hvc_console: rework setup to replace irq functions with callbacks
This patch tries to change hvc_console to not use request_irq/free_irq if
the backend does not use irqs. This allows virtio_console to use hvc_console
without having a linker reference to request_irq/free_irq.
In addition, together with patch 2/3 it improves the performance for virtio
console input. (an earlier version of this patch was tested by Yajin on lguest)
The irq specific code is moved to hvc_irq.c and selected by the drivers that
use irqs (System p, System i, XEN).
I replaced "int irq" with the opaque "int data". The request_irq and
free_irq calls are replaced with notifier_add and notifier_del. I have also
changed the code a bit to call the notifier_add and notifier_del inside the
spinlock area as the callbacks are found via hp->ops.
Changes since last version:
o remove ifdef
o reintroduce "irq_requested" as "notified"
o cleanups, sparse..
I did not move the timer based polling into a separate polling scheme. I
played with several variants, but it seems we need to sleep/schedule in
a thread even for irq based consoles, as there are throttleing and buffer
size constraints.
I also kept hvc_struct defined in hvc_console.h so that hvc_irq.c can access
the irq_requested element.
Feedback is appreciated. virtio_console is currently the only available console
for kvm on s390. I plan to push this change as soon as all affected parties
agree on it. I would love to get test results from System p, Xen etc.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 67b0757..d825361 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -578,11 +578,14 @@
It will automatically be selected if one of the back-end console drivers
is selected.
+config HVC_IRQ
+ bool
config HVC_CONSOLE
bool "pSeries Hypervisor Virtual Console support"
depends on PPC_PSERIES
select HVC_DRIVER
+ select HVC_IRQ
help
pSeries machines when partitioned support a hypervisor virtual
console. This driver allows each pSeries partition to have a console
@@ -593,6 +596,7 @@
depends on PPC_ISERIES
default y
select HVC_DRIVER
+ select HVC_IRQ
help
iSeries machines support a hypervisor virtual console.
@@ -614,6 +618,7 @@
bool "Xen Hypervisor Console support"
depends on XEN
select HVC_DRIVER
+ select HVC_IRQ
default y
help
Xen virtual console device driver