/* * Synopsys DesignWare 8250 driver. * * Copyright 2011 Picochip, Jamie Iles. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * The Synopsys DesignWare 8250 has an extra feature whereby it detects if the * LCR is written whilst busy. If it is, then a busy detect interrupt is * raised, the LCR needs to be rewritten and the uart status register read. */ #include <linux/device.h> #include <linux/init.h> #include <linux/io.h> #include <linux/module.h> #include <linux/serial_8250.h> #include <linux/serial_core.h> #include <linux/serial_reg.h> #include <linux/of.h> #include <linux/of_irq.h> #include <linux/of_platform.h> #include <linux/platform_device.h> #include <linux/slab.h> struct dw8250_data { int last_lcr; int line; }; static void dw8250_serial_out(struct uart_port *p, int offset, int value) { struct dw8250_data *d = p->private_data; if (offset == UART_LCR) d->last_lcr = value; offset <<= p->regshift; writeb(value, p->membase + offset); } static unsigned int dw8250_serial_in(struct uart_port *p, int offset) { offset <<= p->regshift; return readb(p->membase + offset); } static void dw8250_serial_out32(struct uart_port *p, int offset, int value) { struct dw8250_data *d = p->private_data; if (offset == UART_LCR) d->last_lcr = value; offset <<= p->regshift; writel(value, p->membase + offset); } static unsigned int dw8250_serial_in32(struct uart_port *p, int offset) { offset <<= p->regshift; return readl(p->membase + offset); } /* Offset for the DesignWare's UART Status Register. */ #define UART_USR 0x1f static int dw8250_handle_irq(struct uart_port *p) { struct dw8250_data *d = p->private_data; unsigned int iir = p->serial_in(p, UART_IIR); if (serial8250_handle_irq(p, iir)) { return 1; } else if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) { /* Clear the USR and write the LCR again. */ (void)p->serial_in(p, UART_USR); p->serial_out(p, d->last_lcr, UART_LCR); return 1; } return 0; } static int __devinit dw8250_probe(struct platform_device *pdev) { struct uart_port port = {}; struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); struct device_node *np = pdev->dev.of_node; u32 val; struct dw8250_data *data; if (!regs || !irq) { dev_err(&pdev->dev, "no registers/irq defined\n"); return -EINVAL; } data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; port.private_data = data; spin_lock_init(&port.lock); port.mapbase = regs->start; port.irq = irq->start; port.handle_irq = dw8250_handle_irq; port.type = PORT_8250; port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP | UPF_FIXED_PORT | UPF_FIXED_TYPE; port.dev = &pdev->dev; port.iotype = UPIO_MEM; port.serial_in = dw8250_serial_in; port.serial_out = dw8250_serial_out; if (!of_property_read_u32(np, "reg-io-width", &val)) { switch (val) { case 1: break; case 4: port.iotype = UPIO_MEM32; port.serial_in = dw8250_serial_in32; port.serial_out = dw8250_serial_out32; break; default: dev_err(&pdev->dev, "unsupported reg-io-width (%u)\n", val); return -EINVAL; } } if (!of_property_read_u32(np, "reg-shift", &val)) port.regshift = val; if (of_property_read_u32(np, "clock-frequency", &val)) { dev_err(&pdev->dev, "no clock-frequency property set\n"); return -EINVAL; } port.uartclk = val; data->line = serial8250_register_port(&port); if (data->line < 0) return data->line; platform_set_drvdata(pdev, data); return 0; } static int __devexit dw8250_remove(struct platform_device *pdev) { struct dw8250_data *data = platform_get_drvdata(pdev); serial8250_unregister_port(data->line); return 0; } static const struct of_device_id dw8250_match[] = { { .compatible = "snps,dw-apb-uart" }, { /* Sentinel */ } }; MODULE_DEVICE_TABLE(of, dw8250_match); static struct platform_driver dw8250_platform_driver = { .driver = { .name = "dw-apb-uart", .owner = THIS_MODULE, .of_match_table = dw8250_match, }, .probe = dw8250_probe, .remove = __devexit_p(dw8250_remove), }; module_platform_driver(dw8250_platform_driver); MODULE_AUTHOR("Jamie Iles"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Synopsys DesignWare 8250 serial port driver");