OSCL-LXR linux-6.0.1/​drivers/​tty/​serial/​sunhv.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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,
                   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

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