[SERIAL] Convert fifosize to an unsigned int

Some UARTs have more than 255 bytes of FIFO, which can't be
represented by an unsigned char.  Change the kernel's internal
structure to be an unsigned int, but still export an unsigned char
via the TIOCGSERIAL ioctl.  If the TIOCSSERIAL ioctl provides a
fifo size of 0, assume this means "don't change" otherwise we'll
corrupt the larger fifo sizes.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.c
index 6459edc..1b2cdc9 100644 (file)
--- a/drivers/serial/mpc52xx_uart.c
+++ b/drivers/serial/mpc52xx_uart.c
@@ -728,8 +728,7 @@ mpc52xx_uart_probe(struct platform_device *dev)
 
        spin_lock_init(&port->lock);
        port->uartclk   = __res.bi_ipbfreq / 2; /* Look at CTLR doc */
-       port->fifosize  = 255; /* Should be 512 ! But it can't be */
-                              /* stored in a unsigned char       */
+       port->fifosize  = 512;
        port->iotype    = UPIO_MEM;
        port->flags     = UPF_BOOT_AUTOCONF |
                          ( uart_console(port) ? 0 : UPF_IOREMAP );

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 17839e7..3805f46 100644 (file)
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -691,7 +691,8 @@ static int uart_set_info(struct uart_state *state,
                    (new_serial.baud_base != port->uartclk / 16) ||
                    (close_delay != state->close_delay) ||
                    (closing_wait != state->closing_wait) ||
-                   (new_serial.xmit_fifo_size != port->fifosize) ||
+                   (new_serial.xmit_fifo_size &&
+                    new_serial.xmit_fifo_size != port->fifosize) ||
                    (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
                        goto exit;
                port->flags = ((port->flags & ~UPF_USR_MASK) |
@@ -796,7 +797,8 @@ static int uart_set_info(struct uart_state *state,
        port->custom_divisor   = new_serial.custom_divisor;
        state->close_delay     = close_delay;
        state->closing_wait    = closing_wait;
-       port->fifosize         = new_serial.xmit_fifo_size;
+       if (new_serial.xmit_fifo_size)
+               port->fifosize = new_serial.xmit_fifo_size;
        if (state->info->tty)
                state->info->tty->low_latency =
                        (port->flags & UPF_LOW_LATENCY) ? 1 : 0;

diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index bd14858..966e2e8 100644 (file)
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -214,10 +214,11 @@ struct uart_port {
        unsigned char __iomem   *membase;               /* read/write[bwl] */
        unsigned int            irq;                    /* irq number */
        unsigned int            uartclk;                /* base uart clock */
-       unsigned char           fifosize;               /* tx fifo size */
+       unsigned int            fifosize;               /* tx fifo size */
        unsigned char           x_char;                 /* xon/xoff char */
        unsigned char           regshift;               /* reg offset shift */
        unsigned char           iotype;                 /* io access style */
+       unsigned char           unused1;
 
 #define UPIO_PORT              (0)
 #define UPIO_HUB6              (1)