/* sunhv.c: Serial driver for SUN4V hypervisor console. * * Copyright (C) 2006, 2007 David S. Miller (davem@davemloft.net) */ #include <linux/module.h> #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> #if defined(CONFIG_MAGIC_SYSRQ) #define SUPPORT_SYSRQ #endif #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) { int saw_console_brk = 0; 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 (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); } for (i = 0; i < bytes_read; i++) uart_handle_sysrq_char(port, con_read_page[i]); 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 struct sunhv_ops bychar_ops = { .transmit_chars = transmit_chars_putchar, .receive_chars = receive_chars_getchar, }; static struct sunhv_ops bywrite_ops = { .transmit_chars = transmit_chars_write, .receive_chars = receive_chars_read, }; static 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; 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 held by caller. */ static void sunhv_enable_ms(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, 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 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, .enable_ms = sunhv_enable_ms, .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 = "ttyS", .major = TTY_MAJOR, }; static struct uart_port *sunhv_port; /* 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; local_irq_save(flags); if (port->sysrq) { locked = 0; } else if (oops_in_progress) { locked = spin_trylock(&port->lock); } else spin_lock(&port->lock); 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(&port->lock); local_irq_restore(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; local_irq_save(flags); if (port->sysrq) { locked = 0; } else if (oops_in_progress) { locked = spin_trylock(&port->lock); } else spin_lock(&port->lock); for (i = 0; i < n; i++) { if (*s == '\n') sunhv_console_putchar(port, '\r'); sunhv_console_putchar(port, *s++); } if (locked) spin_unlock(&port->lock); local_irq_restore(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->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; dev_set_drvdata(&op->dev, 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 = dev_get_drvdata(&dev->dev); free_irq(port->irq, port); uart_remove_one_port(&sunhv_reg, port); sunserial_unregister_minors(&sunhv_reg, 1); kfree(port); sunhv_port = NULL; dev_set_drvdata(&dev->dev, NULL); return 0; } static const struct of_device_id hv_match[] = { { .name = "console", .compatible = "qcn", }, { .name = "console", .compatible = "SUNW,sun4v-console", }, {}, }; MODULE_DEVICE_TABLE(of, hv_match); static struct platform_driver hv_driver = { .driver = { .name = "hv", .owner = THIS_MODULE, .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); } static void __exit sunhv_exit(void) { platform_driver_unregister(&hv_driver); } module_init(sunhv_init); module_exit(sunhv_exit); MODULE_AUTHOR("David S. Miller"); MODULE_DESCRIPTION("SUN4V Hypervisor console driver"); MODULE_VERSION("2.0"); MODULE_LICENSE("GPL");