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| author | Gabriel Somlo <gsomlo@gmail.com> | 2022-11-23 08:04:58 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-19 14:59:40 +0100 |
| commit | 5602cf99dcdcc0bf8f9a5979b7443fbe46686995 (patch) | |
| tree | 155aa1e12045f95da9ef52ff360e82eb6af06f2c /drivers/tty/serial/liteuart.c | |
| parent | 7121d86effddc28dc21fec38d59923ea12d5a873 (diff) | |
| download | linux-stable-5602cf99dcdcc0bf8f9a5979b7443fbe46686995.tar.gz linux-stable-5602cf99dcdcc0bf8f9a5979b7443fbe46686995.tar.bz2 linux-stable-5602cf99dcdcc0bf8f9a5979b7443fbe46686995.zip | |
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>
Diffstat (limited to 'drivers/tty/serial/liteuart.c')
| -rw-r--r-- | drivers/tty/serial/liteuart.c | 81 |
1 files changed, 74 insertions, 7 deletions
diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c index 0b9d96e5efcf..8685c97d391e 100644 --- a/drivers/tty/serial/liteuart.c +++ b/drivers/tty/serial/liteuart.c @@ -7,6 +7,7 @@ #include <linux/bits.h> #include <linux/console.h> +#include <linux/interrupt.h> #include <linux/litex.h> #include <linux/module.h> #include <linux/of.h> @@ -46,6 +47,7 @@ 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) @@ -76,6 +78,19 @@ static void liteuart_putchar(struct uart_port *port, unsigned char ch) litex_write8(port->membase + OFF_RXTX, ch); } +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) { } @@ -129,13 +144,32 @@ static void liteuart_rx_chars(struct uart_port *port) tty_flip_buffer_push(&port->state->port); } +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); + 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_rx_chars(port); - + liteuart_interrupt(0, port); mod_timer(&uart->timer, jiffies + uart_poll_timeout(port)); } @@ -161,19 +195,46 @@ static unsigned int liteuart_get_mctrl(struct uart_port *port) static int liteuart_startup(struct uart_port *port) { 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; + } + } - /* disable events */ - litex_write8(port->membase + OFF_EV_ENABLE, 0); + 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); - /* prepare timer for polling */ - timer_setup(&uart->timer, liteuart_timer, 0); - mod_timer(&uart->timer, jiffies + uart_poll_timeout(port)); + if (!port->irq) { + timer_setup(&uart->timer, liteuart_timer, 0); + mod_timer(&uart->timer, jiffies + uart_poll_timeout(port)); + } return 0; } static void liteuart_shutdown(struct uart_port *port) { + struct liteuart_port *uart = to_liteuart_port(port); + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + liteuart_update_irq_reg(port, false, EV_RX | EV_TX); + spin_unlock_irqrestore(&port->lock, flags); + + 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, @@ -262,6 +323,12 @@ static int liteuart_probe(struct platform_device *pdev) 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; |