/* * altera_jtaguart.c -- Altera JTAG UART driver * * Based on mcf.c -- Freescale ColdFire UART driver * * (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com> * (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw> * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch> * * 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. */ #include <linux/kernel.h> #include <linux/init.h> #include <linux/interrupt.h> #include <linux/module.h> #include <linux/console.h> #include <linux/tty.h> #include <linux/tty_flip.h> #include <linux/serial.h> #include <linux/serial_core.h> #include <linux/platform_device.h> #include <linux/io.h> #include <linux/altera_jtaguart.h> #define DRV_NAME "altera_jtaguart" /* * Altera JTAG UART register definitions according to the Altera JTAG UART * datasheet: http://www.altera.com/literature/hb/nios2/n2cpu_nii51009.pdf */ #define ALTERA_JTAGUART_SIZE 8 #define ALTERA_JTAGUART_DATA_REG 0 #define ALTERA_JTAGUART_DATA_DATA_MSK 0x000000FF #define ALTERA_JTAGUART_DATA_RVALID_MSK 0x00008000 #define ALTERA_JTAGUART_DATA_RAVAIL_MSK 0xFFFF0000 #define ALTERA_JTAGUART_DATA_RAVAIL_OFF 16 #define ALTERA_JTAGUART_CONTROL_REG 4 #define ALTERA_JTAGUART_CONTROL_RE_MSK 0x00000001 #define ALTERA_JTAGUART_CONTROL_WE_MSK 0x00000002 #define ALTERA_JTAGUART_CONTROL_RI_MSK 0x00000100 #define ALTERA_JTAGUART_CONTROL_RI_OFF 8 #define ALTERA_JTAGUART_CONTROL_WI_MSK 0x00000200 #define ALTERA_JTAGUART_CONTROL_AC_MSK 0x00000400 #define ALTERA_JTAGUART_CONTROL_WSPACE_MSK 0xFFFF0000 #define ALTERA_JTAGUART_CONTROL_WSPACE_OFF 16 /* * Local per-uart structure. */ struct altera_jtaguart { struct uart_port port; unsigned int sigs; /* Local copy of line sigs */ unsigned long imr; /* Local IMR mirror */ }; static unsigned int altera_jtaguart_tx_empty(struct uart_port *port) { return (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) & ALTERA_JTAGUART_CONTROL_WSPACE_MSK) ? TIOCSER_TEMT : 0; } static unsigned int altera_jtaguart_get_mctrl(struct uart_port *port) { return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; } static void altera_jtaguart_set_mctrl(struct uart_port *port, unsigned int sigs) { } static void altera_jtaguart_start_tx(struct uart_port *port) { struct altera_jtaguart *pp = container_of(port, struct altera_jtaguart, port); pp->imr |= ALTERA_JTAGUART_CONTROL_WE_MSK; writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG); } static void altera_jtaguart_stop_tx(struct uart_port *port) { struct altera_jtaguart *pp = container_of(port, struct altera_jtaguart, port); pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK; writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG); } static void altera_jtaguart_stop_rx(struct uart_port *port) { struct altera_jtaguart *pp = container_of(port, struct altera_jtaguart, port); pp->imr &= ~ALTERA_JTAGUART_CONTROL_RE_MSK; writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG); } static void altera_jtaguart_break_ctl(struct uart_port *port, int break_state) { } static void altera_jtaguart_enable_ms(struct uart_port *port) { } static void altera_jtaguart_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { /* Just copy the old termios settings back */ if (old) tty_termios_copy_hw(termios, old); } static void altera_jtaguart_rx_chars(struct altera_jtaguart *pp) { struct uart_port *port = &pp->port; unsigned char ch, flag; unsigned long status; while ((status = readl(port->membase + ALTERA_JTAGUART_DATA_REG)) & ALTERA_JTAGUART_DATA_RVALID_MSK) { ch = status & ALTERA_JTAGUART_DATA_DATA_MSK; flag = TTY_NORMAL; port->icount.rx++; if (uart_handle_sysrq_char(port, ch)) continue; uart_insert_char(port, 0, 0, ch, flag); } tty_flip_buffer_push(port->state->port.tty); } static void altera_jtaguart_tx_chars(struct altera_jtaguart *pp) { struct uart_port *port = &pp->port; struct circ_buf *xmit = &port->state->xmit; unsigned int pending, count; if (port->x_char) { /* Send special char - probably flow control */ writel(port->x_char, port->membase + ALTERA_JTAGUART_DATA_REG); port->x_char = 0; port->icount.tx++; return; } pending = uart_circ_chars_pending(xmit); if (pending > 0) { count = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) & ALTERA_JTAGUART_CONTROL_WSPACE_MSK) >> ALTERA_JTAGUART_CONTROL_WSPACE_OFF; if (count > pending) count = pending; if (count > 0) { pending -= count; while (count--) { writel(xmit->buf[xmit->tail], port->membase + ALTERA_JTAGUART_DATA_REG); xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); port->icount.tx++; } if (pending < WAKEUP_CHARS) uart_write_wakeup(port); } } if (pending == 0) { pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK; writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG); } } static irqreturn_t altera_jtaguart_interrupt(int irq, void *data) { struct uart_port *port = data; struct altera_jtaguart *pp = container_of(port, struct altera_jtaguart, port); unsigned int isr; isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >> ALTERA_JTAGUART_CONTROL_RI_OFF) & pp->imr; spin_lock(&port->lock); if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK) altera_jtaguart_rx_chars(pp); if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK) altera_jtaguart_tx_chars(pp); spin_unlock(&port->lock); return IRQ_RETVAL(isr); } static void altera_jtaguart_config_port(struct uart_port *port, int flags) { port->type = PORT_ALTERA_JTAGUART; /* Clear mask, so no surprise interrupts. */ writel(0, port->membase + ALTERA_JTAGUART_CONTROL_REG); } static int altera_jtaguart_startup(struct uart_port *port) { struct altera_jtaguart *pp = container_of(port, struct altera_jtaguart, port); unsigned long flags; int ret; ret = request_irq(port->irq, altera_jtaguart_interrupt, IRQF_DISABLED, DRV_NAME, port); if (ret) { pr_err(DRV_NAME ": unable to attach Altera JTAG UART %d " "interrupt vector=%d\n", port->line, port->irq); return ret; } spin_lock_irqsave(&port->lock, flags); /* Enable RX interrupts now */ pp->imr = ALTERA_JTAGUART_CONTROL_RE_MSK; writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG); spin_unlock_irqrestore(&port->lock, flags); return 0; } static void altera_jtaguart_shutdown(struct uart_port *port) { struct altera_jtaguart *pp = container_of(port, struct altera_jtaguart, port); unsigned long flags; spin_lock_irqsave(&port->lock, flags); /* Disable all interrupts now */ pp->imr = 0; writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG); spin_unlock_irqrestore(&port->lock, flags); free_irq(port->irq, port); } static const char *altera_jtaguart_type(struct uart_port *port) { return (port->type == PORT_ALTERA_JTAGUART) ? "Altera JTAG UART" : NULL; } static int altera_jtaguart_request_port(struct uart_port *port) { /* UARTs always present */ return 0; } static void altera_jtaguart_release_port(struct uart_port *port) { /* Nothing to release... */ } static int altera_jtaguart_verify_port(struct uart_port *port, struct serial_struct *ser) { if (ser->type != PORT_UNKNOWN && ser->type != PORT_ALTERA_JTAGUART) return -EINVAL; return 0; } /* * Define the basic serial functions we support. */ static struct uart_ops altera_jtaguart_ops = { .tx_empty = altera_jtaguart_tx_empty, .get_mctrl = altera_jtaguart_get_mctrl, .set_mctrl = altera_jtaguart_set_mctrl, .start_tx = altera_jtaguart_start_tx, .stop_tx = altera_jtaguart_stop_tx, .stop_rx = altera_jtaguart_stop_rx, .enable_ms = altera_jtaguart_enable_ms, .break_ctl = altera_jtaguart_break_ctl, .startup = altera_jtaguart_startup, .shutdown = altera_jtaguart_shutdown, .set_termios = altera_jtaguart_set_termios, .type = altera_jtaguart_type, .request_port = altera_jtaguart_request_port, .release_port = altera_jtaguart_release_port, .config_port = altera_jtaguart_config_port, .verify_port = altera_jtaguart_verify_port, }; #define ALTERA_JTAGUART_MAXPORTS 1 static struct altera_jtaguart altera_jtaguart_ports[ALTERA_JTAGUART_MAXPORTS]; #if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE) #if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS) static void altera_jtaguart_console_putc(struct console *co, const char c) { struct uart_port *port = &(altera_jtaguart_ports + co->index)->port; unsigned long status; unsigned long flags; spin_lock_irqsave(&port->lock, flags); while (((status = readl(port->membase + ALTERA_JTAGUART_CONTROL_REG)) & ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) { if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) { spin_unlock_irqrestore(&port->lock, flags); return; /* no connection activity */ } spin_unlock_irqrestore(&port->lock, flags); cpu_relax(); spin_lock_irqsave(&port->lock, flags); } writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); spin_unlock_irqrestore(&port->lock, flags); } #else static void altera_jtaguart_console_putc(struct console *co, const char c) { struct uart_port *port = &(altera_jtaguart_ports + co->index)->port; unsigned long flags; spin_lock_irqsave(&port->lock, flags); while ((readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) & ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) { spin_unlock_irqrestore(&port->lock, flags); cpu_relax(); spin_lock_irqsave(&port->lock, flags); } writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); spin_unlock_irqrestore(&port->lock, flags); } #endif static void altera_jtaguart_console_write(struct console *co, const char *s, unsigned int count) { for (; count; count--, s++) { altera_jtaguart_console_putc(co, *s); if (*s == '\n') altera_jtaguart_console_putc(co, '\r'); } } static int __init altera_jtaguart_console_setup(struct console *co, char *options) { struct uart_port *port; if (co->index < 0 || co->index >= ALTERA_JTAGUART_MAXPORTS) return -EINVAL; port = &altera_jtaguart_ports[co->index].port; if (port->membase == NULL) return -ENODEV; return 0; } static struct uart_driver altera_jtaguart_driver; static struct console altera_jtaguart_console = { .name = "ttyJ", .write = altera_jtaguart_console_write, .device = uart_console_device, .setup = altera_jtaguart_console_setup, .flags = CON_PRINTBUFFER, .index = -1, .data = &altera_jtaguart_driver, }; static int __init altera_jtaguart_console_init(void) { register_console(&altera_jtaguart_console); return 0; } console_initcall(altera_jtaguart_console_init); #define ALTERA_JTAGUART_CONSOLE (&altera_jtaguart_console) #else #define ALTERA_JTAGUART_CONSOLE NULL #endif /* CONFIG_ALTERA_JTAGUART_CONSOLE */ static struct uart_driver altera_jtaguart_driver = { .owner = THIS_MODULE, .driver_name = "altera_jtaguart", .dev_name = "ttyJ", .major = ALTERA_JTAGUART_MAJOR, .minor = ALTERA_JTAGUART_MINOR, .nr = ALTERA_JTAGUART_MAXPORTS, .cons = ALTERA_JTAGUART_CONSOLE, }; static int __devinit altera_jtaguart_probe(struct platform_device *pdev) { struct altera_jtaguart_platform_uart *platp = pdev->dev.platform_data; struct uart_port *port; struct resource *res_irq, *res_mem; int i = pdev->id; /* -1 emphasizes that the platform must have one port, no .N suffix */ if (i == -1) i = 0; if (i >= ALTERA_JTAGUART_MAXPORTS) return -EINVAL; port = &altera_jtaguart_ports[i].port; res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (res_mem) port->mapbase = res_mem->start; else if (platp) port->mapbase = platp->mapbase; else return -ENODEV; res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if (res_irq) port->irq = res_irq->start; else if (platp) port->irq = platp->irq; else return -ENODEV; port->membase = ioremap(port->mapbase, ALTERA_JTAGUART_SIZE); if (!port->membase) return -ENOMEM; port->line = i; port->type = PORT_ALTERA_JTAGUART; port->iotype = SERIAL_IO_MEM; port->ops = &altera_jtaguart_ops; port->flags = UPF_BOOT_AUTOCONF; uart_add_one_port(&altera_jtaguart_driver, port); return 0; } static int __devexit altera_jtaguart_remove(struct platform_device *pdev) { struct uart_port *port; int i = pdev->id; if (i == -1) i = 0; port = &altera_jtaguart_ports[i].port; uart_remove_one_port(&altera_jtaguart_driver, port); return 0; } #ifdef CONFIG_OF static struct of_device_id altera_jtaguart_match[] = { { .compatible = "ALTR,juart-1.0", }, {}, }; MODULE_DEVICE_TABLE(of, altera_jtaguart_match); #else #define altera_jtaguart_match NULL #endif /* CONFIG_OF */ static struct platform_driver altera_jtaguart_platform_driver = { .probe = altera_jtaguart_probe, .remove = __devexit_p(altera_jtaguart_remove), .driver = { .name = DRV_NAME, .owner = THIS_MODULE, .of_match_table = altera_jtaguart_match, }, }; static int __init altera_jtaguart_init(void) { int rc; rc = uart_register_driver(&altera_jtaguart_driver); if (rc) return rc; rc = platform_driver_register(&altera_jtaguart_platform_driver); if (rc) { uart_unregister_driver(&altera_jtaguart_driver); return rc; } return 0; } static void __exit altera_jtaguart_exit(void) { platform_driver_unregister(&altera_jtaguart_platform_driver); uart_unregister_driver(&altera_jtaguart_driver); } module_init(altera_jtaguart_init); module_exit(altera_jtaguart_exit); MODULE_DESCRIPTION("Altera JTAG UART driver"); MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:" DRV_NAME);