* Peter Hurley | 2015-02-12 11:32:04 [-0500]:
>That said, I don't think serial8250_do_startup() is really doing that much
>for OMAP h/w startup; open-coding what omap_8250 really needs is probably
>< 10 loc.
10 loc? I have a few more. serial8250_clear_fifos(),
serial_link_irq_chain() aren't exported. serial8250_set_mctrl() can
maybe accessed via uart_ops->set_mctrl(). Maybe I'm not removing the
obvious not required code but here it looks better to just a BUG flag for
the Omap.
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -557,9 +557,74 @@ static int omap_8250_startup(struct uart_port *port)
pm_runtime_get_sync(port->dev);
- ret = serial8250_do_startup(port);
- if (ret)
- goto err;
+ up->mcr = 0;
+
+ /*
+ * Clear the FIFO buffers and disable them.
+ * (they will be reenabled in set_termios())
+ */
+ serial8250_clear_fifos(up);
+
+ /*
+ * Clear the interrupt registers.
+ */
+ if (serial_port_in(port, UART_LSR) & UART_LSR_DR)
+ serial_port_in(port, UART_RX);
+ serial_port_in(port, UART_IIR);
+ serial_port_in(port, UART_MSR);
+
+ retval = serial_link_irq_chain(up);
+ if (retval)
+ goto out;
+
+ /*
+ * Now, initialize the UART
+ */
+ serial_port_out(port, UART_LCR, UART_LCR_WLEN8);
+
+ spin_lock_irqsave(&port->lock, flags);
+ /*
+ * Most PC uarts need OUT2 raised to enable interrupts.
+ */
+ if (port->irq)
+ up->port.mctrl |= TIOCM_OUT2;
+
+ serial8250_set_mctrl(port, port->mctrl);
+
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ /*
+ * Clear the interrupt registers again for luck, and clear the
+ * saved flags to avoid getting false values from polling
+ * routines or the previous session.
+ */
+ if (serial_port_in(port, UART_LSR) & UART_LSR_DR)
+ serial_port_in(port, UART_RX);
+ serial_port_in(port, UART_IIR);
+ serial_port_in(port, UART_MSR);
+ up->lsr_saved_flags = 0;
+ up->msr_saved_flags = 0;
+
+ /*
+ * Request DMA channels for both RX and TX.
+ */
+ if (up->dma) {
+ retval = serial8250_request_dma(up);
+ if (retval) {
+ pr_warn_ratelimited("ttyS%d - failed to request DMA\n",
+ serial_index(port));
+ up->dma = NULL;
+ }
+ }
+
+ /*
+ * Finally, enable interrupts. Note: Modem status interrupts
+ * are set via set_termios(), which will be occurring imminently
+ * anyway, so we don't enable them here.
+ */
+ up->ier = UART_IER_RLSI | UART_IER_RDI;
+ serial_port_out(port, UART_IER, up->ier);
+
#ifdef CONFIG_PM
up->capabilities |= UART_CAP_RPM;
Sebastian
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