Patchwork sparc32: forced setting of mode of sun4m per-cpu timers

login
register
mail settings
Submitter Kirill Tkhai
Date Jan. 10, 2012, 11:17 p.m.
Message ID <1326237423.7307.13.camel@hp>
Download mbox | patch
Permalink /patch/135325/
State Accepted
Delegated to: David Miller
Headers show

Comments

Kirill Tkhai - Jan. 10, 2012, 11:17 p.m.
SUN4M per-cpu timers have two modes of work. These are timer mode and
counter mode. Kernel doesn't write anything to the register, which is
connected with mode choice.
So, the mode is chosen by bootloader. This patch forces to use timer
mode from the kernel and to be independent of bootloader.

I had this problem with OpenBIOS. Timers don't tick and kernel fails on
QEMU, when it's compiled with SMP support. The patch fixes problem.

Signed-off-by: Tkhai Kirill <tkhai@yandex.ru>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
---


--
To unsubscribe from this list: send the line "unsubscribe sparclinux" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
David Miller - Jan. 11, 2012, 12:28 a.m.
From: Kirill Tkhai <tkhai@yandex.ru>
Date: Wed, 11 Jan 2012 03:17:03 +0400

> SUN4M per-cpu timers have two modes of work. These are timer mode and
> counter mode. Kernel doesn't write anything to the register, which is
> connected with mode choice.
> So, the mode is chosen by bootloader. This patch forces to use timer
> mode from the kernel and to be independent of bootloader.
> 
> I had this problem with OpenBIOS. Timers don't tick and kernel fails on
> QEMU, when it's compiled with SMP support. The patch fixes problem.
> 
> Signed-off-by: Tkhai Kirill <tkhai@yandex.ru>
> Acked-by: Sam Ravnborg <sam@ravnborg.org>

Applied, thanks.
--
To unsubscribe from this list: send the line "unsubscribe sparclinux" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/arch/sparc/kernel/sun4m_irq.c b/arch/sparc/kernel/sun4m_irq.c
index 422c16d..e611651 100644
--- a/arch/sparc/kernel/sun4m_irq.c
+++ b/arch/sparc/kernel/sun4m_irq.c
@@ -399,6 +399,9 @@  static void __init sun4m_init_timers(irq_handler_t counter_fn)
 	timers_global = (void __iomem *)
 		(unsigned long) addr[num_cpu_timers];
 
+	/* Every per-cpu timer works in timer mode */
+	sbus_writel(0x00000000, &timers_global->timer_config);
+
 	sbus_writel((((1000000/HZ) + 1) << 10), &timers_global->l10_limit);
 
 	master_l10_counter = &timers_global->l10_count;