abb4a23907
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>
145 lines
3.7 KiB
C
145 lines
3.7 KiB
C
/*
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* Serial Port driver for Open Firmware platform devices
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*
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* Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/serial_core.h>
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#include <linux/serial_8250.h>
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#include <asm/of_platform.h>
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#include <asm/prom.h>
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/*
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* Fill a struct uart_port for a given device node
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*/
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static int __devinit of_platform_serial_setup(struct of_device *ofdev,
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int type, struct uart_port *port)
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{
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struct resource resource;
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struct device_node *np = ofdev->node;
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const unsigned int *clk, *spd;
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int ret;
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memset(port, 0, sizeof *port);
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spd = get_property(np, "current-speed", NULL);
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clk = get_property(np, "clock-frequency", NULL);
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if (!clk) {
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dev_warn(&ofdev->dev, "no clock-frequency property set\n");
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return -ENODEV;
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}
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ret = of_address_to_resource(np, 0, &resource);
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if (ret) {
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dev_warn(&ofdev->dev, "invalid address\n");
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return ret;
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}
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spin_lock_init(&port->lock);
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port->mapbase = resource.start;
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port->irq = irq_of_parse_and_map(np, 0);
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port->iotype = UPIO_MEM;
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port->type = type;
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port->uartclk = *clk;
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port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
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| UPF_FIXED_PORT;
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port->dev = &ofdev->dev;
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port->custom_divisor = *clk / (16 * (*spd));
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return 0;
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}
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/*
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* Try to register a serial port
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*/
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static int __devinit of_platform_serial_probe(struct of_device *ofdev,
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const struct of_device_id *id)
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{
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struct uart_port port;
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int port_type;
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int ret;
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if (of_find_property(ofdev->node, "used-by-rtas", NULL))
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return -EBUSY;
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port_type = (unsigned long)id->data;
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ret = of_platform_serial_setup(ofdev, port_type, &port);
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if (ret)
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goto out;
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switch (port_type) {
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case PORT_UNKNOWN:
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dev_info(&ofdev->dev, "Unknown serial port found, "
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"attempting to use 8250 driver\n");
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/* fallthrough */
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case PORT_8250 ... PORT_MAX_8250:
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ret = serial8250_register_port(&port);
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break;
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default:
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/* need to add code for these */
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ret = -ENODEV;
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break;
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}
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if (ret < 0)
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goto out;
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ofdev->dev.driver_data = (void *)(unsigned long)ret;
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return 0;
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out:
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irq_dispose_mapping(port.irq);
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return ret;
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}
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/*
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* Release a line
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*/
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static int of_platform_serial_remove(struct of_device *ofdev)
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{
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int line = (unsigned long)ofdev->dev.driver_data;
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serial8250_unregister_port(line);
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return 0;
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}
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/*
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* A few common types, add more as needed.
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*/
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static struct of_device_id __devinitdata of_platform_serial_table[] = {
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{ .type = "serial", .compatible = "ns8250", .data = (void *)PORT_8250, },
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{ .type = "serial", .compatible = "ns16450", .data = (void *)PORT_16450, },
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{ .type = "serial", .compatible = "ns16550", .data = (void *)PORT_16550, },
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{ .type = "serial", .compatible = "ns16750", .data = (void *)PORT_16750, },
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{ .type = "serial", .data = (void *)PORT_UNKNOWN, },
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{ /* end of list */ },
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};
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static struct of_platform_driver __devinitdata of_platform_serial_driver = {
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.owner = THIS_MODULE,
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.name = "of_serial",
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.probe = of_platform_serial_probe,
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.remove = of_platform_serial_remove,
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.match_table = of_platform_serial_table,
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};
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static int __init of_platform_serial_init(void)
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{
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return of_register_platform_driver(&of_platform_serial_driver);
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}
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module_init(of_platform_serial_init);
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static void __exit of_platform_serial_exit(void)
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{
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return of_unregister_platform_driver(&of_platform_serial_driver);
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};
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module_exit(of_platform_serial_exit);
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MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");
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