drivers/tty/serial/8250/8250_platform.c

// SPDX-License-Identifier: GPL-2.0+
/*
 *  Universal/legacy platform driver for 8250/16550-type serial ports
 *
 *  Supports:
 *	      ISA-compatible 8250/16550 ports
 *	      ACPI 8250/16550 ports
 *	      PNP 8250/16550 ports
 *	      "serial8250" platform devices
 */
#include <linux/acpi.h>
#include <linux/array_size.h>
#include <linux/cleanup.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/once.h>
#include <linux/platform_device.h>

#include <linux/serial_8250.h>

#ifdef CONFIG_SPARC
#include <linux/sunserialcore.h>
#endif

#include "8250.h"

/*
 * Configuration:
 * share_irqs:     Whether we pass IRQF_SHARED to request_irq().
 *                 This option is unsafe when used on edge-triggered interrupts.
 */
static bool share_irqs = IS_ENABLED(CONFIG_SERIAL_8250_SHARE_IRQ);

unsigned int nr_uarts = CONFIG_SERIAL_8250_RUNTIME_UARTS;

#include <asm/serial.h>

/*
 * SERIAL_PORT_DFNS tells us about built-in ports that have no
 * standard enumeration mechanism. Platforms that can find all
 * serial ports via mechanisms like ACPI or PCI need not supply it.
 */
#ifndef SERIAL_PORT_DFNS
#define SERIAL_PORT_DFNS
#endif

static const struct old_serial_port old_serial_port[] = {
	SERIAL_PORT_DFNS /* defined in asm/serial.h */
};

serial8250_isa_config_fn serial8250_isa_config;
void serial8250_set_isa_configurator(serial8250_isa_config_fn v)
{
	serial8250_isa_config = v;
}
EXPORT_SYMBOL(serial8250_set_isa_configurator);

static void __init __serial8250_isa_init_ports(void)
{
	int i;

	if (nr_uarts > UART_NR)
		nr_uarts = UART_NR;

	/*
	 * Set up initial ISA ports based on nr_uart module param, or else
	 * default to CONFIG_SERIAL_8250_RUNTIME_UARTS. Note that we do not
	 * need to increase nr_uarts when setting up the initial ISA ports.
	 */
	for (i = 0; i < nr_uarts; i++)
		serial8250_setup_port(i);

	/* chain base port ops to support Remote Supervisor Adapter */
	univ8250_port_ops = *univ8250_port_base_ops;
	univ8250_rsa_support(&univ8250_port_ops, univ8250_port_base_ops);

	for (i = 0; i < ARRAY_SIZE(old_serial_port) && i < nr_uarts; i++) {
		struct uart_8250_port *up = serial8250_get_port(i);
		struct uart_port *port = &up->port;

		port->iobase   = old_serial_port[i].port;
		port->irq      = irq_canonicalize(old_serial_port[i].irq);
		port->irqflags = 0;
		port->uartclk  = old_serial_port[i].baud_base * 16;
		port->flags    = old_serial_port[i].flags;
		port->hub6     = 0;
		port->membase  = old_serial_port[i].iomem_base;
		port->iotype   = old_serial_port[i].io_type;
		port->regshift = old_serial_port[i].iomem_reg_shift;

		if (share_irqs)
			port->irqflags |= IRQF_SHARED;

		if (serial8250_isa_config != NULL)
			serial8250_isa_config(i, &up->port, &up->capabilities);
	}
}

void __init serial8250_isa_init_ports(void)
{
	DO_ONCE(__serial8250_isa_init_ports);
}

/*
 * Generic 16550A platform devices
 */
static int serial8250_probe_acpi(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct resource *regs;
	int ret, line;

	struct uart_8250_port *uart __free(kfree) = kzalloc_obj(*uart);
	if (!uart)
		return -ENOMEM;

	regs = platform_get_mem_or_io(pdev, 0);
	if (!regs)
		return dev_err_probe(dev, -EINVAL, "no registers defined\n");

	switch (resource_type(regs)) {
	case IORESOURCE_IO:
		uart->port.iobase = regs->start;
		break;
	case IORESOURCE_MEM:
		uart->port.mapbase = regs->start;
		uart->port.mapsize = resource_size(regs);
		uart->port.flags = UPF_IOREMAP;
		break;
	default:
		return -EINVAL;
	}

	/* default clock frequency */
	uart->port.uartclk = 1843200;
	uart->port.type = PORT_16550A;
	uart->port.dev = &pdev->dev;
	uart->port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;

	ret = uart_read_and_validate_port_properties(&uart->port);
	/* no interrupt -> fall back to polling */
	if (ret == -ENXIO)
		ret = 0;
	if (ret)
		return ret;

	line = serial8250_register_8250_port(uart);
	if (line < 0)
		return line;

	return 0;
}

static int serial8250_probe_platform(struct platform_device *dev, struct plat_serial8250_port *p)
{
	int ret, i;

	struct uart_8250_port *uart __free(kfree) = kzalloc_obj(*uart);
	if (!uart)
		return -ENOMEM;

	for (i = 0; p && p->flags != 0; p++, i++) {
		uart->port.iobase	= p->iobase;
		uart->port.membase	= p->membase;
		uart->port.irq		= p->irq;
		uart->port.irqflags	= p->irqflags;
		uart->port.uartclk	= p->uartclk;
		uart->port.regshift	= p->regshift;
		uart->port.iotype	= p->iotype;
		uart->port.flags		= p->flags;
		uart->port.mapbase	= p->mapbase;
		uart->port.mapsize	= p->mapsize;
		uart->port.hub6		= p->hub6;
		uart->port.has_sysrq	= p->has_sysrq;
		uart->port.private_data	= p->private_data;
		uart->port.type		= p->type;
		uart->bugs		= p->bugs;
		uart->port.serial_in	= p->serial_in;
		uart->port.serial_out	= p->serial_out;
		uart->dl_read		= p->dl_read;
		uart->dl_write		= p->dl_write;
		uart->port.handle_irq	= p->handle_irq;
		uart->port.handle_break	= p->handle_break;
		uart->port.set_termios	= p->set_termios;
		uart->port.set_ldisc	= p->set_ldisc;
		uart->port.get_mctrl	= p->get_mctrl;
		uart->port.pm		= p->pm;
		uart->port.dev		= &dev->dev;

		if (share_irqs)
			uart->port.irqflags |= IRQF_SHARED;

		ret = serial8250_register_8250_port(uart);
		if (ret < 0) {
			dev_err(&dev->dev, "unable to register port at index %d "
				"(IO%lx MEM%llx IRQ%d): %d\n", i,
				p->iobase, (unsigned long long)p->mapbase,
				p->irq, ret);
		}
	}
	return 0;
}

/*
 * Register a set of serial devices attached to a platform device.
 * The list is terminated with a zero flags entry, which means we expect
 * all entries to have at least UPF_BOOT_AUTOCONF set.
 */
static int serial8250_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct plat_serial8250_port *p;

	p = dev_get_platdata(dev);
	if (p)
		return serial8250_probe_platform(pdev, p);

	/*
	 * Probe platform UART devices defined using standard hardware
	 * discovery mechanism like ACPI or DT. Support only ACPI based
	 * serial device for now.
	 */
	if (has_acpi_companion(dev))
		return serial8250_probe_acpi(pdev);

	return 0;
}

/*
 * Remove serial ports registered against a platform device.
 */
static void serial8250_remove(struct platform_device *dev)
{
	int i;

	for (i = 0; i < nr_uarts; i++) {
		struct uart_8250_port *up = serial8250_get_port(i);

		if (up->port.dev == &dev->dev)
			serial8250_unregister_port(i);
	}
}

static int serial8250_suspend(struct platform_device *dev, pm_message_t state)
{
	int i;

	for (i = 0; i < UART_NR; i++) {
		struct uart_8250_port *up = serial8250_get_port(i);

		if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
			uart_suspend_port(&serial8250_reg, &up->port);
	}

	return 0;
}

static int serial8250_resume(struct platform_device *dev)
{
	int i;

	for (i = 0; i < UART_NR; i++) {
		struct uart_8250_port *up = serial8250_get_port(i);

		if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
			serial8250_resume_port(i);
	}

	return 0;
}

static const struct acpi_device_id acpi_platform_serial_table[] = {
	{ "RSCV0003" }, /* RISC-V Generic 16550A UART */
	{ }
};
MODULE_DEVICE_TABLE(acpi, acpi_platform_serial_table);

static struct platform_driver serial8250_isa_driver = {
	.probe		= serial8250_probe,
	.remove		= serial8250_remove,
	.suspend	= serial8250_suspend,
	.resume		= serial8250_resume,
	.driver		= {
		.name	= "serial8250",
		.acpi_match_table = acpi_platform_serial_table,
		.probe_type = PROBE_FORCE_SYNCHRONOUS,
	},
};

/*
 * This "device" covers _all_ ISA 8250-compatible serial devices listed
 * in the table in include/asm/serial.h.
 */
struct platform_device *serial8250_isa_devs;

static int __init serial8250_init(void)
{
	int ret;

	if (nr_uarts == 0)
		return -ENODEV;

	serial8250_isa_init_ports();

	pr_info("Serial: 8250/16550 driver, %d ports, IRQ sharing %s\n",
		nr_uarts, str_enabled_disabled(share_irqs));

#ifdef CONFIG_SPARC
	ret = sunserial_register_minors(&serial8250_reg, UART_NR);
#else
	serial8250_reg.nr = UART_NR;
	ret = uart_register_driver(&serial8250_reg);
#endif
	if (ret)
		goto out;

	ret = serial8250_pnp_init();
	if (ret)
		goto unreg_uart_drv;

	serial8250_isa_devs = platform_device_alloc("serial8250", PLAT8250_DEV_LEGACY);
	if (!serial8250_isa_devs) {
		ret = -ENOMEM;
		goto unreg_pnp;
	}

	ret = platform_device_add(serial8250_isa_devs);
	if (ret)
		goto put_dev;

	serial8250_register_ports(&serial8250_reg, &serial8250_isa_devs->dev);

	ret = platform_driver_register(&serial8250_isa_driver);
	if (ret == 0)
		goto out;

	platform_device_del(serial8250_isa_devs);
put_dev:
	platform_device_put(serial8250_isa_devs);
unreg_pnp:
	serial8250_pnp_exit();
unreg_uart_drv:
#ifdef CONFIG_SPARC
	sunserial_unregister_minors(&serial8250_reg, UART_NR);
#else
	uart_unregister_driver(&serial8250_reg);
#endif
out:
	return ret;
}
module_init(serial8250_init);

static void __exit serial8250_exit(void)
{
	struct platform_device *isa_dev = serial8250_isa_devs;

	/*
	 * This tells serial8250_unregister_port() not to re-register
	 * the ports (thereby making serial8250_isa_driver permanently
	 * in use).
	 */
	serial8250_isa_devs = NULL;

	platform_driver_unregister(&serial8250_isa_driver);
	platform_device_unregister(isa_dev);

	serial8250_pnp_exit();

#ifdef CONFIG_SPARC
	sunserial_unregister_minors(&serial8250_reg, UART_NR);
#else
	uart_unregister_driver(&serial8250_reg);
#endif
}
module_exit(serial8250_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Generic 8250/16x50 serial platform driver");

module_param_hw(share_irqs, bool, other, 0644);
MODULE_PARM_DESC(share_irqs, "Share IRQs with other non-8250/16x50 devices (unsafe)");

module_param(nr_uarts, uint, 0644);
MODULE_PARM_DESC(nr_uarts, "Maximum number of UARTs supported. (1-" __MODULE_STRING(CONFIG_SERIAL_8250_NR_UARTS) ")");

MODULE_ALIAS_CHARDEV_MAJOR(TTY_MAJOR);