From: Ryan Arnold This is an hvc_console patch which provides driver and ppc64 architecture fixes to enable the hvc_console driver to register itself as a vio device with the vio bus, provide hotplug add/remove for vty adapters, and act as an interrupt driven driver on Power-5 hardware or remain as a polling driver on Power-4 hardware. arch/ppc64/kernel/hvconsole.c ----------------------------------------------------------------------- - Changed hvc_get_chars() and hvc_put_chars() api to take vtermno rather than index number. - Added hvc_find_vtys() function which walks the bus looking for vterm/vty devices to callback to the hvc_console driver. This provides console output functionality prior to early console init (pre mem init and pre device probe). include/asm-ppc64/hvconsole.h ----------------------------------------------------------------------- - Changed hvc_get_chars() and hvc_put_chars() api to take vtermno rather than index number. - Added hvc_find_vtys() function. - Added hvc_instantiate() function which is implemented by a console driver wanting to receive a callback of and early console init. drivers/char/hvc_console.c ----------------------------------------------------------------------- - Switch khvcd from kernel_threads to kthreads which got rid of deprecated daemonize(). - Added module exit clause to be thorough (not terribly necessary with a console driver of course) - Added early discovery of vterm/vty adapters by doing a bus walk on early console init which results in hvc_instantiate() callback and addition of the vtermno into a static array of vtermnos supported as console adapters (meaning the console api's work against these vtermnos prior to full console initialization). - This driver is now registered as a vio driver which means that vty adapters are now managed via probe/remove. This means hvc_console supports hotplug vty adapters. - Driver now requests more device nodes than what was found on the initial bus walk when registered as a tty driver to make room for hotplug vty adapters. These secondary vty adapters provide a tty tunnel between partitions. - Removed static hvc_struct array and replaced with a linux list that has elements (hvc_struct instances) added/removed on probe/remove AFTER early console init. This is important because kmalloc can't be done at early console init. - Driver now either runs in interrupt driven mode or in polling mode on older hardware. The khvcd is smart enough to not 'schedule()' when there are no interrupts. - kobjects are now used for ref counting on the hvc_struct instances. - This driver puts the tty layer to sleep on hvc_close() if there are pending data writes being blocked by firmware. - Removed useless spinlocks in hvc_chars_in_buffer() and hvc_write_room. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Ryan S. Arnold Signed-off-by: Andrew Morton --- 25-akpm/arch/ppc64/kernel/hvconsole.c | 68 ++- 25-akpm/drivers/char/hvc_console.c | 750 +++++++++++++++++++++++++++------- 25-akpm/include/asm-ppc64/hvconsole.h | 18 3 files changed, 676 insertions(+), 160 deletions(-) diff -puN arch/ppc64/kernel/hvconsole.c~interrupt-driven-hvc_console-as-vio-device arch/ppc64/kernel/hvconsole.c --- 25/arch/ppc64/kernel/hvconsole.c~interrupt-driven-hvc_console-as-vio-device 2004-08-28 14:43:41.645911328 -0700 +++ 25-akpm/arch/ppc64/kernel/hvconsole.c 2004-08-28 14:43:41.652910264 -0700 @@ -1,6 +1,10 @@ /* * hvconsole.c * Copyright (C) 2004 Hollis Blanchard, IBM Corporation + * Copyright (C) 2004 IBM Corporation + * + * Additional Author(s): + * Ryan S. Arnold * * LPAR console support. * @@ -22,14 +26,22 @@ #include #include #include -#include #include +#include -int hvc_get_chars(int index, char *buf, int count) +/** + * hvc_get_chars - retrieve characters from firmware for denoted vterm adatper + * @vtermno: The vtermno or unit_address of the adapter from which to fetch the + * data. + * @buf: The character buffer into which to put the character data fetched from + * firmware. + * @count: not used? + */ +int hvc_get_chars(uint32_t vtermno, char *buf, int count) { unsigned long got; - if (plpar_hcall(H_GET_TERM_CHAR, index, 0, 0, 0, &got, + if (plpar_hcall(H_GET_TERM_CHAR, vtermno, 0, 0, 0, &got, (unsigned long *)buf, (unsigned long *)buf+1) == H_Success) { /* * Work around a HV bug where it gives us a null @@ -53,40 +65,56 @@ int hvc_get_chars(int index, char *buf, EXPORT_SYMBOL(hvc_get_chars); -int hvc_put_chars(int index, const char *buf, int count) +/** + * hvc_put_chars: send characters to firmware for denoted vterm adapter + * @vtermno: The vtermno or unit_address of the adapter from which the data + * originated. + * @buf: The character buffer that contains the character data to send to + * firmware. + * @count: Send this number of characters. + */ +int hvc_put_chars(uint32_t vtermno, const char *buf, int count) { unsigned long *lbuf = (unsigned long *) buf; long ret; - ret = plpar_hcall_norets(H_PUT_TERM_CHAR, index, count, lbuf[0], + ret = plpar_hcall_norets(H_PUT_TERM_CHAR, vtermno, count, lbuf[0], lbuf[1]); if (ret == H_Success) return count; if (ret == H_Busy) return 0; - return -1; + return -EIO; } EXPORT_SYMBOL(hvc_put_chars); -/* return the number of client vterms present */ -/* XXX this requires an interface change to handle multiple discontiguous - * vterms */ -int hvc_count(int *start_termno) +/* + * We hope/assume that the first vty found corresponds to the first console + * device. + */ +int hvc_find_vtys(void) { struct device_node *vty; int num_found = 0; - /* consider only the first vty node. - * we should _always_ be able to find one. */ - vty = of_find_node_by_name(NULL, "vty"); - if (vty && device_is_compatible(vty, "hvterm1")) { - u32 *termno = (u32 *)get_property(vty, "reg", NULL); - - if (termno && start_termno) - *start_termno = *termno; - num_found = 1; - of_node_put(vty); + for (vty = of_find_node_by_name(NULL, "vty"); vty != NULL; + vty = of_find_node_by_name(vty, "vty")) { + uint32_t *vtermno; + + /* We have statically defined space for only a certain number of + * console adapters. */ + if (num_found >= MAX_NR_HVC_CONSOLES) + break; + + vtermno = (uint32_t *)get_property(vty, "reg", NULL); + if (!vtermno) + continue; + + if (device_is_compatible(vty, "hvterm1")) { + hvc_instantiate(*vtermno, num_found); + ++num_found; + } } return num_found; diff -puN drivers/char/hvc_console.c~interrupt-driven-hvc_console-as-vio-device drivers/char/hvc_console.c --- 25/drivers/char/hvc_console.c~interrupt-driven-hvc_console-as-vio-device 2004-08-28 14:43:41.646911176 -0700 +++ 25-akpm/drivers/char/hvc_console.c 2004-08-28 14:43:41.657909504 -0700 @@ -1,6 +1,11 @@ /* * Copyright (C) 2001 Anton Blanchard , IBM * Copyright (C) 2001 Paul Mackerras , IBM + * Copyright (C) 2004 Benjamin Herrenschmidt , IBM Corp. + * Copyright (C) 2004 IBM Corporation + * + * Additional Author(s): + * Ryan S. Arnold * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -17,38 +22,51 @@ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ +#include +#include #include +#include +#include +#include +#include +#include #include -#include #include -#include #include #include #include #include -#include -#include #include -#include - -extern int hvc_count(int *); -extern int hvc_get_chars(int index, char *buf, int count); -extern int hvc_put_chars(int index, const char *buf, int count); +#include +#include +#include #define HVC_MAJOR 229 #define HVC_MINOR 0 -#define MAX_NR_HVC_CONSOLES 4 - #define TIMEOUT ((HZ + 99) / 100) +/* + * Wait this long per iteration while trying to push buffered data to the + * hypervisor before allowing the tty to complete a close operation. + */ +#define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */ + +/* + * The Linux TTY code does not support dynamic addition of tty derived devices + * so we need to know how many tty devices we might need when space is allocated + * for the tty device. Since this driver supports hotplug of vty adapters we + * need to make sure we have enough allocated. + */ +#define HVC_ALLOC_TTY_ADAPTERS 8 + static struct tty_driver *hvc_driver; -static int hvc_offset; #ifdef CONFIG_MAGIC_SYSRQ static int sysrq_pressed; #endif #define N_OUTBUF 16 +#define N_INBUF 16 #define __ALIGNED__ __attribute__((__aligned__(8))) @@ -60,59 +78,244 @@ struct hvc_struct { int do_wakeup; char outbuf[N_OUTBUF] __ALIGNED__; int n_outbuf; + uint32_t vtermno; + int irq_requested; + int irq; + struct list_head next; + struct kobject kobj; /* ref count & hvc_struct lifetime */ + struct vio_dev *vdev; }; -struct hvc_struct hvc_struct[MAX_NR_HVC_CONSOLES]; +/* dynamic list of hvc_struct instances */ +static struct list_head hvc_structs = LIST_HEAD_INIT(hvc_structs); -static int hvc_open(struct tty_struct *tty, struct file * filp) +/* + * Protect the list of hvc_struct instances from inserts and removals during + * list traversal. + */ +static spinlock_t hvc_structs_lock = SPIN_LOCK_UNLOCKED; + +/* + * Initial console vtermnos for console API usage prior to full console + * initialization. Any vty adapter outside this range will not have usable + * console interfaces but can still be used as a tty device. This has to be + * static because kmalloc will not work during early console init. + */ +static uint32_t vtermnos[MAX_NR_HVC_CONSOLES]; + +/* Used for accounting purposes */ +static int num_vterms = 0; + +static struct task_struct *hvc_task; + +/* + * This value is used to associate a tty->index value to a hvc_struct based + * upon order of exposure via hvc_probe(). + */ +static int hvc_count = -1; + +/* Picks up late kicks after list walk but before schedule() */ +static int hvc_kicked; + +/* Wake the sleeping khvcd */ +static void hvc_kick(void) +{ + hvc_kicked = 1; + wake_up_process(hvc_task); +} + +/* + * NOTE: This API isn't used if the console adapter doesn't support interrupts. + * In this case the console is poll driven. + */ +static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs) +{ + hvc_kick(); + return IRQ_HANDLED; +} + +static void hvc_unthrottle(struct tty_struct *tty) +{ + hvc_kick(); +} + +/* + * Do not call this function with either the hvc_strucst_lock or the hvc_struct + * lock held. If successful, this function increments the kobject reference + * count against the target hvc_struct so it should be released when finished. + */ +struct hvc_struct *hvc_get_by_index(int index) { - int line = tty->index; struct hvc_struct *hp; unsigned long flags; - if (line < 0 || line >= MAX_NR_HVC_CONSOLES) + spin_lock(&hvc_structs_lock); + + list_for_each_entry(hp, &hvc_structs, next) { + spin_lock_irqsave(&hp->lock, flags); + if (hp->index == index) { + kobject_get(&hp->kobj); + spin_unlock_irqrestore(&hp->lock, flags); + spin_unlock(&hvc_structs_lock); + return hp; + } + spin_unlock_irqrestore(&hp->lock, flags); + } + hp = NULL; + + spin_unlock(&hvc_structs_lock); + return hp; +} + +/* + * The TTY interface won't be used until after the vio layer has exposed the vty + * adapter to the kernel. + */ +static int hvc_open(struct tty_struct *tty, struct file * filp) +{ + struct hvc_struct *hp; + unsigned long flags; + int irq = NO_IRQ; + int rc = 0; + struct kobject *kobjp; + + /* Auto increments kobject reference if found. */ + if (!(hp = hvc_get_by_index(tty->index))) { + printk(KERN_WARNING "hvc_console: tty open failed, no vty associated with tty.\n"); return -ENODEV; - hp = &hvc_struct[line]; + } - tty->driver_data = hp; spin_lock_irqsave(&hp->lock, flags); + /* Check and then increment for fast path open. */ + if (hp->count++ > 0) { + spin_unlock_irqrestore(&hp->lock, flags); + hvc_kick(); + return 0; + } /* else count == 0 */ + + tty->driver_data = hp; hp->tty = tty; - hp->count++; + /* Save for request_irq outside of spin_lock. */ + irq = hp->irq; + if (irq != NO_IRQ) + hp->irq_requested = 1; + + kobjp = &hp->kobj; + spin_unlock_irqrestore(&hp->lock, flags); + /* check error, fallback to non-irq */ + if (irq != NO_IRQ) + rc = request_irq(irq, hvc_handle_interrupt, SA_INTERRUPT, "hvc_console", hp); + + /* + * If the request_irq() fails and we return an error. The tty layer + * will call hvc_close() after a failed open but we don't want to clean + * up there so we'll clean up here and clear out the previously set + * tty fields and return the kobject reference. + */ + if (rc) { + spin_lock_irqsave(&hp->lock, flags); + hp->tty = NULL; + hp->irq_requested = 0; + spin_unlock_irqrestore(&hp->lock, flags); + tty->driver_data = NULL; + kobject_put(kobjp); + } + /* Force wakeup of the polling thread */ + hvc_kick(); - return 0; + return rc; } static void hvc_close(struct tty_struct *tty, struct file * filp) { - struct hvc_struct *hp = tty->driver_data; + struct hvc_struct *hp; + struct kobject *kobjp; + int irq = NO_IRQ; unsigned long flags; if (tty_hung_up_p(filp)) return; + + /* + * No driver_data means that this close was issued after a failed + * hvcs_open by the tty layer's release_dev() function and we can just + * exit cleanly because the kobject reference wasn't made. + */ + if (!tty->driver_data) + return; + + hp = tty->driver_data; spin_lock_irqsave(&hp->lock, flags); - if (--hp->count == 0) + + kobjp = &hp->kobj; + if (--hp->count == 0) { + if (hp->irq_requested) + irq = hp->irq; + hp->irq_requested = 0; + + /* We are done with the tty pointer now. */ hp->tty = NULL; - else if (hp->count < 0) - printk(KERN_ERR "hvc_close %lu: oops, count is %d\n", - hp - hvc_struct, hp->count); - spin_unlock_irqrestore(&hp->lock, flags); + spin_unlock_irqrestore(&hp->lock, flags); + + /* + * Chain calls chars_in_buffer() and returns immediately if + * there is no buffered data otherwise sleeps on a wait queue + * waking periodically to check chars_in_buffer(). + */ + tty_wait_until_sent(tty, HVC_CLOSE_WAIT); + + tty->driver_data = NULL; + + if (irq != NO_IRQ) + free_irq(irq, hp); + + } else { + if (hp->count < 0) + printk(KERN_ERR "hvc_close %X: oops, count is %d\n", + hp->vtermno, hp->count); + spin_unlock_irqrestore(&hp->lock, flags); + } + + kobject_put(kobjp); } static void hvc_hangup(struct tty_struct *tty) { struct hvc_struct *hp = tty->driver_data; + unsigned long flags; + int irq = NO_IRQ; + int temp_open_count; + struct kobject *kobjp; + spin_lock_irqsave(&hp->lock, flags); + kobjp = &hp->kobj; + temp_open_count = hp->count; hp->count = 0; + hp->n_outbuf = 0; hp->tty = NULL; + if (hp->irq_requested) + /* Saved for use outside of spin_lock. */ + irq = hp->irq; + hp->irq_requested = 0; + spin_unlock_irqrestore(&hp->lock, flags); + if (irq != NO_IRQ) + free_irq(irq, hp); + while(temp_open_count) { + --temp_open_count; + kobject_put(kobjp); + } } -/* called with hp->lock held */ +/* + * Push buffered characters whether they were just recently buffered or waiting + * on a blocked hypervisor. Call this function with hp->lock held. + */ static void hvc_push(struct hvc_struct *hp) { int n; - n = hvc_put_chars(hp->index + hvc_offset, hp->outbuf, hp->n_outbuf); + n = hvc_put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); if (n <= 0) { if (n == 0) return; @@ -127,77 +330,122 @@ static void hvc_push(struct hvc_struct * hp->do_wakeup = 1; } -static int hvc_write(struct tty_struct *tty, int from_user, - const unsigned char *buf, int count) +static inline int __hvc_write_user(struct hvc_struct *hp, + const unsigned char *buf, int count) { - struct hvc_struct *hp = tty->driver_data; char *tbuf, *p; int tbsize, rsize, written = 0; unsigned long flags; - if (from_user) { - tbsize = min(count, (int)PAGE_SIZE); - if (!(tbuf = kmalloc(tbsize, GFP_KERNEL))) - return -ENOMEM; - - while ((rsize = count - written) > 0) { - int wsize; - if (rsize > tbsize) - rsize = tbsize; - - p = tbuf; - rsize -= copy_from_user(p, buf, rsize); - if (!rsize) { - if (written == 0) - written = -EFAULT; - break; - } - buf += rsize; - written += rsize; - - spin_lock_irqsave(&hp->lock, flags); - for (wsize = N_OUTBUF - hp->n_outbuf; rsize && wsize; - wsize = N_OUTBUF - hp->n_outbuf) { - if (wsize > rsize) - wsize = rsize; - memcpy(hp->outbuf + hp->n_outbuf, p, wsize); - hp->n_outbuf += wsize; - hvc_push(hp); - rsize -= wsize; - p += wsize; - } - spin_unlock_irqrestore(&hp->lock, flags); - - if (rsize) - break; + tbsize = min(count, (int)PAGE_SIZE); + if (!(tbuf = kmalloc(tbsize, GFP_KERNEL))) + return -ENOMEM; - if (count < tbsize) - tbsize = count; + while ((rsize = count - written) > 0) { + int wsize; + if (rsize > tbsize) + rsize = tbsize; + + p = tbuf; + rsize -= copy_from_user(p, buf, rsize); + if (!rsize) { + if (written == 0) + written = -EFAULT; + break; } + buf += rsize; - kfree(tbuf); - } else { spin_lock_irqsave(&hp->lock, flags); - while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) { - if (rsize > count) - rsize = count; - memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); - count -= rsize; - buf += rsize; - hp->n_outbuf += rsize; - written += rsize; + + /* Push pending writes: make some room in buffer */ + if (hp->n_outbuf > 0) + hvc_push(hp); + + for (wsize = N_OUTBUF - hp->n_outbuf; rsize && wsize; + wsize = N_OUTBUF - hp->n_outbuf) { + if (wsize > rsize) + wsize = rsize; + memcpy(hp->outbuf + hp->n_outbuf, p, wsize); + hp->n_outbuf += wsize; hvc_push(hp); + rsize -= wsize; + p += wsize; + written += wsize; } spin_unlock_irqrestore(&hp->lock, flags); + + if (rsize) + break; + + if (count < tbsize) + tbsize = count; + } + + kfree(tbuf); + + return written; +} + +static inline int __hvc_write_kernel(struct hvc_struct *hp, + const unsigned char *buf, int count) +{ + unsigned long flags; + int rsize, written = 0; + + spin_lock_irqsave(&hp->lock, flags); + + /* Push pending writes */ + if (hp->n_outbuf > 0) + hvc_push(hp); + + while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) { + if (rsize > count) + rsize = count; + memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); + count -= rsize; + buf += rsize; + hp->n_outbuf += rsize; + written += rsize; + hvc_push(hp); } + spin_unlock_irqrestore(&hp->lock, flags); + + return written; +} +static int hvc_write(struct tty_struct *tty, int from_user, + const unsigned char *buf, int count) +{ + struct hvc_struct *hp = tty->driver_data; + int written; + + if (from_user) + written = __hvc_write_user(hp, buf, count); + else + written = __hvc_write_kernel(hp, buf, count); + + /* + * Racy, but harmless, kick thread if there is still pending data. + * There really is nothing wrong with kicking the thread, even if there + * is no buffered data. + */ + if (hp->n_outbuf) + hvc_kick(); return written; } +/* + * This is actually a contract between the driver and the tty layer outlining + * how much write room the driver can guarentee will be sent OR BUFFERED. This + * driver MUST honor the return value. + */ static int hvc_write_room(struct tty_struct *tty) { struct hvc_struct *hp = tty->driver_data; + if (!hp) + return -1; + return N_OUTBUF - hp->n_outbuf; } @@ -205,57 +453,111 @@ static int hvc_chars_in_buffer(struct tt { struct hvc_struct *hp = tty->driver_data; + if (!hp) + return -1; return hp->n_outbuf; } -static void hvc_poll(int index) +#define HVC_POLL_READ 0x00000001 +#define HVC_POLL_WRITE 0x00000002 +#define HVC_POLL_QUICK 0x00000004 + +static int hvc_poll(struct hvc_struct *hp) { - struct hvc_struct *hp = &hvc_struct[index]; struct tty_struct *tty; - int i, n; - char buf[16] __ALIGNED__; + int i, n, poll_mask = 0; + char buf[N_INBUF] __ALIGNED__; unsigned long flags; + int read_total = 0; spin_lock_irqsave(&hp->lock, flags); + /* Push pending writes */ if (hp->n_outbuf > 0) hvc_push(hp); + /* Reschedule us if still some write pending */ + if (hp->n_outbuf > 0) + poll_mask |= HVC_POLL_WRITE; + /* No tty attached, just skip */ tty = hp->tty; - if (tty) { - for (;;) { - if (TTY_FLIPBUF_SIZE - tty->flip.count < sizeof(buf)) - break; - n = hvc_get_chars(index + hvc_offset, buf, sizeof(buf)); - if (n <= 0) - break; - for (i = 0; i < n; ++i) { -#ifdef CONFIG_MAGIC_SYSRQ /* Handle the SysRq Hack */ - if (buf[i] == '\x0f') { /* ^O -- should support a sequence */ - sysrq_pressed = 1; - continue; - } else if (sysrq_pressed) { - handle_sysrq(buf[i], NULL, tty); - sysrq_pressed = 0; - continue; - } -#endif - tty_insert_flip_char(tty, buf[i], 0); + if (tty == NULL) + goto bail; + + /* Now check if we can get data (are we throttled ?) */ + if (test_bit(TTY_THROTTLED, &tty->flags)) + goto throttled; + + /* If we aren't interrupt driven and aren't throttled, we always + * request a reschedule + */ + if (hp->irq == NO_IRQ) + poll_mask |= HVC_POLL_READ; + + /* Read data if any */ + for (;;) { + int count = N_INBUF; + if (count > (TTY_FLIPBUF_SIZE - tty->flip.count)) + count = TTY_FLIPBUF_SIZE - tty->flip.count; + + /* If flip is full, just reschedule a later read */ + if (count == 0) { + poll_mask |= HVC_POLL_READ; + break; + } + + n = hvc_get_chars(hp->vtermno, buf, count); + if (n <= 0) { + /* Hangup the tty when disconnected from host */ + if (n == -EPIPE) { + spin_unlock_irqrestore(&hp->lock, flags); + tty_hangup(tty); + spin_lock_irqsave(&hp->lock, flags); + } + break; + } + for (i = 0; i < n; ++i) { +#ifdef CONFIG_MAGIC_SYSRQ + /* Handle the SysRq Hack */ + if (buf[i] == '\x0f') { /* ^O -- should support a sequence */ + sysrq_pressed = 1; + continue; + } else if (sysrq_pressed) { + handle_sysrq(buf[i], NULL, tty); + sysrq_pressed = 0; + continue; } +#endif /* CONFIG_MAGIC_SYSRQ */ + tty_insert_flip_char(tty, buf[i], 0); } + if (tty->flip.count) tty_schedule_flip(tty); - if (hp->do_wakeup) { - hp->do_wakeup = 0; - if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) - && tty->ldisc.write_wakeup) - (tty->ldisc.write_wakeup)(tty); - wake_up_interruptible(&tty->write_wait); + /* + * Account for the total amount read in one loop, and if above + * 64 bytes, we do a quick schedule loop to let the tty grok the + * data and eventually throttle us. + */ + read_total += n; + if (read_total >= 64) { + poll_mask |= HVC_POLL_QUICK; + break; } } - + throttled: + /* Wakeup write queue if necessary */ + if (hp->do_wakeup) { + hp->do_wakeup = 0; + if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) + && tty->ldisc.write_wakeup) + (tty->ldisc.write_wakeup)(tty); + wake_up_interruptible(&tty->write_wait); + } + bail: spin_unlock_irqrestore(&hp->lock, flags); + + return poll_mask; } #if defined(CONFIG_XMON) && defined(CONFIG_SMP) @@ -264,21 +566,47 @@ extern cpumask_t cpus_in_xmon; static const cpumask_t cpus_in_xmon = CPU_MASK_NONE; #endif - +/* + * This kthread is either polling or interrupt driven. This is determined by + * calling hvc_poll() who determines whether a console adapter support + * interrupts. + */ int khvcd(void *unused) { - int i; - - daemonize("khvcd"); + int poll_mask; + struct hvc_struct *hp; - for (;;) { + __set_current_state(TASK_RUNNING); + do { + poll_mask = 0; + hvc_kicked = 0; + wmb(); if (cpus_empty(cpus_in_xmon)) { - for (i = 0; i < MAX_NR_HVC_CONSOLES; ++i) - hvc_poll(i); + spin_lock(&hvc_structs_lock); + list_for_each_entry(hp, &hvc_structs, next) { + /*hp = list_entry(node, struct hvc_struct, * next); */ + poll_mask |= hvc_poll(hp); + } + spin_unlock(&hvc_structs_lock); + } else + poll_mask |= HVC_POLL_READ; + if (hvc_kicked) + continue; + if (poll_mask & HVC_POLL_QUICK) { + yield(); + continue; } set_current_state(TASK_INTERRUPTIBLE); - schedule_timeout(TIMEOUT); - } + if (!hvc_kicked) { + if (poll_mask == 0) + schedule(); + else + schedule_timeout(TIMEOUT); + } + __set_current_state(TASK_RUNNING); + } while (!kthread_should_stop()); + + return 0; } static struct tty_operations hvc_ops = { @@ -286,19 +614,124 @@ static struct tty_operations hvc_ops = { .close = hvc_close, .write = hvc_write, .hangup = hvc_hangup, + .unthrottle = hvc_unthrottle, .write_room = hvc_write_room, .chars_in_buffer = hvc_chars_in_buffer, }; -int __init hvc_init(void) +char hvc_driver_name[] = "hvc_console"; + +static struct vio_device_id hvc_driver_table[] __devinitdata= { + {"serial", "hvterm1"}, + { 0, } +}; +MODULE_DEVICE_TABLE(vio, hvc_driver_table); + +/* callback when the kboject ref count reaches zero. */ +static void destroy_hvc_struct(struct kobject *kobj) { - int num = hvc_count(&hvc_offset); - int i; + struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj); + unsigned long flags; + + spin_lock(&hvc_structs_lock); + + spin_lock_irqsave(&hp->lock, flags); + list_del(&(hp->next)); + spin_unlock_irqrestore(&hp->lock, flags); + + spin_unlock(&hvc_structs_lock); + + kfree(hp); +} + +static struct kobj_type hvc_kobj_type = { + .release = destroy_hvc_struct, +}; + +static int __devinit hvc_probe( + struct vio_dev *dev, + const struct vio_device_id *id) +{ + struct hvc_struct *hp; + + /* probed with invalid parameters. */ + if (!dev || !id) + return -EPERM; + + hp = kmalloc(sizeof(*hp), GFP_KERNEL); + if (!hp) + return -ENOMEM; + + memset(hp, 0x00, sizeof(*hp)); + hp->vtermno = dev->unit_address; + hp->vdev = dev; + hp->vdev->dev.driver_data = hp; + hp->irq = dev->irq; + + kobject_init(&hp->kobj); + hp->kobj.ktype = &hvc_kobj_type; + + hp->lock = SPIN_LOCK_UNLOCKED; + spin_lock(&hvc_structs_lock); + hp->index = ++hvc_count; + list_add_tail(&(hp->next), &hvc_structs); + spin_unlock(&hvc_structs_lock); + + return 0; +} + +static int __devexit hvc_remove(struct vio_dev *dev) +{ + struct hvc_struct *hp = dev->dev.driver_data; + unsigned long flags; + struct kobject *kobjp; + struct tty_struct *tty; + + spin_lock_irqsave(&hp->lock, flags); + tty = hp->tty; + kobjp = &hp->kobj; - if (num > MAX_NR_HVC_CONSOLES) - num = MAX_NR_HVC_CONSOLES; + if (hp->index < MAX_NR_HVC_CONSOLES) + vtermnos[hp->index] = -1; - hvc_driver = alloc_tty_driver(num); + /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ + + spin_unlock_irqrestore(&hp->lock, flags); + + /* + * We 'put' the instance that was grabbed when the kobject instance + * was intialized using kobject_init(). Let the last holder of this + * kobject cause it to be removed, which will probably be the tty_hangup + * below. + */ + kobject_put(kobjp); + + /* + * This function call will auto chain call hvc_hangup. The tty should + * always be valid at this time unless a simultaneous tty close already + * cleaned up the hvc_struct. + */ + if (tty) + tty_hangup(tty); + return 0; +} + +static struct vio_driver hvc_vio_driver = { + .name = hvc_driver_name, + .id_table = hvc_driver_table, + .probe = hvc_probe, + .remove = hvc_remove, +}; + +/* Driver initialization. Follow console initialization. This is where the TTY + * interfaces start to become available. */ +int __init hvc_init(void) +{ + int rc; + + /* We need more than num_vterms adapters due to hotplug additions. */ + hvc_driver = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); + /* hvc_driver = alloc_tty_driver(num_vterms); */ if (!hvc_driver) return -ENOMEM; @@ -312,31 +745,73 @@ int __init hvc_init(void) hvc_driver->init_termios = tty_std_termios; hvc_driver->flags = TTY_DRIVER_REAL_RAW; tty_set_operations(hvc_driver, &hvc_ops); - for (i = 0; i < num; i++) { - hvc_struct[i].lock = SPIN_LOCK_UNLOCKED; - hvc_struct[i].index = i; - } if (tty_register_driver(hvc_driver)) panic("Couldn't register hvc console driver\n"); - if (num > 0) - kernel_thread(khvcd, NULL, CLONE_KERNEL); + /* Always start the kthread because there can be hotplug vty adapters + * added later. */ + hvc_task = kthread_run(khvcd, NULL, "khvcd"); + if (IS_ERR(hvc_task)) { + panic("Couldn't create kthread for console.\n"); + put_tty_driver(hvc_driver); + return -EIO; + } + + /* Register as a vio device to receive callbacks */ + rc = vio_register_driver(&hvc_vio_driver); - return 0; + return rc; } +/* This isn't particularily necessary due to this being a console driver but it + * is nice to be thorough */ static void __exit hvc_exit(void) { + kthread_stop(hvc_task); + + vio_unregister_driver(&hvc_vio_driver); + tty_unregister_driver(hvc_driver); + /* return tty_struct instances allocated in hvc_init(). */ + put_tty_driver(hvc_driver); +} + +/* + * Console APIs, NOT TTY. These APIs are available immediately when + * hvc_console_setup() finds adapters. + */ + +/* + * hvc_instantiate() is an early console discovery method which locates consoles + * prior to the vio subsystem discovering them. Hotplugged vty adapters do NOT + * get an hvc_instantiate() callback since the appear after early console init. + */ +int hvc_instantiate(uint32_t vtermno, int index) +{ + if (index < 0 || index >= MAX_NR_HVC_CONSOLES) + return -1; + + if (vtermnos[index] != -1) + return -1; + + vtermnos[index] = vtermno; + return 0; } void hvc_console_print(struct console *co, const char *b, unsigned count) { char c[16] __ALIGNED__; - unsigned i, n; + unsigned i, n = 0; int r, donecr = 0; - i = n = 0; + /* Console access attempt outside of acceptable console range. */ + if (co->index >= MAX_NR_HVC_CONSOLES) + return; + + /* This console adapter was removed so it is not useable. */ + if (vtermnos[co->index] < 0) + return; + while (count > 0 || i > 0) { if (count > 0 && i < sizeof(c)) { if (b[n] == '\n' && !donecr) { @@ -348,7 +823,7 @@ void hvc_console_print(struct console *c --count; } } else { - r = hvc_put_chars(co->index + hvc_offset, c, i); + r = hvc_put_chars(vtermnos[co->index], c, i); if (r < 0) { /* throw away chars on error */ i = 0; @@ -369,9 +844,6 @@ static struct tty_driver *hvc_console_de static int __init hvc_console_setup(struct console *co, char *options) { - if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES - || co->index >= hvc_count(&hvc_offset)) - return -1; return 0; } @@ -384,8 +856,14 @@ struct console hvc_con_driver = { .index = -1, }; +/* Early console initialization. Preceeds driver initialization. */ static int __init hvc_console_init(void) { + int i; + + for (i=0; i