LXR linux/drivers/tty/serial/imx

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Copyright 2020 NXP
   4 */
   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, int 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 __init
  36imx_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