* Copyright (C) 2019-2020 Antmicro <www.antmicro.com>
*/
+#include <linux/bits.h>
#include <linux/console.h>
+#include <linux/interrupt.h>
#include <linux/litex.h>
#include <linux/module.h>
#include <linux/of.h>
#define OFF_EV_ENABLE 0x14
/* events */
-#define EV_TX 0x1
-#define EV_RX 0x2
+#define EV_TX BIT(0)
+#define EV_RX BIT(1)
struct liteuart_port {
struct uart_port port;
struct timer_list timer;
u32 id;
+ u8 irq_reg;
};
#define to_liteuart_port(port) container_of(port, struct liteuart_port, port)
static struct uart_driver liteuart_driver = {
.owner = THIS_MODULE,
- .driver_name = "liteuart",
+ .driver_name = KBUILD_MODNAME,
.dev_name = "ttyLXU",
.major = 0,
.minor = 0,
#endif
};
-static void liteuart_timer(struct timer_list *t)
+static void liteuart_update_irq_reg(struct uart_port *port, bool set, u8 mask)
+{
+ struct liteuart_port *uart = to_liteuart_port(port);
+
+ if (set)
+ uart->irq_reg |= mask;
+ else
+ uart->irq_reg &= ~mask;
+
+ if (port->irq)
+ litex_write8(port->membase + OFF_EV_ENABLE, uart->irq_reg);
+}
+
+static void liteuart_stop_tx(struct uart_port *port)
+{
+ liteuart_update_irq_reg(port, false, EV_TX);
+}
+
+static void liteuart_start_tx(struct uart_port *port)
+{
+ liteuart_update_irq_reg(port, true, EV_TX);
+}
+
+static void liteuart_stop_rx(struct uart_port *port)
+{
+ struct liteuart_port *uart = to_liteuart_port(port);
+
+ /* just delete timer */
+ del_timer(&uart->timer);
+}
+
+static void liteuart_rx_chars(struct uart_port *port)
{
- struct liteuart_port *uart = from_timer(uart, t, timer);
- struct uart_port *port = &uart->port;
unsigned char __iomem *membase = port->membase;
- unsigned int flg = TTY_NORMAL;
- int ch;
- unsigned long status;
+ u8 ch;
- while ((status = !litex_read8(membase + OFF_RXEMPTY)) == 1) {
+ while (!litex_read8(membase + OFF_RXEMPTY)) {
ch = litex_read8(membase + OFF_RXTX);
port->icount.rx++;
/* necessary for RXEMPTY to refresh its value */
- litex_write8(membase + OFF_EV_PENDING, EV_TX | EV_RX);
+ litex_write8(membase + OFF_EV_PENDING, EV_RX);
/* no overflow bits in status */
if (!(uart_handle_sysrq_char(port, ch)))
- uart_insert_char(port, status, 0, ch, flg);
-
- tty_flip_buffer_push(&port->state->port);
+ uart_insert_char(port, 1, 0, ch, TTY_NORMAL);
}
- mod_timer(&uart->timer, jiffies + uart_poll_timeout(port));
+ tty_flip_buffer_push(&port->state->port);
}
-static void liteuart_putchar(struct uart_port *port, unsigned char ch)
+static void liteuart_tx_chars(struct uart_port *port)
{
- while (litex_read8(port->membase + OFF_TXFULL))
- cpu_relax();
+ u8 ch;
- litex_write8(port->membase + OFF_RXTX, ch);
+ uart_port_tx(port, ch,
+ !litex_read8(port->membase + OFF_TXFULL),
+ litex_write8(port->membase + OFF_RXTX, ch));
+}
+
+static irqreturn_t liteuart_interrupt(int irq, void *data)
+{
+ struct liteuart_port *uart = data;
+ struct uart_port *port = &uart->port;
+ unsigned long flags;
+ u8 isr;
+
+ /*
+ * if polling, the context would be "in_serving_softirq", so use
+ * irq[save|restore] spin_lock variants to cover all possibilities
+ */
+ spin_lock_irqsave(&port->lock, flags);
+ isr = litex_read8(port->membase + OFF_EV_PENDING) & uart->irq_reg;
+ if (isr & EV_RX)
+ liteuart_rx_chars(port);
+ if (isr & EV_TX)
+ liteuart_tx_chars(port);
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ return IRQ_RETVAL(isr);
+}
+
+static void liteuart_timer(struct timer_list *t)
+{
+ struct liteuart_port *uart = from_timer(uart, t, timer);
+ struct uart_port *port = &uart->port;
+
+ liteuart_interrupt(0, port);
+ mod_timer(&uart->timer, jiffies + uart_poll_timeout(port));
}
static unsigned int liteuart_tx_empty(struct uart_port *port)
return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
}
-static void liteuart_stop_tx(struct uart_port *port)
-{
-}
-
-static void liteuart_start_tx(struct uart_port *port)
+static int liteuart_startup(struct uart_port *port)
{
- struct circ_buf *xmit = &port->state->xmit;
- unsigned char ch;
-
- if (unlikely(port->x_char)) {
- litex_write8(port->membase + OFF_RXTX, port->x_char);
- port->icount.tx++;
- port->x_char = 0;
- } else if (!uart_circ_empty(xmit)) {
- while (xmit->head != xmit->tail) {
- ch = xmit->buf[xmit->tail];
- uart_xmit_advance(port, 1);
- liteuart_putchar(port, ch);
+ struct liteuart_port *uart = to_liteuart_port(port);
+ unsigned long flags;
+ int ret;
+
+ if (port->irq) {
+ ret = request_irq(port->irq, liteuart_interrupt, 0,
+ KBUILD_MODNAME, uart);
+ if (ret) {
+ dev_warn(port->dev,
+ "line %d irq %d failed: switch to polling\n",
+ port->line, port->irq);
+ port->irq = 0;
}
}
- if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
- uart_write_wakeup(port);
-}
-
-static void liteuart_stop_rx(struct uart_port *port)
-{
- struct liteuart_port *uart = to_liteuart_port(port);
+ spin_lock_irqsave(&port->lock, flags);
+ /* only enabling rx irqs during startup */
+ liteuart_update_irq_reg(port, true, EV_RX);
+ spin_unlock_irqrestore(&port->lock, flags);
- /* just delete timer */
- del_timer(&uart->timer);
-}
+ if (!port->irq) {
+ timer_setup(&uart->timer, liteuart_timer, 0);
+ mod_timer(&uart->timer, jiffies + uart_poll_timeout(port));
+ }
-static void liteuart_break_ctl(struct uart_port *port, int break_state)
-{
- /* LiteUART doesn't support sending break signal */
+ return 0;
}
-static int liteuart_startup(struct uart_port *port)
+static void liteuart_shutdown(struct uart_port *port)
{
struct liteuart_port *uart = to_liteuart_port(port);
+ unsigned long flags;
- /* disable events */
- litex_write8(port->membase + OFF_EV_ENABLE, 0);
-
- /* prepare timer for polling */
- timer_setup(&uart->timer, liteuart_timer, 0);
- mod_timer(&uart->timer, jiffies + uart_poll_timeout(port));
-
- return 0;
-}
+ spin_lock_irqsave(&port->lock, flags);
+ liteuart_update_irq_reg(port, false, EV_RX | EV_TX);
+ spin_unlock_irqrestore(&port->lock, flags);
-static void liteuart_shutdown(struct uart_port *port)
-{
+ if (port->irq)
+ free_irq(port->irq, port);
+ else
+ del_timer_sync(&uart->timer);
}
static void liteuart_set_termios(struct uart_port *port, struct ktermios *new,
return "liteuart";
}
-static void liteuart_release_port(struct uart_port *port)
-{
-}
-
-static int liteuart_request_port(struct uart_port *port)
-{
- return 0;
-}
-
static void liteuart_config_port(struct uart_port *port, int flags)
{
/*
.stop_tx = liteuart_stop_tx,
.start_tx = liteuart_start_tx,
.stop_rx = liteuart_stop_rx,
- .break_ctl = liteuart_break_ctl,
.startup = liteuart_startup,
.shutdown = liteuart_shutdown,
.set_termios = liteuart_set_termios,
.type = liteuart_type,
- .release_port = liteuart_release_port,
- .request_port = liteuart_request_port,
.config_port = liteuart_config_port,
.verify_port = liteuart_verify_port,
};
goto err_erase_id;
}
+ ret = platform_get_irq_optional(pdev, 0);
+ if (ret < 0 && ret != -ENXIO)
+ return ret;
+ if (ret > 0)
+ port->irq = ret;
+
/* values not from device tree */
port->dev = &pdev->dev;
port->iotype = UPIO_MEM;
port->flags = UPF_BOOT_AUTOCONF;
port->ops = &liteuart_ops;
- port->regshift = 2;
port->fifosize = 16;
- port->iobase = 1;
port->type = PORT_UNKNOWN;
port->line = dev_id;
spin_lock_init(&port->lock);
.probe = liteuart_probe,
.remove = liteuart_remove,
.driver = {
- .name = "liteuart",
+ .name = KBUILD_MODNAME,
.of_match_table = liteuart_of_match,
},
};
#ifdef CONFIG_SERIAL_LITEUART_CONSOLE
+static void liteuart_putchar(struct uart_port *port, unsigned char ch)
+{
+ while (litex_read8(port->membase + OFF_TXFULL))
+ cpu_relax();
+
+ litex_write8(port->membase + OFF_RXTX, ch);
+}
+
static void liteuart_console_write(struct console *co, const char *s,
unsigned int count)
{
}
static struct console liteuart_console = {
- .name = "liteuart",
+ .name = KBUILD_MODNAME,
.write = liteuart_console_write,
.device = uart_console_device,
.setup = liteuart_console_setup,
return res;
res = platform_driver_register(&liteuart_platform_driver);
- if (res) {
+ if (res)
uart_unregister_driver(&liteuart_driver);
- return res;
- }
- return 0;
+ return res;
}
static void __exit liteuart_exit(void)
projects / platform / kernel / linux-starfive.git / blobdiff