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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Copyright 2020 NXP4 */5 6#include <linux/module.h>7#include <linux/ioport.h>8#include <linux/init.h>9#include <linux/serial_core.h>10#include <linux/serial.h>11#include <linux/delay.h>12#include <linux/of.h>13#include <linux/io.h>14 15#define URTX0 0x40 /* Transmitter Register */16#define UTS_TXFULL (1<<4) /* TxFIFO full */17#define IMX21_UTS 0xb4 /* UART Test Register on all other i.mx*/18 19static void imx_uart_console_early_putchar(struct uart_port *port, unsigned char ch)20{21 while (readl_relaxed(port->membase + IMX21_UTS) & UTS_TXFULL)22 cpu_relax();23 24 writel_relaxed(ch, port->membase + URTX0);25}26 27static void imx_uart_console_early_write(struct console *con, const char *s,28 unsigned count)29{30 struct earlycon_device *dev = con->data;31 32 uart_console_write(&dev->port, s, count, imx_uart_console_early_putchar);33}34 35static int __init36imx_console_early_setup(struct earlycon_device *dev, const char *opt)37{38 if (!dev->port.membase)39 return -ENODEV;40 41 dev->con->write = imx_uart_console_early_write;42 43 return 0;44}45OF_EARLYCON_DECLARE(ec_imx6q, "fsl,imx6q-uart", imx_console_early_setup);46OF_EARLYCON_DECLARE(ec_imx21, "fsl,imx21-uart", imx_console_early_setup);47 48MODULE_AUTHOR("NXP");49MODULE_DESCRIPTION("IMX earlycon driver");50MODULE_LICENSE("GPL");51