From: cyril@ti•com (Cyril Chemparathy)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 1/2] ARM: arch_timers: enable the use of the virtual timer
Date: Sat, 11 Aug 2012 09:37:54 -0400 [thread overview]
Message-ID: <50266032.9070702@ti.com> (raw)
In-Reply-To: <1344681091-12652-2-git-send-email-marc.zyngier@arm.com>
Marc,
On 8/11/2012 6:31 AM, Marc Zyngier wrote:
> At the moment, the arch_timer driver only uses the physical timer,
> which can cause problem if PL2 hasn't enabled PL1 access in CNTHCTL,
> which is likely in a virtualized environment. Instead, the virtual
> timer is always available.
>
> This patch enables the use of both the virtual timer, unless no
> interrupt is provided in the DT for it, in which case is falls
> back to the physical timer.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm•com>
> ---
> arch/arm/kernel/arch_timer.c | 261 +++++++++++++++++++++++++++++++----------
> 1 files changed, 197 insertions(+), 64 deletions(-)
>
> diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
> index cf25880..4a64733 100644
[...]
> + if (arch_timer_use_virtual) {
> + ppi = arch_timer_ppi[VIRT_PPI];
> + err = request_percpu_irq(ppi, arch_timer_handler,
> + "arch_timer", arch_timer_evt);
> + } else {
> + ppi = arch_timer_ppi[PHYS_SECURE_PPI];
> + err = request_percpu_irq(ppi, arch_timer_handler,
> + "arch_timer", arch_timer_evt);
> + if (!err) {
> + ppi = arch_timer_ppi[PHYS_NONSECURE_PPI];
> + err = request_percpu_irq(ppi, arch_timer_handler,
> + "arch_timer", arch_timer_evt);
> + if (err)
> + free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
> + arch_timer_evt);
> + }
> + }
> +
> if (err) {
> pr_err("arch_timer: can't register interrupt %d (%d)\n",
> - arch_timer_ppi, err);
> + ppi, err);
> goto out_free;
> }
>
> - if (arch_timer_ppi2) {
> - err = request_percpu_irq(arch_timer_ppi2, arch_timer_handler,
> - "arch_timer", arch_timer_evt);
> - if (err) {
> - pr_err("arch_timer: can't register interrupt %d (%d)\n",
> - arch_timer_ppi2, err);
> - arch_timer_ppi2 = 0;
> - goto out_free_irq;
> - }
> - }
> -
In the original code, arch_timer_ppi2 appears to have been entirely
optional.
With this change, the code appears to mandate that both nonsecure and
secure PPIs be available (if !arch_timer_use_virtual). Could you please
explain this change?
--
Thanks
- Cyril
next prev parent reply other threads:[~2012-08-11 13:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-11 10:31 [PATCH v2 0/2] arch_timers patches to enable KVM support Marc Zyngier
2012-08-11 10:31 ` [PATCH v2 1/2] ARM: arch_timers: enable the use of the virtual timer Marc Zyngier
2012-08-11 13:37 ` Cyril Chemparathy [this message]
2012-08-11 14:28 ` Cyril Chemparathy
2012-08-13 15:30 ` Marc Zyngier
2012-08-11 10:31 ` [PATCH v2 2/2] ARM: arch_timers: register a time/cycle counter Marc Zyngier
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