/* * Copyright (C) 2010 Alexey Charkov <alchark@gmail.com> * * Based on msm_serial.c, which is: * Copyright (C) 2007 Google, Inc. * Author: Robert Love <rlove@google.com> * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and * may be copied, distributed, and modified under those terms. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #if defined(CONFIG_SERIAL_VT8500_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) # define SUPPORT_SYSRQ #endif #include <linux/hrtimer.h> #include <linux/delay.h> #include <linux/module.h> #include <linux/io.h> #include <linux/ioport.h> #include <linux/irq.h> #include <linux/init.h> #include <linux/console.h> #include <linux/tty.h> #include <linux/tty_flip.h> #include <linux/serial_core.h> #include <linux/serial.h> #include <linux/slab.h> #include <linux/clk.h> #include <linux/platform_device.h> #include <linux/of.h> #include <linux/err.h> /* * UART Register offsets */ #define VT8500_URTDR 0x0000 /* Transmit data */ #define VT8500_URRDR 0x0004 /* Receive data */ #define VT8500_URDIV 0x0008 /* Clock/Baud rate divisor */ #define VT8500_URLCR 0x000C /* Line control */ #define VT8500_URICR 0x0010 /* IrDA control */ #define VT8500_URIER 0x0014 /* Interrupt enable */ #define VT8500_URISR 0x0018 /* Interrupt status */ #define VT8500_URUSR 0x001c /* UART status */ #define VT8500_URFCR 0x0020 /* FIFO control */ #define VT8500_URFIDX 0x0024 /* FIFO index */ #define VT8500_URBKR 0x0028 /* Break signal count */ #define VT8500_URTOD 0x002c /* Time out divisor */ #define VT8500_TXFIFO 0x1000 /* Transmit FIFO (16x8) */ #define VT8500_RXFIFO 0x1020 /* Receive FIFO (16x10) */ /* * Interrupt enable and status bits */ #define TXDE (1 << 0) /* Tx Data empty */ #define RXDF (1 << 1) /* Rx Data full */ #define TXFAE (1 << 2) /* Tx FIFO almost empty */ #define TXFE (1 << 3) /* Tx FIFO empty */ #define RXFAF (1 << 4) /* Rx FIFO almost full */ #define RXFF (1 << 5) /* Rx FIFO full */ #define TXUDR (1 << 6) /* Tx underrun */ #define RXOVER (1 << 7) /* Rx overrun */ #define PER (1 << 8) /* Parity error */ #define FER (1 << 9) /* Frame error */ #define TCTS (1 << 10) /* Toggle of CTS */ #define RXTOUT (1 << 11) /* Rx timeout */ #define BKDONE (1 << 12) /* Break signal done */ #define ERR (1 << 13) /* AHB error response */ #define RX_FIFO_INTS (RXFAF | RXFF | RXOVER | PER | FER | RXTOUT) #define TX_FIFO_INTS (TXFAE | TXFE | TXUDR) #define VT8500_MAX_PORTS 6 struct vt8500_port { struct uart_port uart; char name[16]; struct clk *clk; unsigned int ier; }; /* * we use this variable to keep track of which ports * have been allocated as we can't use pdev->id in * devicetree */ static unsigned long vt8500_ports_in_use; static inline void vt8500_write(struct uart_port *port, unsigned int val, unsigned int off) { writel(val, port->membase + off); } static inline unsigned int vt8500_read(struct uart_port *port, unsigned int off) { return readl(port->membase + off); } static void vt8500_stop_tx(struct uart_port *port) { struct vt8500_port *vt8500_port = container_of(port, struct vt8500_port, uart); vt8500_port->ier &= ~TX_FIFO_INTS; vt8500_write(port, vt8500_port->ier, VT8500_URIER); } static void vt8500_stop_rx(struct uart_port *port) { struct vt8500_port *vt8500_port = container_of(port, struct vt8500_port, uart); vt8500_port->ier &= ~RX_FIFO_INTS; vt8500_write(port, vt8500_port->ier, VT8500_URIER); } static void vt8500_enable_ms(struct uart_port *port) { struct vt8500_port *vt8500_port = container_of(port, struct vt8500_port, uart); vt8500_port->ier |= TCTS; vt8500_write(port, vt8500_port->ier, VT8500_URIER); } static void handle_rx(struct uart_port *port) { struct tty_port *tport = &port->state->port; /* * Handle overrun */ if ((vt8500_read(port, VT8500_URISR) & RXOVER)) { port->icount.overrun++; tty_insert_flip_char(tport, 0, TTY_OVERRUN); } /* and now the main RX loop */ while (vt8500_read(port, VT8500_URFIDX) & 0x1f00) { unsigned int c; char flag = TTY_NORMAL; c = readw(port->membase + VT8500_RXFIFO) & 0x3ff; /* Mask conditions we're ignorning. */ c &= ~port->read_status_mask; if (c & FER) { port->icount.frame++; flag = TTY_FRAME; } else if (c & PER) { port->icount.parity++; flag = TTY_PARITY; } port->icount.rx++; if (!uart_handle_sysrq_char(port, c)) tty_insert_flip_char(tport, c, flag); } tty_flip_buffer_push(tport); } static void handle_tx(struct uart_port *port) { struct circ_buf *xmit = &port->state->xmit; if (port->x_char) { writeb(port->x_char, port->membase + VT8500_TXFIFO); port->icount.tx++; port->x_char = 0; } if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { vt8500_stop_tx(port); return; } while ((vt8500_read(port, VT8500_URFIDX) & 0x1f) < 16) { if (uart_circ_empty(xmit)) break; writeb(xmit->buf[xmit->tail], port->membase + VT8500_TXFIFO); xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); port->icount.tx++; } if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); if (uart_circ_empty(xmit)) vt8500_stop_tx(port); } static void vt8500_start_tx(struct uart_port *port) { struct vt8500_port *vt8500_port = container_of(port, struct vt8500_port, uart); vt8500_port->ier &= ~TX_FIFO_INTS; vt8500_write(port, vt8500_port->ier, VT8500_URIER); handle_tx(port); vt8500_port->ier |= TX_FIFO_INTS; vt8500_write(port, vt8500_port->ier, VT8500_URIER); } static void handle_delta_cts(struct uart_port *port) { port->icount.cts++; wake_up_interruptible(&port->state->port.delta_msr_wait); } static irqreturn_t vt8500_irq(int irq, void *dev_id) { struct uart_port *port = dev_id; unsigned long isr; spin_lock(&port->lock); isr = vt8500_read(port, VT8500_URISR); /* Acknowledge active status bits */ vt8500_write(port, isr, VT8500_URISR); if (isr & RX_FIFO_INTS) handle_rx(port); if (isr & TX_FIFO_INTS) handle_tx(port); if (isr & TCTS) handle_delta_cts(port); spin_unlock(&port->lock); return IRQ_HANDLED; } static unsigned int vt8500_tx_empty(struct uart_port *port) { return (vt8500_read(port, VT8500_URFIDX) & 0x1f) < 16 ? TIOCSER_TEMT : 0; } static unsigned int vt8500_get_mctrl(struct uart_port *port) { unsigned int usr; usr = vt8500_read(port, VT8500_URUSR); if (usr & (1 << 4)) return TIOCM_CTS; else return 0; } static void vt8500_set_mctrl(struct uart_port *port, unsigned int mctrl) { } static void vt8500_break_ctl(struct uart_port *port, int break_ctl) { if (break_ctl) vt8500_write(port, vt8500_read(port, VT8500_URLCR) | (1 << 9), VT8500_URLCR); } static int vt8500_set_baud_rate(struct uart_port *port, unsigned int baud) { unsigned long div; unsigned int loops = 1000; div = vt8500_read(port, VT8500_URDIV) & ~(0x3ff); if (unlikely((baud < 900) || (baud > 921600))) div |= 7; else div |= (921600 / baud) - 1; while ((vt8500_read(port, VT8500_URUSR) & (1 << 5)) && --loops) cpu_relax(); vt8500_write(port, div, VT8500_URDIV); return baud; } static int vt8500_startup(struct uart_port *port) { struct vt8500_port *vt8500_port = container_of(port, struct vt8500_port, uart); int ret; snprintf(vt8500_port->name, sizeof(vt8500_port->name), "vt8500_serial%d", port->line); ret = request_irq(port->irq, vt8500_irq, IRQF_TRIGGER_HIGH, vt8500_port->name, port); if (unlikely(ret)) return ret; vt8500_write(port, 0x03, VT8500_URLCR); /* enable TX & RX */ return 0; } static void vt8500_shutdown(struct uart_port *port) { struct vt8500_port *vt8500_port = container_of(port, struct vt8500_port, uart); vt8500_port->ier = 0; /* disable interrupts and FIFOs */ vt8500_write(&vt8500_port->uart, 0, VT8500_URIER); vt8500_write(&vt8500_port->uart, 0x880, VT8500_URFCR); free_irq(port->irq, port); } static void vt8500_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { struct vt8500_port *vt8500_port = container_of(port, struct vt8500_port, uart); unsigned long flags; unsigned int baud, lcr; unsigned int loops = 1000; spin_lock_irqsave(&port->lock, flags); /* calculate and set baud rate */ baud = uart_get_baud_rate(port, termios, old, 900, 921600); baud = vt8500_set_baud_rate(port, baud); if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); /* calculate parity */ lcr = vt8500_read(&vt8500_port->uart, VT8500_URLCR); lcr &= ~((1 << 5) | (1 << 4)); if (termios->c_cflag & PARENB) { lcr |= (1 << 4); termios->c_cflag &= ~CMSPAR; if (termios->c_cflag & PARODD) lcr |= (1 << 5); } /* calculate bits per char */ lcr &= ~(1 << 2); switch (termios->c_cflag & CSIZE) { case CS7: break; case CS8: default: lcr |= (1 << 2); termios->c_cflag &= ~CSIZE; termios->c_cflag |= CS8; break; } /* calculate stop bits */ lcr &= ~(1 << 3); if (termios->c_cflag & CSTOPB) lcr |= (1 << 3); /* set parity, bits per char, and stop bit */ vt8500_write(&vt8500_port->uart, lcr, VT8500_URLCR); /* Configure status bits to ignore based on termio flags. */ port->read_status_mask = 0; if (termios->c_iflag & IGNPAR) port->read_status_mask = FER | PER; uart_update_timeout(port, termios->c_cflag, baud); /* Reset FIFOs */ vt8500_write(&vt8500_port->uart, 0x88c, VT8500_URFCR); while ((vt8500_read(&vt8500_port->uart, VT8500_URFCR) & 0xc) && --loops) cpu_relax(); /* Every possible FIFO-related interrupt */ vt8500_port->ier = RX_FIFO_INTS | TX_FIFO_INTS; /* * CTS flow control */ if (UART_ENABLE_MS(&vt8500_port->uart, termios->c_cflag)) vt8500_port->ier |= TCTS; vt8500_write(&vt8500_port->uart, 0x881, VT8500_URFCR); vt8500_write(&vt8500_port->uart, vt8500_port->ier, VT8500_URIER); spin_unlock_irqrestore(&port->lock, flags); } static const char *vt8500_type(struct uart_port *port) { struct vt8500_port *vt8500_port = container_of(port, struct vt8500_port, uart); return vt8500_port->name; } static void vt8500_release_port(struct uart_port *port) { } static int vt8500_request_port(struct uart_port *port) { return 0; } static void vt8500_config_port(struct uart_port *port, int flags) { port->type = PORT_VT8500; } static int vt8500_verify_port(struct uart_port *port, struct serial_struct *ser) { if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_VT8500)) return -EINVAL; if (unlikely(port->irq != ser->irq)) return -EINVAL; return 0; } static struct vt8500_port *vt8500_uart_ports[VT8500_MAX_PORTS]; static struct uart_driver vt8500_uart_driver; #ifdef CONFIG_SERIAL_VT8500_CONSOLE static inline void wait_for_xmitr(struct uart_port *port) { unsigned int status, tmout = 10000; /* Wait up to 10ms for the character(s) to be sent. */ do { status = vt8500_read(port, VT8500_URFIDX); if (--tmout == 0) break; udelay(1); } while (status & 0x10); } static void vt8500_console_putchar(struct uart_port *port, int c) { wait_for_xmitr(port); writeb(c, port->membase + VT8500_TXFIFO); } static void vt8500_console_write(struct console *co, const char *s, unsigned int count) { struct vt8500_port *vt8500_port = vt8500_uart_ports[co->index]; unsigned long ier; BUG_ON(co->index < 0 || co->index >= vt8500_uart_driver.nr); ier = vt8500_read(&vt8500_port->uart, VT8500_URIER); vt8500_write(&vt8500_port->uart, VT8500_URIER, 0); uart_console_write(&vt8500_port->uart, s, count, vt8500_console_putchar); /* * Finally, wait for transmitter to become empty * and switch back to FIFO */ wait_for_xmitr(&vt8500_port->uart); vt8500_write(&vt8500_port->uart, VT8500_URIER, ier); } static int __init vt8500_console_setup(struct console *co, char *options) { struct vt8500_port *vt8500_port; int baud = 9600; int bits = 8; int parity = 'n'; int flow = 'n'; if (unlikely(co->index >= vt8500_uart_driver.nr || co->index < 0)) return -ENXIO; vt8500_port = vt8500_uart_ports[co->index]; if (!vt8500_port) return -ENODEV; if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); return uart_set_options(&vt8500_port->uart, co, baud, parity, bits, flow); } static struct console vt8500_console = { .name = "ttyWMT", .write = vt8500_console_write, .device = uart_console_device, .setup = vt8500_console_setup, .flags = CON_PRINTBUFFER, .index = -1, .data = &vt8500_uart_driver, }; #define VT8500_CONSOLE (&vt8500_console) #else #define VT8500_CONSOLE NULL #endif static struct uart_ops vt8500_uart_pops = { .tx_empty = vt8500_tx_empty, .set_mctrl = vt8500_set_mctrl, .get_mctrl = vt8500_get_mctrl, .stop_tx = vt8500_stop_tx, .start_tx = vt8500_start_tx, .stop_rx = vt8500_stop_rx, .enable_ms = vt8500_enable_ms, .break_ctl = vt8500_break_ctl, .startup = vt8500_startup, .shutdown = vt8500_shutdown, .set_termios = vt8500_set_termios, .type = vt8500_type, .release_port = vt8500_release_port, .request_port = vt8500_request_port, .config_port = vt8500_config_port, .verify_port = vt8500_verify_port, }; static struct uart_driver vt8500_uart_driver = { .owner = THIS_MODULE, .driver_name = "vt8500_serial", .dev_name = "ttyWMT", .nr = 6, .cons = VT8500_CONSOLE, }; static int vt8500_serial_probe(struct platform_device *pdev) { struct vt8500_port *vt8500_port; struct resource *mmres, *irqres; struct device_node *np = pdev->dev.of_node; int ret; int port; mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0); irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if (!mmres || !irqres) return -ENODEV; if (np) port = of_alias_get_id(np, "serial"); if (port >= VT8500_MAX_PORTS) port = -1; else port = -1; if (port < 0) { /* calculate the port id */ port = find_first_zero_bit(&vt8500_ports_in_use, sizeof(vt8500_ports_in_use)); } if (port >= VT8500_MAX_PORTS) return -ENODEV; /* reserve the port id */ if (test_and_set_bit(port, &vt8500_ports_in_use)) { /* port already in use - shouldn't really happen */ return -EBUSY; } vt8500_port = devm_kzalloc(&pdev->dev, sizeof(struct vt8500_port), GFP_KERNEL); if (!vt8500_port) return -ENOMEM; vt8500_port->uart.membase = devm_ioremap_resource(&pdev->dev, mmres); if (IS_ERR(vt8500_port->uart.membase)) return PTR_ERR(vt8500_port->uart.membase); vt8500_port->clk = of_clk_get(pdev->dev.of_node, 0); if (IS_ERR(vt8500_port->clk)) { dev_err(&pdev->dev, "failed to get clock\n"); return -EINVAL; } ret = clk_prepare_enable(vt8500_port->clk); if (ret) { dev_err(&pdev->dev, "failed to enable clock\n"); return ret; } vt8500_port->uart.type = PORT_VT8500; vt8500_port->uart.iotype = UPIO_MEM; vt8500_port->uart.mapbase = mmres->start; vt8500_port->uart.irq = irqres->start; vt8500_port->uart.fifosize = 16; vt8500_port->uart.ops = &vt8500_uart_pops; vt8500_port->uart.line = port; vt8500_port->uart.dev = &pdev->dev; vt8500_port->uart.flags = UPF_IOREMAP | UPF_BOOT_AUTOCONF; vt8500_port->uart.uartclk = clk_get_rate(vt8500_port->clk); snprintf(vt8500_port->name, sizeof(vt8500_port->name), "VT8500 UART%d", pdev->id); vt8500_uart_ports[port] = vt8500_port; uart_add_one_port(&vt8500_uart_driver, &vt8500_port->uart); platform_set_drvdata(pdev, vt8500_port); return 0; } static int vt8500_serial_remove(struct platform_device *pdev) { struct vt8500_port *vt8500_port = platform_get_drvdata(pdev); platform_set_drvdata(pdev, NULL); clk_disable_unprepare(vt8500_port->clk); uart_remove_one_port(&vt8500_uart_driver, &vt8500_port->uart); return 0; } static const struct of_device_id wmt_dt_ids[] = { { .compatible = "via,vt8500-uart", }, {} }; static struct platform_driver vt8500_platform_driver = { .probe = vt8500_serial_probe, .remove = vt8500_serial_remove, .driver = { .name = "vt8500_serial", .owner = THIS_MODULE, .of_match_table = of_match_ptr(wmt_dt_ids), }, }; static int __init vt8500_serial_init(void) { int ret; ret = uart_register_driver(&vt8500_uart_driver); if (unlikely(ret)) return ret; ret = platform_driver_register(&vt8500_platform_driver); if (unlikely(ret)) uart_unregister_driver(&vt8500_uart_driver); return ret; } static void __exit vt8500_serial_exit(void) { #ifdef CONFIG_SERIAL_VT8500_CONSOLE unregister_console(&vt8500_console); #endif platform_driver_unregister(&vt8500_platform_driver); uart_unregister_driver(&vt8500_uart_driver); } module_init(vt8500_serial_init); module_exit(vt8500_serial_exit); MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>"); MODULE_DESCRIPTION("Driver for vt8500 serial device"); MODULE_LICENSE("GPL v2");