	#define UCR2_IRTS (1<<14) /* Ignore RTS pin */
	#define UCR2_CTSC (1<<13) /* CTS pin control */
	#define UCR2_CTS (1<<12) /* Clear to send */
	#define UCR2_ESCEN (1<<11) /* Escape enable */
	#define UCR2_PREN (1<<8) /* Parity enable */
	#define UCR2_PROE (1<<7) /* Parity odd/even */
	#define UCR2_STPB (1<<6) /* Stop */
	#define UCR2_WS (1<<5) /* Word size */
	#define UCR2_RTSEN (1<<4) /* Request to send interrupt enable */
	#define UCR2_TXEN (1<<2) /* Transmitter enabled */
	#define UCR2_RXEN (1<<1) /* Receiver enabled */
	#define UCR2_SRST (1<<0) /* SW reset */
	#define UCR3_DTREN (1<<13) /* DTR interrupt enable */
	#define UCR3_PARERREN (1<<12) /* Parity enable */
	#define UCR3_FRAERREN (1<<11) /* Frame error interrupt enable */
	#define UCR3_DSR (1<<10) /* Data set ready */
	#define UCR3_DCD (1<<9) /* Data carrier detect */
	#define UCR3_RI (1<<8) /* Ring indicator */
	#define UCR3_ADNIMP (1<<7) /* Autobaud Detection Not Improved */
	#define UCR3_RXDSEN (1<<6) /* Receive status interrupt enable */
	#define UCR3_AIRINTEN (1<<5) /* Async IR wake interrupt enable */
	#define UCR3_AWAKEN (1<<4) /* Async wake interrupt enable */
	#define UCR3_REF25 (1<<3) /* Ref freq 25 MHz */
	#define UCR3_REF30 (1<<2) /* Ref Freq 30 MHz */

	/* imx8 names these bitsfields instead: */
	#define UCR3_DTRDEN BIT(3) /* bit not used in this chip */
	#define UCR3_RXDMUXSEL BIT(2) /* RXD muxed input selected; 'should always be set' */

	#define UCR3_INVT (1<<1) /* Inverted Infrared transmission */
	#define UCR3_BPEN (1<<0) /* Preset registers enable */
	#define UCR4_CTSTL_32 (32<<10) /* CTS trigger level (32 chars) */
	#define UCR4_INVR (1<<9) /* Inverted infrared reception */
	#define UCR4_ENIRI (1<<8) /* Serial infrared interrupt enable */
	#define UCR4_WKEN (1<<7) /* Wake interrupt enable */
	#define UCR4_REF16 (1<<6) /* Ref freq 16 MHz */
	#define UCR4_IRSC (1<<5) /* IR special case */
	#define UCR4_TCEN (1<<3) /* Transmit complete interrupt enable */
	#define UCR4_BKEN (1<<2) /* Break condition interrupt enable */
	#define UCR4_OREN (1<<1) /* Receiver overrun interrupt enable */
	#define UCR4_DREN (1<<0) /* Recv data ready interrupt enable */
	#define UFCR_RXTL_SHF 0 /* Receiver trigger level shift */
	#define UFCR_RFDIV (7<<7) /* Reference freq divider mask */
	#define UFCR_RFDIV_SHF 7 /* Reference freq divider shift */
	#define RFDIV 4 /* divide input clock by 2 */
	#define UFCR_DCEDTE (1<<6) /* DTE mode select */
	#define UFCR_TXTL_SHF 10 /* Transmitter trigger level shift */
	#define USR1_PARITYERR (1<<15) /* Parity error interrupt flag */
	#define USR1_RTSS (1<<14) /* RTS pin status */
	#define USR1_TRDY (1<<13) /* Transmitter ready interrupt/dma flag */
	#define USR1_RTSD (1<<12) /* RTS delta */
	#define USR1_ESCF (1<<11) /* Escape seq interrupt flag */
	#define USR1_FRAMERR (1<<10) /* Frame error interrupt flag */
	#define USR1_RRDY (1<<9) /* Receiver ready interrupt/dma flag */
	#define USR1_TIMEOUT (1<<7) /* Receive timeout interrupt status */
	#define USR1_RXDS (1<<6) /* Receiver idle interrupt flag */
	#define USR1_AIRINT (1<<5) /* Async IR wake interrupt flag */
	#define USR1_AWAKE (1<<4) /* Aysnc wake interrupt flag */
	#define USR2_ADET (1<<15) /* Auto baud rate detect complete */
	#define USR2_TXFE (1<<14) /* Transmit buffer FIFO empty */
	#define USR2_DTRF (1<<13) /* DTR edge interrupt flag */
	#define USR2_IDLE (1<<12) /* Idle condition */
	#define USR2_IRINT (1<<8) /* Serial infrared interrupt flag */
	#define USR2_WAKE (1<<7) /* Wake */
	#define USR2_RTSF (1<<4) /* RTS edge interrupt flag */
	#define USR2_TXDC (1<<3) /* Transmitter complete */
	#define USR2_BRCD (1<<2) /* Break condition */
	#define USR2_ORE (1<<1) /* Overrun error */
	#define USR2_RDR (1<<0) /* Recv data ready */
	#define UTS_FRCPERR (1<<13) /* Force parity error */
	#define UTS_LOOP (1<<12) /* Loop tx and rx */
	#define UTS_TXEMPTY (1<<6) /* TxFIFO empty */
	#define UTS_RXEMPTY (1<<5) /* RxFIFO empty */
	#define UTS_TXFULL (1<<4) /* TxFIFO full */
	#define UTS_RXFULL (1<<3) /* RxFIFO full */
	#define UTS_SOFTRS (1<<0) /* Software reset */
	#define TXTL 2 /* reset default */
	#define RXTL 1 /* reset default */

	DECLARE_GLOBAL_DATA_PTR;

	struct mxc_uart {
	u32 rxd;
	u32 spare0[15];

	u32 txd;
	u32 spare1[15];

	u32 cr1;
	u32 cr2;
	u32 cr3;
	u32 cr4;

	u32 fcr;
	u32 sr1;
	u32 sr2;
	u32 esc;

	u32 tim;
	u32 bir;
	u32 bmr;
	u32 brc;

	u32 onems;
	u32 ts;
	};

	static void _mxc_serial_init(struct mxc_uart *base, int use_dte)
	{
	writel(0, &base->cr1);
	writel(0, &base->cr2);

	while (!(readl(&base->cr2) & UCR2_SRST));

	if (use_dte)
	writel(0x404 \| UCR3_ADNIMP, &base->cr3);
	else
	writel(0x704 \| UCR3_ADNIMP, &base->cr3);

	writel(0x704 \| UCR3_ADNIMP, &base->cr3);
	writel(0x8000, &base->cr4);
	writel(0x2b, &base->esc);
	writel(0, &base->tim);

	writel(0, &base->ts);
	}

	static void _mxc_serial_setbrg(struct mxc_uart *base, unsigned long clk,
	unsigned long baudrate, bool use_dte)
	{
	u32 tmp;

	tmp = RFDIV << UFCR_RFDIV_SHF;
	if (use_dte)
	tmp \|= UFCR_DCEDTE;
	else
	tmp \|= (TXTL << UFCR_TXTL_SHF) \| (RXTL << UFCR_RXTL_SHF);
	writel(tmp, &base->fcr);

	writel(0xf, &base->bir);
	writel(clk / (2 * baudrate), &base->bmr);

	writel(UCR2_WS \| UCR2_IRTS \| UCR2_RXEN \| UCR2_TXEN \| UCR2_SRST,
	&base->cr2);

	/*
	* setting the baudrate triggers a reset, returning cr3 to its
	* reset value but UCR3_RXDMUXSEL "should always be set."
	* according to the imx8 reference-manual
	*/
	writel(readl(&base->cr3) \| UCR3_RXDMUXSEL, &base->cr3);

	writel(UCR1_UARTEN, &base->cr1);
	}

	#if !CONFIG_IS_ENABLED(DM_SERIAL)

	#ifndef CONFIG_MXC_UART_BASE
	#error "define CONFIG_MXC_UART_BASE to use the MXC UART driver"
	#endif

	#define mxc_base ((struct mxc_uart *)CONFIG_MXC_UART_BASE)

	static void mxc_serial_setbrg(void)
	{
	u32 clk = imx_get_uartclk();

	if (!gd->baudrate)
	gd->baudrate = CONFIG_BAUDRATE;

	_mxc_serial_setbrg(mxc_base, clk, gd->baudrate, false);
	}

	static int mxc_serial_getc(void)
	{
	while (readl(&mxc_base->ts) & UTS_RXEMPTY)
	schedule();
	return (readl(&mxc_base->rxd) & URXD_RX_DATA); /* mask out status from upper word */
	}

	static void mxc_serial_putc(const char c)
	{
	/* If \n, also do \r */
	if (c == '\n')
	serial_putc('\r');

	writel(c, &mxc_base->txd);

	/* wait for transmitter to be ready */
	while (!(readl(&mxc_base->ts) & UTS_TXEMPTY))
	schedule();
	}

	/* Test whether a character is in the RX buffer */
	static int mxc_serial_tstc(void)
	{
	/* If receive fifo is empty, return false */
	if (readl(&mxc_base->ts) & UTS_RXEMPTY)
	return 0;
	return 1;
	}

	/*
	* Initialise the serial port with the given baudrate. The settings
	* are always 8 data bits, no parity, 1 stop bit, no start bits.
	*/
	static int mxc_serial_init(void)
	{
	_mxc_serial_init(mxc_base, false);

	serial_setbrg();

	return 0;
	}

	static struct serial_device mxc_serial_drv = {
	.name = "mxc_serial",
	.start = mxc_serial_init,
	.stop = NULL,
	.setbrg = mxc_serial_setbrg,
	.putc = mxc_serial_putc,
	.puts = default_serial_puts,
	.getc = mxc_serial_getc,
	.tstc = mxc_serial_tstc,
	};

	void mxc_serial_initialize(void)
	{
	serial_register(&mxc_serial_drv);
	}

	__weak struct serial_device *default_serial_console(void)
	{
	return &mxc_serial_drv;
	}
	#endif

	#if CONFIG_IS_ENABLED(DM_SERIAL)

	int mxc_serial_setbrg(struct udevice *dev, int baudrate)
	{
	struct mxc_serial_plat *plat = dev_get_plat(dev);
	u32 clk = imx_get_uartclk();

	_mxc_serial_setbrg(plat->reg, clk, baudrate, plat->use_dte);

	return 0;
	}

	static int mxc_serial_probe(struct udevice *dev)
	{
	struct mxc_serial_plat *plat = dev_get_plat(dev);

	_mxc_serial_init(plat->reg, plat->use_dte);

	return 0;
	}

	static int mxc_serial_getc(struct udevice *dev)
	{
	struct mxc_serial_plat *plat = dev_get_plat(dev);
	struct mxc_uart *const uart = plat->reg;

	if (readl(&uart->ts) & UTS_RXEMPTY)
	return -EAGAIN;

	return readl(&uart->rxd) & URXD_RX_DATA;
	}

	static int mxc_serial_putc(struct udevice *dev, const char ch)
	{
	struct mxc_serial_plat *plat = dev_get_plat(dev);
	struct mxc_uart *const uart = plat->reg;

	if (readl(&uart->ts) & UTS_TXFULL)
	return -EAGAIN;

	writel(ch, &uart->txd);

	return 0;
	}

	static int mxc_serial_pending(struct udevice *dev, bool input)
	{
	struct mxc_serial_plat *plat = dev_get_plat(dev);
	struct mxc_uart *const uart = plat->reg;
	uint32_t sr2 = readl(&uart->sr2);

	if (input)
	return sr2 & USR2_RDR ? 1 : 0;
	else
	return sr2 & USR2_TXDC ? 0 : 1;
	}

	static const struct dm_serial_ops mxc_serial_ops = {
	.putc = mxc_serial_putc,
	.pending = mxc_serial_pending,
	.getc = mxc_serial_getc,
	.setbrg = mxc_serial_setbrg,
	};

	#if CONFIG_IS_ENABLED(OF_CONTROL)
	static int mxc_serial_of_to_plat(struct udevice *dev)
	{
	struct mxc_serial_plat *plat = dev_get_plat(dev);
	fdt_addr_t addr;

	addr = dev_read_addr(dev);
	if (addr == FDT_ADDR_T_NONE)
	return -EINVAL;

	plat->reg = (struct mxc_uart *)addr;

	plat->use_dte = fdtdec_get_bool(gd->fdt_blob, dev_of_offset(dev),
	"fsl,dte-mode");
	return 0;
	}

	static const struct udevice_id mxc_serial_ids[] = {
	{ .compatible = "fsl,imx21-uart" },
	{ .compatible = "fsl,imx53-uart" },
	{ .compatible = "fsl,imx6sx-uart" },
	{ .compatible = "fsl,imx6ul-uart" },
	{ .compatible = "fsl,imx7d-uart" },
	{ .compatible = "fsl,imx6q-uart" },
	{ }
	};
	#endif

	U_BOOT_DRIVER(serial_mxc) = {
	.name = "serial_mxc",
	.id = UCLASS_SERIAL,
	#if CONFIG_IS_ENABLED(OF_CONTROL)
	.of_match = mxc_serial_ids,
	.of_to_plat = mxc_serial_of_to_plat,
	.plat_auto = sizeof(struct mxc_serial_plat),
	#endif
	.probe = mxc_serial_probe,
	.ops = &mxc_serial_ops,
	.flags = DM_FLAG_PRE_RELOC,
	};
	#endif

	#ifdef CONFIG_DEBUG_UART_MXC
	#include <debug_uart.h>

	static inline void _debug_uart_init(void)
	{
	struct mxc_uart base = (struct mxc_uart )CONFIG_VAL(DEBUG_UART_BASE);

	_mxc_serial_init(base, false);
	_mxc_serial_setbrg(base, CONFIG_DEBUG_UART_CLOCK,
	CONFIG_BAUDRATE, false);
	}

	static inline void _debug_uart_putc(int ch)
	{
	struct mxc_uart base = (struct mxc_uart )CONFIG_VAL(DEBUG_UART_BASE);

	while (!(readl(&base->ts) & UTS_TXEMPTY))
	schedule();

	writel(ch, &base->txd);
	}

	DEBUG_UART_FUNCS

	#endif