Re: [PATCH 1/1] microblaze: Added fdt chosen capability for timer
From: John Williams <hidden>
Date: 2011-11-10 14:21:50
On Thu, Nov 10, 2011 at 11:10 PM, Michal Simek [off-list ref] wrote:
quoted hunk
From: "Peter A. G. Crosthwaite" <redacted> This lets a dts author flag a particular timer in the system as the system timer. If the chosen node contains a "system-timer=<&foo>" entry than that handle will be used to determine the system timer. In no such entry exists then the first found timer will be used (current behaviour). Signed-off-by: Peter A. G. Crosthwaite <redacted> Signed-off-by: Michal Simek <redacted> --- arch/microblaze/kernel/timer.c | 12 ++++++++---- 1 files changed, 8 insertions(+), 4 deletions(-)diff --git a/arch/microblaze/kernel/timer.c b/arch/microblaze/kernel/timer.c index 91804cd..c289412 100644 --- a/arch/microblaze/kernel/timer.c +++ b/arch/microblaze/kernel/timer.c@@ -267,11 +267,15 @@ void __init time_init(void)NULL }; - for (i = 0; timer_list[i] != NULL; i++) { + prop = of_get_property(of_chosen, "system-timer", NULL); + if (prop) + timer = of_find_node_by_phandle(be32_to_cpup(prop));
Suggest expanding this code to check that the chosen timer meets the kernel requirements - IRQ connected, dual channel etc. If it fails, then perhaps fall through to finding the first suitable one, or panic()?
+ else + printk(KERN_INFO "No chosen timer found, using default\n"); + + for (i = 0; timer_list[i] != NULL && !timer; i++) timer = of_find_compatible_node(NULL, NULL, timer_list[i]); - if (timer) - break;
There is another issue I think - can we somehow mark the system timer instance as 'taken' so it can't be bound by another driver that might be compatible (esp. generic-uio for example). Currently if you mark the timer as generic-uio then a UIO app can mess with it - not good. John -- PetaLogix - Linux Solutions for a Reconfigurable World w: www.petalogix.com p: +61-7-30090663 f: +61-7-30090663