diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/tty/serial/21285.c | 539 |
1 files changed, 539 insertions, 0 deletions
diff --git a/drivers/tty/serial/21285.c b/drivers/tty/serial/21285.c new file mode 100644 index 000000000..c7d34823f --- /dev/null +++ b/drivers/tty/serial/21285.c @@ -0,0 +1,539 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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/system_info.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"; + +/* + * We only need 2 bits of data, so instead of creating a whole structure for + * this, use bits of the private_data pointer of the uart port structure. + */ +#define tx_enabled_bit 0 +#define rx_enabled_bit 1 + +static bool is_enabled(struct uart_port *port, int bit) +{ + unsigned long *private_data = (unsigned long *)&port->private_data; + + if (test_bit(bit, private_data)) + return true; + return false; +} + +static void enable(struct uart_port *port, int bit) +{ + unsigned long *private_data = (unsigned long *)&port->private_data; + + set_bit(bit, private_data); +} + +static void disable(struct uart_port *port, int bit) +{ + unsigned long *private_data = (unsigned long *)&port->private_data; + + clear_bit(bit, private_data); +} + +#define is_tx_enabled(port) is_enabled(port, tx_enabled_bit) +#define tx_enable(port) enable(port, tx_enabled_bit) +#define tx_disable(port) disable(port, tx_enabled_bit) + +#define is_rx_enabled(port) is_enabled(port, rx_enabled_bit) +#define rx_enable(port) enable(port, rx_enabled_bit) +#define rx_disable(port) disable(port, rx_enabled_bit) + +/* + * 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 (is_tx_enabled(port)) { + disable_irq_nosync(IRQ_CONTX); + tx_disable(port); + } +} + +static void serial21285_start_tx(struct uart_port *port) +{ + if (!is_tx_enabled(port)) { + enable_irq(IRQ_CONTX); + tx_enable(port); + } +} + +static void serial21285_stop_rx(struct uart_port *port) +{ + if (is_rx_enabled(port)) { + disable_irq_nosync(IRQ_CONRX); + rx_disable(port); + } +} + +static irqreturn_t serial21285_rx_chars(int irq, void *dev_id) +{ + struct uart_port *port = dev_id; + 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(&port->state->port); + + 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_enable(port); + rx_enable(port); + + 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, + const 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 <= 0) + ret = -EINVAL; + if (ser->baud_base != port->uartclk / 16) + ret = -EINVAL; + return ret; +} + +static const 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, + .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 = 0, + .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, unsigned char 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'; + + /* + * 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); |