path: root/drivers/tty/serial/xilinx_uartps.c

/*
 * Cadence UART driver (found in Xilinx Zynq)
 *
 * 2011 - 2014 (C) Xilinx Inc.
 *
 * This program is free software; you can redistribute it
 * and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation;
 * either version 2 of the License, or (at your option) any
 * later version.
 *
 * This driver has originally been pushed by Xilinx using a Zynq-branding. This
 * still shows in the naming of this file, the kconfig symbols and some symbols
 * in the code.
 */

#if defined(CONFIG_SERIAL_XILINX_PS_UART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/platform_device.h>
#include <linux/serial.h>
#include <linux/console.h>
#include <linux/serial_core.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/clk.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/module.h>

#define CDNS_UART_TTY_NAME	"ttyPS"
#define CDNS_UART_NAME		"xuartps"
#define CDNS_UART_MAJOR		0	/* use dynamic node allocation */
#define CDNS_UART_MINOR		0	/* works best with devtmpfs */
#define CDNS_UART_NR_PORTS	2
#define CDNS_UART_FIFO_SIZE	64	/* FIFO size */
#define CDNS_UART_REGISTER_SPACE	0x1000

/* Rx Trigger level */
static int rx_trigger_level = 56;
module_param(rx_trigger_level, uint, S_IRUGO);
MODULE_PARM_DESC(rx_trigger_level, "Rx trigger level, 1-63 bytes");

/* Rx Timeout */
static int rx_timeout = 10;
module_param(rx_timeout, uint, S_IRUGO);
MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");

/* Register offsets for the UART. */
#define CDNS_UART_CR		0x00  /* Control Register */
#define CDNS_UART_MR		0x04  /* Mode Register */
#define CDNS_UART_IER		0x08  /* Interrupt Enable */
#define CDNS_UART_IDR		0x0C  /* Interrupt Disable */
#define CDNS_UART_IMR		0x10  /* Interrupt Mask */
#define CDNS_UART_ISR		0x14  /* Interrupt Status */
#define CDNS_UART_BAUDGEN	0x18  /* Baud Rate Generator */
#define CDNS_UART_RXTOUT	0x1C  /* RX Timeout */
#define CDNS_UART_RXWM		0x20  /* RX FIFO Trigger Level */
#define CDNS_UART_MODEMCR	0x24  /* Modem Control */
#define CDNS_UART_MODEMSR	0x28  /* Modem Status */
#define CDNS_UART_SR		0x2C  /* Channel Status */
#define CDNS_UART_FIFO		0x30  /* FIFO */
#define CDNS_UART_BAUDDIV	0x34  /* Baud Rate Divider */
#define CDNS_UART_FLOWDEL	0x38  /* Flow Delay */
#define CDNS_UART_IRRX_PWIDTH	0x3C  /* IR Min Received Pulse Width */
#define CDNS_UART_IRTX_PWIDTH	0x40  /* IR Transmitted pulse Width */
#define CDNS_UART_TXWM		0x44  /* TX FIFO Trigger Level */
#define CDNS_UART_RXBS		0x48  /* RX FIFO byte status register */

/* Control Register Bit Definitions */
#define CDNS_UART_CR_STOPBRK	0x00000100  /* Stop TX break */
#define CDNS_UART_CR_STARTBRK	0x00000080  /* Set TX break */
#define CDNS_UART_CR_TX_DIS	0x00000020  /* TX disabled. */
#define CDNS_UART_CR_TX_EN	0x00000010  /* TX enabled */
#define CDNS_UART_CR_RX_DIS	0x00000008  /* RX disabled. */
#define CDNS_UART_CR_RX_EN	0x00000004  /* RX enabled */
#define CDNS_UART_CR_TXRST	0x00000002  /* TX logic reset */
#define CDNS_UART_CR_RXRST	0x00000001  /* RX logic reset */
#define CDNS_UART_CR_RST_TO	0x00000040  /* Restart Timeout Counter */
#define CDNS_UART_RXBS_PARITY    0x00000001 /* Parity error status */
#define CDNS_UART_RXBS_FRAMING   0x00000002 /* Framing error status */
#define CDNS_UART_RXBS_BRK       0x00000004 /* Overrun error status */

/*
 * Mode Register:
 * The mode register (MR) defines the mode of transfer as well as the data
 * format. If this register is modified during transmission or reception,
 * data validity cannot be guaranteed.
 */
#define CDNS_UART_MR_CLKSEL		0x00000001  /* Pre-scalar selection */
#define CDNS_UART_MR_CHMODE_L_LOOP	0x00000200  /* Local loop back mode */
#define CDNS_UART_MR_CHMODE_NORM	0x00000000  /* Normal mode */

#define CDNS_UART_MR_STOPMODE_2_BIT	0x00000080  /* 2 stop bits */
#define CDNS_UART_MR_STOPMODE_1_BIT	0x00000000  /* 1 stop bit */

#define CDNS_UART_MR_PARITY_NONE	0x00000020  /* No parity mode */
#define CDNS_UART_MR_PARITY_MARK	0x00000018  /* Mark parity mode */
#define CDNS_UART_MR_PARITY_SPACE	0x00000010  /* Space parity mode */
#define CDNS_UART_MR_PARITY_ODD		0x00000008