xref: /optee_os/core/drivers/imx_lpuart.c (revision 601976a55d4cf036f46c90c1274340605c85fb43)

// SPDX-License-Identifier: BSD-2-Clause
/*
 * Copyright 2017-2019 NXP
 */

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

#define STAT		0x14
#define DATA		0x1C
#define STAT_TDRE	BIT(23)
#define STAT_RDRF	BIT(21)
#define STAT_OR		BIT(19)

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_lpuart_flush(struct serial_chip *chip __unused)
{
}

static int imx_lpuart_getchar(struct serial_chip *chip)
{
	int ch = 0;
	vaddr_t base = chip_to_base(chip);

	while (io_read32(base + STAT) & STAT_RDRF)
		;

	ch = io_read32(base + DATA) & 0x3ff;

	if (io_read32(base + STAT) & STAT_OR)
		io_write32(base + STAT, STAT_OR);

	return ch;
}

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

	while (!(io_read32(base + STAT) & STAT_TDRE))
		;

	io_write32(base + DATA, ch);
}

static const struct serial_ops imx_lpuart_ops = {
	.flush = imx_lpuart_flush,
	.getchar = imx_lpuart_getchar,
	.putc = imx_lpuart_putc,
};
KEEP_PAGER(imx_lpuart_ops);

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

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