diff options
Diffstat (limited to 'drivers/tty/serial/altera_uart.c')
| -rw-r--r-- | drivers/tty/serial/altera_uart.c | 674 |
1 files changed, 674 insertions, 0 deletions
diff --git a/drivers/tty/serial/altera_uart.c b/drivers/tty/serial/altera_uart.c new file mode 100644 index 000000000..1203d1e08 --- /dev/null +++ b/drivers/tty/serial/altera_uart.c @@ -0,0 +1,674 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * altera_uart.c -- Altera UART driver + * + * Based on mcf.c -- Freescale ColdFire UART driver + * + * (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com> + * (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw> + * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch> + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/timer.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/console.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/serial.h> +#include <linux/serial_core.h> +#include <linux/platform_device.h> +#include <linux/of.h> +#include <linux/io.h> +#include <linux/altera_uart.h> + +#define DRV_NAME "altera_uart" +#define SERIAL_ALTERA_MAJOR 204 +#define SERIAL_ALTERA_MINOR 213 + +/* + * Altera UART register definitions according to the Nios UART datasheet: + * http://www.altera.com/literature/ds/ds_nios_uart.pdf + */ + +#define ALTERA_UART_SIZE 32 + +#define ALTERA_UART_RXDATA_REG 0 +#define ALTERA_UART_TXDATA_REG 4 +#define ALTERA_UART_STATUS_REG 8 +#define ALTERA_UART_CONTROL_REG 12 +#define ALTERA_UART_DIVISOR_REG 16 +#define ALTERA_UART_EOP_REG 20 + +#define ALTERA_UART_STATUS_PE_MSK 0x0001 /* parity error */ +#define ALTERA_UART_STATUS_FE_MSK 0x0002 /* framing error */ +#define ALTERA_UART_STATUS_BRK_MSK 0x0004 /* break */ +#define ALTERA_UART_STATUS_ROE_MSK 0x0008 /* RX overrun error */ +#define ALTERA_UART_STATUS_TOE_MSK 0x0010 /* TX overrun error */ +#define ALTERA_UART_STATUS_TMT_MSK 0x0020 /* TX shift register state */ +#define ALTERA_UART_STATUS_TRDY_MSK 0x0040 /* TX ready */ +#define ALTERA_UART_STATUS_RRDY_MSK 0x0080 /* RX ready */ +#define ALTERA_UART_STATUS_E_MSK 0x0100 /* exception condition */ +#define ALTERA_UART_STATUS_DCTS_MSK 0x0400 /* CTS logic-level change */ +#define ALTERA_UART_STATUS_CTS_MSK 0x0800 /* CTS logic state */ +#define ALTERA_UART_STATUS_EOP_MSK 0x1000 /* EOP written/read */ + + /* Enable interrupt on... */ +#define ALTERA_UART_CONTROL_PE_MSK 0x0001 /* ...parity error */ +#define ALTERA_UART_CONTROL_FE_MSK 0x0002 /* ...framing error */ +#define ALTERA_UART_CONTROL_BRK_MSK 0x0004 /* ...break */ +#define ALTERA_UART_CONTROL_ROE_MSK 0x0008 /* ...RX overrun */ +#define ALTERA_UART_CONTROL_TOE_MSK 0x0010 /* ...TX overrun */ +#define ALTERA_UART_CONTROL_TMT_MSK 0x0020 /* ...TX shift register empty */ +#define ALTERA_UART_CONTROL_TRDY_MSK 0x0040 /* ...TX ready */ +#define ALTERA_UART_CONTROL_RRDY_MSK 0x0080 /* ...RX ready */ +#define ALTERA_UART_CONTROL_E_MSK 0x0100 /* ...exception*/ + +#define ALTERA_UART_CONTROL_TRBK_MSK 0x0200 /* TX break */ +#define ALTERA_UART_CONTROL_DCTS_MSK 0x0400 /* Interrupt on CTS change */ +#define ALTERA_UART_CONTROL_RTS_MSK 0x0800 /* RTS signal */ +#define ALTERA_UART_CONTROL_EOP_MSK 0x1000 /* Interrupt on EOP */ + +/* + * Local per-uart structure. + */ +struct altera_uart { + struct uart_port port; + struct timer_list tmr; + unsigned int sigs; /* Local copy of line sigs */ + unsigned short imr; /* Local IMR mirror */ +}; + +static u32 altera_uart_readl(struct uart_port *port, int reg) +{ + return readl(port->membase + (reg << port->regshift)); +} + +static void altera_uart_writel(struct uart_port *port, u32 dat, int reg) +{ + writel(dat, port->membase + (reg << port->regshift)); +} + +static unsigned int altera_uart_tx_empty(struct uart_port *port) +{ + return (altera_uart_readl(port, ALTERA_UART_STATUS_REG) & + ALTERA_UART_STATUS_TMT_MSK) ? TIOCSER_TEMT : 0; +} + +static unsigned int altera_uart_get_mctrl(struct uart_port *port) +{ + struct altera_uart *pp = container_of(port, struct altera_uart, port); + unsigned int sigs; + + sigs = (altera_uart_readl(port, ALTERA_UART_STATUS_REG) & + ALTERA_UART_STATUS_CTS_MSK) ? TIOCM_CTS : 0; + sigs |= (pp->sigs & TIOCM_RTS); + + return sigs; +} + +static void altera_uart_update_ctrl_reg(struct altera_uart *pp) +{ + unsigned short imr = pp->imr; + + /* + * If the device doesn't have an irq, ensure that the irq bits are + * masked out to keep the irq line inactive. + */ + if (!pp->port.irq) + imr &= ALTERA_UART_CONTROL_TRBK_MSK | ALTERA_UART_CONTROL_RTS_MSK; + + altera_uart_writel(&pp->port, imr, ALTERA_UART_CONTROL_REG); +} + +static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs) +{ + struct altera_uart *pp = container_of(port, struct altera_uart, port); + + pp->sigs = sigs; + if (sigs & TIOCM_RTS) + pp->imr |= ALTERA_UART_CONTROL_RTS_MSK; + else + pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK; + altera_uart_update_ctrl_reg(pp); +} + +static void altera_uart_start_tx(struct uart_port *port) +{ + struct altera_uart *pp = container_of(port, struct altera_uart, port); + + pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK; + altera_uart_update_ctrl_reg(pp); +} + +static void altera_uart_stop_tx(struct uart_port *port) +{ + struct altera_uart *pp = container_of(port, struct altera_uart, port); + + pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK; + altera_uart_update_ctrl_reg(pp); +} + +static void altera_uart_stop_rx(struct uart_port *port) +{ + struct altera_uart *pp = container_of(port, struct altera_uart, port); + + pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK; + altera_uart_update_ctrl_reg(pp); +} + +static void altera_uart_break_ctl(struct uart_port *port, int break_state) +{ + struct altera_uart *pp = container_of(port, struct altera_uart, port); + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + if (break_state == -1) + pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK; + else + pp->imr &= ~ALTERA_UART_CONTROL_TRBK_MSK; + altera_uart_update_ctrl_reg(pp); + spin_unlock_irqrestore(&port->lock, flags); +} + +static void altera_uart_set_termios(struct uart_port *port, + struct ktermios *termios, + const struct ktermios *old) +{ + unsigned long flags; + unsigned int baud, baudclk; + + baud = uart_get_baud_rate(port, termios, old, 0, 4000000); + baudclk = port->uartclk / baud; + + if (old) + tty_termios_copy_hw(termios, old); + tty_termios_encode_baud_rate(termios, baud, baud); + + spin_lock_irqsave(&port->lock, flags); + uart_update_timeout(port, termios->c_cflag, baud); + altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG); + spin_unlock_irqrestore(&port->lock, flags); + + /* + * FIXME: port->read_status_mask and port->ignore_status_mask + * need to be initialized based on termios settings for + * INPCK, IGNBRK, IGNPAR, PARMRK, BRKINT + */ +} + +static void altera_uart_rx_chars(struct uart_port *port) +{ + unsigned char ch, flag; + unsigned short status; + + while ((status = altera_uart_readl(port, ALTERA_UART_STATUS_REG)) & + ALTERA_UART_STATUS_RRDY_MSK) { + ch = altera_uart_readl(port, ALTERA_UART_RXDATA_REG); + flag = TTY_NORMAL; + port->icount.rx++; + + if (status & ALTERA_UART_STATUS_E_MSK) { + altera_uart_writel(port, status, + ALTERA_UART_STATUS_REG); + + if (status & ALTERA_UART_STATUS_BRK_MSK) { + port->icount.brk++; + if (uart_handle_break(port)) + continue; + } else if (status & ALTERA_UART_STATUS_PE_MSK) { + port->icount.parity++; + } else if (status & ALTERA_UART_STATUS_ROE_MSK) { + port->icount.overrun++; + } else if (status & ALTERA_UART_STATUS_FE_MSK) { + port->icount.frame++; + } + + status &= port->read_status_mask; + + if (status & ALTERA_UART_STATUS_BRK_MSK) + flag = TTY_BREAK; + else if (status & ALTERA_UART_STATUS_PE_MSK) + flag = TTY_PARITY; + else if (status & ALTERA_UART_STATUS_FE_MSK) + flag = TTY_FRAME; + } + + if (uart_handle_sysrq_char(port, ch)) + continue; + uart_insert_char(port, status, ALTERA_UART_STATUS_ROE_MSK, ch, + flag); + } + + tty_flip_buffer_push(&port->state->port); +} + +static void altera_uart_tx_chars(struct uart_port *port) +{ + struct circ_buf *xmit = &port->state->xmit; + + if (port->x_char) { + /* Send special char - probably flow control */ + altera_uart_writel(port, port->x_char, ALTERA_UART_TXDATA_REG); + port->x_char = 0; + port->icount.tx++; + return; + } + + while (altera_uart_readl(port, ALTERA_UART_STATUS_REG) & + ALTERA_UART_STATUS_TRDY_MSK) { + if (xmit->head == xmit->tail) + break; + altera_uart_writel(port, xmit->buf[xmit->tail], + ALTERA_UART_TXDATA_REG); + 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)) + altera_uart_stop_tx(port); +} + +static irqreturn_t altera_uart_interrupt(int irq, void *data) +{ + struct uart_port *port = data; + struct altera_uart *pp = container_of(port, struct altera_uart, port); + unsigned long flags; + unsigned int isr; + + isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr; + + spin_lock_irqsave(&port->lock, flags); + if (isr & ALTERA_UART_STATUS_RRDY_MSK) + altera_uart_rx_chars(port); + if (isr & ALTERA_UART_STATUS_TRDY_MSK) + altera_uart_tx_chars(port); + spin_unlock_irqrestore(&port->lock, flags); + + return IRQ_RETVAL(isr); +} + +static void altera_uart_timer(struct timer_list *t) +{ + struct altera_uart *pp = from_timer(pp, t, tmr); + struct uart_port *port = &pp->port; + + altera_uart_interrupt(0, port); + mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port)); +} + +static void altera_uart_config_port(struct uart_port *port, int flags) +{ + port->type = PORT_ALTERA_UART; + + /* Clear mask, so no surprise interrupts. */ + altera_uart_writel(port, 0, ALTERA_UART_CONTROL_REG); + /* Clear status register */ + altera_uart_writel(port, 0, ALTERA_UART_STATUS_REG); +} + +static int altera_uart_startup(struct uart_port *port) +{ + struct altera_uart *pp = container_of(port, struct altera_uart, port); + unsigned long flags; + + if (!port->irq) { + timer_setup(&pp->tmr, altera_uart_timer, 0); + mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port)); + } else { + int ret; + + ret = request_irq(port->irq, altera_uart_interrupt, 0, + DRV_NAME, port); + if (ret) { + pr_err(DRV_NAME ": unable to attach Altera UART %d " + "interrupt vector=%d\n", port->line, port->irq); + return ret; + } + } + + spin_lock_irqsave(&port->lock, flags); + + /* Enable RX interrupts now */ + pp->imr = ALTERA_UART_CONTROL_RRDY_MSK; + altera_uart_update_ctrl_reg(pp); + + spin_unlock_irqrestore(&port->lock, flags); + + return 0; +} + +static void altera_uart_shutdown(struct uart_port *port) +{ + struct altera_uart *pp = container_of(port, struct altera_uart, port); + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + + /* Disable all interrupts now */ + pp->imr = 0; + altera_uart_update_ctrl_reg(pp); + + spin_unlock_irqrestore(&port->lock, flags); + + if (port->irq) + free_irq(port->irq, port); + else + del_timer_sync(&pp->tmr); +} + +static const char *altera_uart_type(struct uart_port *port) +{ + return (port->type == PORT_ALTERA_UART) ? "Altera UART" : NULL; +} + +static int altera_uart_request_port(struct uart_port *port) +{ + /* UARTs always present */ + return 0; +} + +static void altera_uart_release_port(struct uart_port *port) +{ + /* Nothing to release... */ +} + +static int altera_uart_verify_port(struct uart_port *port, + struct serial_struct *ser) +{ + if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_ALTERA_UART)) + return -EINVAL; + return 0; +} + +#ifdef CONFIG_CONSOLE_POLL +static int altera_uart_poll_get_char(struct uart_port *port) +{ + while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) & + ALTERA_UART_STATUS_RRDY_MSK)) + cpu_relax(); + + return altera_uart_readl(port, ALTERA_UART_RXDATA_REG); +} + +static void altera_uart_poll_put_char(struct uart_port *port, unsigned char c) +{ + while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) & + ALTERA_UART_STATUS_TRDY_MSK)) + cpu_relax(); + + altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG); +} +#endif + +/* + * Define the basic serial functions we support. + */ +static const struct uart_ops altera_uart_ops = { + .tx_empty = altera_uart_tx_empty, + .get_mctrl = altera_uart_get_mctrl, + .set_mctrl = altera_uart_set_mctrl, + .start_tx = altera_uart_start_tx, + .stop_tx = altera_uart_stop_tx, + .stop_rx = altera_uart_stop_rx, + .break_ctl = altera_uart_break_ctl, + .startup = altera_uart_startup, + .shutdown = altera_uart_shutdown, + .set_termios = altera_uart_set_termios, + .type = altera_uart_type, + .request_port = altera_uart_request_port, + .release_port = altera_uart_release_port, + .config_port = altera_uart_config_port, + .verify_port = altera_uart_verify_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = altera_uart_poll_get_char, + .poll_put_char = altera_uart_poll_put_char, +#endif +}; + +static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS]; + +#if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE) + +static void altera_uart_console_putc(struct uart_port *port, unsigned char c) +{ + while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) & + ALTERA_UART_STATUS_TRDY_MSK)) + cpu_relax(); + + altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG); +} + +static void altera_uart_console_write(struct console *co, const char *s, + unsigned int count) +{ + struct uart_port *port = &(altera_uart_ports + co->index)->port; + + uart_console_write(port, s, count, altera_uart_console_putc); +} + +static int __init altera_uart_console_setup(struct console *co, char *options) +{ + struct uart_port *port; + int baud = CONFIG_SERIAL_ALTERA_UART_BAUDRATE; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + + if (co->index < 0 || co->index >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS) + return -EINVAL; + port = &altera_uart_ports[co->index].port; + 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 altera_uart_driver; + +static struct console altera_uart_console = { + .name = "ttyAL", + .write = altera_uart_console_write, + .device = uart_console_device, + .setup = altera_uart_console_setup, + .flags = CON_PRINTBUFFER, + .index = -1, + .data = &altera_uart_driver, +}; + +static int __init altera_uart_console_init(void) +{ + register_console(&altera_uart_console); + return 0; +} + +console_initcall(altera_uart_console_init); + +#define ALTERA_UART_CONSOLE (&altera_uart_console) + +static void altera_uart_earlycon_write(struct console *co, const char *s, + unsigned int count) +{ + struct earlycon_device *dev = co->data; + + uart_console_write(&dev->port, s, count, altera_uart_console_putc); +} + +static int __init altera_uart_earlycon_setup(struct earlycon_device *dev, + const char *options) +{ + struct uart_port *port = &dev->port; + + if (!port->membase) + return -ENODEV; + + /* Enable RX interrupts now */ + altera_uart_writel(port, ALTERA_UART_CONTROL_RRDY_MSK, + ALTERA_UART_CONTROL_REG); + + if (dev->baud) { + unsigned int baudclk = port->uartclk / dev->baud; + + altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG); + } + + dev->con->write = altera_uart_earlycon_write; + return 0; +} + +OF_EARLYCON_DECLARE(uart, "altr,uart-1.0", altera_uart_earlycon_setup); + +#else + +#define ALTERA_UART_CONSOLE NULL + +#endif /* CONFIG_SERIAL_ALTERA_UART_CONSOLE */ + +/* + * Define the altera_uart UART driver structure. + */ +static struct uart_driver altera_uart_driver = { + .owner = THIS_MODULE, + .driver_name = DRV_NAME, + .dev_name = "ttyAL", + .major = SERIAL_ALTERA_MAJOR, + .minor = SERIAL_ALTERA_MINOR, + .nr = CONFIG_SERIAL_ALTERA_UART_MAXPORTS, + .cons = ALTERA_UART_CONSOLE, +}; + +static int altera_uart_probe(struct platform_device *pdev) +{ + struct altera_uart_platform_uart *platp = dev_get_platdata(&pdev->dev); + struct uart_port *port; + struct resource *res_mem; + int i = pdev->id; + int ret; + + /* if id is -1 scan for a free id and use that one */ + if (i == -1) { + for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS; i++) + if (altera_uart_ports[i].port.mapbase == 0) + break; + } + + if (i < 0 || i >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS) + return -EINVAL; + + port = &altera_uart_ports[i].port; + + res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (res_mem) + port->mapbase = res_mem->start; + else if (platp) + port->mapbase = platp->mapbase; + else + return -EINVAL; + + ret = platform_get_irq_optional(pdev, 0); + if (ret < 0 && ret != -ENXIO) + return ret; + if (ret > 0) + port->irq = ret; + else if (platp) + port->irq = platp->irq; + + /* Check platform data first so we can override device node data */ + if (platp) + port->uartclk = platp->uartclk; + else { + ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency", + &port->uartclk); + if (ret) + return ret; + } + + port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE); + if (!port->membase) + return -ENOMEM; + + if (platp) + port->regshift = platp->bus_shift; + else + port->regshift = 0; + + port->line = i; + port->type = PORT_ALTERA_UART; + port->iotype = SERIAL_IO_MEM; + port->ops = &altera_uart_ops; + port->flags = UPF_BOOT_AUTOCONF; + port->dev = &pdev->dev; + + platform_set_drvdata(pdev, port); + + uart_add_one_port(&altera_uart_driver, port); + + return 0; +} + +static int altera_uart_remove(struct platform_device *pdev) +{ + struct uart_port *port = platform_get_drvdata(pdev); + + if (port) { + uart_remove_one_port(&altera_uart_driver, port); + port->mapbase = 0; + iounmap(port->membase); + } + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id altera_uart_match[] = { + { .compatible = "ALTR,uart-1.0", }, + { .compatible = "altr,uart-1.0", }, + {}, +}; +MODULE_DEVICE_TABLE(of, altera_uart_match); +#endif /* CONFIG_OF */ + +static struct platform_driver altera_uart_platform_driver = { + .probe = altera_uart_probe, + .remove = altera_uart_remove, + .driver = { + .name = DRV_NAME, + .of_match_table = of_match_ptr(altera_uart_match), + }, +}; + +static int __init altera_uart_init(void) +{ + int rc; + + rc = uart_register_driver(&altera_uart_driver); + if (rc) + return rc; + rc = platform_driver_register(&altera_uart_platform_driver); + if (rc) + uart_unregister_driver(&altera_uart_driver); + return rc; +} + +static void __exit altera_uart_exit(void) +{ + platform_driver_unregister(&altera_uart_platform_driver); + uart_unregister_driver(&altera_uart_driver); +} + +module_init(altera_uart_init); +module_exit(altera_uart_exit); + +MODULE_DESCRIPTION("Altera UART driver"); +MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" DRV_NAME); +MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_ALTERA_MAJOR); |