326 lines
8.7 KiB
C
326 lines
8.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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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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#include <linux/bits.h>
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#include <linux/console.h>
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#include <linux/math.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/serial_core.h>
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#include <linux/serial_reg.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/of_platform.h>
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#include <linux/pm_runtime.h>
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#include <linux/clk.h>
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#include <linux/reset.h>
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#include "8250.h"
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struct of_serial_info {
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struct clk *clk;
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struct reset_control *rst;
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int type;
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int line;
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};
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/* Nuvoton NPCM timeout register */
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#define UART_NPCM_TOR 7
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#define UART_NPCM_TOIE BIT(7) /* Timeout Interrupt Enable */
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static int npcm_startup(struct uart_port *port)
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{
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/*
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* Nuvoton calls the scratch register 'UART_TOR' (timeout
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* register). Enable it, and set TIOC (timeout interrupt
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* comparator) to be 0x20 for correct operation.
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*/
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serial_port_out(port, UART_NPCM_TOR, UART_NPCM_TOIE | 0x20);
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return serial8250_do_startup(port);
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}
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/* Nuvoton NPCM UARTs have a custom divisor calculation */
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static unsigned int npcm_get_divisor(struct uart_port *port, unsigned int baud,
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unsigned int *frac)
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{
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return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2;
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}
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static int npcm_setup(struct uart_port *port)
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{
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port->get_divisor = npcm_get_divisor;
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port->startup = npcm_startup;
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return 0;
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}
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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 of_platform_serial_setup(struct platform_device *ofdev,
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int type, struct uart_8250_port *up,
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struct of_serial_info *info)
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{
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struct resource resource;
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struct device *dev = &ofdev->dev;
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struct device_node *np = dev->of_node;
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struct uart_port *port = &up->port;
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u32 spd;
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int ret;
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memset(port, 0, sizeof *port);
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pm_runtime_enable(&ofdev->dev);
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pm_runtime_get_sync(&ofdev->dev);
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ret = of_address_to_resource(np, 0, &resource);
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if (ret) {
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dev_err_probe(dev, ret, "invalid address\n");
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goto err_pmruntime;
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}
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port->dev = &ofdev->dev;
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port->flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_FIXED_TYPE;
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spin_lock_init(&port->lock);
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if (resource_type(&resource) == IORESOURCE_IO) {
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port->iotype = UPIO_PORT;
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port->iobase = resource.start;
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} else {
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port->mapbase = resource.start;
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port->mapsize = resource_size(&resource);
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port->flags |= UPF_IOREMAP;
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}
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ret = uart_read_and_validate_port_properties(port);
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if (ret)
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goto err_pmruntime;
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/* Get clk rate through clk driver if present */
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if (!port->uartclk) {
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info->clk = devm_clk_get_enabled(dev, NULL);
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if (IS_ERR(info->clk)) {
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ret = dev_err_probe(dev, PTR_ERR(info->clk), "failed to get clock\n");
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goto err_pmruntime;
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}
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port->uartclk = clk_get_rate(info->clk);
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}
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/* If current-speed was set, then try not to change it. */
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if (of_property_read_u32(np, "current-speed", &spd) == 0)
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port->custom_divisor = port->uartclk / (16 * spd);
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/* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */
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if (of_device_is_compatible(np, "mrvl,mmp-uart"))
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port->regshift = 2;
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info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
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if (IS_ERR(info->rst)) {
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ret = PTR_ERR(info->rst);
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goto err_pmruntime;
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}
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ret = reset_control_deassert(info->rst);
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if (ret)
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goto err_pmruntime;
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port->type = type;
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port->rs485_config = serial8250_em485_config;
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port->rs485_supported = serial8250_em485_supported;
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up->rs485_start_tx = serial8250_em485_start_tx;
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up->rs485_stop_tx = serial8250_em485_stop_tx;
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switch (type) {
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case PORT_RT2880:
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ret = rt288x_setup(port);
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break;
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case PORT_NPCM:
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ret = npcm_setup(port);
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break;
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default:
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/* Nothing to do */
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ret = 0;
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break;
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}
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if (ret)
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goto err_pmruntime;
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if (IS_REACHABLE(CONFIG_SERIAL_8250_FSL) &&
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(of_device_is_compatible(np, "fsl,ns16550") ||
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of_device_is_compatible(np, "fsl,16550-FIFO64"))) {
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port->handle_irq = fsl8250_handle_irq;
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port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
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}
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return 0;
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err_pmruntime:
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pm_runtime_put_sync(&ofdev->dev);
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pm_runtime_disable(&ofdev->dev);
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return ret;
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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 of_platform_serial_probe(struct platform_device *ofdev)
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{
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struct of_serial_info *info;
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struct uart_8250_port port8250;
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unsigned int port_type;
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u32 tx_threshold;
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int ret;
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if (IS_ENABLED(CONFIG_SERIAL_8250_BCM7271) &&
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of_device_is_compatible(ofdev->dev.of_node, "brcm,bcm7271-uart"))
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return -ENODEV;
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port_type = (unsigned long)of_device_get_match_data(&ofdev->dev);
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if (port_type == PORT_UNKNOWN)
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return -EINVAL;
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if (of_property_read_bool(ofdev->dev.of_node, "used-by-rtas"))
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return -EBUSY;
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info = kzalloc(sizeof(*info), GFP_KERNEL);
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if (info == NULL)
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return -ENOMEM;
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memset(&port8250, 0, sizeof(port8250));
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ret = of_platform_serial_setup(ofdev, port_type, &port8250, info);
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if (ret)
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goto err_free;
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if (port8250.port.fifosize)
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port8250.capabilities = UART_CAP_FIFO;
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/* Check for TX FIFO threshold & set tx_loadsz */
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if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold",
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&tx_threshold) == 0) &&
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(tx_threshold < port8250.port.fifosize))
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port8250.tx_loadsz = port8250.port.fifosize - tx_threshold;
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if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control"))
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port8250.capabilities |= UART_CAP_AFE;
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if (of_property_read_u32(ofdev->dev.of_node,
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"overrun-throttle-ms",
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&port8250.overrun_backoff_time_ms) != 0)
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port8250.overrun_backoff_time_ms = 0;
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ret = serial8250_register_8250_port(&port8250);
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if (ret < 0)
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goto err_dispose;
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info->type = port_type;
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info->line = ret;
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platform_set_drvdata(ofdev, info);
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return 0;
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err_dispose:
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pm_runtime_put_sync(&ofdev->dev);
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pm_runtime_disable(&ofdev->dev);
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err_free:
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kfree(info);
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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 void of_platform_serial_remove(struct platform_device *ofdev)
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{
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struct of_serial_info *info = platform_get_drvdata(ofdev);
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serial8250_unregister_port(info->line);
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reset_control_assert(info->rst);
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pm_runtime_put_sync(&ofdev->dev);
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pm_runtime_disable(&ofdev->dev);
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kfree(info);
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}
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#ifdef CONFIG_PM_SLEEP
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static int of_serial_suspend(struct device *dev)
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{
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struct of_serial_info *info = dev_get_drvdata(dev);
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struct uart_8250_port *port8250 = serial8250_get_port(info->line);
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struct uart_port *port = &port8250->port;
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serial8250_suspend_port(info->line);
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if (!uart_console(port) || console_suspend_enabled) {
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pm_runtime_put_sync(dev);
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clk_disable_unprepare(info->clk);
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}
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return 0;
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}
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static int of_serial_resume(struct device *dev)
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{
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struct of_serial_info *info = dev_get_drvdata(dev);
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struct uart_8250_port *port8250 = serial8250_get_port(info->line);
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struct uart_port *port = &port8250->port;
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if (!uart_console(port) || console_suspend_enabled) {
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pm_runtime_get_sync(dev);
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clk_prepare_enable(info->clk);
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}
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serial8250_resume_port(info->line);
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return 0;
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}
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#endif
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static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
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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 const struct of_device_id of_platform_serial_table[] = {
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{ .compatible = "ns8250", .data = (void *)PORT_8250, },
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{ .compatible = "ns16450", .data = (void *)PORT_16450, },
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{ .compatible = "ns16550a", .data = (void *)PORT_16550A, },
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{ .compatible = "ns16550", .data = (void *)PORT_16550, },
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{ .compatible = "ns16750", .data = (void *)PORT_16750, },
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{ .compatible = "ns16850", .data = (void *)PORT_16850, },
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{ .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
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{ .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
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{ .compatible = "intel,xscale-uart", .data = (void *)PORT_XSCALE, },
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{ .compatible = "altr,16550-FIFO32",
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.data = (void *)PORT_ALTR_16550_F32, },
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{ .compatible = "altr,16550-FIFO64",
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.data = (void *)PORT_ALTR_16550_F64, },
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{ .compatible = "altr,16550-FIFO128",
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.data = (void *)PORT_ALTR_16550_F128, },
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{ .compatible = "fsl,16550-FIFO64",
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.data = (void *)PORT_16550A_FSL64, },
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{ .compatible = "mediatek,mtk-btif",
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.data = (void *)PORT_MTK_BTIF, },
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{ .compatible = "mrvl,mmp-uart",
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.data = (void *)PORT_XSCALE, },
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{ .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
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{ .compatible = "nuvoton,wpcm450-uart", .data = (void *)PORT_NPCM, },
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{ .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, },
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{ /* end of list */ },
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};
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MODULE_DEVICE_TABLE(of, of_platform_serial_table);
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static struct platform_driver of_platform_serial_driver = {
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.driver = {
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.name = "of_serial",
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.of_match_table = of_platform_serial_table,
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.pm = &of_serial_pm_ops,
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},
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.probe = of_platform_serial_probe,
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.remove_new = of_platform_serial_remove,
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};
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module_platform_driver(of_platform_serial_driver);
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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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