/* * Driver for the serial port on the 21285 StrongArm-110 core logic chip. * * Based on drivers/char/serial.c */ #include <linux/module.h> #include <linux/tty.h> #include <linux/ioport.h> #include <linux/init.h> #include <linux/console.h> #include <linux/device.h> #include <linux/tty_flip.h> #include <linux/serial_core.h> #include <linux/serial.h> #include <linux/io.h> #include <asm/irq.h> #include <asm/mach-types.h> #include <asm/hardware/dec21285.h> #include <mach/hardware.h> #define BAUD_BASE (mem_fclk_21285/64) #define SERIAL_21285_NAME "ttyFB" #define SERIAL_21285_MAJOR 204 #define SERIAL_21285_MINOR 4 #define RXSTAT_DUMMY_READ 0x80000000 #define RXSTAT_FRAME (1 << 0) #define RXSTAT_PARITY (1 << 1) #define RXSTAT_OVERRUN (1 << 2) #define RXSTAT_ANYERR (RXSTAT_FRAME|RXSTAT_PARITY|RXSTAT_OVERRUN) #define H_UBRLCR_BREAK (1 << 0) #define H_UBRLCR_PARENB (1 << 1) #define H_UBRLCR_PAREVN (1 << 2) #define H_UBRLCR_STOPB (1 << 3) #define H_UBRLCR_FIFO (1 << 4) static const char serial21285_name[] = "Footbridge UART"; #define tx_enabled(port) ((port)->unused[0]) #define rx_enabled(port) ((port)->unused[1]) /* * The documented expression for selecting the divisor is: * BAUD_BASE / baud - 1 * However, typically BAUD_BASE is not divisible by baud, so * we want to select the divisor that gives us the minimum * error. Therefore, we want: * int(BAUD_BASE / baud - 0.5) -> * int(BAUD_BASE / baud - (baud >> 1) / baud) -> * int((BAUD_BASE - (baud >> 1)) / baud) */ static void serial21285_stop_tx(struct uart_port *port) { if (tx_enabled(port)) { disable_irq_nosync(IRQ_CONTX); tx_enabled(port) = 0; } } static void serial21285_start_tx(struct uart_port *port) { if (!tx_enabled(port)) { enable_irq(IRQ_CONTX); tx_enabled(port) = 1; } } static void serial21285_stop_rx(struct uart_port *port) { if (rx_enabled(port)) { disable_irq_nosync(IRQ_CONRX); rx_enabled(port) = 0; } } static void serial21285_enable_ms(struct uart_port *port) { } static irqreturn_t serial21285_rx_chars(int irq, void *dev_id) { struct uart_port *port = dev_id; struct tty_struct *tty = port->state->port.tty; unsigned int status, ch, flag, rxs, max_count = 256; status = *CSR_UARTFLG; while (!(status & 0x10) && max_count--) { ch = *CSR_UARTDR; flag = TTY_NORMAL; port->icount.rx++; rxs = *CSR_RXSTAT | RXSTAT_DUMMY_READ; if (unlikely(rxs & RXSTAT_ANYERR)) { if (rxs & RXSTAT_PARITY) port->icount.parity++; else if (rxs & RXSTAT_FRAME) port->icount.frame++; if (rxs & RXSTAT_OVERRUN) port->icount.overrun++; rxs &= port->read_status_mask; if (rxs & RXSTAT_PARITY) flag = TTY_PARITY; else if (rxs & RXSTAT_FRAME) flag = TTY_FRAME; } uart_insert_char(port, rxs, RXSTAT_OVERRUN, ch, flag); status = *CSR_UARTFLG; } tty_flip_buffer_push(tty); return IRQ_HANDLED; } static irqreturn_t serial21285_tx_chars(int irq, void *dev_id) { struct uart_port *port = dev_id; struct circ_buf *xmit = &port->state->xmit; int count = 256; if (port->x_char) { *CSR_UARTDR = port->x_char; port->icount.tx++; port->x_char = 0; goto out; } if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { serial21285_stop_tx(port); goto out; } do { *CSR_UARTDR = 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 && !(*CSR_UARTFLG & 0x20)); if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); if (uart_circ_empty(xmit)) serial21285_stop_tx(port); out: return IRQ_HANDLED; } static unsigned int serial21285_tx_empty(struct uart_port *port) { return (*CSR_UARTFLG & 8) ? 0 : TIOCSER_TEMT; } /* no modem control lines */ static unsigned int serial21285_get_mctrl(struct uart_port *port) { return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; } static void serial21285_set_mctrl(struct uart_port *port, unsigned int mctrl) { } static void serial21285_break_ctl(struct uart_port *port, int break_state) { unsigned long flags; unsigned int h_lcr; spin_lock_irqsave(&port->lock, flags); h_lcr = *CSR_H_UBRLCR; if (break_state) h_lcr |= H_UBRLCR_BREAK; else h_lcr &= ~H_UBRLCR_BREAK; *CSR_H_UBRLCR = h_lcr; spin_unlock_irqrestore(&port->lock, flags); } static int serial21285_startup(struct uart_port *port) { int ret; tx_enabled(port) = 1; rx_enabled(port) = 1; ret = request_irq(IRQ_CONRX, serial21285_rx_chars, 0, serial21285_name, port); if (ret == 0) { ret = request_irq(IRQ_CONTX, serial21285_tx_chars, 0, serial21285_name, port); if (ret) free_irq(IRQ_CONRX, port); } return ret; } static void serial21285_shutdown(struct uart_port *port) { free_irq(IRQ_CONTX, port); free_irq(IRQ_CONRX, port); } static void serial21285_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { unsigned long flags; unsigned int baud, quot, h_lcr, b; /* * We don't support modem control lines. */ termios->c_cflag &= ~(HUPCL | CRTSCTS | CMSPAR); termios->c_cflag |= CLOCAL; /* * We don't support BREAK character recognition. */ termios->c_iflag &= ~(IGNBRK | BRKINT); /* * 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); b = port->uartclk / (16 * quot); tty_termios_encode_baud_rate(termios, b, b); switch (termios->c_cflag & CSIZE) { case CS5: h_lcr = 0x00; break; case CS6: h_lcr = 0x20; break; case CS7: h_lcr = 0x40; break; default: /* CS8 */ h_lcr = 0x60; break; } if (termios->c_cflag & CSTOPB) h_lcr |= H_UBRLCR_STOPB; if (termios->c_cflag & PARENB) { h_lcr |= H_UBRLCR_PARENB; if (!(termios->c_cflag & PARODD)) h_lcr |= H_UBRLCR_PAREVN; } if (port->fifosize) h_lcr |= H_UBRLCR_FIFO; spin_lock_irqsave(&port->lock, flags); /* * Update the per-port timeout. */ uart_update_timeout(port, termios->c_cflag, baud); /* * Which character status flags are we interested in? */ port->read_status_mask = RXSTAT_OVERRUN; if (termios->c_iflag & INPCK) port->read_status_mask |= RXSTAT_FRAME | RXSTAT_PARITY; /* * Which character status flags should we ignore? */ port->ignore_status_mask = 0; if (termios->c_iflag & IGNPAR) port->ignore_status_mask |= RXSTAT_FRAME | RXSTAT_PARITY; if (termios->c_iflag & IGNBRK && termios->c_iflag & IGNPAR) port->ignore_status_mask |= RXSTAT_OVERRUN; /* * Ignore all characters if CREAD is not set. */ if ((termios->c_cflag & CREAD) == 0) port->ignore_status_mask |= RXSTAT_DUMMY_READ; quot -= 1; *CSR_UARTCON = 0; *CSR_L_UBRLCR = quot & 0xff; *CSR_M_UBRLCR = (quot >> 8) & 0x0f; *CSR_H_UBRLCR = h_lcr; *CSR_UARTCON = 1; spin_unlock_irqrestore(&port->lock, flags); } static const char *serial21285_type(struct uart_port *port) { return port->type == PORT_21285 ? "DC21285" : NULL; } static void serial21285_release_port(struct uart_port *port) { release_mem_region(port->mapbase, 32); } static int serial21285_request_port(struct uart_port *port) { return request_mem_region(port->mapbase, 32, serial21285_name) != NULL ? 0 : -EBUSY; } static void serial21285_config_port(struct uart_port *port, int flags) { if (flags & UART_CONFIG_TYPE && serial21285_request_port(port) == 0) port->type = PORT_21285; } /* * verify the new serial_struct (for TIOCSSERIAL). */ static int serial21285_verify_port(struct uart_port *port, struct serial_struct *ser) { int ret = 0; if (ser->type != PORT_UNKNOWN && ser->type != PORT_21285) ret = -EINVAL; if (ser->irq != NO_IRQ) ret = -EINVAL; if (ser->baud_base != port->uartclk / 16) ret = -EINVAL; return ret; } static struct uart_ops serial21285_ops = { .tx_empty = serial21285_tx_empty, .get_mctrl = serial21285_get_mctrl, .set_mctrl = serial21285_set_mctrl, .stop_tx = serial21285_stop_tx, .start_tx = serial21285_start_tx, .stop_rx = serial21285_stop_rx, .enable_ms = serial21285_enable_ms, .break_ctl = serial21285_break_ctl, .startup = serial21285_startup, .shutdown = serial21285_shutdown, .set_termios = serial21285_set_termios, .type = serial21285_type, .release_port = serial21285_release_port, .request_port = serial21285_request_port, .config_port = serial21285_config_port, .verify_port = serial21285_verify_port, }; static struct uart_port serial21285_port = { .mapbase = 0x42000160, .iotype = UPIO_MEM, .irq = NO_IRQ, .fifosize = 16, .ops = &serial21285_ops, .flags = UPF_BOOT_AUTOCONF, }; static void serial21285_setup_ports(void) { serial21285_port.uartclk = mem_fclk_21285 / 4; } #ifdef CONFIG_SERIAL_21285_CONSOLE static void serial21285_console_putchar(struct uart_port *port, int ch) { while (*CSR_UARTFLG & 0x20) barrier(); *CSR_UARTDR = ch; } static void serial21285_console_write(struct console *co, const char *s, unsigned int count) { uart_console_write(&serial21285_port, s, count, serial21285_console_putchar); } static void __init serial21285_get_options(struct uart_port *port, int *baud, int *parity, int *bits) { if (*CSR_UARTCON == 1) { unsigned int tmp; tmp = *CSR_H_UBRLCR; switch (tmp & 0x60) { case 0x00: *bits = 5; break; case 0x20: *bits = 6; break; case 0x40: *bits = 7; break; default: case 0x60: *bits = 8; break; } if (tmp & H_UBRLCR_PARENB) { *parity = 'o'; if (tmp & H_UBRLCR_PAREVN) *parity = 'e'; } tmp = *CSR_L_UBRLCR | (*CSR_M_UBRLCR << 8); *baud = port->uartclk / (16 * (tmp + 1)); } } static int __init serial21285_console_setup(struct console *co, char *options) { struct uart_port *port = &serial21285_port; int baud = 9600; int bits = 8; int parity = 'n'; int flow = 'n'; if (machine_is_personal_server()) baud = 57600; /* * Check whether an invalid uart number has been specified, and * if so, search for the first available port that does have * console support. */ if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); else serial21285_get_options(port, &baud, &parity, &bits); return uart_set_options(port, co, baud, parity, bits, flow); } static struct uart_driver serial21285_reg; static struct console serial21285_console = { .name = SERIAL_21285_NAME, .write = serial21285_console_write, .device = uart_console_device, .setup = serial21285_console_setup, .flags = CON_PRINTBUFFER, .index = -1, .data = &serial21285_reg, }; static int __init rs285_console_init(void) { serial21285_setup_ports(); register_console(&serial21285_console); return 0; } console_initcall(rs285_console_init); #define SERIAL_21285_CONSOLE &serial21285_console #else #define SERIAL_21285_CONSOLE NULL #endif static struct uart_driver serial21285_reg = { .owner = THIS_MODULE, .driver_name = "ttyFB", .dev_name = "ttyFB", .major = SERIAL_21285_MAJOR, .minor = SERIAL_21285_MINOR, .nr = 1, .cons = SERIAL_21285_CONSOLE, }; static int __init serial21285_init(void) { int ret; printk(KERN_INFO "Serial: 21285 driver\n"); serial21285_setup_ports(); ret = uart_register_driver(&serial21285_reg); if (ret == 0) uart_add_one_port(&serial21285_reg, &serial21285_port); return ret; } static void __exit serial21285_exit(void) { uart_remove_one_port(&serial21285_reg, &serial21285_port); uart_unregister_driver(&serial21285_reg); } module_init(serial21285_init); module_exit(serial21285_exit); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Intel Footbridge (21285) serial driver"); MODULE_ALIAS_CHARDEV(SERIAL_21285_MAJOR, SERIAL_21285_MINOR);