Merge tag 'io_uring-5.6-2020-02-22' of git://git.kernel.dk/linux-block

[linux.git] / drivers / tty / serial / serial_core.c

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 7c278278573634df5e0e82833ad6ff827ef6a13f..76e506ee335cebfc21a3490a5f29ae83bca4b0b6 100644 (file)
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2603,6 +2603,7 @@ struct tty_driver *uart_console_device(struct console *co, int *index)
        *index = co->index;
        return p->tty_driver;
 }
+EXPORT_SYMBOL_GPL(uart_console_device);
 
 static ssize_t uart_get_attr_uartclk(struct device *dev,
        struct device_attribute *attr, char *buf)
@@ -3081,6 +3082,89 @@ void uart_insert_char(struct uart_port *port, unsigned int status,
 }
 EXPORT_SYMBOL_GPL(uart_insert_char);
 
+int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
+{
+       if (!IS_ENABLED(CONFIG_MAGIC_SYSRQ_SERIAL))
+               return 0;
+
+       if (!port->has_sysrq || !port->sysrq)
+               return 0;
+
+       if (ch && time_before(jiffies, port->sysrq)) {
+               handle_sysrq(ch);
+               port->sysrq = 0;
+               return 1;
+       }
+       port->sysrq = 0;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(uart_handle_sysrq_char);
+
+int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
+{
+       if (!IS_ENABLED(CONFIG_MAGIC_SYSRQ_SERIAL))
+               return 0;
+
+       if (!port->has_sysrq || !port->sysrq)
+               return 0;
+
+       if (ch && time_before(jiffies, port->sysrq)) {
+               port->sysrq_ch = ch;
+               port->sysrq = 0;
+               return 1;
+       }
+       port->sysrq = 0;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(uart_prepare_sysrq_char);
+
+void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
+{
+       int sysrq_ch;
+
+       if (!port->has_sysrq) {
+               spin_unlock_irqrestore(&port->lock, irqflags);
+               return;
+       }
+
+       sysrq_ch = port->sysrq_ch;
+       port->sysrq_ch = 0;
+
+       spin_unlock_irqrestore(&port->lock, irqflags);
+
+       if (sysrq_ch)
+               handle_sysrq(sysrq_ch);
+}
+EXPORT_SYMBOL_GPL(uart_unlock_and_check_sysrq);
+
+/*
+ * We do the SysRQ and SAK checking like this...
+ */
+int uart_handle_break(struct uart_port *port)
+{
+       struct uart_state *state = port->state;
+
+       if (port->handle_break)
+               port->handle_break(port);
+
+       if (port->has_sysrq) {
+               if (port->cons && port->cons->index == port->line) {
+                       if (!port->sysrq) {
+                               port->sysrq = jiffies + HZ*5;
+                               return 1;
+                       }
+                       port->sysrq = 0;
+               }
+       }
+
+       if (port->flags & UPF_SAK)
+               do_SAK(state->port.tty);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(uart_handle_break);
+
 EXPORT_SYMBOL(uart_write_wakeup);
 EXPORT_SYMBOL(uart_register_driver);
 EXPORT_SYMBOL(uart_unregister_driver);