/* * 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_PL011_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 <linux/clk.h> #include <asm/io.h> #include <asm/sizes.h> #define UART_NR 14 #define SERIAL_AMBA_MAJOR 204 #define SERIAL_AMBA_MINOR 64 #define SERIAL_AMBA_NR UART_NR #define AMBA_ISR_PASS_LIMIT 256 #define UART_DR_ERROR (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE) #define UART_DUMMY_DR_RX (1 << 16) /* * We wrap our port structure around the generic uart_port. */ struct uart_amba_port { struct uart_port port; struct clk *clk; unsigned int im; /* interrupt mask */ unsigned int old_status; }; static void pl011_stop_tx(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; uap->im &= ~UART011_TXIM; writew(uap->im, uap->port.membase + UART011_IMSC); } static void pl011_start_tx(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; uap->im |= UART011_TXIM; writew(uap->im, uap->port.membase + UART011_IMSC); } static void pl011_stop_rx(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; uap->im &= ~(UART011_RXIM|UART011_RTIM|UART011_FEIM| UART011_PEIM|UART011_BEIM|UART011_OEIM); writew(uap->im, uap->port.membase + UART011_IMSC); } static void pl011_enable_ms(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; uap->im |= UART011_RIMIM|UART011_CTSMIM|UART011_DCDMIM|UART011_DSRMIM; writew(uap->im, uap->port.membase + UART011_IMSC); } static void pl011_rx_chars(struct uart_amba_port *uap) { struct tty_struct *tty = uap->port.info->tty; unsigned int status, ch, flag, max_count = 256; status = readw(uap->port.membase + UART01x_FR); while ((status & UART01x_FR_RXFE) == 0 && max_count--) { ch = readw(uap->port.membase + UART01x_DR) | UART_DUMMY_DR_RX; flag = TTY_NORMAL; uap->port.icount.rx++; /* * Note that the error handling code is * out of the main execution path */ if (unlikely(ch & UART_DR_ERROR)) { if (ch & UART011_DR_BE) { ch &= ~(UART011_DR_FE | UART011_DR_PE); uap->port.icount.brk++; if (uart_handle_break(&uap->port)) goto ignore_char; } else if (ch & UART011_DR_PE) uap->port.icount.parity++; else if (ch & UART011_DR_FE) uap->port.icount.frame++; if (ch & UART011_DR_OE) uap->port.icount.overrun++; ch &= uap->port.read_status_mask; if (ch & UART011_DR_BE) flag = TTY_BREAK; else if (ch & UART011_DR_PE) flag = TTY_PARITY; else if (ch & UART011_DR_FE) flag = TTY_FRAME; } if (uart_handle_sysrq_char(&uap->port, ch & 255)) goto ignore_char; uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag); ignore_char: status = readw(uap->port.membase + UART01x_FR); } tty_flip_buffer_push(tty); return; } static void pl011_tx_chars(struct uart_amba_port *uap) { struct circ_buf *xmit = &uap->port.info->xmit; int count; if (uap->port.x_char) { writew(uap->port.x_char, uap->port.membase + UART01x_DR); uap->port.icount.tx++; uap->port.x_char = 0; return; } if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) { pl011_stop_tx(&uap->port); return; } count = uap->port.fifosize >> 1; do { writew(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR); xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); uap->port.icount.tx++; if (uart_circ_empty(xmit)) break; } while (--count > 0); if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(&uap->port); if (uart_circ_empty(xmit)) pl011_stop_tx(&uap->port); } static void pl011_modem_status(struct uart_amba_port *uap) { unsigned int status, delta; status = readw(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 pl011_int(int irq, void *dev_id) { struct uart_amba_port *uap = dev_id; unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT; int handled = 0; spin_lock(&uap->port.lock); status = readw(uap->port.membase + UART011_MIS); if (status) { do { writew(status & ~(UART011_TXIS|UART011_RTIS| UART011_RXIS), uap->port.membase + UART011_ICR); if (status & (UART011_RTIS|UART011_RXIS)) pl011_rx_chars(uap); if (status & (UART011_DSRMIS|UART011_DCDMIS| UART011_CTSMIS|UART011_RIMIS)) pl011_modem_status(uap); if (status & UART011_TXIS) pl011_tx_chars(uap); if (pass_counter-- == 0) break; status = readw(uap->port.membase + UART011_MIS); } while (status != 0); handled = 1; } spin_unlock(&uap->port.lock); return IRQ_RETVAL(handled); } static unsigned int pl01x_tx_empty(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; unsigned int status = readw(uap->port.membase + UART01x_FR); return status & (UART01x_FR_BUSY|UART01x_FR_TXFF) ? 0 : TIOCSER_TEMT; } static unsigned int pl01x_get_mctrl(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; unsigned int result = 0; unsigned int status = readw(uap->port.membase + UART01x_FR); #define BIT(uartbit, tiocmbit) \ if (status & uartbit) \ result |= tiocmbit BIT(UART01x_FR_DCD, TIOCM_CAR); BIT(UART01x_FR_DSR, TIOCM_DSR); BIT(UART01x_FR_CTS, TIOCM_CTS); BIT(UART011_FR_RI, TIOCM_RNG); #undef BIT return result; } static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl) { struct uart_amba_port *uap = (struct uart_amba_port *)port; unsigned int cr; cr = readw(uap->port.membase + UART011_CR); #define BIT(tiocmbit, uartbit) \ if (mctrl & tiocmbit) \ cr |= uartbit; \ else \ cr &= ~uartbit BIT(TIOCM_RTS, UART011_CR_RTS); BIT(TIOCM_DTR, UART011_CR_DTR); BIT(TIOCM_OUT1, UART011_CR_OUT1); BIT(TIOCM_OUT2, UART011_CR_OUT2); BIT(TIOCM_LOOP, UART011_CR_LBE); #undef BIT writew(cr, uap->port.membase + UART011_CR); } static void pl011_break_ctl(struct uart_port *port, int break_state) { struct uart_amba_port *uap = (struct uart_amba_port *)port; unsigned long flags; unsigned int lcr_h; spin_lock_irqsave(&uap->port.lock, flags); lcr_h = readw(uap->port.membase + UART011_LCRH); if (break_state == -1) lcr_h |= UART01x_LCRH_BRK; else lcr_h &= ~UART01x_LCRH_BRK; writew(lcr_h, uap->port.membase + UART011_LCRH); spin_unlock_irqrestore(&uap->port.lock, flags); } static int pl011_startup(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; unsigned int cr; int retval; /* * Try to enable the clock producer. */ retval = clk_enable(uap->clk); if (retval) goto out; uap->port.uartclk = clk_get_rate(uap->clk); /* * Allocate the IRQ */ retval = request_irq(uap->port.irq, pl011_int, 0, "uart-pl011", uap); if (retval) goto clk_dis; writew(UART011_IFLS_RX4_8|UART011_IFLS_TX4_8, uap->port.membase + UART011_IFLS); /* * Provoke TX FIFO interrupt into asserting. */ cr = UART01x_CR_UARTEN | UART011_CR_TXE | UART011_CR_LBE; writew(cr, uap->port.membase + UART011_CR); writew(0, uap->port.membase + UART011_FBRD); writew(1, uap->port.membase + UART011_IBRD); writew(0, uap->port.membase + UART011_LCRH); writew(0, uap->port.membase + UART01x_DR); while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY) barrier(); cr = UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE; writew(cr, uap->port.membase + UART011_CR); /* * initialise the old status of the modem signals */ uap->old_status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY; /* * Finally, enable interrupts */ spin_lock_irq(&uap->port.lock); uap->im = UART011_RXIM | UART011_RTIM; writew(uap->im, uap->port.membase + UART011_IMSC); spin_unlock_irq(&uap->port.lock); return 0; clk_dis: clk_disable(uap->clk); out: return retval; } static void pl011_shutdown(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; unsigned long val; /* * disable all interrupts */ spin_lock_irq(&uap->port.lock); uap->im = 0; writew(uap->im, uap->port.membase + UART011_IMSC); writew(0xffff, uap->port.membase + UART011_ICR); spin_unlock_irq(&uap->port.lock); /* * Free the interrupt */ free_irq(uap->port.irq, uap); /* * disable the port */ writew(UART01x_CR_UARTEN | UART011_CR_TXE, uap->port.membase + UART011_CR); /* * disable break condition and fifos */ val = readw(uap->port.membase + UART011_LCRH); val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN); writew(val, uap->port.membase + UART011_LCRH); /* * Shut down the clock producer */ clk_disable(uap->clk); } static void pl011_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 = port->uartclk * 4 / 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 = UART011_DR_OE | 255; if (termios->c_iflag & INPCK) port->read_status_mask |= UART011_DR_FE | UART011_DR_PE; if (termios->c_iflag & (BRKINT | PARMRK)) port->read_status_mask |= UART011_DR_BE; /* * Characters to ignore */ port->ignore_status_mask = 0; if (termios->c_iflag & IGNPAR) port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE; if (termios->c_iflag & IGNBRK) { port->ignore_status_mask |= UART011_DR_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 |= UART011_DR_OE; } /* * Ignore all characters if CREAD is not set. */ if ((termios->c_cflag & CREAD) == 0) port->ignore_status_mask |= UART_DUMMY_DR_RX; if (UART_ENABLE_MS(port, termios->c_cflag)) pl011_enable_ms(port); /* first, disable everything */ old_cr = readw(port->membase + UART011_CR); writew(0, port->membase + UART011_CR); /* Set baud rate */ writew(quot & 0x3f, port->membase + UART011_FBRD); writew(quot >> 6, port->membase + UART011_IBRD); /* * ----------v----------v----------v----------v----- * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L * ----------^----------^----------^----------^----- */ writew(lcr_h, port->membase + UART011_LCRH); writew(old_cr, port->membase + UART011_CR); spin_unlock_irqrestore(&port->lock, flags); } static const char *pl011_type(struct uart_port *port) { return port->type == PORT_AMBA ? "AMBA/PL011" : NULL; } /* * Release the memory region(s) being used by 'port' */ static void pl010_release_port(struct uart_port *port) { release_mem_region(port->mapbase, SZ_4K); } /* * Request the memory region(s) being used by 'port' */ static int pl010_request_port(struct uart_port *port) { return request_mem_region(port->mapbase, SZ_4K, "uart-pl011") != 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_pl011_pops = { .tx_empty = pl01x_tx_empty, .set_mctrl = pl011_set_mctrl, .get_mctrl = pl01x_get_mctrl, .stop_tx = pl011_stop_tx, .start_tx = pl011_start_tx, .stop_rx = pl011_stop_rx, .enable_ms = pl011_enable_ms, .break_ctl = pl011_break_ctl, .startup = pl011_startup, .shutdown = pl011_shutdown, .set_termios = pl011_set_termios, .type = pl011_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_PL011_CONSOLE static void pl011_console_putchar(struct uart_port *port, int ch) { struct uart_amba_port *uap = (struct uart_amba_port *)port; while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) barrier(); writew(ch, uap->port.membase + UART01x_DR); } static void pl011_console_write(struct console *co, const char *s, unsigned int count) { struct uart_amba_port *uap = amba_ports[co->index]; unsigned int status, old_cr, new_cr; clk_enable(uap->clk); /* * First save the CR then disable the interrupts */ old_cr = readw(uap->port.membase + UART011_CR); new_cr = old_cr & ~UART011_CR_CTSEN; new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE; writew(new_cr, uap->port.membase + UART011_CR); uart_console_write(&uap->port, s, count, pl011_console_putchar); /* * Finally, wait for transmitter to become empty * and restore the TCR */ do { status = readw(uap->port.membase + UART01x_FR); } while (status & UART01x_FR_BUSY); writew(old_cr, uap->port.membase + UART011_CR); clk_disable(uap->clk); } static void __init pl011_console_get_options(struct uart_amba_port *uap, int *baud, int *parity, int *bits) { if (readw(uap->port.membase + UART011_CR) & UART01x_CR_UARTEN) { unsigned int lcr_h, ibrd, fbrd; lcr_h = readw(uap->port.membase + UART011_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; ibrd = readw(uap->port.membase + UART011_IBRD); fbrd = readw(uap->port.membase + UART011_FBRD); *baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd); } } static int __init pl011_console_setup(struct console *co, char *options) { struct uart_amba_port *uap; 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; uap = amba_ports[co->index]; uap->port.uartclk = clk_get_rate(uap->clk); if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); else pl011_console_get_options(uap, &baud, &parity, &bits); return uart_set_options(&uap->port, co, baud, parity, bits, flow); } static struct uart_driver amba_reg; static struct console amba_console = { .name = "ttyAMA", .write = pl011_console_write, .device = uart_console_device, .setup = pl011_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 = "ttyAMA", .dev_name = "ttyAMA", .major = SERIAL_AMBA_MAJOR, .minor = SERIAL_AMBA_MINOR, .nr = UART_NR, .cons = AMBA_CONSOLE, }; static int pl011_probe(struct amba_device *dev, void *id) { struct uart_amba_port *uap; 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; } uap = kmalloc(sizeof(struct uart_amba_port), GFP_KERNEL); if (uap == NULL) { ret = -ENOMEM; goto out; } base = ioremap(dev->res.start, PAGE_SIZE); if (!base) { ret = -ENOMEM; goto free; } memset(uap, 0, sizeof(struct uart_amba_port)); uap->clk = clk_get(&dev->dev, "UARTCLK"); if (IS_ERR(uap->clk)) { ret = PTR_ERR(uap->clk); goto unmap; } uap->port.dev = &dev->dev; uap->port.mapbase = dev->res.start; uap->port.membase = base; uap->port.iotype = UPIO_MEM; uap->port.irq = dev->irq[0]; uap->port.fifosize = 16; uap->port.ops = &amba_pl011_pops; uap->port.flags = UPF_BOOT_AUTOCONF; uap->port.line = i; amba_ports[i] = uap; amba_set_drvdata(dev, uap); ret = uart_add_one_port(&amba_reg, &uap->port); if (ret) { amba_set_drvdata(dev, NULL); amba_ports[i] = NULL; clk_put(uap->clk); unmap: iounmap(base); free: kfree(uap); } out: return ret; } static int pl011_remove(struct amba_device *dev) { struct uart_amba_port *uap = amba_get_drvdata(dev); int i; amba_set_drvdata(dev, NULL); uart_remove_one_port(&amba_reg, &uap->port); for (i = 0; i < ARRAY_SIZE(amba_ports); i++) if (amba_ports[i] == uap) amba_ports[i] = NULL; iounmap(uap->port.membase); clk_put(uap->clk); kfree(uap); return 0; } static struct amba_id pl011_ids[] __initdata = { { .id = 0x00041011, .mask = 0x000fffff, }, { 0, 0 }, }; static struct amba_driver pl011_driver = { .drv = { .name = "uart-pl011", }, .id_table = pl011_ids, .probe = pl011_probe, .remove = pl011_remove, }; static int __init pl011_init(void) { int ret; printk(KERN_INFO "Serial: AMBA PL011 UART driver\n"); ret = uart_register_driver(&amba_reg); if (ret == 0) { ret = amba_driver_register(&pl011_driver); if (ret) uart_unregister_driver(&amba_reg); } return ret; } static void __exit pl011_exit(void) { amba_driver_unregister(&pl011_driver); uart_unregister_driver(&amba_reg); } module_init(pl011_init); module_exit(pl011_exit); MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd"); MODULE_DESCRIPTION("ARM AMBA serial port driver"); MODULE_LICENSE("GPL");