diff options
Diffstat (limited to 'target/linux/adm8668/files/arch/mips/adm8668/serial.c')
| -rw-r--r-- | target/linux/adm8668/files/arch/mips/adm8668/serial.c | 638 |
1 files changed, 638 insertions, 0 deletions
diff --git a/target/linux/adm8668/files/arch/mips/adm8668/serial.c b/target/linux/adm8668/files/arch/mips/adm8668/serial.c new file mode 100644 index 000000000..7d684b810 --- /dev/null +++ b/target/linux/adm8668/files/arch/mips/adm8668/serial.c @@ -0,0 +1,638 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * ADM8668 serial driver, totally ripped the source from BCM63xx and changed + * all the registers to fit our hardware, and removed all the features that + * I didn't know because our GPL'd serial driver was way lame. + * + * Copyright (C) 2010 Scott Nicholas <neutronscott@scottn.us> + * Derived directly from bcm63xx_uart + * Copyright (C) 2008 Maxime Bizon <mbizon@freebox.fr> + * + */ + +#if defined(CONFIG_SERIAL_ADM8668_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) +#define SUPPORT_SYSRQ +#endif + +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/init.h> +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/console.h> +#include <linux/clk.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/sysrq.h> +#include <linux/serial.h> +#include <linux/serial_core.h> +#include <adm8668.h> + +#define ADM8668_NR_UARTS 1 + +static struct uart_port ports[ADM8668_NR_UARTS]; + +/* + * handy uart register accessor + */ +static inline unsigned int adm_uart_readl(struct uart_port *port, + unsigned int offset) +{ + return (*(volatile unsigned int *)(port->membase + offset)); +} + +static inline void adm_uart_writel(struct uart_port *port, + unsigned int value, unsigned int offset) +{ + (*((volatile unsigned int *)(port->membase + offset))) = value; +} + +/* + * serial core request to check if uart tx fifo is empty + */ +static unsigned int adm_uart_tx_empty(struct uart_port *port) +{ + /* we always wait for completion, no buffer is made... */ + return 1; +} + +/* + * serial core request to set RTS and DTR pin state and loopback mode + */ +static void adm_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ +} + +/* + * serial core request to return RI, CTS, DCD and DSR pin state + */ +static unsigned int adm_uart_get_mctrl(struct uart_port *port) +{ + return 0; +} + +/* + * serial core request to disable tx ASAP (used for flow control) + */ +static void adm_uart_stop_tx(struct uart_port *port) +{ + unsigned int val; + + val = adm_uart_readl(port, UART_CR_REG); + val &= ~(UART_TX_INT_EN); + adm_uart_writel(port, val, UART_CR_REG); +} + +/* + * serial core request to (re)enable tx + */ +static void adm_uart_start_tx(struct uart_port *port) +{ + unsigned int val; + + val = adm_uart_readl(port, UART_CR_REG); + val |= UART_TX_INT_EN; + adm_uart_writel(port, val, UART_CR_REG); +} + +/* + * serial core request to stop rx, called before port shutdown + */ +static void adm_uart_stop_rx(struct uart_port *port) +{ + unsigned int val; + + val = adm_uart_readl(port, UART_CR_REG); + val &= ~UART_RX_INT_EN; + adm_uart_writel(port, val, UART_CR_REG); +} + +/* + * serial core request to enable modem status interrupt reporting + */ +static void adm_uart_enable_ms(struct uart_port *port) +{ +} + +/* + * serial core request to start/stop emitting break char + */ +static void adm_uart_break_ctl(struct uart_port *port, int ctl) +{ +} + +/* + * return port type in string format + */ +static const char *adm_uart_type(struct uart_port *port) +{ + return (port->type == PORT_ADM8668) ? "adm8668_uart" : NULL; +} + +/* + * read all chars in rx fifo and send them to core + */ +static void adm_uart_do_rx(struct uart_port *port) +{ + struct tty_struct *tty; + unsigned int max_count; + + /* limit number of char read in interrupt, should not be + * higher than fifo size anyway since we're much faster than + * serial port */ + max_count = 32; + tty = port->state->port.tty; + do { + unsigned int iestat, c, cstat; + char flag; + + /* get overrun/fifo empty information from ier + * register */ + iestat = adm_uart_readl(port, UART_FR_REG); + if (iestat & UART_RX_FIFO_EMPTY) + break; + + /* recieve status */ + cstat = adm_uart_readl(port, UART_RSR_REG); + /* clear errors */ + adm_uart_writel(port, cstat, UART_RSR_REG); + + c = adm_uart_readl(port, UART_DR_REG); + port->icount.rx++; + flag = TTY_NORMAL; + + if (unlikely((cstat & UART_RX_STATUS_MASK))) { + /* do stats first */ + if (cstat & UART_BREAK_ERR) { + port->icount.brk++; + if (uart_handle_break(port)) + continue; + } + + if (cstat & UART_PARITY_ERR) + port->icount.parity++; + if (cstat & UART_FRAMING_ERR) + port->icount.frame++; + if (cstat & UART_OVERRUN_ERR) { + port->icount.overrun++; + tty_insert_flip_char(tty, 0, TTY_OVERRUN); + } + + /* update flag wrt read_status_mask */ + cstat &= port->read_status_mask; + if (cstat & UART_BREAK_ERR) + flag = TTY_BREAK; + if (cstat & UART_FRAMING_ERR) + flag = TTY_FRAME; + if (cstat & UART_PARITY_ERR) + flag = TTY_PARITY; + } + + if (uart_handle_sysrq_char(port, c)) + continue; + + /* fixthis */ + if ((cstat & port->ignore_status_mask) == 0) + tty_insert_flip_char(tty, c, flag); + } while (max_count--); + + tty_flip_buffer_push(tty); +} + +/* + * fill tx fifo with chars to send, stop when fifo is about to be full + * or when all chars have been sent. + */ +static void adm_uart_do_tx(struct uart_port *port) +{ + struct circ_buf *xmit; + + if (port->x_char) { + adm_uart_writel(port, port->x_char, UART_DR_REG); + port->icount.tx++; + port->x_char = 0; + return; + } + + if (uart_tx_stopped(port)) + adm_uart_stop_tx(port); + + xmit = &port->state->xmit; + + if (uart_circ_empty(xmit)) + goto txq_empty; + do + { + while ((adm_uart_readl(port, UART_FR_REG) & UART_TX_FIFO_FULL) != 0) + ; + adm_uart_writel(port, xmit->buf[xmit->tail], UART_DR_REG); + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); + port->icount.tx++; + if (uart_circ_empty(xmit)) + break; + } while (1); + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(port); + + if (uart_circ_empty(xmit)) + goto txq_empty; + + return; + +txq_empty: + adm_uart_stop_tx(port); +} + +/* + * process uart interrupt + */ +static irqreturn_t adm_uart_interrupt(int irq, void *dev_id) +{ + struct uart_port *port; + unsigned int irqstat; + + port = dev_id; + spin_lock(&port->lock); + + irqstat = adm_uart_readl(port, UART_IIR_REG); + + if (irqstat & (UART_RX_INT|UART_RX_TIMEOUT_INT)) { + adm_uart_do_rx(port); + } + + if (irqstat & UART_TX_INT) { + adm_uart_do_tx(port); + } + spin_unlock(&port->lock); + return IRQ_HANDLED; +} + +/* + * enable rx & tx operation on uart + */ +static void adm_uart_enable(struct uart_port *port) +{ + unsigned int val; + + val = adm_uart_readl(port, UART_CR_REG); + // BREAK_INT too + val |= (UART_RX_INT_EN | UART_RX_TIMEOUT_INT_EN); + adm_uart_writel(port, val, UART_CR_REG); +} + +/* + * disable rx & tx operation on uart + */ +static void adm_uart_disable(struct uart_port *port) +{ + unsigned int val; + + val = adm_uart_readl(port, UART_CR_REG); + val &= ~(UART_TX_INT_EN | UART_RX_INT_EN | UART_RX_TIMEOUT_INT_EN); + adm_uart_writel(port, val, UART_CR_REG); +} + +/* + * clear all unread data in rx fifo and unsent data in tx fifo + */ +static void adm_uart_flush(struct uart_port *port) +{ + /* read any pending char to make sure all irq status are + * cleared */ + (void)adm_uart_readl(port, UART_DR_REG); +} + +/* + * serial core request to initialize uart and start rx operation + */ +static int adm_uart_startup(struct uart_port *port) +{ + int ret; + + /* clear any pending external input interrupt */ + (void)adm_uart_readl(port, UART_IIR_REG); + + /* register irq and enable rx interrupts */ + ret = request_irq(port->irq, adm_uart_interrupt, 0, + adm_uart_type(port), port); + if (ret) + return ret; + + adm_uart_enable(port); + + return 0; +} + +/* + * serial core request to flush & disable uart + */ +static void adm_uart_shutdown(struct uart_port *port) +{ + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); +// adm_uart_writel(port, 0, UART_CR_REG); + spin_unlock_irqrestore(&port->lock, flags); + + adm_uart_disable(port); + adm_uart_flush(port); + free_irq(port->irq, port); +} + +/* + * serial core request to change current uart setting + */ +static void adm_uart_set_termios(struct uart_port *port, + struct ktermios *new, + struct ktermios *old) +{ + port->ignore_status_mask = 0; + uart_update_timeout(port, new->c_cflag, 115200); +} + +/* + * serial core request to claim uart iomem + */ +static int adm_uart_request_port(struct uart_port *port) +{ + unsigned int size = 0xf; + if (!request_mem_region(port->mapbase, size, "adm8668")) { + dev_err(port->dev, "Memory region busy\n"); + return -EBUSY; + } + + port->membase = ioremap(port->mapbase, size); + if (!port->membase) { + dev_err(port->dev, "Unable to map registers\n"); + release_mem_region(port->mapbase, size); + return -EBUSY; + } + return 0; +} + +/* + * serial core request to release uart iomem + */ +static void adm_uart_release_port(struct uart_port *port) +{ + release_mem_region(port->mapbase, 0xf); + iounmap(port->membase); +} + +/* + * serial core request to do any port required autoconfiguration + */ +static void adm_uart_config_port(struct uart_port *port, int flags) +{ + if (flags & UART_CONFIG_TYPE) { + if (adm_uart_request_port(port)) + return; + port->type = PORT_ADM8668; + } +} + +/* + * serial core request to check that port information in serinfo are + * suitable + */ +static int adm_uart_verify_port(struct uart_port *port, + struct serial_struct *serinfo) +{ + if (port->type != PORT_ADM8668) + return -EINVAL; + if (port->irq != serinfo->irq) + return -EINVAL; + if (port->iotype != serinfo->io_type) + return -EINVAL; + if (port->mapbase != (unsigned long)serinfo->iomem_base) + return -EINVAL; + return 0; +} + +/* serial core callbacks */ +static struct uart_ops adm_uart_ops = { + .tx_empty = adm_uart_tx_empty, + .get_mctrl = adm_uart_get_mctrl, + .set_mctrl = adm_uart_set_mctrl, + .start_tx = adm_uart_start_tx, + .stop_tx = adm_uart_stop_tx, + .stop_rx = adm_uart_stop_rx, + .enable_ms = adm_uart_enable_ms, + .break_ctl = adm_uart_break_ctl, + .startup = adm_uart_startup, + .shutdown = adm_uart_shutdown, + .set_termios = adm_uart_set_termios, + .type = adm_uart_type, + .release_port = adm_uart_release_port, + .request_port = adm_uart_request_port, + .config_port = adm_uart_config_port, + .verify_port = adm_uart_verify_port, +}; + +#ifdef CONFIG_SERIAL_ADM8668_CONSOLE +static inline void wait_for_xmitr(struct uart_port *port) +{ + while ((adm_uart_readl(port, UART_FR_REG) & UART_TX_FIFO_FULL) != 0) + ; +} + +/* + * output given char + */ +static void adm_console_putchar(struct uart_port *port, int ch) +{ + wait_for_xmitr(port); + adm_uart_writel(port, ch, UART_DR_REG); +} + +/* + * console core request to output given string + */ +static void adm_console_write(struct console *co, const char *s, + unsigned int count) +{ + struct uart_port *port; + unsigned long flags; + int locked; + + port = &ports[co->index]; + + local_irq_save(flags); + if (port->sysrq) { + /* adm_uart_interrupt() already took the lock */ + locked = 0; + } else if (oops_in_progress) { + locked = spin_trylock(&port->lock); + } else { + spin_lock(&port->lock); + locked = 1; + } + + /* call helper to deal with \r\n */ + uart_console_write(port, s, count, adm_console_putchar); + + /* and wait for char to be transmitted */ + wait_for_xmitr(port); + + if (locked) + spin_unlock(&port->lock); + local_irq_restore(flags); +} + +/* + * console core request to setup given console, find matching uart + * port and setup it. + */ +static int adm_console_setup(struct console *co, char *options) +{ + struct uart_port *port; + int baud = 115200; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + + if (co->index < 0 || co->index >= ADM8668_NR_UARTS) + return -EINVAL; + port = &ports[co->index]; + if (!port->membase) + return -ENODEV; + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + + return uart_set_options(port, co, baud, parity, bits, flow); +} + +static struct uart_driver adm_uart_driver; + +static struct console adm8668_console = { + .name = "ttyS", + .write = adm_console_write, + .device = uart_console_device, + .setup = adm_console_setup, + .flags = CON_PRINTBUFFER, + .index = -1, + .data = &adm_uart_driver, +}; + +static int __init adm8668_console_init(void) +{ + register_console(&adm8668_console); + return 0; +} + +console_initcall(adm8668_console_init); + +#define ADM8668_CONSOLE (&adm8668_console) +#else +#define ADM8668_CONSOLE NULL +#endif /* CONFIG_SERIAL_ADM8668_CONSOLE */ + +static struct uart_driver adm_uart_driver = { + .owner = THIS_MODULE, + .driver_name = "adm8668_uart", + .dev_name = "ttyS", + .major = TTY_MAJOR, + .minor = 64, + .nr = 1, + .cons = ADM8668_CONSOLE, +}; + +/* + * platform driver probe/remove callback + */ +static int __devinit adm_uart_probe(struct platform_device *pdev) +{ + struct resource *res_mem, *res_irq; + struct uart_port *port; + int ret; + + if (pdev->id < 0 || pdev->id >= ADM8668_NR_UARTS) + return -EINVAL; + + if (ports[pdev->id].membase) + return -EBUSY; + + res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res_mem) + return -ENODEV; + + res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (!res_irq) + return -ENODEV; + + port = &ports[pdev->id]; + memset(port, 0, sizeof(*port)); + port->iotype = UPIO_MEM; + port->mapbase = res_mem->start; + port->irq = res_irq->start; + port->ops = &adm_uart_ops; + port->flags = UPF_BOOT_AUTOCONF; + port->dev = &pdev->dev; + port->fifosize = 8; + port->uartclk = ADM8668_UARTCLK_FREQ; + + ret = uart_add_one_port(&adm_uart_driver, port); + if (ret) { + ports[pdev->id].membase = 0; + return ret; + } + platform_set_drvdata(pdev, port); + return 0; +} + +static int __devexit adm_uart_remove(struct platform_device *pdev) +{ + struct uart_port *port; + + port = platform_get_drvdata(pdev); + uart_remove_one_port(&adm_uart_driver, port); + platform_set_drvdata(pdev, NULL); + /* mark port as free */ + ports[pdev->id].membase = 0; + return 0; +} + +/* + * platform driver stuff + */ +static struct platform_driver adm_uart_platform_driver = { + .probe = adm_uart_probe, + .remove = __devexit_p(adm_uart_remove), + .driver = { + .owner = THIS_MODULE, + .name = "adm8668_uart", + }, +}; + +static int __init adm_uart_init(void) +{ + int ret; + + ret = uart_register_driver(&adm_uart_driver); + if (ret) + return ret; + + ret = platform_driver_register(&adm_uart_platform_driver); + if (ret) + uart_unregister_driver(&adm_uart_driver); + + return ret; +} + +static void __exit adm_uart_exit(void) +{ + platform_driver_unregister(&adm_uart_platform_driver); + uart_unregister_driver(&adm_uart_driver); +} + +module_init(adm_uart_init); +module_exit(adm_uart_exit); + +MODULE_AUTHOR("Scott Nicholas <neutronscott@scottn.us>"); +MODULE_DESCRIPTION("ADM8668 integrated uart driver"); +MODULE_LICENSE("GPL"); |