core/drivers/imx_uart.c

// SPDX-License-Identifier: BSD-2-Clause
/*
 * Copyright (C) 2015 Freescale Semiconductor, Inc.
 * All rights reserved.
 * Copyright 2018-2019 NXP.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <assert.h>
#include <drivers/imx_uart.h>
#include <io.h>
#include <keep.h>
#include <kernel/dt.h>
#include <util.h>

/* Register definitions */
#define URXD  0x0  /* Receiver Register */
#define UTXD  0x40 /* Transmitter Register */
#define UCR1  0x80 /* Control Register 1 */
#define UCR2  0x84 /* Control Register 2 */
#define UCR3  0x88 /* Control Register 3 */
#define UCR4  0x8c /* Control Register 4 */
#define UFCR  0x90 /* FIFO Control Register */
#define USR1  0x94 /* Status Register 1 */
#define USR2  0x98 /* Status Register 2 */
#define UESC  0x9c /* Escape Character Register */
#define UTIM  0xa0 /* Escape Timer Register */
#define UBIR  0xa4 /* BRM Incremental Register */
#define UBMR  0xa8 /* BRM Modulator Register */
#define UBRC  0xac /* Baud Rate Count Register */
#define UTS   0xb4 /* UART Test Register (mx31) */

/* 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  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_SOFTRST	 (1<<0)	 /* Software reset */

static vaddr_t chip_to_base(struct serial_chip *chip)
{
	struct imx_uart_data *pd =
		container_of(chip, struct imx_uart_data, chip);

	return io_pa_or_va(&pd->base);
}

static void imx_uart_flush(struct serial_chip *chip)
{
	vaddr_t base = chip_to_base(chip);


	while (!(io_read32(base + UTS) & UTS_TXEMPTY))
		if (!(io_read32(base + UCR1) & UCR1_UARTEN))
			return;
}

static int imx_uart_getchar(struct serial_chip *chip)
{
	vaddr_t base = chip_to_base(chip);

	while (io_read32(base + UTS) & UTS_RXEMPTY)
		;

	return (io_read32(base + URXD) & URXD_RX_DATA);
}

static void imx_uart_putc(struct serial_chip *chip, int ch)
{
	vaddr_t base = chip_to_base(chip);

	/* Wait until there's space in the TX FIFO */
	while (io_read32(base + UTS) & UTS_TXFULL)
		if (!(io_read32(base + UCR1) & UCR1_UARTEN))
			return;

	io_write32(base + UTXD, ch);
}

static const struct serial_ops imx_uart_ops = {
	.flush = imx_uart_flush,
	.getchar = imx_uart_getchar,
	.putc = imx_uart_putc,
};
KEEP_PAGER(imx_uart_ops);

void imx_uart_init(struct imx_uart_data *pd, paddr_t base)
{
	pd->base.pa = base;
	pd->chip.ops = &imx_uart_ops;

	/*
	 * Do nothing, debug uart(uart0) share with normal world,
	 * everything for uart0 initialization is done in bootloader.
	 */
}

#ifdef CFG_DT
static struct serial_chip *imx_uart_dev_alloc(void)
{
	struct imx_uart_data *pd = calloc(1, sizeof(*pd));

	if (!pd)
		return NULL;

	return &pd->chip;
}

static int imx_uart_dev_init(struct serial_chip *chip, const void *fdt,
			     int offs, const char *parms)
{
	struct imx_uart_data *pd =
		container_of(chip, struct imx_uart_data, chip);
	vaddr_t vbase = 0;
	paddr_t pbase = 0;
	size_t size = 0;

	if (parms && parms[0])
		IMSG("imx_uart: device parameters ignored (%s)", parms);

	if (dt_map_dev(fdt, offs, &vbase, &size) < 0)
		return -1;

	pbase = virt_to_phys((void *)vbase);
	imx_uart_init(pd, pbase);

	return 0;
}

static void imx_uart_dev_free(struct serial_chip *chip)
{
	struct imx_uart_data *pd =
		container_of(chip, struct imx_uart_data, chip);

	free(pd);
}

static const struct serial_driver imx_uart_driver = {
	.dev_alloc = imx_uart_dev_alloc,
	.dev_init = imx_uart_dev_init,
	.dev_free = imx_uart_dev_free,
};

static const struct dt_device_match imx_match_table[] = {
	{ .compatible = "fsl,imx6q-uart" },
	{ 0 }
};

const struct dt_driver imx_dt_driver __dt_driver = {
	.name = "imx_uart",
	.match_table = imx_match_table,
	.driver = &imx_uart_driver,
};

#endif /* CFG_DT */