diff options
Diffstat (limited to 'drivers/serial/apbuart.c')
| -rw-r--r-- | drivers/serial/apbuart.c | 710 |
1 files changed, 710 insertions, 0 deletions
diff --git a/drivers/serial/apbuart.c b/drivers/serial/apbuart.c new file mode 100644 index 0000000..fe91319 --- /dev/null +++ b/drivers/serial/apbuart.c @@ -0,0 +1,710 @@ +/* + * Driver for GRLIB serial ports (APBUART) + * + * Based on linux/drivers/serial/amba.c + * + * Copyright (C) 2000 Deep Blue Solutions Ltd. + * Copyright (C) 2003 Konrad Eisele <eiselekd@web.de> + * Copyright (C) 2006 Daniel Hellstrom <daniel@gaisler.com>, Aeroflex Gaisler AB + * Copyright (C) 2008 Gilead Kutnick <kutnickg@zin-tech.com> + * Copyright (C) 2009 Kristoffer Glembo <kristoffer@gaisler.com>, Aeroflex Gaisler AB + */ + +#if defined(CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) +#define SUPPORT_SYSRQ +#endif + +#include <linux/module.h> +#include <linux/tty.h> +#include <linux/ioport.h> +#include <linux/init.h> +#include <linux/serial.h> +#include <linux/console.h> +#include <linux/sysrq.h> +#include <linux/kthread.h> +#include <linux/device.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/io.h> +#include <linux/serial_core.h> +#include <asm/irq.h> + +#include "apbuart.h" + +#define SERIAL_APBUART_MAJOR TTY_MAJOR +#define SERIAL_APBUART_MINOR 64 +#define UART_DUMMY_RSR_RX 0x8000 /* for ignore all read */ + +static void apbuart_tx_chars(struct uart_port *port); + +static void apbuart_stop_tx(struct uart_port *port) +{ + unsigned int cr; + + cr = UART_GET_CTRL(port); + cr &= ~UART_CTRL_TI; + UART_PUT_CTRL(port, cr); +} + +static void apbuart_start_tx(struct uart_port *port) +{ + unsigned int cr; + + cr = UART_GET_CTRL(port); + cr |= UART_CTRL_TI; + UART_PUT_CTRL(port, cr); + + if (UART_GET_STATUS(port) & UART_STATUS_THE) + apbuart_tx_chars(port); +} + +static void apbuart_stop_rx(struct uart_port *port) +{ + unsigned int cr; + + cr = UART_GET_CTRL(port); + cr &= ~(UART_CTRL_RI); + UART_PUT_CTRL(port, cr); +} + +static void apbuart_enable_ms(struct uart_port *port) +{ + /* No modem status change interrupts for APBUART */ +} + +static void apbuart_rx_chars(struct uart_port *port) +{ + struct tty_struct *tty = port->state->port.tty; + unsigned int status, ch, rsr, flag; + unsigned int max_chars = port->fifosize; + + status = UART_GET_STATUS(port); + + while (UART_RX_DATA(status) && (max_chars--)) { + + ch = UART_GET_CHAR(port); + flag = TTY_NORMAL; + + port->icount.rx++; + + rsr = UART_GET_STATUS(port) | UART_DUMMY_RSR_RX; + UART_PUT_STATUS(port, 0); + if (rsr & UART_STATUS_ERR) { + + if (rsr & UART_STATUS_BR) { + rsr &= ~(UART_STATUS_FE | UART_STATUS_PE); + port->icount.brk++; + if (uart_handle_break(port)) + goto ignore_char; + } else if (rsr & UART_STATUS_PE) { + port->icount.parity++; + } else if (rsr & UART_STATUS_FE) { + port->icount.frame++; + } + if (rsr & UART_STATUS_OE) + port->icount.overrun++; + + rsr &= port->read_status_mask; + + if (rsr & UART_STATUS_PE) + flag = TTY_PARITY; + else if (rsr & UART_STATUS_FE) + flag = TTY_FRAME; + } + + if (uart_handle_sysrq_char(port, ch)) + goto ignore_char; + + uart_insert_char(port, rsr, UART_STATUS_OE, ch, flag); + + + ignore_char: + status = UART_GET_STATUS(port); + } + + tty_flip_buffer_push(tty); +} + +static void apbuart_tx_chars(struct uart_port *port) +{ + struct circ_buf *xmit = &port->state->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)) { + apbuart_stop_tx(port); + return; + } + + /* amba: fill FIFO */ + 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_write_wakeup(port); + + if (uart_circ_empty(xmit)) + apbuart_stop_tx(port); +} + +static irqreturn_t apbuart_int(int irq, void *dev_id) +{ + struct uart_port *port = dev_id; + unsigned int status; + + spin_lock(&port->lock); + + status = UART_GET_STATUS(port); + if (status & UART_STATUS_DR) + apbuart_rx_chars(port); + if (status & UART_STATUS_THE) + apbuart_tx_chars(port); + + spin_unlock(&port->lock); + + return IRQ_HANDLED; +} + +static unsigned int apbuart_tx_empty(struct uart_port *port) +{ + unsigned int status = UART_GET_STATUS(port); + return status & UART_STATUS_THE ? TIOCSER_TEMT : 0; +} + +static unsigned int apbuart_get_mctrl(struct uart_port *port) +{ + /* The GRLIB APBUART handles flow control in hardware */ + return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; +} + +static void apbuart_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + /* The GRLIB APBUART handles flow control in hardware */ +} + +static void apbuart_break_ctl(struct uart_port *port, int break_state) +{ + /* We don't support sending break */ +} + +static int apbuart_startup(struct uart_port *port) +{ + int retval; + unsigned int cr; + + /* Allocate the IRQ */ + retval = request_irq(port->irq, apbuart_int, 0, "apbuart", port); + if (retval) + return retval; + + /* Finally, enable interrupts */ + cr = UART_GET_CTRL(port); + UART_PUT_CTRL(port, + cr | UART_CTRL_RE | UART_CTRL_TE | + UART_CTRL_RI | UART_CTRL_TI); + + return 0; +} + +static void apbuart_shutdown(struct uart_port *port) +{ + unsigned int cr; + + /* disable all interrupts, disable the port */ + cr = UART_GET_CTRL(port); + UART_PUT_CTRL(port, + cr & ~(UART_CTRL_RE | UART_CTRL_TE | + UART_CTRL_RI | UART_CTRL_TI)); + + /* Free the interrupt */ + free_irq(port->irq, port); +} + +static void apbuart_set_termios(struct uart_port *port, + struct ktermios *termios, struct ktermios *old) +{ + unsigned int 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); + if (baud == 0) + panic("invalid baudrate %i\n", port->uartclk / 16); + + /* uart_get_divisor calc a *16 uart freq, apbuart is *8 */ + quot = (uart_get_divisor(port, baud)) * 2; + cr = UART_GET_CTRL(port); + cr &= ~(UART_CTRL_PE | UART_CTRL_PS); + + if (termios->c_cflag & PARENB) { + cr |= UART_CTRL_PE; + if ((termios->c_cflag & PARODD)) + cr |= UART_CTRL_PS; + } + + /* Enable flow control. */ + if (termios->c_cflag & CRTSCTS) + cr |= UART_CTRL_FL; + + spin_lock_irqsave(&port->lock, flags); + + /* Update the per-port timeout. */ + uart_update_timeout(port, termios->c_cflag, baud); + + port->read_status_mask = UART_STATUS_OE; + if (termios->c_iflag & INPCK) + port->read_status_mask |= UART_STATUS_FE | UART_STATUS_PE; + + /* Characters to ignore */ + port->ignore_status_mask = 0; + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= UART_STATUS_FE | UART_STATUS_PE; + + /* Ignore all characters if CREAD is not set. */ + if ((termios->c_cflag & CREAD) == 0) + port->ignore_status_mask |= UART_DUMMY_RSR_RX; + + /* Set baud rate */ + quot -= 1; + UART_PUT_SCAL(port, quot); + UART_PUT_CTRL(port, cr); + + spin_unlock_irqrestore(&port->lock, flags); +} + +static const char *apbuart_type(struct uart_port *port) +{ + return port->type == PORT_APBUART ? "GRLIB/APBUART" : NULL; +} + +static void apbuart_release_port(struct uart_port *port) +{ + release_mem_region(port->mapbase, 0x100); +} + +static int apbuart_request_port(struct uart_port *port) +{ + return request_mem_region(port->mapbase, 0x100, "grlib-apbuart") + != NULL ? 0 : -EBUSY; + return 0; +} + +/* Configure/autoconfigure the port */ +static void apbuart_config_port(struct uart_port *port, int flags) +{ + if (flags & UART_CONFIG_TYPE) { + port->type = PORT_APBUART; + apbuart_request_port(port); + } +} + +/* Verify the new serial_struct (for TIOCSSERIAL) */ +static int apbuart_verify_port(struct uart_port *port, + struct serial_struct *ser) +{ + int ret = 0; + if (ser->type != PORT_UNKNOWN && ser->type != PORT_APBUART) + 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 grlib_apbuart_ops = { + .tx_empty = apbuart_tx_empty, + .set_mctrl = apbuart_set_mctrl, + .get_mctrl = apbuart_get_mctrl, + .stop_tx = apbuart_stop_tx, + .start_tx = apbuart_start_tx, + .stop_rx = apbuart_stop_rx, + .enable_ms = apbuart_enable_ms, + .break_ctl = apbuart_break_ctl, + .startup = apbuart_startup, + .shutdown = apbuart_shutdown, + .set_termios = apbuart_set_termios, + .type = apbuart_type, + .release_port = apbuart_release_port, + .request_port = apbuart_request_port, + .config_port = apbuart_config_port, + .verify_port = apbuart_verify_port, +}; + +static struct uart_port grlib_apbuart_ports[UART_NR]; +static struct device_node *grlib_apbuart_nodes[UART_NR]; + +static int apbuart_scan_fifo_size(struct uart_port *port, int portnumber) +{ + int ctrl, loop = 0; + int status; + int fifosize; + unsigned long flags; + + ctrl = UART_GET_CTRL(port); + + /* + * Enable the transceiver and wait for it to be ready to send data. + * Clear interrupts so that this process will not be externally + * interrupted in the middle (which can cause the transceiver to + * drain prematurely). + */ + + local_irq_save(flags); + + UART_PUT_CTRL(port, ctrl | UART_CTRL_TE); + + while (!UART_TX_READY(UART_GET_STATUS(port))) + loop++; + + /* + * Disable the transceiver so data isn't actually sent during the + * actual test. + */ + + UART_PUT_CTRL(port, ctrl & ~(UART_CTRL_TE)); + + fifosize = 1; + UART_PUT_CHAR(port, 0); + + /* + * So long as transmitting a character increments the tranceivier FIFO + * length the FIFO must be at least that big. These bytes will + * automatically drain off of the FIFO. + */ + + status = UART_GET_STATUS(port); + while (((status >> 20) & 0x3F) == fifosize) { + fifosize++; + UART_PUT_CHAR(port, 0); + status = UART_GET_STATUS(port); + } + + fifosize--; + + UART_PUT_CTRL(port, ctrl); + local_irq_restore(flags); + + if (fifosize == 0) + fifosize = 1; + + return fifosize; +} + +static void apbuart_flush_fifo(struct uart_port *port) +{ + int i; + + for (i = 0; i < port->fifosize; i++) + UART_GET_CHAR(port); +} + + +/* ======================================================================== */ +/* Console driver, if enabled */ +/* ======================================================================== */ + +#ifdef CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE + +static void apbuart_console_putchar(struct uart_port *port, int ch) +{ + unsigned int status; + do { + status = UART_GET_STATUS(port); + } while (!UART_TX_READY(status)); + UART_PUT_CHAR(port, ch); +} + +static void +apbuart_console_write(struct console *co, const char *s, unsigned int count) +{ + struct uart_port *port = &grlib_apbuart_ports[co->index]; + unsigned int status, old_cr, new_cr; + + /* First save the CR then disable the interrupts */ + old_cr = UART_GET_CTRL(port); + new_cr = old_cr & ~(UART_CTRL_RI | UART_CTRL_TI); + UART_PUT_CTRL(port, new_cr); + + uart_console_write(port, s, count, apbuart_console_putchar); + + /* + * Finally, wait for transmitter to become empty + * and restore the TCR + */ + do { + status = UART_GET_STATUS(port); + } while (!UART_TX_READY(status)); + UART_PUT_CTRL(port, old_cr); +} + +static void __init +apbuart_console_get_options(struct uart_port *port, int *baud, + int *parity, int *bits) +{ + if (UART_GET_CTRL(port) & (UART_CTRL_RE | UART_CTRL_TE)) { + + unsigned int quot, status; + status = UART_GET_STATUS(port); + + *parity = 'n'; + if (status & UART_CTRL_PE) { + if ((status & UART_CTRL_PS) == 0) + *parity = 'e'; + else + *parity = 'o'; + } + + *bits = 8; + quot = UART_GET_SCAL(port) / 8; + *baud = port->uartclk / (16 * (quot + 1)); + } +} + +static int __init apbuart_console_setup(struct console *co, char *options) +{ + struct uart_port *port; + int baud = 38400; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + + pr_debug("apbuart_console_setup co=%p, co->index=%i, options=%s\n", + co, co->index, options); + + /* + * 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 >= grlib_apbuart_port_nr) + co->index = 0; + + port = &grlib_apbuart_ports[co->index]; + + spin_lock_init(&port->lock); + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + else + apbuart_console_get_options(port, &baud, &parity, &bits); + + return uart_set_options(port, co, baud, parity, bits, flow); +} + +static struct uart_driver grlib_apbuart_driver; + +static struct console grlib_apbuart_console = { + .name = "ttyS", + .write = apbuart_console_write, + .device = uart_console_device, + .setup = apbuart_console_setup, + .flags = CON_PRINTBUFFER, + .index = -1, + .data = &grlib_apbuart_driver, +}; + + +static void grlib_apbuart_configure(void); + +static int __init apbuart_console_init(void) +{ + grlib_apbuart_configure(); + register_console(&grlib_apbuart_console); + return 0; +} + +console_initcall(apbuart_console_init); + +#define APBUART_CONSOLE (&grlib_apbuart_console) +#else +#define APBUART_CONSOLE NULL +#endif + +static struct uart_driver grlib_apbuart_driver = { + .owner = THIS_MODULE, + .driver_name = "serial", + .dev_name = "ttyS", + .major = SERIAL_APBUART_MAJOR, + .minor = SERIAL_APBUART_MINOR, + .nr = UART_NR, + .cons = APBUART_CONSOLE, +}; + + +/* ======================================================================== */ +/* OF Platform Driver */ +/* ======================================================================== */ + +static int __devinit apbuart_probe(struct of_device *op, + const struct of_device_id *match) +{ + int i = -1; + struct uart_port *port = NULL; + + i = 0; + for (i = 0; i < grlib_apbuart_port_nr; i++) { + if (op->node == grlib_apbuart_nodes[i]) + break; + } + + port = &grlib_apbuart_ports[i]; + port->dev = &op->dev; + + uart_add_one_port(&grlib_apbuart_driver, (struct uart_port *) port); + + apbuart_flush_fifo((struct uart_port *) port); + + printk(KERN_INFO "grlib-apbuart at 0x%llx, irq %d\n", + (unsigned long long) port->mapbase, port->irq); + return 0; + +} + +static struct of_device_id __initdata apbuart_match[] = { + { + .name = "GAISLER_APBUART", + }, + {}, +}; + +static struct of_platform_driver grlib_apbuart_of_driver = { + .match_table = apbuart_match, + .probe = apbuart_probe, + .driver = { + .owner = THIS_MODULE, + .name = "grlib-apbuart", + }, +}; + + +static void grlib_apbuart_configure(void) +{ + static int enum_done; + struct device_node *np, *rp; + struct uart_port *port = NULL; + const u32 *prop; + int freq_khz; + int v = 0, d = 0; + unsigned int addr; + int irq, line; + struct amba_prom_registers *regs; + + if (enum_done) + return; + + /* Get bus frequency */ + rp = of_find_node_by_path("/"); + rp = of_get_next_child(rp, NULL); + prop = of_get_property(rp, "clock-frequency", NULL); + freq_khz = *prop; + + line = 0; + for_each_matching_node(np, apbuart_match) { + + int *vendor = (int *) of_get_property(np, "vendor", NULL); + int *device = (int *) of_get_property(np, "device", NULL); + int *irqs = (int *) of_get_property(np, "interrupts", NULL); + regs = (struct amba_prom_registers *) + of_get_property(np, "reg", NULL); + + if (vendor) + v = *vendor; + if (device) + d = *device; + + if (!irqs || !regs) + return; + + grlib_apbuart_nodes[line] = np; + + addr = regs->phys_addr; + irq = *irqs; + + port = &grlib_apbuart_ports[line]; + + port->mapbase = addr; + port->membase = ioremap(addr, sizeof(struct grlib_apbuart_regs_map)); + port->irq = irq; + port->iotype = UPIO_MEM; + port->ops = &grlib_apbuart_ops; + port->flags = UPF_BOOT_AUTOCONF; + port->line = line; + port->uartclk = freq_khz * 1000; + port->fifosize = apbuart_scan_fifo_size((struct uart_port *) port, line); + line++; + + /* We support maximum UART_NR uarts ... */ + if (line == UART_NR) + break; + + } + + enum_done = 1; + + grlib_apbuart_driver.nr = grlib_apbuart_port_nr = line; +} + +static int __init grlib_apbuart_init(void) +{ + int ret; + + /* Find all APBUARTS in device the tree and initialize their ports */ + grlib_apbuart_configure(); + + printk(KERN_INFO "Serial: GRLIB APBUART driver\n"); + + ret = uart_register_driver(&grlib_apbuart_driver); + + if (ret) { + printk(KERN_ERR "%s: uart_register_driver failed (%i)\n", + __FILE__, ret); + return ret; + } + + ret = of_register_platform_driver(&grlib_apbuart_of_driver); + if (ret) { + printk(KERN_ERR + "%s: of_register_platform_driver failed (%i)\n", + __FILE__, ret); + uart_unregister_driver(&grlib_apbuart_driver); + return ret; + } + + return ret; +} + +static void __exit grlib_apbuart_exit(void) +{ + int i; + + for (i = 0; i < grlib_apbuart_port_nr; i++) + uart_remove_one_port(&grlib_apbuart_driver, + &grlib_apbuart_ports[i]); + + uart_unregister_driver(&grlib_apbuart_driver); + of_unregister_platform_driver(&grlib_apbuart_of_driver); +} + +module_init(grlib_apbuart_init); +module_exit(grlib_apbuart_exit); + +MODULE_AUTHOR("Aeroflex Gaisler AB"); +MODULE_DESCRIPTION("GRLIB APBUART serial driver"); +MODULE_VERSION("2.1"); +MODULE_LICENSE("GPL"); |
