From 92057a493af4bb56928a762ad0423200b835d995 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Mon, 23 Jul 2012 21:33:13 +0000 Subject: hvc_console: Better kernel console support hvc_console has two methods to instanciate the consoles. hvc_instanciate is meant to be called at early boot, while hvc_alloc is called for more dynamically probed objects. Currently, it only deals with adding kernel consoles in the former case, which means for example that if a console only uses dynamic probing, it will never be usable as a kernel console even when specifying console=hvc0 explicitly, which could be considered annoying... More specifically, on pseries, we only do the early instanciate for the console currently used by the firmware, so if you have your firmware configured to go to a video card, for example, you cannot get your kernel console, oops messages, etc... on your serial port or hypervisor console, which would be handy to deal with oopses. This fixes it by checking if hvc_console.flags & CON_ENABLED is set when registering a new dynamic console, and if not, redo the index check and re-register the console if the index matches, allowing console=hvcN to work. Signed-off-by: Benjamin Herrenschmidt --- drivers/tty/hvc/hvc_console.c | 33 ++++++++++++++++++++++++++------- 1 file changed, 26 insertions(+), 7 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c index 2d691eb7c40a..f1d4d96a4a07 100644 --- a/drivers/tty/hvc/hvc_console.c +++ b/drivers/tty/hvc/hvc_console.c @@ -245,6 +245,20 @@ static void hvc_port_destruct(struct tty_port *port) kfree(hp); } +static void hvc_check_console(int index) +{ + /* Already enabled, bail out */ + if (hvc_console.flags & CON_ENABLED) + return; + + /* If this index is what the user requested, then register + * now (setup won't fail at this point). It's ok to just + * call register again if previously .setup failed. + */ + if (index == hvc_console.index) + register_console(&hvc_console); +} + /* * hvc_instantiate() is an early console discovery method which locates * consoles * prior to the vio subsystem discovering them. Hotplugged @@ -275,12 +289,8 @@ int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops) if (last_hvc < index) last_hvc = index; - /* if this index is what the user requested, then register - * now (setup won't fail at this point). It's ok to just - * call register again if previously .setup failed. - */ - if (index == hvc_console.index) - register_console(&hvc_console); + /* check if we need to re-register the kernel console */ + hvc_check_console(index); return 0; } @@ -858,10 +868,15 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, i = ++last_hvc; hp->index = i; + cons_ops[i] = ops; + vtermnos[i] = vtermno; list_add_tail(&(hp->next), &hvc_structs); spin_unlock(&hvc_structs_lock); + /* check if we need to re-register the kernel console */ + hvc_check_console(i); + return hp; } EXPORT_SYMBOL_GPL(hvc_alloc); @@ -874,8 +889,12 @@ int hvc_remove(struct hvc_struct *hp) tty = tty_port_tty_get(&hp->port); spin_lock_irqsave(&hp->lock, flags); - if (hp->index < MAX_NR_HVC_CONSOLES) + if (hp->index < MAX_NR_HVC_CONSOLES) { + console_lock(); vtermnos[hp->index] = -1; + cons_ops[hp->index] = NULL; + console_unlock(); + } /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ -- cgit v1.2.2 From d1cfc0ce5d3196ccd88b9d868bb7cbcab61e0a31 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Mon, 23 Jul 2012 21:47:38 +0000 Subject: hvc_vio: Improve registration of udbg backend The pseries hvterm driver only registers a udbg backend (for xmon and other low level debugging mechanisms) when hvc0 is recognized as the firmware console at boot time, not if it's detected later on, for example because the firmware is using a graphics card. This can make debugging challenging especially under X11, and there's really no good reason for that limitation, so let's hookup udbg whenever hvc0 is detected instead. Signed-off-by: Benjamin Herrenschmidt --- drivers/tty/hvc/hvc_vio.c | 123 ++++++++++++++++++++++++++-------------------- 1 file changed, 70 insertions(+), 53 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/hvc/hvc_vio.c b/drivers/tty/hvc/hvc_vio.c index ee307799271a..070c0ee68642 100644 --- a/drivers/tty/hvc/hvc_vio.c +++ b/drivers/tty/hvc/hvc_vio.c @@ -230,6 +230,69 @@ static const struct hv_ops hvterm_hvsi_ops = { .tiocmset = hvterm_hvsi_tiocmset, }; +static void udbg_hvc_putc(char c) +{ + int count = -1; + + if (!hvterm_privs[0]) + return; + + if (c == '\n') + udbg_hvc_putc('\r'); + + do { + switch(hvterm_privs[0]->proto) { + case HV_PROTOCOL_RAW: + count = hvterm_raw_put_chars(0, &c, 1); + break; + case HV_PROTOCOL_HVSI: + count = hvterm_hvsi_put_chars(0, &c, 1); + break; + } + } while(count == 0); +} + +static int udbg_hvc_getc_poll(void) +{ + int rc = 0; + char c; + + if (!hvterm_privs[0]) + return -1; + + switch(hvterm_privs[0]->proto) { + case HV_PROTOCOL_RAW: + rc = hvterm_raw_get_chars(0, &c, 1); + break; + case HV_PROTOCOL_HVSI: + rc = hvterm_hvsi_get_chars(0, &c, 1); + break; + } + if (!rc) + return -1; + return c; +} + +static int udbg_hvc_getc(void) +{ + int ch; + + if (!hvterm_privs[0]) + return -1; + + for (;;) { + ch = udbg_hvc_getc_poll(); + if (ch == -1) { + /* This shouldn't be needed...but... */ + volatile unsigned long delay; + for (delay=0; delay < 2000000; delay++) + ; + } else { + return ch; + } + } +} + static int __devinit hvc_vio_probe(struct vio_dev *vdev, const struct vio_device_id *id) { @@ -289,6 +352,13 @@ static int __devinit hvc_vio_probe(struct vio_dev *vdev, return PTR_ERR(hp); dev_set_drvdata(&vdev->dev, hp); + /* register udbg if it's not there already for console 0 */ + if (hp->index == 0 && !udbg_putc) { + udbg_putc = udbg_hvc_putc; + udbg_getc = udbg_hvc_getc; + udbg_getc_poll = udbg_hvc_getc_poll; + } + return 0; } @@ -331,59 +401,6 @@ static void __exit hvc_vio_exit(void) } module_exit(hvc_vio_exit); -static void udbg_hvc_putc(char c) -{ - int count = -1; - - if (c == '\n') - udbg_hvc_putc('\r'); - - do { - switch(hvterm_priv0.proto) { - case HV_PROTOCOL_RAW: - count = hvterm_raw_put_chars(0, &c, 1); - break; - case HV_PROTOCOL_HVSI: - count = hvterm_hvsi_put_chars(0, &c, 1); - break; - } - } while(count == 0); -} - -static int udbg_hvc_getc_poll(void) -{ - int rc = 0; - char c; - - switch(hvterm_priv0.proto) { - case HV_PROTOCOL_RAW: - rc = hvterm_raw_get_chars(0, &c, 1); - break; - case HV_PROTOCOL_HVSI: - rc = hvterm_hvsi_get_chars(0, &c, 1); - break; - } - if (!rc) - return -1; - return c; -} - -static int udbg_hvc_getc(void) -{ - int ch; - for (;;) { - ch = udbg_hvc_getc_poll(); - if (ch == -1) { - /* This shouldn't be needed...but... */ - volatile unsigned long delay; - for (delay=0; delay < 2000000; delay++) - ; - } else { - return ch; - } - } -} - void __init hvc_vio_init_early(void) { struct device_node *stdout_node; -- cgit v1.2.2