linux/drivers/tty/serial/digicolor-usart.c
Guenter Roeck dd9b55883e tty/serial: digicolor: Fix bad usage of IS_ERR_VALUE
IS_ERR_VALUE() assumes that its parameter is an unsigned long.
It can not be used to check if an unsigned int reflects an error.
Doing so can result in the following build warning.

drivers/tty/serial/digicolor-usart.c: In function ‘digicolor_uart_probe’:
include/linux/err.h:21:38: warning:
	comparison is always false due to limited range of data type
drivers/tty/serial/digicolor-usart.c:485:6: note:
	in expansion of macro ‘IS_ERR_VALUE’

If that warning is seen, an error return from platform_get_irq() is missed.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-14 17:39:36 -08:00

562 lines
14 KiB
C

/*
* Driver for Conexant Digicolor serial ports (USART)
*
* Author: Baruch Siach <baruch@tkos.co.il>
*
* Copyright (C) 2014 Paradox Innovation Ltd.
*
* 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.
*/
#include <linux/module.h>
#include <linux/console.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/workqueue.h>
#define UA_ENABLE 0x00
#define UA_ENABLE_ENABLE BIT(0)
#define UA_CONTROL 0x01
#define UA_CONTROL_RX_ENABLE BIT(0)
#define UA_CONTROL_TX_ENABLE BIT(1)
#define UA_CONTROL_SOFT_RESET BIT(2)
#define UA_STATUS 0x02
#define UA_STATUS_PARITY_ERR BIT(0)
#define UA_STATUS_FRAME_ERR BIT(1)
#define UA_STATUS_OVERRUN_ERR BIT(2)
#define UA_STATUS_TX_READY BIT(6)
#define UA_CONFIG 0x03
#define UA_CONFIG_CHAR_LEN BIT(0)
#define UA_CONFIG_STOP_BITS BIT(1)
#define UA_CONFIG_PARITY BIT(2)
#define UA_CONFIG_ODD_PARITY BIT(4)
#define UA_EMI_REC 0x04
#define UA_HBAUD_LO 0x08
#define UA_HBAUD_HI 0x09
#define UA_STATUS_FIFO 0x0a
#define UA_STATUS_FIFO_RX_EMPTY BIT(2)
#define UA_STATUS_FIFO_RX_INT_ALMOST BIT(3)
#define UA_STATUS_FIFO_TX_FULL BIT(4)
#define UA_STATUS_FIFO_TX_INT_ALMOST BIT(7)
#define UA_CONFIG_FIFO 0x0b
#define UA_CONFIG_FIFO_RX_THRESH 7
#define UA_CONFIG_FIFO_RX_FIFO_MODE BIT(3)
#define UA_CONFIG_FIFO_TX_FIFO_MODE BIT(7)
#define UA_INTFLAG_CLEAR 0x1c
#define UA_INTFLAG_SET 0x1d
#define UA_INT_ENABLE 0x1e
#define UA_INT_STATUS 0x1f
#define UA_INT_TX BIT(0)
#define UA_INT_RX BIT(1)
#define DIGICOLOR_USART_NR 3
/*
* We use the 16 bytes hardware FIFO to buffer Rx traffic. Rx interrupt is
* only produced when the FIFO is filled more than a certain configurable
* threshold. Unfortunately, there is no way to set this threshold below half
* FIFO. This means that we must periodically poll the FIFO status register to
* see whether there are waiting Rx bytes.
*/
struct digicolor_port {
struct uart_port port;
struct delayed_work rx_poll_work;
};
static struct uart_port *digicolor_ports[DIGICOLOR_USART_NR];
static bool digicolor_uart_tx_full(struct uart_port *port)
{
return !!(readb_relaxed(port->membase + UA_STATUS_FIFO) &
UA_STATUS_FIFO_TX_FULL);
}
static bool digicolor_uart_rx_empty(struct uart_port *port)
{
return !!(readb_relaxed(port->membase + UA_STATUS_FIFO) &
UA_STATUS_FIFO_RX_EMPTY);
}
static void digicolor_uart_stop_tx(struct uart_port *port)
{
u8 int_enable = readb_relaxed(port->membase + UA_INT_ENABLE);
int_enable &= ~UA_INT_TX;
writeb_relaxed(int_enable, port->membase + UA_INT_ENABLE);
}
static void digicolor_uart_start_tx(struct uart_port *port)
{
u8 int_enable = readb_relaxed(port->membase + UA_INT_ENABLE);
int_enable |= UA_INT_TX;
writeb_relaxed(int_enable, port->membase + UA_INT_ENABLE);
}
static void digicolor_uart_stop_rx(struct uart_port *port)
{
u8 int_enable = readb_relaxed(port->membase + UA_INT_ENABLE);
int_enable &= ~UA_INT_RX;
writeb_relaxed(int_enable, port->membase + UA_INT_ENABLE);
}
static void digicolor_rx_poll(struct work_struct *work)
{
struct digicolor_port *dp =
container_of(to_delayed_work(work),
struct digicolor_port, rx_poll_work);
if (!digicolor_uart_rx_empty(&dp->port))
/* force RX interrupt */
writeb_relaxed(UA_INT_RX, dp->port.membase + UA_INTFLAG_SET);
schedule_delayed_work(&dp->rx_poll_work, msecs_to_jiffies(100));
}
static void digicolor_uart_rx(struct uart_port *port)
{
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
while (1) {
u8 status, ch;
unsigned int ch_flag;
if (digicolor_uart_rx_empty(port))
break;
ch = readb_relaxed(port->membase + UA_EMI_REC);
status = readb_relaxed(port->membase + UA_STATUS);
port->icount.rx++;
ch_flag = TTY_NORMAL;
if (status) {
if (status & UA_STATUS_PARITY_ERR)
port->icount.parity++;
else if (status & UA_STATUS_FRAME_ERR)
port->icount.frame++;
else if (status & UA_STATUS_OVERRUN_ERR)
port->icount.overrun++;
status &= port->read_status_mask;
if (status & UA_STATUS_PARITY_ERR)
ch_flag = TTY_PARITY;
else if (status & UA_STATUS_FRAME_ERR)
ch_flag = TTY_FRAME;
else if (status & UA_STATUS_OVERRUN_ERR)
ch_flag = TTY_OVERRUN;
}
if (status & port->ignore_status_mask)
continue;
uart_insert_char(port, status, UA_STATUS_OVERRUN_ERR, ch,
ch_flag);
}
spin_unlock_irqrestore(&port->lock, flags);
tty_flip_buffer_push(&port->state->port);
}
static void digicolor_uart_tx(struct uart_port *port)
{
struct circ_buf *xmit = &port->state->xmit;
unsigned long flags;
if (digicolor_uart_tx_full(port))
return;
spin_lock_irqsave(&port->lock, flags);
if (port->x_char) {
writeb_relaxed(port->x_char, port->membase + UA_EMI_REC);
port->icount.tx++;
port->x_char = 0;
goto out;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
digicolor_uart_stop_tx(port);
goto out;
}
while (!uart_circ_empty(xmit)) {
writeb(xmit->buf[xmit->tail], port->membase + UA_EMI_REC);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
if (digicolor_uart_tx_full(port))
break;
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
out:
spin_unlock_irqrestore(&port->lock, flags);
}
static irqreturn_t digicolor_uart_int(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
u8 int_status = readb_relaxed(port->membase + UA_INT_STATUS);
writeb_relaxed(UA_INT_RX | UA_INT_TX,
port->membase + UA_INTFLAG_CLEAR);
if (int_status & UA_INT_RX)
digicolor_uart_rx(port);
if (int_status & UA_INT_TX)
digicolor_uart_tx(port);
return IRQ_HANDLED;
}
static unsigned int digicolor_uart_tx_empty(struct uart_port *port)
{
u8 status = readb_relaxed(port->membase + UA_STATUS);
return (status & UA_STATUS_TX_READY) ? TIOCSER_TEMT : 0;
}
static unsigned int digicolor_uart_get_mctrl(struct uart_port *port)
{
return TIOCM_CTS;
}
static void digicolor_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
}
static void digicolor_uart_break_ctl(struct uart_port *port, int state)
{
}
static int digicolor_uart_startup(struct uart_port *port)
{
struct digicolor_port *dp =
container_of(port, struct digicolor_port, port);
writeb_relaxed(UA_ENABLE_ENABLE, port->membase + UA_ENABLE);
writeb_relaxed(UA_CONTROL_SOFT_RESET, port->membase + UA_CONTROL);
writeb_relaxed(0, port->membase + UA_CONTROL);
writeb_relaxed(UA_CONFIG_FIFO_RX_FIFO_MODE
| UA_CONFIG_FIFO_TX_FIFO_MODE | UA_CONFIG_FIFO_RX_THRESH,
port->membase + UA_CONFIG_FIFO);
writeb_relaxed(UA_STATUS_FIFO_RX_INT_ALMOST,
port->membase + UA_STATUS_FIFO);
writeb_relaxed(UA_CONTROL_RX_ENABLE | UA_CONTROL_TX_ENABLE,
port->membase + UA_CONTROL);
writeb_relaxed(UA_INT_TX | UA_INT_RX,
port->membase + UA_INT_ENABLE);
schedule_delayed_work(&dp->rx_poll_work, msecs_to_jiffies(100));
return 0;
}
static void digicolor_uart_shutdown(struct uart_port *port)
{
struct digicolor_port *dp =
container_of(port, struct digicolor_port, port);
writeb_relaxed(0, port->membase + UA_ENABLE);
cancel_delayed_work_sync(&dp->rx_poll_work);
}
static void digicolor_uart_set_termios(struct uart_port *port,
struct ktermios *termios,
struct ktermios *old)
{
unsigned int baud, divisor;
u8 config = 0;
unsigned long flags;
/* Mask termios capabilities we don't support */
termios->c_cflag &= ~CMSPAR;
termios->c_iflag &= ~(BRKINT | IGNBRK);
/* Limit baud rates so that we don't need the fractional divider */
baud = uart_get_baud_rate(port, termios, old,
port->uartclk / (0x10000*16),
port->uartclk / 256);
divisor = uart_get_divisor(port, baud) - 1;
switch (termios->c_cflag & CSIZE) {
case CS7:
break;
case CS8:
default:
config |= UA_CONFIG_CHAR_LEN;
break;
}
if (termios->c_cflag & CSTOPB)
config |= UA_CONFIG_STOP_BITS;
if (termios->c_cflag & PARENB) {
config |= UA_CONFIG_PARITY;
if (termios->c_cflag & PARODD)
config |= UA_CONFIG_ODD_PARITY;
}
/* Set read status mask */
port->read_status_mask = UA_STATUS_OVERRUN_ERR;
if (termios->c_iflag & INPCK)
port->read_status_mask |= UA_STATUS_PARITY_ERR
| UA_STATUS_FRAME_ERR;
/* Set status ignore mask */
port->ignore_status_mask = 0;
if (!(termios->c_cflag & CREAD))
port->ignore_status_mask |= UA_STATUS_OVERRUN_ERR
| UA_STATUS_PARITY_ERR | UA_STATUS_FRAME_ERR;
spin_lock_irqsave(&port->lock, flags);
uart_update_timeout(port, termios->c_cflag, baud);
writeb_relaxed(config, port->membase + UA_CONFIG);
writeb_relaxed(divisor & 0xff, port->membase + UA_HBAUD_LO);
writeb_relaxed(divisor >> 8, port->membase + UA_HBAUD_HI);
spin_unlock_irqrestore(&port->lock, flags);
}
static const char *digicolor_uart_type(struct uart_port *port)
{
return (port->type == PORT_DIGICOLOR) ? "DIGICOLOR USART" : NULL;
}
static void digicolor_uart_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE)
port->type = PORT_DIGICOLOR;
}
static void digicolor_uart_release_port(struct uart_port *port)
{
}
static int digicolor_uart_request_port(struct uart_port *port)
{
return 0;
}
static const struct uart_ops digicolor_uart_ops = {
.tx_empty = digicolor_uart_tx_empty,
.set_mctrl = digicolor_uart_set_mctrl,
.get_mctrl = digicolor_uart_get_mctrl,
.stop_tx = digicolor_uart_stop_tx,
.start_tx = digicolor_uart_start_tx,
.stop_rx = digicolor_uart_stop_rx,
.break_ctl = digicolor_uart_break_ctl,
.startup = digicolor_uart_startup,
.shutdown = digicolor_uart_shutdown,
.set_termios = digicolor_uart_set_termios,
.type = digicolor_uart_type,
.config_port = digicolor_uart_config_port,
.release_port = digicolor_uart_release_port,
.request_port = digicolor_uart_request_port,
};
static void digicolor_uart_console_putchar(struct uart_port *port, int ch)
{
while (digicolor_uart_tx_full(port))
cpu_relax();
writeb_relaxed(ch, port->membase + UA_EMI_REC);
}
static void digicolor_uart_console_write(struct console *co, const char *c,
unsigned n)
{
struct uart_port *port = digicolor_ports[co->index];
u8 status;
unsigned long flags;
int locked = 1;
if (oops_in_progress)
locked = spin_trylock_irqsave(&port->lock, flags);
else
spin_lock_irqsave(&port->lock, flags);
uart_console_write(port, c, n, digicolor_uart_console_putchar);
if (locked)
spin_unlock_irqrestore(&port->lock, flags);
/* Wait for transmitter to become empty */
do {
status = readb_relaxed(port->membase + UA_STATUS);
} while ((status & UA_STATUS_TX_READY) == 0);
}
static int digicolor_uart_console_setup(struct console *co, char *options)
{
int baud = 115200, bits = 8, parity = 'n', flow = 'n';
struct uart_port *port;
if (co->index < 0 || co->index >= DIGICOLOR_USART_NR)
return -EINVAL;
port = digicolor_ports[co->index];
if (!port)
return -ENODEV;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static struct console digicolor_console = {
.name = "ttyS",
.device = uart_console_device,
.write = digicolor_uart_console_write,
.setup = digicolor_uart_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
};
static struct uart_driver digicolor_uart = {
.driver_name = "digicolor-usart",
.dev_name = "ttyS",
.nr = DIGICOLOR_USART_NR,
};
static int digicolor_uart_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
int irq, ret, index;
struct digicolor_port *dp;
struct resource *res;
struct clk *uart_clk;
if (!np) {
dev_err(&pdev->dev, "Missing device tree node\n");
return -ENXIO;
}
index = of_alias_get_id(np, "serial");
if (index < 0 || index >= DIGICOLOR_USART_NR)
return -EINVAL;
dp = devm_kzalloc(&pdev->dev, sizeof(*dp), GFP_KERNEL);
if (!dp)
return -ENOMEM;
uart_clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(uart_clk))
return PTR_ERR(uart_clk);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
dp->port.mapbase = res->start;
dp->port.membase = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(dp->port.membase))
return PTR_ERR(dp->port.membase);
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
dp->port.irq = irq;
dp->port.iotype = UPIO_MEM;
dp->port.uartclk = clk_get_rate(uart_clk);
dp->port.fifosize = 16;
dp->port.dev = &pdev->dev;
dp->port.ops = &digicolor_uart_ops;
dp->port.line = index;
dp->port.type = PORT_DIGICOLOR;
spin_lock_init(&dp->port.lock);
digicolor_ports[index] = &dp->port;
platform_set_drvdata(pdev, &dp->port);
INIT_DELAYED_WORK(&dp->rx_poll_work, digicolor_rx_poll);
ret = devm_request_irq(&pdev->dev, dp->port.irq, digicolor_uart_int, 0,
dev_name(&pdev->dev), &dp->port);
if (ret)
return ret;
return uart_add_one_port(&digicolor_uart, &dp->port);
}
static int digicolor_uart_remove(struct platform_device *pdev)
{
struct uart_port *port = platform_get_drvdata(pdev);
uart_remove_one_port(&digicolor_uart, port);
return 0;
}
static const struct of_device_id digicolor_uart_dt_ids[] = {
{ .compatible = "cnxt,cx92755-usart", },
{ }
};
MODULE_DEVICE_TABLE(of, digicolor_uart_dt_ids);
static struct platform_driver digicolor_uart_platform = {
.driver = {
.name = "digicolor-usart",
.of_match_table = of_match_ptr(digicolor_uart_dt_ids),
},
.probe = digicolor_uart_probe,
.remove = digicolor_uart_remove,
};
static int __init digicolor_uart_init(void)
{
int ret;
if (IS_ENABLED(CONFIG_SERIAL_CONEXANT_DIGICOLOR_CONSOLE)) {
digicolor_uart.cons = &digicolor_console;
digicolor_console.data = &digicolor_uart;
}
ret = uart_register_driver(&digicolor_uart);
if (ret)
return ret;
return platform_driver_register(&digicolor_uart_platform);
}
module_init(digicolor_uart_init);
static void __exit digicolor_uart_exit(void)
{
platform_driver_unregister(&digicolor_uart_platform);
uart_unregister_driver(&digicolor_uart);
}
module_exit(digicolor_uart_exit);
MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
MODULE_DESCRIPTION("Conexant Digicolor USART serial driver");
MODULE_LICENSE("GPL");