diff options
Diffstat (limited to 'drivers/tty/serial/sunhv.c')
| -rw-r--r-- | drivers/tty/serial/sunhv.c | 652 |
1 files changed, 652 insertions, 0 deletions
diff --git a/drivers/tty/serial/sunhv.c b/drivers/tty/serial/sunhv.c new file mode 100644 index 000000000..1938ba5e9 --- /dev/null +++ b/drivers/tty/serial/sunhv.c @@ -0,0 +1,652 @@ +// SPDX-License-Identifier: GPL-2.0 +/* sunhv.c: Serial driver for SUN4V hypervisor console. + * + * Copyright (C) 2006, 2007 David S. Miller (davem@davemloft.net) + */ + +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/major.h> +#include <linux/circ_buf.h> +#include <linux/serial.h> +#include <linux/sysrq.h> +#include <linux/console.h> +#include <linux/spinlock.h> +#include <linux/slab.h> +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/of_device.h> + +#include <asm/hypervisor.h> +#include <asm/spitfire.h> +#include <asm/prom.h> +#include <asm/irq.h> +#include <asm/setup.h> + +#include <linux/serial_core.h> +#include <linux/sunserialcore.h> + +#define CON_BREAK ((long)-1) +#define CON_HUP ((long)-2) + +#define IGNORE_BREAK 0x1 +#define IGNORE_ALL 0x2 + +static char *con_write_page; +static char *con_read_page; + +static int hung_up = 0; + +static void transmit_chars_putchar(struct uart_port *port, struct circ_buf *xmit) +{ + while (!uart_circ_empty(xmit)) { + long status = sun4v_con_putchar(xmit->buf[xmit->tail]); + + if (status != HV_EOK) + break; + + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); + port->icount.tx++; + } +} + +static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit) +{ + while (!uart_circ_empty(xmit)) { + unsigned long ra = __pa(xmit->buf + xmit->tail); + unsigned long len, status, sent; + + len = CIRC_CNT_TO_END(xmit->head, xmit->tail, + UART_XMIT_SIZE); + status = sun4v_con_write(ra, len, &sent); + if (status != HV_EOK) + break; + xmit->tail = (xmit->tail + sent) & (UART_XMIT_SIZE - 1); + port->icount.tx += sent; + } +} + +static int receive_chars_getchar(struct uart_port *port) +{ + int saw_console_brk = 0; + int limit = 10000; + + while (limit-- > 0) { + long status; + long c = sun4v_con_getchar(&status); + + if (status == HV_EWOULDBLOCK) + break; + + if (c == CON_BREAK) { + if (uart_handle_break(port)) + continue; + saw_console_brk = 1; + c = 0; + } + + if (c == CON_HUP) { + hung_up = 1; + uart_handle_dcd_change(port, 0); + } else if (hung_up) { + hung_up = 0; + uart_handle_dcd_change(port, 1); + } + + if (port->state == NULL) { + uart_handle_sysrq_char(port, c); + continue; + } + + port->icount.rx++; + + if (uart_handle_sysrq_char(port, c)) + continue; + + tty_insert_flip_char(&port->state->port, c, TTY_NORMAL); + } + + return saw_console_brk; +} + +static int receive_chars_read(struct uart_port *port) +{ + static int saw_console_brk; + int limit = 10000; + + while (limit-- > 0) { + unsigned long ra = __pa(con_read_page); + unsigned long bytes_read, i; + long stat = sun4v_con_read(ra, PAGE_SIZE, &bytes_read); + + if (stat != HV_EOK) { + bytes_read = 0; + + if (stat == CON_BREAK) { + if (saw_console_brk) + sun_do_break(); + + if (uart_handle_break(port)) + continue; + saw_console_brk = 1; + *con_read_page = 0; + bytes_read = 1; + } else if (stat == CON_HUP) { + hung_up = 1; + uart_handle_dcd_change(port, 0); + continue; + } else { + /* HV_EWOULDBLOCK, etc. */ + break; + } + } + + if (hung_up) { + hung_up = 0; + uart_handle_dcd_change(port, 1); + } + + if (port->sysrq != 0 && *con_read_page) { + for (i = 0; i < bytes_read; i++) + uart_handle_sysrq_char(port, con_read_page[i]); + saw_console_brk = 0; + } + + if (port->state == NULL) + continue; + + port->icount.rx += bytes_read; + + tty_insert_flip_string(&port->state->port, con_read_page, + bytes_read); + } + + return saw_console_brk; +} + +struct sunhv_ops { + void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit); + int (*receive_chars)(struct uart_port *port); +}; + +static const struct sunhv_ops bychar_ops = { + .transmit_chars = transmit_chars_putchar, + .receive_chars = receive_chars_getchar, +}; + +static const struct sunhv_ops bywrite_ops = { + .transmit_chars = transmit_chars_write, + .receive_chars = receive_chars_read, +}; + +static const struct sunhv_ops *sunhv_ops = &bychar_ops; + +static struct tty_port *receive_chars(struct uart_port *port) +{ + struct tty_port *tport = NULL; + + if (port->state != NULL) /* Unopened serial console */ + tport = &port->state->port; + + if (sunhv_ops->receive_chars(port)) + sun_do_break(); + + return tport; +} + +static void transmit_chars(struct uart_port *port) +{ + struct circ_buf *xmit; + + if (!port->state) + return; + + xmit = &port->state->xmit; + if (uart_circ_empty(xmit) || uart_tx_stopped(port)) + return; + + sunhv_ops->transmit_chars(port, xmit); + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(port); +} + +static irqreturn_t sunhv_interrupt(int irq, void *dev_id) +{ + struct uart_port *port = dev_id; + struct tty_port *tport; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + tport = receive_chars(port); + transmit_chars(port); + spin_unlock_irqrestore(&port->lock, flags); + + if (tport) + tty_flip_buffer_push(tport); + + return IRQ_HANDLED; +} + +/* port->lock is not held. */ +static unsigned int sunhv_tx_empty(struct uart_port *port) +{ + /* Transmitter is always empty for us. If the circ buffer + * is non-empty or there is an x_char pending, our caller + * will do the right thing and ignore what we return here. + */ + return TIOCSER_TEMT; +} + +/* port->lock held by caller. */ +static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + return; +} + +/* port->lock is held by caller and interrupts are disabled. */ +static unsigned int sunhv_get_mctrl(struct uart_port *port) +{ + return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS; +} + +/* port->lock held by caller. */ +static void sunhv_stop_tx(struct uart_port *port) +{ + return; +} + +/* port->lock held by caller. */ +static void sunhv_start_tx(struct uart_port *port) +{ + transmit_chars(port); +} + +/* port->lock is not held. */ +static void sunhv_send_xchar(struct uart_port *port, char ch) +{ + unsigned long flags; + int limit = 10000; + + if (ch == __DISABLED_CHAR) + return; + + spin_lock_irqsave(&port->lock, flags); + + while (limit-- > 0) { + long status = sun4v_con_putchar(ch); + if (status == HV_EOK) + break; + udelay(1); + } + + spin_unlock_irqrestore(&port->lock, flags); +} + +/* port->lock held by caller. */ +static void sunhv_stop_rx(struct uart_port *port) +{ +} + +/* port->lock is not held. */ +static void sunhv_break_ctl(struct uart_port *port, int break_state) +{ + if (break_state) { + unsigned long flags; + int limit = 10000; + + spin_lock_irqsave(&port->lock, flags); + + while (limit-- > 0) { + long status = sun4v_con_putchar(CON_BREAK); + if (status == HV_EOK) + break; + udelay(1); + } + + spin_unlock_irqrestore(&port->lock, flags); + } +} + +/* port->lock is not held. */ +static int sunhv_startup(struct uart_port *port) +{ + return 0; +} + +/* port->lock is not held. */ +static void sunhv_shutdown(struct uart_port *port) +{ +} + +/* port->lock is not held. */ +static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios, + const struct ktermios *old) +{ + unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000); + unsigned int quot = uart_get_divisor(port, baud); + unsigned int iflag, cflag; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + + iflag = termios->c_iflag; + cflag = termios->c_cflag; + + port->ignore_status_mask = 0; + if (iflag & IGNBRK) + port->ignore_status_mask |= IGNORE_BREAK; + if ((cflag & CREAD) == 0) + port->ignore_status_mask |= IGNORE_ALL; + + /* XXX */ + uart_update_timeout(port, cflag, + (port->uartclk / (16 * quot))); + + spin_unlock_irqrestore(&port->lock, flags); +} + +static const char *sunhv_type(struct uart_port *port) +{ + return "SUN4V HCONS"; +} + +static void sunhv_release_port(struct uart_port *port) +{ +} + +static int sunhv_request_port(struct uart_port *port) +{ + return 0; +} + +static void sunhv_config_port(struct uart_port *port, int flags) +{ +} + +static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser) +{ + return -EINVAL; +} + +static const struct uart_ops sunhv_pops = { + .tx_empty = sunhv_tx_empty, + .set_mctrl = sunhv_set_mctrl, + .get_mctrl = sunhv_get_mctrl, + .stop_tx = sunhv_stop_tx, + .start_tx = sunhv_start_tx, + .send_xchar = sunhv_send_xchar, + .stop_rx = sunhv_stop_rx, + .break_ctl = sunhv_break_ctl, + .startup = sunhv_startup, + .shutdown = sunhv_shutdown, + .set_termios = sunhv_set_termios, + .type = sunhv_type, + .release_port = sunhv_release_port, + .request_port = sunhv_request_port, + .config_port = sunhv_config_port, + .verify_port = sunhv_verify_port, +}; + +static struct uart_driver sunhv_reg = { + .owner = THIS_MODULE, + .driver_name = "sunhv", + .dev_name = "ttyHV", + .major = TTY_MAJOR, +}; + +static struct uart_port *sunhv_port; + +void sunhv_migrate_hvcons_irq(int cpu) +{ + /* Migrate hvcons irq to param cpu */ + irq_force_affinity(sunhv_port->irq, cpumask_of(cpu)); +} + +/* Copy 's' into the con_write_page, decoding "\n" into + * "\r\n" along the way. We have to return two lengths + * because the caller needs to know how much to advance + * 's' and also how many bytes to output via con_write_page. + */ +static int fill_con_write_page(const char *s, unsigned int n, + unsigned long *page_bytes) +{ + const char *orig_s = s; + char *p = con_write_page; + int left = PAGE_SIZE; + + while (n--) { + if (*s == '\n') { + if (left < 2) + break; + *p++ = '\r'; + left--; + } else if (left < 1) + break; + *p++ = *s++; + left--; + } + *page_bytes = p - con_write_page; + return s - orig_s; +} + +static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n) +{ + struct uart_port *port = sunhv_port; + unsigned long flags; + int locked = 1; + + if (port->sysrq || oops_in_progress) + locked = spin_trylock_irqsave(&port->lock, flags); + else + spin_lock_irqsave(&port->lock, flags); + + while (n > 0) { + unsigned long ra = __pa(con_write_page); + unsigned long page_bytes; + unsigned int cpy = fill_con_write_page(s, n, + &page_bytes); + + n -= cpy; + s += cpy; + while (page_bytes > 0) { + unsigned long written; + int limit = 1000000; + + while (limit--) { + unsigned long stat; + + stat = sun4v_con_write(ra, page_bytes, + &written); + if (stat == HV_EOK) + break; + udelay(1); + } + if (limit < 0) + break; + page_bytes -= written; + ra += written; + } + } + + if (locked) + spin_unlock_irqrestore(&port->lock, flags); +} + +static inline void sunhv_console_putchar(struct uart_port *port, char c) +{ + int limit = 1000000; + + while (limit-- > 0) { + long status = sun4v_con_putchar(c); + if (status == HV_EOK) + break; + udelay(1); + } +} + +static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n) +{ + struct uart_port *port = sunhv_port; + unsigned long flags; + int i, locked = 1; + + if (port->sysrq || oops_in_progress) + locked = spin_trylock_irqsave(&port->lock, flags); + else + spin_lock_irqsave(&port->lock, flags); + + for (i = 0; i < n; i++) { + if (*s == '\n') + sunhv_console_putchar(port, '\r'); + sunhv_console_putchar(port, *s++); + } + + if (locked) + spin_unlock_irqrestore(&port->lock, flags); +} + +static struct console sunhv_console = { + .name = "ttyHV", + .write = sunhv_console_write_bychar, + .device = uart_console_device, + .flags = CON_PRINTBUFFER, + .index = -1, + .data = &sunhv_reg, +}; + +static int hv_probe(struct platform_device *op) +{ + struct uart_port *port; + unsigned long minor; + int err; + + if (op->archdata.irqs[0] == 0xffffffff) + return -ENODEV; + + port = kzalloc(sizeof(struct uart_port), GFP_KERNEL); + if (unlikely(!port)) + return -ENOMEM; + + minor = 1; + if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 && + minor >= 1) { + err = -ENOMEM; + con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL); + if (!con_write_page) + goto out_free_port; + + con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL); + if (!con_read_page) + goto out_free_con_write_page; + + sunhv_console.write = sunhv_console_write_paged; + sunhv_ops = &bywrite_ops; + } + + sunhv_port = port; + + port->has_sysrq = 1; + port->line = 0; + port->ops = &sunhv_pops; + port->type = PORT_SUNHV; + port->uartclk = ( 29491200 / 16 ); /* arbitrary */ + + port->membase = (unsigned char __iomem *) __pa(port); + + port->irq = op->archdata.irqs[0]; + + port->dev = &op->dev; + + err = sunserial_register_minors(&sunhv_reg, 1); + if (err) + goto out_free_con_read_page; + + sunserial_console_match(&sunhv_console, op->dev.of_node, + &sunhv_reg, port->line, false); + + err = uart_add_one_port(&sunhv_reg, port); + if (err) + goto out_unregister_driver; + + err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port); + if (err) + goto out_remove_port; + + platform_set_drvdata(op, port); + + return 0; + +out_remove_port: + uart_remove_one_port(&sunhv_reg, port); + +out_unregister_driver: + sunserial_unregister_minors(&sunhv_reg, 1); + +out_free_con_read_page: + kfree(con_read_page); + +out_free_con_write_page: + kfree(con_write_page); + +out_free_port: + kfree(port); + sunhv_port = NULL; + return err; +} + +static int hv_remove(struct platform_device *dev) +{ + struct uart_port *port = platform_get_drvdata(dev); + + free_irq(port->irq, port); + + uart_remove_one_port(&sunhv_reg, port); + + sunserial_unregister_minors(&sunhv_reg, 1); + kfree(con_read_page); + kfree(con_write_page); + kfree(port); + sunhv_port = NULL; + + return 0; +} + +static const struct of_device_id hv_match[] = { + { + .name = "console", + .compatible = "qcn", + }, + { + .name = "console", + .compatible = "SUNW,sun4v-console", + }, + {}, +}; + +static struct platform_driver hv_driver = { + .driver = { + .name = "hv", + .of_match_table = hv_match, + }, + .probe = hv_probe, + .remove = hv_remove, +}; + +static int __init sunhv_init(void) +{ + if (tlb_type != hypervisor) + return -ENODEV; + + return platform_driver_register(&hv_driver); +} +device_initcall(sunhv_init); + +#if 0 /* ...def MODULE ; never supported as such */ +MODULE_AUTHOR("David S. Miller"); +MODULE_DESCRIPTION("SUN4V Hypervisor console driver"); +MODULE_VERSION("2.0"); +MODULE_LICENSE("GPL"); +#endif |