diff options
Diffstat (limited to 'drivers/tty/serial/altera_jtaguart.c')
-rw-r--r-- | drivers/tty/serial/altera_jtaguart.c | 486 |
1 files changed, 486 insertions, 0 deletions
diff --git a/drivers/tty/serial/altera_jtaguart.c b/drivers/tty/serial/altera_jtaguart.c new file mode 100644 index 0000000000..5fab4c9788 --- /dev/null +++ b/drivers/tty/serial/altera_jtaguart.c @@ -0,0 +1,486 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * altera_jtaguart.c -- Altera JTAG 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/bitfield.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/console.h> +#include <linux/of.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/io.h> +#include <linux/altera_jtaguart.h> + +#define DRV_NAME "altera_jtaguart" + +/* + * Altera JTAG UART register definitions according to the Altera JTAG UART + * datasheet: https://www.altera.com/literature/hb/nios2/n2cpu_nii51009.pdf + */ + +#define ALTERA_JTAGUART_SIZE 8 + +#define ALTERA_JTAGUART_DATA_REG 0 + +#define ALTERA_JTAGUART_DATA_DATA_MSK 0x000000FF +#define ALTERA_JTAGUART_DATA_RVALID_MSK 0x00008000 +#define ALTERA_JTAGUART_DATA_RAVAIL_MSK 0xFFFF0000 +#define ALTERA_JTAGUART_DATA_RAVAIL_OFF 16 + +#define ALTERA_JTAGUART_CONTROL_REG 4 + +#define ALTERA_JTAGUART_CONTROL_RE_MSK 0x00000001 +#define ALTERA_JTAGUART_CONTROL_WE_MSK 0x00000002 +#define ALTERA_JTAGUART_CONTROL_RI_MSK 0x00000100 +#define ALTERA_JTAGUART_CONTROL_RI_OFF 8 +#define ALTERA_JTAGUART_CONTROL_WI_MSK 0x00000200 +#define ALTERA_JTAGUART_CONTROL_AC_MSK 0x00000400 +#define ALTERA_JTAGUART_CONTROL_WSPACE_MSK 0xFFFF0000 + +static unsigned int altera_jtaguart_tx_space(struct uart_port *port, u32 *ctlp) +{ + u32 ctl = readl(port->membase + ALTERA_JTAGUART_CONTROL_REG); + + if (ctlp) + *ctlp = ctl; + + return FIELD_GET(ALTERA_JTAGUART_CONTROL_WSPACE_MSK, ctl); +} + +static unsigned int altera_jtaguart_tx_empty(struct uart_port *port) +{ + return altera_jtaguart_tx_space(port, NULL) ? TIOCSER_TEMT : 0; +} + +static unsigned int altera_jtaguart_get_mctrl(struct uart_port *port) +{ + return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; +} + +static void altera_jtaguart_set_mctrl(struct uart_port *port, unsigned int sigs) +{ +} + +static void altera_jtaguart_start_tx(struct uart_port *port) +{ + port->read_status_mask |= ALTERA_JTAGUART_CONTROL_WE_MSK; + writel(port->read_status_mask, + port->membase + ALTERA_JTAGUART_CONTROL_REG); +} + +static void altera_jtaguart_stop_tx(struct uart_port *port) +{ + port->read_status_mask &= ~ALTERA_JTAGUART_CONTROL_WE_MSK; + writel(port->read_status_mask, + port->membase + ALTERA_JTAGUART_CONTROL_REG); +} + +static void altera_jtaguart_stop_rx(struct uart_port *port) +{ + port->read_status_mask &= ~ALTERA_JTAGUART_CONTROL_RE_MSK; + writel(port->read_status_mask, + port->membase + ALTERA_JTAGUART_CONTROL_REG); +} + +static void altera_jtaguart_break_ctl(struct uart_port *port, int break_state) +{ +} + +static void altera_jtaguart_set_termios(struct uart_port *port, + struct ktermios *termios, + const struct ktermios *old) +{ + /* Just copy the old termios settings back */ + if (old) + tty_termios_copy_hw(termios, old); +} + +static void altera_jtaguart_rx_chars(struct uart_port *port) +{ + u32 status; + u8 ch; + + while ((status = readl(port->membase + ALTERA_JTAGUART_DATA_REG)) & + ALTERA_JTAGUART_DATA_RVALID_MSK) { + ch = status & ALTERA_JTAGUART_DATA_DATA_MSK; + port->icount.rx++; + + if (uart_handle_sysrq_char(port, ch)) + continue; + uart_insert_char(port, 0, 0, ch, TTY_NORMAL); + } + + tty_flip_buffer_push(&port->state->port); +} + +static void altera_jtaguart_tx_chars(struct uart_port *port) +{ + unsigned int count; + u8 ch; + + count = altera_jtaguart_tx_space(port, NULL); + + uart_port_tx_limited(port, ch, count, + true, + writel(ch, port->membase + ALTERA_JTAGUART_DATA_REG), + ({})); +} + +static irqreturn_t altera_jtaguart_interrupt(int irq, void *data) +{ + struct uart_port *port = data; + unsigned int isr; + + isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >> + ALTERA_JTAGUART_CONTROL_RI_OFF) & port->read_status_mask; + + spin_lock(&port->lock); + + if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK) + altera_jtaguart_rx_chars(port); + if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK) + altera_jtaguart_tx_chars(port); + + spin_unlock(&port->lock); + + return IRQ_RETVAL(isr); +} + +static void altera_jtaguart_config_port(struct uart_port *port, int flags) +{ + port->type = PORT_ALTERA_JTAGUART; + + /* Clear mask, so no surprise interrupts. */ + writel(0, port->membase + ALTERA_JTAGUART_CONTROL_REG); +} + +static int altera_jtaguart_startup(struct uart_port *port) +{ + unsigned long flags; + int ret; + + ret = request_irq(port->irq, altera_jtaguart_interrupt, 0, + DRV_NAME, port); + if (ret) { + pr_err(DRV_NAME ": unable to attach Altera JTAG UART %d " + "interrupt vector=%d\n", port->line, port->irq); + return ret; + } + + spin_lock_irqsave(&port->lock, flags); + + /* Enable RX interrupts now */ + port->read_status_mask = ALTERA_JTAGUART_CONTROL_RE_MSK; + writel(port->read_status_mask, + port->membase + ALTERA_JTAGUART_CONTROL_REG); + + spin_unlock_irqrestore(&port->lock, flags); + + return 0; +} + +static void altera_jtaguart_shutdown(struct uart_port *port) +{ + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + + /* Disable all interrupts now */ + port->read_status_mask = 0; + writel(port->read_status_mask, + port->membase + ALTERA_JTAGUART_CONTROL_REG); + + spin_unlock_irqrestore(&port->lock, flags); + + free_irq(port->irq, port); +} + +static const char *altera_jtaguart_type(struct uart_port *port) +{ + return (port->type == PORT_ALTERA_JTAGUART) ? "Altera JTAG UART" : NULL; +} + +static int altera_jtaguart_request_port(struct uart_port *port) +{ + /* UARTs always present */ + return 0; +} + +static void altera_jtaguart_release_port(struct uart_port *port) +{ + /* Nothing to release... */ +} + +static int altera_jtaguart_verify_port(struct uart_port *port, + struct serial_struct *ser) +{ + if (ser->type != PORT_UNKNOWN && ser->type != PORT_ALTERA_JTAGUART) + return -EINVAL; + return 0; +} + +/* + * Define the basic serial functions we support. + */ +static const struct uart_ops altera_jtaguart_ops = { + .tx_empty = altera_jtaguart_tx_empty, + .get_mctrl = altera_jtaguart_get_mctrl, + .set_mctrl = altera_jtaguart_set_mctrl, + .start_tx = altera_jtaguart_start_tx, + .stop_tx = altera_jtaguart_stop_tx, + .stop_rx = altera_jtaguart_stop_rx, + .break_ctl = altera_jtaguart_break_ctl, + .startup = altera_jtaguart_startup, + .shutdown = altera_jtaguart_shutdown, + .set_termios = altera_jtaguart_set_termios, + .type = altera_jtaguart_type, + .request_port = altera_jtaguart_request_port, + .release_port = altera_jtaguart_release_port, + .config_port = altera_jtaguart_config_port, + .verify_port = altera_jtaguart_verify_port, +}; + +#define ALTERA_JTAGUART_MAXPORTS 1 +static struct uart_port altera_jtaguart_ports[ALTERA_JTAGUART_MAXPORTS]; + +#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE) + +#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS) +static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c) +{ + unsigned long flags; + u32 status; + + spin_lock_irqsave(&port->lock, flags); + while (!altera_jtaguart_tx_space(port, &status)) { + spin_unlock_irqrestore(&port->lock, flags); + + if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) { + return; /* no connection activity */ + } + + cpu_relax(); + spin_lock_irqsave(&port->lock, flags); + } + writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); + spin_unlock_irqrestore(&port->lock, flags); +} +#else +static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c) +{ + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + while (!altera_jtaguart_tx_space(port, NULL)) { + spin_unlock_irqrestore(&port->lock, flags); + cpu_relax(); + spin_lock_irqsave(&port->lock, flags); + } + writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); + spin_unlock_irqrestore(&port->lock, flags); +} +#endif + +static void altera_jtaguart_console_write(struct console *co, const char *s, + unsigned int count) +{ + struct uart_port *port = &altera_jtaguart_ports[co->index]; + + uart_console_write(port, s, count, altera_jtaguart_console_putc); +} + +static int __init altera_jtaguart_console_setup(struct console *co, + char *options) +{ + struct uart_port *port; + + if (co->index < 0 || co->index >= ALTERA_JTAGUART_MAXPORTS) + return -EINVAL; + port = &altera_jtaguart_ports[co->index]; + if (port->membase == NULL) + return -ENODEV; + return 0; +} + +static struct uart_driver altera_jtaguart_driver; + +static struct console altera_jtaguart_console = { + .name = "ttyJ", + .write = altera_jtaguart_console_write, + .device = uart_console_device, + .setup = altera_jtaguart_console_setup, + .flags = CON_PRINTBUFFER, + .index = -1, + .data = &altera_jtaguart_driver, +}; + +static int __init altera_jtaguart_console_init(void) +{ + register_console(&altera_jtaguart_console); + return 0; +} + +console_initcall(altera_jtaguart_console_init); + +#define ALTERA_JTAGUART_CONSOLE (&altera_jtaguart_console) + +static void altera_jtaguart_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_jtaguart_console_putc); +} + +static int __init altera_jtaguart_earlycon_setup(struct earlycon_device *dev, + const char *options) +{ + if (!dev->port.membase) + return -ENODEV; + + dev->con->write = altera_jtaguart_earlycon_write; + return 0; +} + +OF_EARLYCON_DECLARE(juart, "altr,juart-1.0", altera_jtaguart_earlycon_setup); + +#else + +#define ALTERA_JTAGUART_CONSOLE NULL + +#endif /* CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE */ + +static struct uart_driver altera_jtaguart_driver = { + .owner = THIS_MODULE, + .driver_name = "altera_jtaguart", + .dev_name = "ttyJ", + .major = ALTERA_JTAGUART_MAJOR, + .minor = ALTERA_JTAGUART_MINOR, + .nr = ALTERA_JTAGUART_MAXPORTS, + .cons = ALTERA_JTAGUART_CONSOLE, +}; + +static int altera_jtaguart_probe(struct platform_device *pdev) +{ + struct altera_jtaguart_platform_uart *platp = + dev_get_platdata(&pdev->dev); + struct uart_port *port; + struct resource *res_mem; + int i = pdev->id; + int irq; + + /* -1 emphasizes that the platform must have one port, no .N suffix */ + if (i == -1) + i = 0; + + if (i >= ALTERA_JTAGUART_MAXPORTS) + return -EINVAL; + + port = &altera_jtaguart_ports[i]; + + 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 -ENODEV; + + irq = platform_get_irq_optional(pdev, 0); + if (irq < 0 && irq != -ENXIO) + return irq; + if (irq > 0) + port->irq = irq; + else if (platp) + port->irq = platp->irq; + else + return -ENODEV; + + port->membase = ioremap(port->mapbase, ALTERA_JTAGUART_SIZE); + if (!port->membase) + return -ENOMEM; + + port->line = i; + port->type = PORT_ALTERA_JTAGUART; + port->iotype = SERIAL_IO_MEM; + port->ops = &altera_jtaguart_ops; + port->flags = UPF_BOOT_AUTOCONF; + port->dev = &pdev->dev; + + uart_add_one_port(&altera_jtaguart_driver, port); + + return 0; +} + +static int altera_jtaguart_remove(struct platform_device *pdev) +{ + struct uart_port *port; + int i = pdev->id; + + if (i == -1) + i = 0; + + port = &altera_jtaguart_ports[i]; + uart_remove_one_port(&altera_jtaguart_driver, port); + iounmap(port->membase); + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id altera_jtaguart_match[] = { + { .compatible = "ALTR,juart-1.0", }, + { .compatible = "altr,juart-1.0", }, + {}, +}; +MODULE_DEVICE_TABLE(of, altera_jtaguart_match); +#endif /* CONFIG_OF */ + +static struct platform_driver altera_jtaguart_platform_driver = { + .probe = altera_jtaguart_probe, + .remove = altera_jtaguart_remove, + .driver = { + .name = DRV_NAME, + .of_match_table = of_match_ptr(altera_jtaguart_match), + }, +}; + +static int __init altera_jtaguart_init(void) +{ + int rc; + + rc = uart_register_driver(&altera_jtaguart_driver); + if (rc) + return rc; + rc = platform_driver_register(&altera_jtaguart_platform_driver); + if (rc) + uart_unregister_driver(&altera_jtaguart_driver); + return rc; +} + +static void __exit altera_jtaguart_exit(void) +{ + platform_driver_unregister(&altera_jtaguart_platform_driver); + uart_unregister_driver(&altera_jtaguart_driver); +} + +module_init(altera_jtaguart_init); +module_exit(altera_jtaguart_exit); + +MODULE_DESCRIPTION("Altera JTAG UART driver"); +MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" DRV_NAME); |