/* * 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. * * Derived from many drivers using generic_serial interface. * * Copyright (C) 2008 Maxime Bizon * * Serial driver for BCM63xx integrated UART. * * Hardware flow control was _not_ tested since I only have RX/TX on * my board. */ #if defined(CONFIG_SERIAL_BCM63XX_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) #define SUPPORT_SYSRQ #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define BCM63XX_NR_UARTS 2 static struct uart_port ports[BCM63XX_NR_UARTS]; /* * rx interrupt mask / stat * * mask: * - rx fifo full * - rx fifo above threshold * - rx fifo not empty for too long */ #define UART_RX_INT_MASK (UART_IR_MASK(UART_IR_RXOVER) | \ UART_IR_MASK(UART_IR_RXTHRESH) | \ UART_IR_MASK(UART_IR_RXTIMEOUT)) #define UART_RX_INT_STAT (UART_IR_STAT(UART_IR_RXOVER) | \ UART_IR_STAT(UART_IR_RXTHRESH) | \ UART_IR_STAT(UART_IR_RXTIMEOUT)) /* * tx interrupt mask / stat * * mask: * - tx fifo empty * - tx fifo below threshold */ #define UART_TX_INT_MASK (UART_IR_MASK(UART_IR_TXEMPTY) | \ UART_IR_MASK(UART_IR_TXTRESH)) #define UART_TX_INT_STAT (UART_IR_STAT(UART_IR_TXEMPTY) | \ UART_IR_STAT(UART_IR_TXTRESH)) /* * external input interrupt * * mask: any edge on CTS, DCD */ #define UART_EXTINP_INT_MASK (UART_EXTINP_IRMASK(UART_EXTINP_IR_CTS) | \ UART_EXTINP_IRMASK(UART_EXTINP_IR_DCD)) /* * handy uart register accessor */ static inline unsigned int bcm_uart_readl(struct uart_port *port, unsigned int offset) { return bcm_readl(port->membase + offset); } static inline void bcm_uart_writel(struct uart_port *port, unsigned int value, unsigned int offset) { bcm_writel(value, port->membase + offset); } /* * serial core request to check if uart tx fifo is empty */ static unsigned int bcm_uart_tx_empty(struct uart_port *port) { unsigned int val; val = bcm_uart_readl(port, UART_IR_REG); return (val & UART_IR_STAT(UART_IR_TXEMPTY)) ? 1 : 0; } /* * serial core request to set RTS and DTR pin state and loopback mode */ static void bcm_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) { unsigned int val; val = bcm_uart_readl(port, UART_MCTL_REG); val &= ~(UART_MCTL_DTR_MASK | UART_MCTL_RTS_MASK); /* invert of written value is reflected on the pin */ if (!(mctrl & TIOCM_DTR)) val |= UART_MCTL_DTR_MASK; if (!(mctrl & TIOCM_RTS)) val |= UART_MCTL_RTS_MASK; bcm_uart_writel(port, val, UART_MCTL_REG); val = bcm_uart_readl(port, UART_CTL_REG); if (mctrl & TIOCM_LOOP) val |= UART_CTL_LOOPBACK_MASK; else val &= ~UART_CTL_LOOPBACK_MASK; bcm_uart_writel(port, val, UART_CTL_REG); } /* * serial core request to return RI, CTS, DCD and DSR pin state */ static unsigned int bcm_uart_get_mctrl(struct uart_port *port) { unsigned int val, mctrl; mctrl = 0; val = bcm_uart_readl(port, UART_EXTINP_REG); if (val & UART_EXTINP_RI_MASK) mctrl |= TIOCM_RI; if (val & UART_EXTINP_CTS_MASK) mctrl |= TIOCM_CTS; if (val & UART_EXTINP_DCD_MASK) mctrl |= TIOCM_CD; if (val & UART_EXTINP_DSR_MASK) mctrl |= TIOCM_DSR; return mctrl; } /* * serial core request to disable tx ASAP (used for flow control) */ static void bcm_uart_stop_tx(struct uart_port *port) { unsigned int val; val = bcm_uart_readl(port, UART_CTL_REG); val &= ~(UART_CTL_TXEN_MASK); bcm_uart_writel(port, val, UART_CTL_REG); val = bcm_uart_readl(port, UART_IR_REG); val &= ~UART_TX_INT_MASK; bcm_uart_writel(port, val, UART_IR_REG); } /* * serial core request to (re)enable tx */ static void bcm_uart_start_tx(struct uart_port *port) { unsigned int val; val = bcm_uart_readl(port, UART_IR_REG); val |= UART_TX_INT_MASK; bcm_uart_writel(port, val, UART_IR_REG); val = bcm_uart_readl(port, UART_CTL_REG); val |= UART_CTL_TXEN_MASK; bcm_uart_writel(port, val, UART_CTL_REG); } /* * serial core request to stop rx, called before port shutdown */ static void bcm_uart_stop_rx(struct uart_port *port) { unsigned int val; val = bcm_uart_readl(port, UART_IR_REG); val &= ~UART_RX_INT_MASK; bcm_uart_writel(port, val, UART_IR_REG); } /* * serial core request to enable modem status interrupt reporting */ static void bcm_uart_enable_ms(struct uart_port *port) { unsigned int val; val = bcm_uart_readl(port, UART_IR_REG); val |= UART_IR_MASK(UART_IR_EXTIP); bcm_uart_writel(port, val, UART_IR_REG); } /* * serial core request to start/stop emitting break char */ static void bcm_uart_break_ctl(struct uart_port *port, int ctl) { unsigned long flags; unsigned int val; spin_lock_irqsave(&port->lock, flags); val = bcm_uart_readl(port, UART_CTL_REG); if (ctl) val |= UART_CTL_XMITBRK_MASK; else val &= ~UART_CTL_XMITBRK_MASK; bcm_uart_writel(port, val, UART_CTL_REG); spin_unlock_irqrestore(&port->lock, flags); } /* * return port type in string format */ static const char *bcm_uart_type(struct uart_port *port) { return (port->type == PORT_BCM63XX) ? "bcm63xx_uart" : NULL; } /* * read all chars in rx fifo and send them to core */ static void bcm_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 = bcm_uart_readl(port, UART_IR_REG); if (unlikely(iestat & UART_IR_STAT(UART_IR_RXOVER))) { unsigned int val; /* fifo reset is required to clear * interrupt */ val = bcm_uart_readl(port, UART_CTL_REG); val |= UART_CTL_RSTRXFIFO_MASK; bcm_uart_writel(port, val, UART_CTL_REG); port->icount.overrun++; tty_insert_flip_char(tty, 0, TTY_OVERRUN); } if (!(iestat & UART_IR_STAT(UART_IR_RXNOTEMPTY))) break; cstat = c = bcm_uart_readl(port, UART_FIFO_REG); port->icount.rx++; flag = TTY_NORMAL; c &= 0xff; if (unlikely((cstat & UART_FIFO_ANYERR_MASK))) { /* do stats first */ if (cstat & UART_FIFO_BRKDET_MASK) { port->icount.brk++; if (uart_handle_break(port)) continue; } if (cstat & UART_FIFO_PARERR_MASK) port->icount.parity++; if (cstat & UART_FIFO_FRAMEERR_MASK) port->icount.frame++; /* update flag wrt read_status_mask */ cstat &= port->read_status_mask; if (cstat & UART_FIFO_BRKDET_MASK) flag = TTY_BREAK; if (cstat & UART_FIFO_FRAMEERR_MASK) flag = TTY_FRAME; if (cstat & UART_FIFO_PARERR_MASK) flag = TTY_PARITY; } if (uart_handle_sysrq_char(port, c)) continue; 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 bcm_uart_do_tx(struct uart_port *port) { struct circ_buf *xmit; unsigned int val, max_count; if (port->x_char) { bcm_uart_writel(port, port->x_char, UART_FIFO_REG); port->icount.tx++; port->x_char = 0; return; } if (uart_tx_stopped(port)) { bcm_uart_stop_tx(port); return; } xmit = &port->state->xmit; if (uart_circ_empty(xmit)) goto txq_empty; val = bcm_uart_readl(port, UART_MCTL_REG); val = (val & UART_MCTL_TXFIFOFILL_MASK) >> UART_MCTL_TXFIFOFILL_SHIFT; max_count = port->fifosize - val; while (max_count--) { unsigned int c; c = xmit->buf[xmit->tail]; bcm_uart_writel(port, c, UART_FIFO_REG); xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); port->icount.tx++; if (uart_circ_empty(xmit)) break; } if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); if (uart_circ_empty(xmit)) goto txq_empty; return; txq_empty: /* nothing to send, disable transmit interrupt */ val = bcm_uart_readl(port, UART_IR_REG); val &= ~UART_TX_INT_MASK; bcm_uart_writel(port, val, UART_IR_REG); return; } /* * process uart interrupt */ static irqreturn_t bcm_uart_interrupt(int irq, void *dev_id) { struct uart_port *port; unsigned int irqstat; port = dev_id; spin_lock(&port->lock); irqstat = bcm_uart_readl(port, UART_IR_REG); if (irqstat & UART_RX_INT_STAT) bcm_uart_do_rx(port); if (irqstat & UART_TX_INT_STAT) bcm_uart_do_tx(port); if (irqstat & UART_IR_MASK(UART_IR_EXTIP)) { unsigned int estat; estat = bcm_uart_readl(port, UART_EXTINP_REG); if (estat & UART_EXTINP_IRSTAT(UART_EXTINP_IR_CTS)) uart_handle_cts_change(port, estat & UART_EXTINP_CTS_MASK); if (estat & UART_EXTINP_IRSTAT(UART_EXTINP_IR_DCD)) uart_handle_dcd_change(port, estat & UART_EXTINP_DCD_MASK); } spin_unlock(&port->lock); return IRQ_HANDLED; } /* * enable rx & tx operation on uart */ static void bcm_uart_enable(struct uart_port *port) { unsigned int val; val = bcm_uart_readl(port, UART_CTL_REG); val |= (UART_CTL_BRGEN_MASK | UART_CTL_TXEN_MASK | UART_CTL_RXEN_MASK); bcm_uart_writel(port, val, UART_CTL_REG); } /* * disable rx & tx operation on uart */ static void bcm_uart_disable(struct uart_port *port) { unsigned int val; val = bcm_uart_readl(port, UART_CTL_REG); val &= ~(UART_CTL_BRGEN_MASK | UART_CTL_TXEN_MASK | UART_CTL_RXEN_MASK); bcm_uart_writel(port, val, UART_CTL_REG); } /* * clear all unread data in rx fifo and unsent data in tx fifo */ static void bcm_uart_flush(struct uart_port *port) { unsigned int val; /* empty rx and tx fifo */ val = bcm_uart_readl(port, UART_CTL_REG); val |= UART_CTL_RSTRXFIFO_MASK | UART_CTL_RSTTXFIFO_MASK; bcm_uart_writel(port, val, UART_CTL_REG); /* read any pending char to make sure all irq status are * cleared */ (void)bcm_uart_readl(port, UART_FIFO_REG); } /* * serial core request to initialize uart and start rx operation */ static int bcm_uart_startup(struct uart_port *port) { unsigned int val; int ret; /* mask all irq and flush port */ bcm_uart_disable(port); bcm_uart_writel(port, 0, UART_IR_REG); bcm_uart_flush(port); /* clear any pending external input interrupt */ (void)bcm_uart_readl(port, UART_EXTINP_REG); /* set rx/tx fifo thresh to fifo half size */ val = bcm_uart_readl(port, UART_MCTL_REG); val &= ~(UART_MCTL_RXFIFOTHRESH_MASK | UART_MCTL_TXFIFOTHRESH_MASK); val |= (port->fifosize / 2) << UART_MCTL_RXFIFOTHRESH_SHIFT; val |= (port->fifosize / 2) << UART_MCTL_TXFIFOTHRESH_SHIFT; bcm_uart_writel(port, val, UART_MCTL_REG); /* set rx fifo timeout to 1 char time */ val = bcm_uart_readl(port, UART_CTL_REG); val &= ~UART_CTL_RXTMOUTCNT_MASK; val |= 1 << UART_CTL_RXTMOUTCNT_SHIFT; bcm_uart_writel(port, val, UART_CTL_REG); /* report any edge on dcd and cts */ val = UART_EXTINP_INT_MASK; val |= UART_EXTINP_DCD_NOSENSE_MASK; val |= UART_EXTINP_CTS_NOSENSE_MASK; bcm_uart_writel(port, val, UART_EXTINP_REG); /* register irq and enable rx interrupts */ ret = request_irq(port->irq, bcm_uart_interrupt, 0, bcm_uart_type(port), port); if (ret) return ret; bcm_uart_writel(port, UART_RX_INT_MASK, UART_IR_REG); bcm_uart_enable(port); return 0; } /* * serial core request to flush & disable uart */ static void bcm_uart_shutdown(struct uart_port *port) { unsigned long flags; spin_lock_irqsave(&port->lock, flags); bcm_uart_writel(port, 0, UART_IR_REG); spin_unlock_irqrestore(&port->lock, flags); bcm_uart_disable(port); bcm_uart_flush(port); free_irq(port->irq, port); } /* * serial core request to change current uart setting */ static void bcm_uart_set_termios(struct uart_port *port, struct ktermios *new, struct ktermios *old) { unsigned int ctl, baud, quot, ier; unsigned long flags; spin_lock_irqsave(&port->lock, flags); /* disable uart while changing speed */ bcm_uart_disable(port); bcm_uart_flush(port); /* update Control register */ ctl = bcm_uart_readl(port, UART_CTL_REG); ctl &= ~UART_CTL_BITSPERSYM_MASK; switch (new->c_cflag & CSIZE) { case CS5: ctl |= (0 << UART_CTL_BITSPERSYM_SHIFT); break; case CS6: ctl |= (1 << UART_CTL_BITSPERSYM_SHIFT); break; case CS7: ctl |= (2 << UART_CTL_BITSPERSYM_SHIFT); break; default: ctl |= (3 << UART_CTL_BITSPERSYM_SHIFT); break; } ctl &= ~UART_CTL_STOPBITS_MASK; if (new->c_cflag & CSTOPB) ctl |= UART_CTL_STOPBITS_2; else ctl |= UART_CTL_STOPBITS_1; ctl &= ~(UART_CTL_RXPAREN_MASK | UART_CTL_TXPAREN_MASK); if (new->c_cflag & PARENB) ctl |= (UART_CTL_RXPAREN_MASK | UART_CTL_TXPAREN_MASK); ctl &= ~(UART_CTL_RXPAREVEN_MASK | UART_CTL_TXPAREVEN_MASK); if (new->c_cflag & PARODD) ctl |= (UART_CTL_RXPAREVEN_MASK | UART_CTL_TXPAREVEN_MASK); bcm_uart_writel(port, ctl, UART_CTL_REG); /* update Baudword register */ baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16); quot = uart_get_divisor(port, baud) - 1; bcm_uart_writel(port, quot, UART_BAUD_REG); /* update Interrupt register */ ier = bcm_uart_readl(port, UART_IR_REG); ier &= ~UART_IR_MASK(UART_IR_EXTIP); if (UART_ENABLE_MS(port, new->c_cflag)) ier |= UART_IR_MASK(UART_IR_EXTIP); bcm_uart_writel(port, ier, UART_IR_REG); /* update read/ignore mask */ port->read_status_mask = UART_FIFO_VALID_MASK; if (new->c_iflag & INPCK) { port->read_status_mask |= UART_FIFO_FRAMEERR_MASK; port->read_status_mask |= UART_FIFO_PARERR_MASK; } if (new->c_iflag & (BRKINT)) port->read_status_mask |= UART_FIFO_BRKDET_MASK; port->ignore_status_mask = 0; if (new->c_iflag & IGNPAR) port->ignore_status_mask |= UART_FIFO_PARERR_MASK; if (new->c_iflag & IGNBRK) port->ignore_status_mask |= UART_FIFO_BRKDET_MASK; if (!(new->c_cflag & CREAD)) port->ignore_status_mask |= UART_FIFO_VALID_MASK; uart_update_timeout(port, new->c_cflag, baud); bcm_uart_enable(port); spin_unlock_irqrestore(&port->lock, flags); } /* * serial core request to claim uart iomem */ static int bcm_uart_request_port(struct uart_port *port) { unsigned int size; size = RSET_UART_SIZE; if (!request_mem_region(port->mapbase, size, "bcm63xx")) { 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 bcm_uart_release_port(struct uart_port *port) { release_mem_region(port->mapbase, RSET_UART_SIZE); iounmap(port->membase); } /* * serial core request to do any port required autoconfiguration */ static void bcm_uart_config_port(struct uart_port *port, int flags) { if (flags & UART_CONFIG_TYPE) { if (bcm_uart_request_port(port)) return; port->type = PORT_BCM63XX; } } /* * serial core request to check that port information in serinfo are * suitable */ static int bcm_uart_verify_port(struct uart_port *port, struct serial_struct *serinfo) { if (port->type != PORT_BCM63XX) 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 bcm_uart_ops = { .tx_empty = bcm_uart_tx_empty, .get_mctrl = bcm_uart_get_mctrl, .set_mctrl = bcm_uart_set_mctrl, .start_tx = bcm_uart_start_tx, .stop_tx = bcm_uart_stop_tx, .stop_rx = bcm_uart_stop_rx, .enable_ms = bcm_uart_enable_ms, .break_ctl = bcm_uart_break_ctl, .startup = bcm_uart_startup, .shutdown = bcm_uart_shutdown, .set_termios = bcm_uart_set_termios, .type = bcm_uart_type, .release_port = bcm_uart_release_port, .request_port = bcm_uart_request_port, .config_port = bcm_uart_config_port, .verify_port = bcm_uart_verify_port, }; #ifdef CONFIG_SERIAL_BCM63XX_CONSOLE static inline void wait_for_xmitr(struct uart_port *port) { unsigned int tmout; /* Wait up to 10ms for the character(s) to be sent. */ tmout = 10000; while (--tmout) { unsigned int val; val = bcm_uart_readl(port, UART_IR_REG); if (val & UART_IR_STAT(UART_IR_TXEMPTY)) break; udelay(1); } /* Wait up to 1s for flow control if necessary */ if (port->flags & UPF_CONS_FLOW) { tmout = 1000000; while (--tmout) { unsigned int val; val = bcm_uart_readl(port, UART_EXTINP_REG); if (val & UART_EXTINP_CTS_MASK) break; udelay(1); } } } /* * output given char */ static void bcm_console_putchar(struct uart_port *port, int ch) { wait_for_xmitr(port); bcm_uart_writel(port, ch, UART_FIFO_REG); } /* * console core request to output given string */ static void bcm_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) { /* bcm_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, bcm_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 bcm_console_setup(struct console *co, char *options) { struct uart_port *port; int baud = 9600; int bits = 8; int parity = 'n'; int flow = 'n'; if (co->index < 0 || co->index >= BCM63XX_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 bcm_uart_driver; static struct console bcm63xx_console = { .name = "ttyS", .write = bcm_console_write, .device = uart_console_device, .setup = bcm_console_setup, .flags = CON_PRINTBUFFER, .index = -1, .data = &bcm_uart_driver, }; static int __init bcm63xx_console_init(void) { register_console(&bcm63xx_console); return 0; } console_initcall(bcm63xx_console_init); #define BCM63XX_CONSOLE (&bcm63xx_console) #else #define BCM63XX_CONSOLE NULL #endif /* CONFIG_SERIAL_BCM63XX_CONSOLE */ static struct uart_driver bcm_uart_driver = { .owner = THIS_MODULE, .driver_name = "bcm63xx_uart", .dev_name = "ttyS", .major = TTY_MAJOR, .minor = 64, .nr = BCM63XX_NR_UARTS, .cons = BCM63XX_CONSOLE, }; /* * platform driver probe/remove callback */ static int __devinit bcm_uart_probe(struct platform_device *pdev) { struct resource *res_mem, *res_irq; struct uart_port *port; struct clk *clk; int ret; if (pdev->id < 0 || pdev->id >= BCM63XX_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; clk = clk_get(&pdev->dev, "periph"); if (IS_ERR(clk)) 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 = &bcm_uart_ops; port->flags = UPF_BOOT_AUTOCONF; port->dev = &pdev->dev; port->fifosize = 16; port->uartclk = clk_get_rate(clk) / 2; port->line = pdev->id; clk_put(clk); ret = uart_add_one_port(&bcm_uart_driver, port); if (ret) { ports[pdev->id].membase = 0; return ret; } platform_set_drvdata(pdev, port); return 0; } static int __devexit bcm_uart_remove(struct platform_device *pdev) { struct uart_port *port; port = platform_get_drvdata(pdev); uart_remove_one_port(&bcm_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 bcm_uart_platform_driver = { .probe = bcm_uart_probe, .remove = __devexit_p(bcm_uart_remove), .driver = { .owner = THIS_MODULE, .name = "bcm63xx_uart", }, }; static int __init bcm_uart_init(void) { int ret; ret = uart_register_driver(&bcm_uart_driver); if (ret) return ret; ret = platform_driver_register(&bcm_uart_platform_driver); if (ret) uart_unregister_driver(&bcm_uart_driver); return ret; } static void __exit bcm_uart_exit(void) { platform_driver_unregister(&bcm_uart_platform_driver); uart_unregister_driver(&bcm_uart_driver); } module_init(bcm_uart_init); module_exit(bcm_uart_exit); MODULE_AUTHOR("Maxime Bizon "); MODULE_DESCRIPTION("Broadcom 63