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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
serial: liteuart: add IRQ support for the RX path
Add support for IRQ-driven RX. Support for the TX path will be added
in a separate commit.
Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20221123130500.1030189-13-gsomlo@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
authored by
Gabriel Somlo
and committed by
Greg Kroah-Hartman
5602cf99
7121d86e
+74
-7
+74
-7
drivers/tty/serial/liteuart.c
+74
-7
drivers/tty/serial/liteuart.c
···
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#include <linux/bits.h>
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#include <linux/console.h>
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#include <linux/interrupt.h>
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#include <linux/litex.h>
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#include <linux/module.h>
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#include <linux/of.h>
···
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struct uart_port port;
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struct timer_list timer;
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u32 id;
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u8 irq_reg;
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};
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#define to_liteuart_port(port) container_of(port, struct liteuart_port, port)
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cpu_relax();
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litex_write8(port->membase + OFF_RXTX, ch);
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}
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static void liteuart_update_irq_reg(struct uart_port *port, bool set, u8 mask)
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{
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struct liteuart_port *uart = to_liteuart_port(port);
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if (set)
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uart->irq_reg |= mask;
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else
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uart->irq_reg &= ~mask;
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if (port->irq)
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litex_write8(port->membase + OFF_EV_ENABLE, uart->irq_reg);
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}
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static void liteuart_stop_tx(struct uart_port *port)
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tty_flip_buffer_push(&port->state->port);
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}
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static irqreturn_t liteuart_interrupt(int irq, void *data)
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{
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struct liteuart_port *uart = data;
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struct uart_port *port = &uart->port;
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unsigned long flags;
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u8 isr;
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/*
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* if polling, the context would be "in_serving_softirq", so use
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* irq[save|restore] spin_lock variants to cover all possibilities
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*/
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spin_lock_irqsave(&port->lock, flags);
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isr = litex_read8(port->membase + OFF_EV_PENDING) & uart->irq_reg;
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if (isr & EV_RX)
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liteuart_rx_chars(port);
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spin_unlock_irqrestore(&port->lock, flags);
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return IRQ_RETVAL(isr);
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}
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static void liteuart_timer(struct timer_list *t)
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{
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struct liteuart_port *uart = from_timer(uart, t, timer);
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struct uart_port *port = &uart->port;
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-
liteuart_rx_chars(port);
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-
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liteuart_interrupt(0, port);
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mod_timer(&uart->timer, jiffies + uart_poll_timeout(port));
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}
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···
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static int liteuart_startup(struct uart_port *port)
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{
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struct liteuart_port *uart = to_liteuart_port(port);
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unsigned long flags;
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int ret;
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/* disable events */
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litex_write8(port->membase + OFF_EV_ENABLE, 0);
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if (port->irq) {
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ret = request_irq(port->irq, liteuart_interrupt, 0,
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KBUILD_MODNAME, uart);
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if (ret) {
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dev_warn(port->dev,
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"line %d irq %d failed: switch to polling\n",
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port->line, port->irq);
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port->irq = 0;
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}
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}
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/* prepare timer for polling */
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timer_setup(&uart->timer, liteuart_timer, 0);
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mod_timer(&uart->timer, jiffies + uart_poll_timeout(port));
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spin_lock_irqsave(&port->lock, flags);
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/* only enabling rx irqs during startup */
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liteuart_update_irq_reg(port, true, EV_RX);
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spin_unlock_irqrestore(&port->lock, flags);
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if (!port->irq) {
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timer_setup(&uart->timer, liteuart_timer, 0);
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mod_timer(&uart->timer, jiffies + uart_poll_timeout(port));
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}
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return 0;
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}
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static void liteuart_shutdown(struct uart_port *port)
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{
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struct liteuart_port *uart = to_liteuart_port(port);
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unsigned long flags;
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spin_lock_irqsave(&port->lock, flags);
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liteuart_update_irq_reg(port, false, EV_RX | EV_TX);
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spin_unlock_irqrestore(&port->lock, flags);
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if (port->irq)
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free_irq(port->irq, port);
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else
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del_timer_sync(&uart->timer);
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}
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static void liteuart_set_termios(struct uart_port *port, struct ktermios *new,
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ret = PTR_ERR(port->membase);
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goto err_erase_id;
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}
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ret = platform_get_irq_optional(pdev, 0);
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if (ret < 0 && ret != -ENXIO)
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return ret;
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if (ret > 0)
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port->irq = ret;
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/* values not from device tree */
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port->dev = &pdev->dev;