serial: 8250: Refactor divisor programming

Refactor divisor register programming into a new function,
serial8250_set_divisor; this allows serial console to reinitialize
early after resume from suspend.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 48 insertions, 39 deletions

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index b63b9c352cc2..fd9e723926cd 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -2478,6 +2478,50 @@ static unsigned char serial8250_compute_lcr(struct uart_8250_port *up,
         return cval;
 }
 
+void serial8250_set_divisor(struct uart_port *port, unsigned int baud,
+                            unsigned int quot)
+{
+        struct uart_8250_port *up = up_to_u8250p(port);
+
+        /* Workaround to enable 115200 baud on OMAP1510 internal ports */
+        if (is_omap1510_8250(up)) {
+                if (baud == 115200) {
+                        quot = 1;
+                        serial_port_out(port, UART_OMAP_OSC_12M_SEL, 1);
+                } else
+                        serial_port_out(port, UART_OMAP_OSC_12M_SEL, 0);
+        }
+
+        /*
+         * For NatSemi, switch to bank 2 not bank 1, to avoid resetting EXCR2,
+         * otherwise just set DLAB
+         */
+        if (up->capabilities & UART_NATSEMI)
+                serial_port_out(port, UART_LCR, 0xe0);
+        else
+                serial_port_out(port, UART_LCR, up->lcr | UART_LCR_DLAB);
+
+        serial_dl_write(up, quot);
+
+        /*
+         * XR17V35x UARTs have an extra fractional divisor register (DLD)
+         *
+         * We need to recalculate all of the registers, because DLM and DLL
+         * are already rounded to a whole integer.
+         *
+         * When recalculating we use a 32x clock instead of a 16x clock to
+         * allow 1-bit for rounding in the fractional part.
+         */
+        if (up->port.type == PORT_XR17V35X) {
+                unsigned int baud_x32 = (port->uartclk * 2) / baud;
+                u16 quot = baud_x32 / 32;
+                u8 quot_frac = DIV_ROUND_CLOSEST(baud_x32 % 32, 2);
+
+                serial_dl_write(up, quot);
+                serial_port_out(port, 0x2, quot_frac & 0xf);
+        }
+}
+
 void
 serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
                           struct ktermios *old)
@@ -2526,6 +2570,8 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
         serial8250_rpm_get(up);
         spin_lock_irqsave(&port->lock, flags);
 
+        up->lcr = cval;                                 /* Save computed LCR */
+
         /*
          * Update the per-port timeout.
          */
@@ -2590,43 +2636,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
                         serial_port_out(port, UART_EFR, efr);
         }
 
-        /* Workaround to enable 115200 baud on OMAP1510 internal ports */
-        if (is_omap1510_8250(up)) {
-                if (baud == 115200) {
-                        quot = 1;
-                        serial_port_out(port, UART_OMAP_OSC_12M_SEL, 1);
-                } else
-                        serial_port_out(port, UART_OMAP_OSC_12M_SEL, 0);
-        }
-
-        /*
-         * For NatSemi, switch to bank 2 not bank 1, to avoid resetting EXCR2,
-         * otherwise just set DLAB
-         */
-        if (up->capabilities & UART_NATSEMI)
-                serial_port_out(port, UART_LCR, 0xe0);
-        else
-                serial_port_out(port, UART_LCR, cval | UART_LCR_DLAB);
-
-        serial_dl_write(up, quot);
-
-        /*
-         * XR17V35x UARTs have an extra fractional divisor register (DLD)
-         *
-         * We need to recalculate all of the registers, because DLM and DLL
-         * are already rounded to a whole integer.
-         *
-         * When recalculating we use a 32x clock instead of a 16x clock to
-         * allow 1-bit for rounding in the fractional part.
-         */
-        if (up->port.type == PORT_XR17V35X) {
-                unsigned int baud_x32 = (port->uartclk * 2) / baud;
-                u16 quot = baud_x32 / 32;
-                u8 quot_frac = DIV_ROUND_CLOSEST(baud_x32 % 32, 2);
-
-                serial_dl_write(up, quot);
-                serial_port_out(port, 0x2, quot_frac & 0xf);
-        }
+        serial8250_set_divisor(port, baud, quot);
 
         /*
          * LCR DLAB must be set to enable 64-byte FIFO mode. If the FCR
@@ -2635,8 +2645,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
         if (port->type == PORT_16750)
                 serial_port_out(port, UART_FCR, up->fcr);
 
-        serial_port_out(port, UART_LCR, cval);          /* reset DLAB */
-        up->lcr = cval;                                 /* Save LCR */
+        serial_port_out(port, UART_LCR, up->lcr);       /* reset DLAB */
         if (port->type != PORT_16750) {
                 /* emulated UARTs (Lucent Venus 167x) need two steps */
                 if (up->fcr & UART_FCR_ENABLE_FIFO)