/* * linux/drivers/char/amba.c * * Driver for AMBA serial ports * * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. * * Copyright 1999 ARM Limited * Copyright (C) 2000 Deep Blue Solutions Ltd. * * 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. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * $Id: amba.c,v 1.41 2002/07/28 10:03:27 rmk Exp $ * * This is a generic driver for ARM AMBA-type serial ports. They * have a lot of 16550-like features, but are not register compatible. * Note that although they do have CTS, DCD and DSR inputs, they do * not have an RI input, nor do they have DTR or RTS outputs. If * required, these have to be supplied via some other means (eg, GPIO) * and hooked into this driver. */ #if defined(CONFIG_SERIAL_AMBA_PL010_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) #define SUPPORT_SYSRQ #endif #include <linux/module.h> #include <linux/ioport.h> #include <linux/init.h> #include <linux/console.h> #include <linux/sysrq.h> #include <linux/device.h> #include <linux/tty.h> #include <linux/tty_flip.h> #include <linux/serial_core.h> #include <linux/serial.h> #include <linux/amba/bus.h> #include <linux/amba/serial.h> #include <asm/io.h> #define UART_NR 8 #define SERIAL_AMBA_MAJOR 204 #define SERIAL_AMBA_MINOR 16 #define SERIAL_AMBA_NR UART_NR #define AMBA_ISR_PASS_LIMIT 256 #define UART_RX_DATA(s) (((s) & UART01x_FR_RXFE) == 0) #define UART_TX_READY(s) (((s) & UART01x_FR_TXFF) == 0) #define UART_DUMMY_RSR_RX 256 #define UART_PORT_SIZE 64 /* * We wrap our port structure around the generic uart_port. */ struct uart_amba_port { struct uart_port port; struct amba_device *dev; struct amba_pl010_data *data; unsigned int old_status; }; static void pl010_stop_tx(struct uart_port *port) { unsigned int cr; cr = readb(port->membase + UART010_CR); cr &= ~UART010_CR_TIE; writel(cr, port->membase + UART010_CR); } static void pl010_start_tx(struct uart_port *port) { unsigned int cr; cr = readb(port->membase + UART010_CR); cr |= UART010_CR_TIE; writel(cr, port->membase + UART010_CR); } static void pl010_stop_rx(struct uart_port *port) { unsigned int cr; cr = readb(port->membase + UART010_CR); cr &= ~(UART010_CR_RIE | UART010_CR_RTIE); writel(cr, port->membase + UART010_CR); } static void pl010_enable_ms(struct uart_port *port) { unsigned int cr; cr = readb(port->membase + UART010_CR); cr |= UART010_CR_MSIE; writel(cr, port->membase + UART010_CR); } static void pl010_rx_chars(struct uart_port *port) { struct tty_struct *tty = port->info->tty; unsigned int status, ch, flag, rsr, max_count = 256; status = readb(port->membase + UART01x_FR); while (UART_RX_DATA(status) && max_count--) { ch = readb(port->membase + UART01x_DR); flag = TTY_NORMAL; port->icount.rx++; /* * Note that the error handling code is * out of the main execution path */ rsr = readb(port->membase + UART01x_RSR) | UART_DUMMY_RSR_RX; if (unlikely(rsr & UART01x_RSR_ANY)) { writel(0, port->membase + UART01x_ECR); if (rsr & UART01x_RSR_BE) { rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE); port->icount.brk++; if (uart_handle_break(port)) goto ignore_char; } else if (rsr & UART01x_RSR_PE) port->icount.parity++; else if (rsr & UART01x_RSR_FE) port->icount.frame++; if (rsr & UART01x_RSR_OE) port->icount.overrun++; rsr &= port->read_status_mask; if (rsr & UART01x_RSR_BE) flag = TTY_BREAK; else if (rsr & UART01x_RSR_PE) flag = TTY_PARITY; else if (rsr & UART01x_RSR_FE) flag = TTY_FRAME; } if (uart_handle_sysrq_char(port, ch)) goto ignore_char; uart_insert_char(port, rsr, UART01x_RSR_OE, ch, flag); ignore_char: status = readb(port->membase + UART01x_FR); } tty_flip_buffer_push(tty); return; } static void pl010_tx_chars(struct uart_port *port) { struct circ_buf *xmit = &port->info->xmit; int count; if (port->x_char) { writel(port->x_char, port->membase + UART01x_DR); port->icount.tx++; port->x_char = 0; return; } if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { pl010_stop_tx(port); return; } count = port->fifosize >> 1; do { writel(xmit->buf[xmit->tail], port->membase + UART01x_DR); xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); port->icount.tx++; if (uart_circ_empty(xmit)) break; } while (--count > 0); if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); if (uart_circ_empty(xmit)) pl010_stop_tx(port); } static void pl010_modem_status(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; unsigned int status, delta; writel(0, uap->port.membase + UART010_ICR); status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY; delta = status ^ uap->old_status; uap->old_status = status; if (!delta) return; if (delta & UART01x_FR_DCD) uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD); if (delta & UART01x_FR_DSR) uap->port.icount.dsr++; if (delta & UART01x_FR_CTS) uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS); wake_up_interruptible(&uap->port.info->delta_msr_wait); } static irqreturn_t pl010_int(int irq, void *dev_id) { struct uart_port *port = dev_id; unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT; int handled = 0; spin_lock(&port->lock); status = readb(port->membase + UART010_IIR); if (status) { do { if (status & (UART010_IIR_RTIS | UART010_IIR_RIS)) pl010_rx_chars(port); if (status & UART010_IIR_MIS) pl010_modem_status(port); if (status & UART010_IIR_TIS) pl010_tx_chars(port); if (pass_counter-- == 0) break; status = readb(port->membase + UART010_IIR); } while (status & (UART010_IIR_RTIS | UART010_IIR_RIS | UART010_IIR_TIS)); handled = 1; } spin_unlock(&port->lock); return IRQ_RETVAL(handled); } static unsigned int pl010_tx_empty(struct uart_port *port) { return readb(port->membase + UART01x_FR) & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT; } static unsigned int pl010_get_mctrl(struct uart_port *port) { unsigned int result = 0; unsigned int status; status = readb(port->membase + UART01x_FR); if (status & UART01x_FR_DCD) result |= TIOCM_CAR; if (status & UART01x_FR_DSR) result |= TIOCM_DSR; if (status & UART01x_FR_CTS) result |= TIOCM_CTS; return result; } static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl) { struct uart_amba_port *uap = (struct uart_amba_port *)port; if (uap->data) uap->data->set_mctrl(uap->dev, uap->port.membase, mctrl); } static void pl010_break_ctl(struct uart_port *port, int break_state) { unsigned long flags; unsigned int lcr_h; spin_lock_irqsave(&port->lock, flags); lcr_h = readb(port->membase + UART010_LCRH); if (break_state == -1) lcr_h |= UART01x_LCRH_BRK; else lcr_h &= ~UART01x_LCRH_BRK; writel(lcr_h, port->membase + UART010_LCRH); spin_unlock_irqrestore(&port->lock, flags); } static int pl010_startup(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; int retval; /* * Allocate the IRQ */ retval = request_irq(port->irq, pl010_int, 0, "uart-pl010", port); if (retval) return retval; /* * initialise the old status of the modem signals */ uap->old_status = readb(port->membase + UART01x_FR) & UART01x_FR_MODEM_ANY; /* * Finally, enable interrupts */ writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE, port->membase + UART010_CR); return 0; } static void pl010_shutdown(struct uart_port *port) { /* * Free the interrupt */ free_irq(port->irq, port); /* * disable all interrupts, disable the port */ writel(0, port->membase + UART010_CR); /* disable break condition and fifos */ writel(readb(port->membase + UART010_LCRH) & ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN), port->membase + UART010_LCRH); } static void pl010_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { unsigned int lcr_h, old_cr; unsigned long flags; unsigned int baud, quot; /* * Ask the core to calculate the divisor for us. */ baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16); quot = uart_get_divisor(port, baud); switch (termios->c_cflag & CSIZE) { case CS5: lcr_h = UART01x_LCRH_WLEN_5; break; case CS6: lcr_h = UART01x_LCRH_WLEN_6; break; case CS7: lcr_h = UART01x_LCRH_WLEN_7; break; default: // CS8 lcr_h = UART01x_LCRH_WLEN_8; break; } if (termios->c_cflag & CSTOPB) lcr_h |= UART01x_LCRH_STP2; if (termios->c_cflag & PARENB) { lcr_h |= UART01x_LCRH_PEN; if (!(termios->c_cflag & PARODD)) lcr_h |= UART01x_LCRH_EPS; } if (port->fifosize > 1) lcr_h |= UART01x_LCRH_FEN; spin_lock_irqsave(&port->lock, flags); /* * Update the per-port timeout. */ uart_update_timeout(port, termios->c_cflag, baud); port->read_status_mask = UART01x_RSR_OE; if (termios->c_iflag & INPCK) port->read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE; if (termios->c_iflag & (BRKINT | PARMRK)) port->read_status_mask |= UART01x_RSR_BE; /* * Characters to ignore */ port->ignore_status_mask = 0; if (termios->c_iflag & IGNPAR) port->ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE; if (termios->c_iflag & IGNBRK) { port->ignore_status_mask |= UART01x_RSR_BE; /* * If we're ignoring parity and break indicators, * ignore overruns too (for real raw support). */ if (termios->c_iflag & IGNPAR) port->ignore_status_mask |= UART01x_RSR_OE; } /* * Ignore all characters if CREAD is not set. */ if ((termios->c_cflag & CREAD) == 0) port->ignore_status_mask |= UART_DUMMY_RSR_RX; /* first, disable everything */ old_cr = readb(port->membase + UART010_CR) & ~UART010_CR_MSIE; if (UART_ENABLE_MS(port, termios->c_cflag)) old_cr |= UART010_CR_MSIE; writel(0, port->membase + UART010_CR); /* Set baud rate */ quot -= 1; writel((quot & 0xf00) >> 8, port->membase + UART010_LCRM); writel(quot & 0xff, port->membase + UART010_LCRL); /* * ----------v----------v----------v----------v----- * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L * ----------^----------^----------^----------^----- */ writel(lcr_h, port->membase + UART010_LCRH); writel(old_cr, port->membase + UART010_CR); spin_unlock_irqrestore(&port->lock, flags); } static const char *pl010_type(struct uart_port *port) { return port->type == PORT_AMBA ? "AMBA" : NULL; } /* * Release the memory region(s) being used by 'port' */ static void pl010_release_port(struct uart_port *port) { release_mem_region(port->mapbase, UART_PORT_SIZE); } /* * Request the memory region(s) being used by 'port' */ static int pl010_request_port(struct uart_port *port) { return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010") != NULL ? 0 : -EBUSY; } /* * Configure/autoconfigure the port. */ static void pl010_config_port(struct uart_port *port, int flags) { if (flags & UART_CONFIG_TYPE) { port->type = PORT_AMBA; pl010_request_port(port); } } /* * verify the new serial_struct (for TIOCSSERIAL). */ static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser) { int ret = 0; if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA) ret = -EINVAL; if (ser->irq < 0 || ser->irq >= NR_IRQS) ret = -EINVAL; if (ser->baud_base < 9600) ret = -EINVAL; return ret; } static struct uart_ops amba_pl010_pops = { .tx_empty = pl010_tx_empty, .set_mctrl = pl010_set_mctrl, .get_mctrl = pl010_get_mctrl, .stop_tx = pl010_stop_tx, .start_tx = pl010_start_tx, .stop_rx = pl010_stop_rx, .enable_ms = pl010_enable_ms, .break_ctl = pl010_break_ctl, .startup = pl010_startup, .shutdown = pl010_shutdown, .set_termios = pl010_set_termios, .type = pl010_type, .release_port = pl010_release_port, .request_port = pl010_request_port, .config_port = pl010_config_port, .verify_port = pl010_verify_port, }; static struct uart_amba_port *amba_ports[UART_NR]; #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE static void pl010_console_putchar(struct uart_port *port, int ch) { unsigned int status; do { status = readb(port->membase + UART01x_FR); barrier(); } while (!UART_TX_READY(status)); writel(ch, port->membase + UART01x_DR); } static void pl010_console_write(struct console *co, const char *s, unsigned int count) { struct uart_port *port = &amba_ports[co->index]->port; unsigned int status, old_cr; /* * First save the CR then disable the interrupts */ old_cr = readb(port->membase + UART010_CR); writel(UART01x_CR_UARTEN, port->membase + UART010_CR); uart_console_write(port, s, count, pl010_console_putchar); /* * Finally, wait for transmitter to become empty * and restore the TCR */ do { status = readb(port->membase + UART01x_FR); barrier(); } while (status & UART01x_FR_BUSY); writel(old_cr, port->membase + UART010_CR); } static void __init pl010_console_get_options(struct uart_port *port, int *baud, int *parity, int *bits) { if (readb(port->membase + UART010_CR) & UART01x_CR_UARTEN) { unsigned int lcr_h, quot; lcr_h = readb(port->membase + UART010_LCRH); *parity = 'n'; if (lcr_h & UART01x_LCRH_PEN) { if (lcr_h & UART01x_LCRH_EPS) *parity = 'e'; else *parity = 'o'; } if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7) *bits = 7; else *bits = 8; quot = readb(port->membase + UART010_LCRL) | readb(port->membase + UART010_LCRM) << 8; *baud = port->uartclk / (16 * (quot + 1)); } } static int __init pl010_console_setup(struct console *co, char *options) { struct uart_port *port; int baud = 38400; int bits = 8; int parity = 'n'; int flow = 'n'; /* * Check whether an invalid uart number has been specified, and * if so, search for the first available port that does have * console support. */ if (co->index >= UART_NR) co->index = 0; port = &amba_ports[co->index]->port; if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); else pl010_console_get_options(port, &baud, &parity, &bits); return uart_set_options(port, co, baud, parity, bits, flow); } static struct uart_driver amba_reg; static struct console amba_console = { .name = "ttyAM", .write = pl010_console_write, .device = uart_console_device, .setup = pl010_console_setup, .flags = CON_PRINTBUFFER, .index = -1, .data = &amba_reg, }; #define AMBA_CONSOLE &amba_console #else #define AMBA_CONSOLE NULL #endif static struct uart_driver amba_reg = { .owner = THIS_MODULE, .driver_name = "ttyAM", .dev_name = "ttyAM", .major = SERIAL_AMBA_MAJOR, .minor = SERIAL_AMBA_MINOR, .nr = UART_NR, .cons = AMBA_CONSOLE, }; static int pl010_probe(struct amba_device *dev, void *id) { struct uart_amba_port *port; void __iomem *base; int i, ret; for (i = 0; i < ARRAY_SIZE(amba_ports); i++) if (amba_ports[i] == NULL) break; if (i == ARRAY_SIZE(amba_ports)) { ret = -EBUSY; goto out; } port = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL); if (!port) { ret = -ENOMEM; goto out; } base = ioremap(dev->res.start, PAGE_SIZE); if (!base) { ret = -ENOMEM; goto free; } port->port.dev = &dev->dev; port->port.mapbase = dev->res.start; port->port.membase = base; port->port.iotype = UPIO_MEM; port->port.irq = dev->irq[0]; port->port.uartclk = 14745600; port->port.fifosize = 16; port->port.ops = &amba_pl010_pops; port->port.flags = UPF_BOOT_AUTOCONF; port->port.line = i; port->dev = dev; port->data = dev->dev.platform_data; amba_ports[i] = port; amba_set_drvdata(dev, port); ret = uart_add_one_port(&amba_reg, &port->port); if (ret) { amba_set_drvdata(dev, NULL); amba_ports[i] = NULL; iounmap(base); free: kfree(port); } out: return ret; } static int pl010_remove(struct amba_device *dev) { struct uart_amba_port *port = amba_get_drvdata(dev); int i; amba_set_drvdata(dev, NULL); uart_remove_one_port(&amba_reg, &port->port); for (i = 0; i < ARRAY_SIZE(amba_ports); i++) if (amba_ports[i] == port) amba_ports[i] = NULL; iounmap(port->port.membase); kfree(port); return 0; } static int pl010_suspend(struct amba_device *dev, pm_message_t state) { struct uart_amba_port *uap = amba_get_drvdata(dev); if (uap) uart_suspend_port(&amba_reg, &uap->port); return 0; } static int pl010_resume(struct amba_device *dev) { struct uart_amba_port *uap = amba_get_drvdata(dev); if (uap) uart_resume_port(&amba_reg, &uap->port); return 0; } static struct amba_id pl010_ids[] __initdata = { { .id = 0x00041010, .mask = 0x000fffff, }, { 0, 0 }, }; static struct amba_driver pl010_driver = { .drv = { .name = "uart-pl010", }, .id_table = pl010_ids, .probe = pl010_probe, .remove = pl010_remove, .suspend = pl010_suspend, .resume = pl010_resume, }; static int __init pl010_init(void) { int ret; printk(KERN_INFO "Serial: AMBA driver $Revision: 1.41 $\n"); ret = uart_register_driver(&amba_reg); if (ret == 0) { ret = amba_driver_register(&pl010_driver); if (ret) uart_unregister_driver(&amba_reg); } return ret; } static void __exit pl010_exit(void) { amba_driver_unregister(&pl010_driver); uart_unregister_driver(&amba_reg); } module_init(pl010_init); module_exit(pl010_exit); MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd"); MODULE_DESCRIPTION("ARM AMBA serial port driver $Revision: 1.41 $"); MODULE_LICENSE("GPL");