forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
561 lines
14 KiB
561 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0+ |
|
/* |
|
* Driver for Conexant Digicolor serial ports (USART) |
|
* |
|
* Author: Baruch Siach <[email protected]> |
|
* |
|
* Copyright (C) 2014 Paradox Innovation Ltd. |
|
*/ |
|
|
|
#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; |
|
|
|
ret = platform_driver_register(&digicolor_uart_platform); |
|
if (ret) |
|
uart_unregister_driver(&digicolor_uart); |
|
|
|
return ret; |
|
} |
|
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 <[email protected]>"); |
|
MODULE_DESCRIPTION("Conexant Digicolor USART serial driver"); |
|
MODULE_LICENSE("GPL");
|
|
|