Re: [PATCH] powerpc/powernv: Support OPAL requested heartbeat
On 11/12/2014 12:03 AM, Benjamin Herrenschmidt wrote: If OPAL requests it, call it back via opal_poll_events() at a regular interval. Some versions of OPAL on some machines require this to operate some internal timeouts properly. I don't see any reason why not, but wanted to ask to make sure: this daemon can be bound to a core, correct? At least manually by taskset or similar? It sounds a lot like the RTAS thread, which I was happy to see go away when running directly on OPAL, and don't want something else to take its place. It was not bindable, but ran periodically on EVERY core, err hardware thread. (Just looking to avoid latency blips.) PC ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH] powerpc/powernv: Support OPAL requested heartbeat
On Thu, 2014-11-13 at 10:59 -0600, Paul Clarke wrote: On 11/12/2014 12:03 AM, Benjamin Herrenschmidt wrote: If OPAL requests it, call it back via opal_poll_events() at a regular interval. Some versions of OPAL on some machines require this to operate some internal timeouts properly. I don't see any reason why not, but wanted to ask to make sure: this daemon can be bound to a core, correct? At least manually by taskset or similar? I think so... it's a kernel thread, but I haven't tried. It should be akin to the existing khvcd. It sounds a lot like the RTAS thread, which I was happy to see go away when running directly on OPAL, and don't want something else to take its place. It was not bindable, but ran periodically on EVERY core, err hardware thread. (Just looking to avoid latency blips.) Right, I know where you come from. But you'll get those blips whether I use a thread or an interrupt. Basically, I'm trying to get the HW guys to give me a modified SLW engine image that I can use to request time by setting up a delayed interrupt. I'm trying to reduce the work done in there, and in fact I'm hoping to only schedule my internal timers that rely on this (or the SLW interrupt) for cases where we have a pending i2c or IPMI command, and possibly only on machines without a functional external interrupt (so lab bringup) or when accessing Centaur i2c (very very rarely). But I do need that source of time... Cheers, Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH] powerpc/powernv: Support OPAL requested heartbeat
Hi Ben,
On Wed, 12 Nov 2014 17:03:14 Benjamin Herrenschmidt wrote:
snip
+
+static int kopald(void *unused)
+{
+ set_freezable();
+ do {
+ try_to_freeze();
+ opal_poll_events(NULL);
Do we need to check for outstanding events (and call opal_do_notifier)? The
Linux OPAL-IPMI interface signals an event which the interrupt handler
(opal_interrupt) checks for, but if interrupts aren't functional no event will
be signalled and hence the Linux IPMI layer won't get a response.
It's probably only an issue for lab bring up though as I would expect
interrupts to generally be working...
+ msleep_interruptible(opal_heartbeat);
+ } while (!kthread_should_stop());
+
+ return 0;
+}
+
Regards,
Alistair
___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH] powerpc/powernv: Support OPAL requested heartbeat
On Fri, 2014-11-14 at 14:01 +1100, Alistair Popple wrote:
Hi Ben,
On Wed, 12 Nov 2014 17:03:14 Benjamin Herrenschmidt wrote:
snip
+
+static int kopald(void *unused)
+{
+ set_freezable();
+ do {
+ try_to_freeze();
+ opal_poll_events(NULL);
Do we need to check for outstanding events (and call opal_do_notifier)? The
Linux OPAL-IPMI interface signals an event which the interrupt handler
(opal_interrupt) checks for, but if interrupts aren't functional no event
will
be signalled and hence the Linux IPMI layer won't get a response.
It's probably only an issue for lab bring up though as I would expect
interrupts to generally be working...
Well, it would somewhat double up with the OCC interrupt ... OPAL will
sent a local OCC interrupt if we change the event mask as a result of a
call that isn't opal_handle_interrupts() ... but yes, I suppose if that
doesn't work either... though this is not known to be problematic unless
the external one.
+ msleep_interruptible(opal_heartbeat);
+ } while (!kthread_should_stop());
+
+ return 0;
+}
+
Regards,
Alistair
___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
[PATCH] powerpc/powernv: Support OPAL requested heartbeat
If OPAL requests it, call it back via opal_poll_events() at a
regular interval. Some versions of OPAL on some machines require
this to operate some internal timeouts properly.
Signed-off-by: Benjamin Herrenschmidt b...@kernel.crashing.org
---
arch/powerpc/platforms/powernv/opal.c | 64 ++-
1 file changed, 55 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/opal.c
b/arch/powerpc/platforms/powernv/opal.c
index f1e0d8c..0153064 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -22,6 +22,8 @@
#include linux/kobject.h
#include linux/delay.h
#include linux/memblock.h
+#include linux/kthread.h
+#include linux/freezer.h
#include asm/machdep.h
#include asm/opal.h
@@ -58,6 +60,7 @@ static struct atomic_notifier_head
opal_msg_notifier_head[OPAL_MSG_TYPE_MAX];
static DEFINE_SPINLOCK(opal_notifier_lock);
static uint64_t last_notified_mask = 0x0ul;
static atomic_t opal_notifier_hold = ATOMIC_INIT(0);
+static uint32_t opal_heartbeat;
static void opal_reinit_cores(void)
{
@@ -633,17 +636,9 @@ static void opal_ipmi_init(struct device_node *opal_node)
of_platform_device_create(np, NULL, NULL);
}
-static int __init opal_init(void)
+static void opal_console_create_devs(void)
{
struct device_node *np, *consoles;
- const __be32 *irqs;
- int rc, i, irqlen;
-
- opal_node = of_find_node_by_path(/ibm,opal);
- if (!opal_node) {
- pr_warn(opal: Node not found\n);
- return -ENODEV;
- }
/* Register OPAL consoles if any ports */
if (firmware_has_feature(FW_FEATURE_OPALv2))
@@ -659,6 +654,13 @@ static int __init opal_init(void)
of_node_put(consoles);
}
+}
+
+static void opal_request_interrupts(void)
+{
+ const __be32 *irqs;
+ int rc, i, irqlen;
+
/* Find all OPAL interrupts and request them */
irqs = of_get_property(opal_node, opal-interrupts, irqlen);
pr_debug(opal: Found %d interrupts reserved for OPAL\n,
@@ -678,6 +680,49 @@ static int __init opal_init(void)
(0x%x)\n, rc, irq, hwirq);
opal_irqs[i] = irq;
}
+}
+
+static int kopald(void *unused)
+{
+ set_freezable();
+ do {
+ try_to_freeze();
+ opal_poll_events(NULL);
+ msleep_interruptible(opal_heartbeat);
+ } while (!kthread_should_stop());
+
+ return 0;
+}
+
+static void opal_init_heartbeat(void)
+{
+ /* Old firwmware, we assume the HVC heartbeat is sufficient */
+ if (of_property_read_u32(opal_node, ibm,heartbeat-freq,
+opal_heartbeat) != 0)
+ opal_heartbeat = 0;
+
+ if (opal_heartbeat)
+ kthread_run(kopald, NULL, kopald);
+}
+
+static int __init opal_init(void)
+{
+ int rc;
+
+ opal_node = of_find_node_by_path(/ibm,opal);
+ if (!opal_node) {
+ pr_warn(opal: Node not found\n);
+ return -ENODEV;
+ }
+
+ /* Setup a heatbeat thread if requested by OPAL */
+ opal_init_heartbeat();
+
+ /* Create console platform devices */
+ opal_console_create_devs();
+
+ /* Register OPAL interrupts */
+ opal_request_interrupts();
/* Create opal kobject under /sys/firmware */
rc = opal_sysfs_init();
@@ -696,6 +741,7 @@ static int __init opal_init(void)
opal_msglog_init();
}
+ /* Initialize OPAL IPMI backend */
opal_ipmi_init(opal_node);
return 0;
___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
