/* * uartlite.c: Serial driver for Xilinx uartlite serial controller * * Copyright (C) 2006 Peter Korsgaard <jacmet@sunsite.dk> * Copyright (C) 2007 Secret Lab Technologies Ltd. * * This file is licensed under the terms of the GNU General Public License * version 2. This program is licensed "as is" without any warranty of any * kind, whether express or implied. */ #include <linux/platform_device.h> #include <linux/module.h> #include <linux/console.h> #include <linux/serial.h> #include <linux/serial_core.h> #include <linux/tty.h> #include <linux/delay.h> #include <linux/interrupt.h> #include <asm/io.h> #if defined(CONFIG_OF) #include <linux/of_device.h> #include <linux/of_platform.h> #endif #define ULITE_NAME "ttyUL" #define ULITE_MAJOR 204 #define ULITE_MINOR 187 #define ULITE_NR_UARTS 4 /* --------------------------------------------------------------------- * Register definitions * * For register details see datasheet: * http://www.xilinx.com/bvdocs/ipcenter/data_sheet/opb_uartlite.pdf */ #define ULITE_RX 0x00 #define ULITE_TX 0x04 #define ULITE_STATUS 0x08 #define ULITE_CONTROL 0x0c #define ULITE_REGION 16 #define ULITE_STATUS_RXVALID 0x01 #define ULITE_STATUS_RXFULL 0x02 #define ULITE_STATUS_TXEMPTY 0x04 #define ULITE_STATUS_TXFULL 0x08 #define ULITE_STATUS_IE 0x10 #define ULITE_STATUS_OVERRUN 0x20 #define ULITE_STATUS_FRAME 0x40 #define ULITE_STATUS_PARITY 0x80 #define ULITE_CONTROL_RST_TX 0x01 #define ULITE_CONTROL_RST_RX 0x02 #define ULITE_CONTROL_IE 0x10 static struct uart_port ulite_ports[ULITE_NR_UARTS]; /* --------------------------------------------------------------------- * Core UART driver operations */ static int ulite_receive(struct uart_port *port, int stat) { struct tty_struct *tty = port->info->tty; unsigned char ch = 0; char flag = TTY_NORMAL; if ((stat & (ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN | ULITE_STATUS_FRAME)) == 0) return 0; /* stats */ if (stat & ULITE_STATUS_RXVALID) { port->icount.rx++; ch = readb(port->membase + ULITE_RX); if (stat & ULITE_STATUS_PARITY) port->icount.parity++; } if (stat & ULITE_STATUS_OVERRUN) port->icount.overrun++; if (stat & ULITE_STATUS_FRAME) port->icount.frame++; /* drop byte with parity error if IGNPAR specificed */ if (stat & port->ignore_status_mask & ULITE_STATUS_PARITY) stat &= ~ULITE_STATUS_RXVALID; stat &= port->read_status_mask; if (stat & ULITE_STATUS_PARITY) flag = TTY_PARITY; stat &= ~port->ignore_status_mask; if (stat & ULITE_STATUS_RXVALID) tty_insert_flip_char(tty, ch, flag); if (stat & ULITE_STATUS_FRAME) tty_insert_flip_char(tty, 0, TTY_FRAME); if (stat & ULITE_STATUS_OVERRUN) tty_insert_flip_char(tty, 0, TTY_OVERRUN); return 1; } static int ulite_transmit(struct uart_port *port, int stat) { struct circ_buf *xmit = &port->info->xmit; if (stat & ULITE_STATUS_TXFULL) return 0; if (port->x_char) { writeb(port->x_char, port->membase + ULITE_TX); port->x_char = 0; port->icount.tx++; return 1; } if (uart_circ_empty(xmit) || uart_tx_stopped(port)) return 0; writeb(xmit->buf[xmit->tail], port->membase + ULITE_TX); xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1); port->icount.tx++; /* wake up */ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); return 1; } static irqreturn_t ulite_isr(int irq, void *dev_id) { struct uart_port *port = (struct uart_port *)dev_id; int busy; do { int stat = readb(port->membase + ULITE_STATUS); busy = ulite_receive(port, stat); busy |= ulite_transmit(port, stat); } while (busy); tty_flip_buffer_push(port->info->tty); return IRQ_HANDLED; } static unsigned int ulite_tx_empty(struct uart_port *port) { unsigned long flags; unsigned int ret; spin_lock_irqsave(&port->lock, flags); ret = readb(port->membase + ULITE_STATUS); spin_unlock_irqrestore(&port->lock, flags); return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0; } static unsigned int ulite_get_mctrl(struct uart_port *port) { return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR; } static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl) { /* N/A */ } static void ulite_stop_tx(struct uart_port *port) { /* N/A */ } static void ulite_start_tx(struct uart_port *port) { ulite_transmit(port, readb(port->membase + ULITE_STATUS)); } static void ulite_stop_rx(struct uart_port *port) { /* don't forward any more data (like !CREAD) */ port->ignore_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN; } static void ulite_enable_ms(struct uart_port *port) { /* N/A */ } static void ulite_break_ctl(struct uart_port *port, int ctl) { /* N/A */ } static int ulite_startup(struct uart_port *port) { int ret; ret = request_irq(port->irq, ulite_isr, IRQF_DISABLED | IRQF_SAMPLE_RANDOM, "uartlite", port); if (ret) return ret; writeb(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX, port->membase + ULITE_CONTROL); writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL); return 0; } static void ulite_shutdown(struct uart_port *port) { writeb(0, port->membase + ULITE_CONTROL); readb(port->membase + ULITE_CONTROL); /* dummy */ free_irq(port->irq, port); } static void ulite_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { unsigned long flags; unsigned int baud; spin_lock_irqsave(&port->lock, flags); port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN | ULITE_STATUS_TXFULL; if (termios->c_iflag & INPCK) port->read_status_mask |= ULITE_STATUS_PARITY | ULITE_STATUS_FRAME; port->ignore_status_mask = 0; if (termios->c_iflag & IGNPAR) port->ignore_status_mask |= ULITE_STATUS_PARITY | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN; /* ignore all characters if CREAD is not set */ if ((termios->c_cflag & CREAD) == 0) port->ignore_status_mask |= ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN; /* update timeout */ baud = uart_get_baud_rate(port, termios, old, 0, 460800); uart_update_timeout(port, termios->c_cflag, baud); spin_unlock_irqrestore(&port->lock, flags); } static const char *ulite_type(struct uart_port *port) { return port->type == PORT_UARTLITE ? "uartlite" : NULL; } static void ulite_release_port(struct uart_port *port) { release_mem_region(port->mapbase, ULITE_REGION); iounmap(port->membase); port->membase = NULL; } static int ulite_request_port(struct uart_port *port) { if (!request_mem_region(port->mapbase, ULITE_REGION, "uartlite")) { dev_err(port->dev, "Memory region busy\n"); return -EBUSY; } port->membase = ioremap(port->mapbase, ULITE_REGION); if (!port->membase) { dev_err(port->dev, "Unable to map registers\n"); release_mem_region(port->mapbase, ULITE_REGION); return -EBUSY; } return 0; } static void ulite_config_port(struct uart_port *port, int flags) { if (!ulite_request_port(port)) port->type = PORT_UARTLITE; } static int ulite_verify_port(struct uart_port *port, struct serial_struct *ser) { /* we don't want the core code to modify any port params */ return -EINVAL; } static struct uart_ops ulite_ops = { .tx_empty = ulite_tx_empty, .set_mctrl = ulite_set_mctrl, .get_mctrl = ulite_get_mctrl, .stop_tx = ulite_stop_tx, .start_tx = ulite_start_tx, .stop_rx = ulite_stop_rx, .enable_ms = ulite_enable_ms, .break_ctl = ulite_break_ctl, .startup = ulite_startup, .shutdown = ulite_shutdown, .set_termios = ulite_set_termios, .type = ulite_type, .release_port = ulite_release_port, .request_port = ulite_request_port, .config_port = ulite_config_port, .verify_port = ulite_verify_port }; /* --------------------------------------------------------------------- * Console driver operations */ #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE static void ulite_console_wait_tx(struct uart_port *port) { int i; u8 val; /* Spin waiting for TX fifo to have space available */ for (i = 0; i < 100000; i++) { val = readb(port->membase + ULITE_STATUS); if ((val & ULITE_STATUS_TXFULL) == 0) break; cpu_relax(); } } static void ulite_console_putchar(struct uart_port *port, int ch) { ulite_console_wait_tx(port); writeb(ch, port->membase + ULITE_TX); } static void ulite_console_write(struct console *co, const char *s, unsigned int count) { struct uart_port *port = &ulite_ports[co->index]; unsigned long flags; unsigned int ier; int locked = 1; if (oops_in_progress) { locked = spin_trylock_irqsave(&port->lock, flags); } else spin_lock_irqsave(&port->lock, flags); /* save and disable interrupt */ ier = readb(port->membase + ULITE_STATUS) & ULITE_STATUS_IE; writeb(0, port->membase + ULITE_CONTROL); uart_console_write(port, s, count, ulite_console_putchar); ulite_console_wait_tx(port); /* restore interrupt state */ if (ier) writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL); if (locked) spin_unlock_irqrestore(&port->lock, flags); } #if defined(CONFIG_OF) static inline void __init ulite_console_of_find_device(int id) { struct device_node *np; struct resource res; const unsigned int *of_id; int rc; for_each_compatible_node(np, NULL, "xilinx,uartlite") { of_id = of_get_property(np, "port-number", NULL); if ((!of_id) || (*of_id != id)) continue; rc = of_address_to_resource(np, 0, &res); if (rc) continue; ulite_ports[id].mapbase = res.start; of_node_put(np); return; } } #else /* CONFIG_OF */ static inline void __init ulite_console_of_find_device(int id) { /* do nothing */ } #endif /* CONFIG_OF */ static int __init ulite_console_setup(struct console *co, char *options) { struct uart_port *port; int baud = 9600; int bits = 8; int parity = 'n'; int flow = 'n'; if (co->index < 0 || co->index >= ULITE_NR_UARTS) return -EINVAL; port = &ulite_ports[co->index]; /* Check if it is an OF device */ if (!port->mapbase) ulite_console_of_find_device(co->index); /* Do we have a device now? */ if (!port->mapbase) { pr_debug("console on ttyUL%i not present\n", co->index); return -ENODEV; } /* not initialized yet? */ if (!port->membase) { if (ulite_request_port(port)) return -ENODEV; } if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); return uart_set_options(port, co, baud, parity, bits, flow); } static struct uart_driver ulite_uart_driver; static struct console ulite_console = { .name = ULITE_NAME, .write = ulite_console_write, .device = uart_console_device, .setup = ulite_console_setup, .flags = CON_PRINTBUFFER, .index = -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */ .data = &ulite_uart_driver, }; static int __init ulite_console_init(void) { register_console(&ulite_console); return 0; } console_initcall(ulite_console_init); #endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */ static struct uart_driver ulite_uart_driver = { .owner = THIS_MODULE, .driver_name = "uartlite", .dev_name = ULITE_NAME, .major = ULITE_MAJOR, .minor = ULITE_MINOR, .nr = ULITE_NR_UARTS, #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE .cons = &ulite_console, #endif }; /* --------------------------------------------------------------------- * Port assignment functions (mapping devices to uart_port structures) */ /** ulite_assign: register a uartlite device with the driver * * @dev: pointer to device structure * @id: requested id number. Pass -1 for automatic port assignment * @base: base address of uartlite registers * @irq: irq number for uartlite * * Returns: 0 on success, <0 otherwise */ static int __devinit ulite_assign(struct device *dev, int id, u32 base, int irq) { struct uart_port *port; int rc; /* if id = -1; then scan for a free id and use that */ if (id < 0) { for (id = 0; id < ULITE_NR_UARTS; id++) if (ulite_ports[id].mapbase == 0) break; } if (id < 0 || id >= ULITE_NR_UARTS) { dev_err(dev, "%s%i too large\n", ULITE_NAME, id); return -EINVAL; } if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) { dev_err(dev, "cannot assign to %s%i; it is already in use\n", ULITE_NAME, id); return -EBUSY; } port = &ulite_ports[id]; spin_lock_init(&port->lock); port->fifosize = 16; port->regshift = 2; port->iotype = UPIO_MEM; port->iobase = 1; /* mark port in use */ port->mapbase = base; port->membase = NULL; port->ops = &ulite_ops; port->irq = irq; port->flags = UPF_BOOT_AUTOCONF; port->dev = dev; port->type = PORT_UNKNOWN; port->line = id; dev_set_drvdata(dev, port); /* Register the port */ rc = uart_add_one_port(&ulite_uart_driver, port); if (rc) { dev_err(dev, "uart_add_one_port() failed; err=%i\n", rc); port->mapbase = 0; dev_set_drvdata(dev, NULL); return rc; } return 0; } /** ulite_release: register a uartlite device with the driver * * @dev: pointer to device structure */ static int __devinit ulite_release(struct device *dev) { struct uart_port *port = dev_get_drvdata(dev); int rc = 0; if (port) { rc = uart_remove_one_port(&ulite_uart_driver, port); dev_set_drvdata(dev, NULL); port->mapbase = 0; } return rc; } /* --------------------------------------------------------------------- * Platform bus binding */ static int __devinit ulite_probe(struct platform_device *pdev) { struct resource *res, *res2; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) return -ENODEV; res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if (!res2) return -ENODEV; return ulite_assign(&pdev->dev, pdev->id, res->start, res2->start); } static int ulite_remove(struct platform_device *pdev) { return ulite_release(&pdev->dev); } static struct platform_driver ulite_platform_driver = { .probe = ulite_probe, .remove = ulite_remove, .driver = { .owner = THIS_MODULE, .name = "uartlite", }, }; /* --------------------------------------------------------------------- * OF bus bindings */ #if defined(CONFIG_OF) static int __devinit ulite_of_probe(struct of_device *op, const struct of_device_id *match) { struct resource res; const unsigned int *id; int irq, rc; dev_dbg(&op->dev, "%s(%p, %p)\n", __FUNCTION__, op, match); rc = of_address_to_resource(op->node, 0, &res); if (rc) { dev_err(&op->dev, "invalid address\n"); return rc; } irq = irq_of_parse_and_map(op->node, 0); id = of_get_property(op->node, "port-number", NULL); return ulite_assign(&op->dev, id ? *id : -1, res.start+3, irq); } static int __devexit ulite_of_remove(struct of_device *op) { return ulite_release(&op->dev); } /* Match table for of_platform binding */ static struct of_device_id __devinit ulite_of_match[] = { { .type = "serial", .compatible = "xilinx,uartlite", }, {}, }; MODULE_DEVICE_TABLE(of, ulite_of_match); static struct of_platform_driver ulite_of_driver = { .owner = THIS_MODULE, .name = "uartlite", .match_table = ulite_of_match, .probe = ulite_of_probe, .remove = __devexit_p(ulite_of_remove), .driver = { .name = "uartlite", }, }; /* Registration helpers to keep the number of #ifdefs to a minimum */ static inline int __init ulite_of_register(void) { pr_debug("uartlite: calling of_register_platform_driver()\n"); return of_register_platform_driver(&ulite_of_driver); } static inline void __exit ulite_of_unregister(void) { of_unregister_platform_driver(&ulite_of_driver); } #else /* CONFIG_OF */ /* CONFIG_OF not enabled; do nothing helpers */ static inline int __init ulite_of_register(void) { return 0; } static inline void __exit ulite_of_unregister(void) { } #endif /* CONFIG_OF */ /* --------------------------------------------------------------------- * Module setup/teardown */ int __init ulite_init(void) { int ret; pr_debug("uartlite: calling uart_register_driver()\n"); ret = uart_register_driver(&ulite_uart_driver); if (ret) goto err_uart; ret = ulite_of_register(); if (ret) goto err_of; pr_debug("uartlite: calling platform_driver_register()\n"); ret = platform_driver_register(&ulite_platform_driver); if (ret) goto err_plat; return 0; err_plat: ulite_of_unregister(); err_of: uart_unregister_driver(&ulite_uart_driver); err_uart: printk(KERN_ERR "registering uartlite driver failed: err=%i", ret); return ret; } void __exit ulite_exit(void) { platform_driver_unregister(&ulite_platform_driver); ulite_of_unregister(); uart_unregister_driver(&ulite_uart_driver); } module_init(ulite_init); module_exit(ulite_exit); MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>"); MODULE_DESCRIPTION("Xilinx uartlite serial driver"); MODULE_LICENSE("GPL");