/* * 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 1.37 2002/07/22 15:27:32 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 compatable. * 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. */ #include <linux/config.h> #include <linux/module.h> #include <linux/errno.h> #include <linux/signal.h> #include <linux/sched.h> #include <linux/interrupt.h> #include <linux/tty.h> #include <linux/tty_flip.h> #include <linux/major.h> #include <linux/string.h> #include <linux/fcntl.h> #include <linux/ptrace.h> #include <linux/ioport.h> #include <linux/mm.h> #include <linux/slab.h> #include <linux/init.h> #include <linux/circ_buf.h> #include <linux/serial.h> #include <linux/console.h> #include <linux/sysrq.h> #include <asm/system.h> #include <asm/io.h> #include <asm/irq.h> #include <asm/uaccess.h> #include <asm/bitops.h> #if defined(CONFIG_SERIAL_AMBA_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) #define SUPPORT_SYSRQ #endif #include <linux/serial_core.h> #include <asm/hardware/serial_amba.h> #define UART_NR 2 #define SERIAL_AMBA_MAJOR 204 #define SERIAL_AMBA_MINOR 16 #define SERIAL_AMBA_NR UART_NR #define AMBA_ISR_PASS_LIMIT 256 /* * Access macros for the AMBA UARTs */ #define UART_GET_INT_STATUS(p) readb((p)->membase + AMBA_UARTIIR) #define UART_PUT_ICR(p, c) writel((c), (p)->membase + AMBA_UARTICR) #define UART_GET_FR(p) readb((p)->membase + AMBA_UARTFR) #define UART_GET_CHAR(p) readb((p)->membase + AMBA_UARTDR) #define UART_PUT_CHAR(p, c) writel((c), (p)->membase + AMBA_UARTDR) #define UART_GET_RSR(p) readb((p)->membase + AMBA_UARTRSR) #define UART_GET_CR(p) readb((p)->membase + AMBA_UARTCR) #define UART_PUT_CR(p,c) writel((c), (p)->membase + AMBA_UARTCR) #define UART_GET_LCRL(p) readb((p)->membase + AMBA_UARTLCR_L) #define UART_PUT_LCRL(p,c) writel((c), (p)->membase + AMBA_UARTLCR_L) #define UART_GET_LCRM(p) readb((p)->membase + AMBA_UARTLCR_M) #define UART_PUT_LCRM(p,c) writel((c), (p)->membase + AMBA_UARTLCR_M) #define UART_GET_LCRH(p) readb((p)->membase + AMBA_UARTLCR_H) #define UART_PUT_LCRH(p,c) writel((c), (p)->membase + AMBA_UARTLCR_H) #define UART_RX_DATA(s) (((s) & AMBA_UARTFR_RXFE) == 0) #define UART_TX_READY(s) (((s) & AMBA_UARTFR_TXFF) == 0) #define UART_TX_EMPTY(p) ((UART_GET_FR(p) & AMBA_UARTFR_TMSK) == 0) #define UART_DUMMY_RSR_RX 256 #define UART_PORT_SIZE 64 /* * On the Integrator platform, the port RTS and DTR are provided by * bits in the following SC_CTRLS register bits: * RTS DTR * UART0 7 6 * UART1 5 4 */ #define SC_CTRLC (IO_ADDRESS(INTEGRATOR_SC_BASE) + INTEGRATOR_SC_CTRLC_OFFSET) #define SC_CTRLS (IO_ADDRESS(INTEGRATOR_SC_BASE) + INTEGRATOR_SC_CTRLS_OFFSET) /* * We wrap our port structure around the generic uart_port. */ struct uart_amba_port { struct uart_port port; unsigned int dtr_mask; unsigned int rts_mask; unsigned int old_status; }; static void ambauart_stop_tx(struct uart_port *port, unsigned int tty_stop) { unsigned int cr; cr = UART_GET_CR(port); cr &= ~AMBA_UARTCR_TIE; UART_PUT_CR(port, cr); } static void ambauart_start_tx(struct uart_port *port, unsigned int tty_start) { unsigned int cr; cr = UART_GET_CR(port); cr |= AMBA_UARTCR_TIE; UART_PUT_CR(port, cr); } static void ambauart_stop_rx(struct uart_port *port) { unsigned int cr; cr = UART_GET_CR(port); cr &= ~(AMBA_UARTCR_RIE | AMBA_UARTCR_RTIE); UART_PUT_CR(port, cr); } static void ambauart_enable_ms(struct uart_port *port) { unsigned long flags; unsigned int cr; spin_lock_irqsave(&port->lock, flags); cr = UART_GET_CR(port); cr |= AMBA_UARTCR_MSIE; UART_PUT_CR(port, cr); spin_unlock_irqrestore(&port->lock, flags); } static void #ifdef SUPPORT_SYSRQ ambauart_rx_chars(struct uart_port *port, struct pt_regs *regs) #else ambauart_rx_chars(struct uart_port *port) #endif { struct tty_struct *tty = port->info->tty; unsigned int status, ch, rsr, max_count = 256; status = UART_GET_FR(port); while (UART_RX_DATA(status) && max_count--) { if (tty->flip.count >= TTY_FLIPBUF_SIZE) { tty->flip.tqueue.routine((void *)tty); if (tty->flip.count >= TTY_FLIPBUF_SIZE) { printk(KERN_WARNING "TTY_DONT_FLIP set\n"); return; } } ch = UART_GET_CHAR(port); *tty->flip.char_buf_ptr = ch; *tty->flip.flag_buf_ptr = TTY_NORMAL; port->icount.rx++; /* * Note that the error handling code is * out of the main execution path */ rsr = UART_GET_RSR(port) | UART_DUMMY_RSR_RX; if (rsr & AMBA_UARTRSR_ANY) { if (rsr & AMBA_UARTRSR_BE) { rsr &= ~(AMBA_UARTRSR_FE | AMBA_UARTRSR_PE); port->icount.brk++; if (uart_handle_break(port)) goto ignore_char; } else if (rsr & AMBA_UARTRSR_PE) port->icount.parity++; else if (rsr & AMBA_UARTRSR_FE) port->icount.frame++; if (rsr & AMBA_UARTRSR_OE) port->icount.overrun++; rsr &= port->read_status_mask; if (rsr & AMBA_UARTRSR_BE) *tty->flip.flag_buf_ptr = TTY_BREAK; else if (rsr & AMBA_UARTRSR_PE) *tty->flip.flag_buf_ptr = TTY_PARITY; else if (rsr & AMBA_UARTRSR_FE) *tty->flip.flag_buf_ptr = TTY_FRAME; } if (uart_handle_sysrq_char(port, ch, regs)) goto ignore_char; if ((rsr & port->ignore_status_mask) == 0) { tty->flip.flag_buf_ptr++; tty->flip.char_buf_ptr++; tty->flip.count++; } if ((rsr & AMBA_UARTRSR_OE) && tty->flip.count < TTY_FLIPBUF_SIZE) { /* * Overrun is special, since it's reported * immediately, and doesn't affect the current * character */ *tty->flip.char_buf_ptr++ = 0; *tty->flip.flag_buf_ptr++ = TTY_OVERRUN; tty->flip.count++; } ignore_char: status = UART_GET_FR(port); } tty_flip_buffer_push(tty); return; } static void ambauart_tx_chars(struct uart_port *port) { struct circ_buf *xmit = &port->info->xmit; int count; if (port->x_char) { UART_PUT_CHAR(port, port->x_char); port->icount.tx++; port->x_char = 0; return; } if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { ambauart_stop_tx(port); return; } count = port->fifosize >> 1; do { UART_PUT_CHAR(port, xmit->buf[xmit->tail]); 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_event(port, EVT_WRITE_WAKEUP); if (uart_circ_empty(xmit)) ambauart_stop_tx(port); } static void ambauart_modem_status(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; unsigned int status, delta; UART_PUT_ICR(&uap->port, 0); status = UART_GET_FR(&uap->port) & AMBA_UARTFR_MODEM_ANY; delta = status ^ uap->old_status; uap->old_status = status; if (!delta) return; if (delta & AMBA_UARTFR_DCD) uart_handle_dcd_change(&uap->port, status & AMBA_UARTFR_DCD); if (delta & AMBA_UARTFR_DSR) uap->port.icount.dsr++; if (delta & AMBA_UARTFR_CTS) uart_handle_cts_change(&uap->port, status & AMBA_UARTFR_CTS); wake_up_interruptible(&uap->port.info->delta_msr_wait); } static void ambauart_int(int irq, void *dev_id, struct pt_regs *regs) { struct uart_port *port = dev_id; unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT; status = UART_GET_INT_STATUS(port); do { if (status & (AMBA_UARTIIR_RTIS | AMBA_UARTIIR_RIS)) #ifdef SUPPORT_SYSRQ ambauart_rx_chars(port, regs); #else ambauart_rx_chars(port); #endif if (status & AMBA_UARTIIR_MIS) ambauart_modem_status(port); if (status & AMBA_UARTIIR_TIS) ambauart_tx_chars(port); if (pass_counter-- == 0) break; status = UART_GET_INT_STATUS(port); } while (status & (AMBA_UARTIIR_RTIS | AMBA_UARTIIR_RIS | AMBA_UARTIIR_TIS)); } static unsigned int ambauart_tx_empty(struct uart_port *port) { return UART_GET_FR(port) & AMBA_UARTFR_BUSY ? 0 : TIOCSER_TEMT; } static unsigned int ambauart_get_mctrl(struct uart_port *port) { unsigned int result = 0; unsigned int status; status = UART_GET_FR(port); if (status & AMBA_UARTFR_DCD) result |= TIOCM_CAR; if (status & AMBA_UARTFR_DSR) result |= TIOCM_DSR; if (status & AMBA_UARTFR_CTS) result |= TIOCM_CTS; return result; } static void ambauart_set_mctrl(struct uart_port *port, unsigned int mctrl) { struct uart_amba_port *uap = (struct uart_amba_port *)port; unsigned int ctrls = 0, ctrlc = 0; if (mctrl & TIOCM_RTS) ctrlc |= uap->rts_mask; else ctrls |= uap->rts_mask; if (mctrl & TIOCM_DTR) ctrlc |= uap->dtr_mask; else ctrls |= uap->dtr_mask; __raw_writel(ctrls, SC_CTRLS); __raw_writel(ctrlc, SC_CTRLC); } static void ambauart_break_ctl(struct uart_port *port, int break_state) { unsigned long flags; unsigned int lcr_h; spin_lock_irqsave(&port->lock, flags); lcr_h = UART_GET_LCRH(port); if (break_state == -1) lcr_h |= AMBA_UARTLCR_H_BRK; else lcr_h &= ~AMBA_UARTLCR_H_BRK; UART_PUT_LCRH(port, lcr_h); spin_unlock_irqrestore(&port->lock, flags); } static int ambauart_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, ambauart_int, 0, "amba", port); if (retval) return retval; /* * initialise the old status of the modem signals */ uap->old_status = UART_GET_FR(port) & AMBA_UARTFR_MODEM_ANY; /* * Finally, enable interrupts */ UART_PUT_CR(port, AMBA_UARTCR_UARTEN | AMBA_UARTCR_RIE | AMBA_UARTCR_RTIE); return 0; } static void ambauart_shutdown(struct uart_port *port) { /* * Free the interrupt */ free_irq(port->irq, port); /* * disable all interrupts, disable the port */ UART_PUT_CR(port, 0); /* disable break condition and fifos */ UART_PUT_LCRH(port, UART_GET_LCRH(port) & ~(AMBA_UARTLCR_H_BRK | AMBA_UARTLCR_H_FEN)); } static void ambauart_change_speed(struct uart_port *port, unsigned int cflag, unsigned int iflag, unsigned int quot) { unsigned int lcr_h, old_cr; unsigned long flags; /* byte size and parity */ switch (cflag & CSIZE) { case CS5: lcr_h = AMBA_UARTLCR_H_WLEN_5; break; case CS6: lcr_h = AMBA_UARTLCR_H_WLEN_6; break; case CS7: lcr_h = AMBA_UARTLCR_H_WLEN_7; break; default: // CS8 lcr_h = AMBA_UARTLCR_H_WLEN_8; break; } if (cflag & CSTOPB) lcr_h |= AMBA_UARTLCR_H_STP2; if (cflag & PARENB) { lcr_h |= AMBA_UARTLCR_H_PEN; if (!(cflag & PARODD)) lcr_h |= AMBA_UARTLCR_H_EPS; } if (port->fifosize > 1) lcr_h |= AMBA_UARTLCR_H_FEN; port->read_status_mask = AMBA_UARTRSR_OE; if (iflag & INPCK) port->read_status_mask |= AMBA_UARTRSR_FE | AMBA_UARTRSR_PE; if (iflag & (BRKINT | PARMRK)) port->read_status_mask |= AMBA_UARTRSR_BE; /* * Characters to ignore */ port->ignore_status_mask = 0; if (iflag & IGNPAR) port->ignore_status_mask |= AMBA_UARTRSR_FE | AMBA_UARTRSR_PE; if (iflag & IGNBRK) { port->ignore_status_mask |= AMBA_UARTRSR_BE; /* * If we're ignoring parity and break indicators, * ignore overruns too (for real raw support). */ if (iflag & IGNPAR) port->ignore_status_mask |= AMBA_UARTRSR_OE; } /* * Ignore all characters if CREAD is not set. */ if ((cflag & CREAD) == 0) port->ignore_status_mask |= UART_DUMMY_RSR_RX; /* first, disable everything */ spin_lock_irqsave(&port->lock, flags); old_cr = UART_GET_CR(port) & ~AMBA_UARTCR_MSIE; if (UART_ENABLE_MS(port, cflag)) old_cr |= AMBA_UARTCR_MSIE; UART_PUT_CR(port, 0); /* Set baud rate */ quot -= 1; UART_PUT_LCRM(port, ((quot & 0xf00) >> 8)); UART_PUT_LCRL(port, (quot & 0xff)); /* * ----------v----------v----------v----------v----- * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L * ----------^----------^----------^----------^----- */ UART_PUT_LCRH(port, lcr_h); UART_PUT_CR(port, old_cr); spin_unlock_irqrestore(&port->lock, flags); } static const char *ambauart_type(struct uart_port *port) { return port->type == PORT_AMBA ? "AMBA" : NULL; } /* * Release the memory region(s) being used by 'port' */ static void ambauart_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 ambauart_request_port(struct uart_port *port) { return request_mem_region(port->mapbase, UART_PORT_SIZE, "serial_amba") != NULL ? 0 : -EBUSY; } /* * Configure/autoconfigure the port. */ static void ambauart_config_port(struct uart_port *port, int flags) { if (flags & UART_CONFIG_TYPE) { port->type = PORT_AMBA; ambauart_request_port(port); } } /* * verify the new serial_struct (for TIOCSSERIAL). */ static int ambauart_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_pops = { .tx_empty = ambauart_tx_empty, .set_mctrl = ambauart_set_mctrl, .get_mctrl = ambauart_get_mctrl, .stop_tx = ambauart_stop_tx, .start_tx = ambauart_start_tx, .stop_rx = ambauart_stop_rx, .enable_ms = ambauart_enable_ms, .break_ctl = ambauart_break_ctl, .startup = ambauart_startup, .shutdown = ambauart_shutdown, .change_speed = ambauart_change_speed, .type = ambauart_type, .release_port = ambauart_release_port, .request_port = ambauart_request_port, .config_port = ambauart_config_port, .verify_port = ambauart_verify_port, }; static struct uart_amba_port amba_ports[UART_NR] = { { .port = { .membase = (void *)IO_ADDRESS(INTEGRATOR_UART0_BASE), .mapbase = INTEGRATOR_UART0_BASE, .iotype = SERIAL_IO_MEM, .irq = IRQ_UARTINT0, .uartclk = 14745600, .fifosize = 16, .ops = &amba_pops, .flags = ASYNC_BOOT_AUTOCONF, .line = 0, }, .dtr_mask = 1 << 5, .rts_mask = 1 << 4, }, { .port = { .membase = (void *)IO_ADDRESS(INTEGRATOR_UART1_BASE), .mapbase = INTEGRATOR_UART1_BASE, .iotype = SERIAL_IO_MEM, .irq = IRQ_UARTINT1, .uartclk = 14745600, .fifosize = 16, .ops = &amba_pops, .flags = ASYNC_BOOT_AUTOCONF, .line = 1, }, .dtr_mask = 1 << 7, .rts_mask = 1 << 6, } }; #ifdef CONFIG_SERIAL_AMBA_CONSOLE static void ambauart_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; int i; /* * First save the CR then disable the interrupts */ old_cr = UART_GET_CR(port); UART_PUT_CR(port, AMBA_UARTCR_UARTEN); /* * Now, do each character */ for (i = 0; i < count; i++) { do { status = UART_GET_FR(port); } while (!UART_TX_READY(status)); UART_PUT_CHAR(port, s[i]); if (s[i] == '\n') { do { status = UART_GET_FR(port); } while (!UART_TX_READY(status)); UART_PUT_CHAR(port, '\r'); } } /* * Finally, wait for transmitter to become empty * and restore the TCR */ do { status = UART_GET_FR(port); } while (status & AMBA_UARTFR_BUSY); UART_PUT_CR(port, old_cr); } static kdev_t ambauart_console_device(struct console *co) { return mk_kdev(SERIAL_AMBA_MAJOR, SERIAL_AMBA_MINOR + co->index); } static void __init ambauart_console_get_options(struct uart_port *port, int *baud, int *parity, int *bits) { if (UART_GET_CR(port) & AMBA_UARTCR_UARTEN) { unsigned int lcr_h, quot; lcr_h = UART_GET_LCRH(port); *parity = 'n'; if (lcr_h & AMBA_UARTLCR_H_PEN) { if (lcr_h & AMBA_UARTLCR_H_EPS) *parity = 'e'; else *parity = 'o'; } if ((lcr_h & 0x60) == AMBA_UARTLCR_H_WLEN_7) *bits = 7; else *bits = 8; quot = UART_GET_LCRL(port) | UART_GET_LCRM(port) << 8; *baud = port->uartclk / (16 * (quot + 1)); } } static int __init ambauart_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 ambauart_console_get_options(port, &baud, &parity, &bits); return uart_set_options(port, co, baud, parity, bits, flow); } static struct console amba_console = { .name = "ttyAM", .write = ambauart_console_write, .device = ambauart_console_device, .setup = ambauart_console_setup, .flags = CON_PRINTBUFFER, .index = -1, }; void __init ambauart_console_init(void) { register_console(&amba_console); } #define AMBA_CONSOLE &amba_console #else #define AMBA_CONSOLE NULL #endif static struct uart_driver amba_reg = { .owner = THIS_MODULE, .driver_name = "ttyAM", #ifdef CONFIG_DEVFS_FS .dev_name = "ttyAM%d", #else .dev_name = "ttyAM", #endif .major = SERIAL_AMBA_MAJOR, .minor = SERIAL_AMBA_MINOR, .nr = UART_NR, .cons = AMBA_CONSOLE, }; static int __init ambauart_init(void) { int ret; printk(KERN_INFO "Serial: AMBA driver $Revision: 1.37 $\n"); ret = uart_register_driver(&amba_reg); if (ret == 0) { int i; for (i = 0; i < UART_NR; i++) uart_add_one_port(&amba_reg, &amba_ports[i].port); } return ret; } static void __exit ambauart_exit(void) { int i; for (i = 0; i < UART_NR; i++) uart_remove_one_port(&amba_reg, &amba_ports[i].port); uart_unregister_driver(&amba_reg); } module_init(ambauart_init); module_exit(ambauart_exit); EXPORT_NO_SYMBOLS; MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd"); MODULE_DESCRIPTION("ARM AMBA serial port driver $Revision: 1.37 $"); MODULE_LICENSE("GPL");