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authorDavid Gibson <david@gibson.dropbear.id.au>2007-05-06 14:48:49 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-07 12:12:50 -0700
commitabb4a2390737867353ebafc012d45f2b03f3f944 (patch)
treee62e2ae859f235667eb2002ef9dd651e7c7a8ea0 /drivers/serial/serial_core.c
parentbd71c182d5a02337305fc381831c11029dd17d64 (diff)
serial: define FIXED_PORT flag for serial_core
At present, the serial core always allows setserial in userspace to change the port address, irq and base clock of any serial port. That makes sense for legacy ISA ports, but not for (say) embedded ns16550 compatible serial ports at peculiar addresses. In these cases, the kernel code configuring the ports must know exactly where they are, and their clocking arrangements (which can be unusual on embedded boards). It doesn't make sense for userspace to change these settings. Therefore, this patch defines a UPF_FIXED_PORT flag for the uart_port structure. If this flag is set when the serial port is configured, any attempts to alter the port's type, io address, irq or base clock with setserial are ignored. In addition this patch uses the new flag for on-chip serial ports probed in arch/powerpc/kernel/legacy_serial.c, and for other hard-wired serial ports probed by drivers/serial/of_serial.c. Signed-off-by: David Gibson <dwg@au1.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/serial/serial_core.c')
-rw-r--r--drivers/serial/serial_core.c22
1 files changed, 13 insertions, 9 deletions
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index a677133ab2d4..f409be37b62f 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -672,19 +672,21 @@ static int uart_set_info(struct uart_state *state,
*/
mutex_lock(&state->mutex);
- change_irq = new_serial.irq != port->irq;
+ change_irq = !(port->flags & UPF_FIXED_PORT)
+ && new_serial.irq != port->irq;
/*
* Since changing the 'type' of the port changes its resource
* allocations, we should treat type changes the same as
* IO port changes.
*/
- change_port = new_port != port->iobase ||
- (unsigned long)new_serial.iomem_base != port->mapbase ||
- new_serial.hub6 != port->hub6 ||
- new_serial.io_type != port->iotype ||
- new_serial.iomem_reg_shift != port->regshift ||
- new_serial.type != port->type;
+ change_port = !(port->flags & UPF_FIXED_PORT)
+ && (new_port != port->iobase ||
+ (unsigned long)new_serial.iomem_base != port->mapbase ||
+ new_serial.hub6 != port->hub6 ||
+ new_serial.io_type != port->iotype ||
+ new_serial.iomem_reg_shift != port->regshift ||
+ new_serial.type != port->type);
old_flags = port->flags;
new_flags = new_serial.flags;
@@ -796,8 +798,10 @@ static int uart_set_info(struct uart_state *state,
}
}
- port->irq = new_serial.irq;
- port->uartclk = new_serial.baud_base * 16;
+ if (change_irq)
+ port->irq = new_serial.irq;
+ if (!(port->flags & UPF_FIXED_PORT))
+ port->uartclk = new_serial.baud_base * 16;
port->flags = (port->flags & ~UPF_CHANGE_MASK) |
(new_flags & UPF_CHANGE_MASK);
port->custom_divisor = new_serial.custom_divisor;