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authorChristian Borntraeger <borntraeger@de.ibm.com>2008-06-20 15:24:08 +0200
committerRusty Russell <rusty@rustcorp.com.au>2008-07-25 12:06:06 +1000
commit611e097d7707741a336a0677d9d69bec40f29f3d (patch)
tree0b0059544914bf027ada51a1ba90f694c54df835 /drivers/char/Kconfig
parent066f4d82a67f621ddd547bfa4b9c94631d8457b0 (diff)
downloadop-kernel-dev-611e097d7707741a336a0677d9d69bec40f29f3d.zip
op-kernel-dev-611e097d7707741a336a0677d9d69bec40f29f3d.tar.gz
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>
Diffstat (limited to 'drivers/char/Kconfig')
-rw-r--r--drivers/char/Kconfig5
1 files changed, 5 insertions, 0 deletions
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 @@ config HVC_DRIVER
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 @@ config HVC_ISERIES
depends on PPC_ISERIES
default y
select HVC_DRIVER
+ select HVC_IRQ
help
iSeries machines support a hypervisor virtual console.
@@ -614,6 +618,7 @@ config HVC_XEN
bool "Xen Hypervisor Console support"
depends on XEN
select HVC_DRIVER
+ select HVC_IRQ
default y
help
Xen virtual console device driver
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