From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc_gonzalez@sigmadesigns.com (Marc Gonzalez) Date: Mon, 5 Oct 2015 11:17:41 +0200 Subject: [PATCH v2] twd: Don't set CLOCK_EVT_FEAT_C3STOP unconditionally In-Reply-To: <56123BD0.8010005@sigmadesigns.com> References: <56123BD0.8010005@sigmadesigns.com> Message-ID: <56124035.6080107@sigmadesigns.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org In 5388a6b266 ("ARM: SMP: Always enable clock event broadcast support") Russell noted that "the TWD local timers are unable to wake up the CPU when it is placed into a low power mode". However, some platforms do not stop the TWD block in low-power mode, and can thus use it without setting up a broadcast device. Make the driver check for the "twd_never_stops" property, and set the CLOCK_EVT_FEAT_C3STOP flag accordingly. Signed-off-by: Marc Gonzalez --- Documentation/devicetree/bindings/arm/twd.txt | 3 +++ arch/arm/kernel/smp_twd.c | 5 ++++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/arm/twd.txt b/Documentation/devicetree/bindings/arm/twd.txt index 75b8610939fa..7724665a437d 100644 --- a/Documentation/devicetree/bindings/arm/twd.txt +++ b/Documentation/devicetree/bindings/arm/twd.txt @@ -19,6 +19,9 @@ interrupts. - reg : Specify the base address and the size of the TWD timer register window. +Optional +- twd_never_stops : Don't set the CLOCK_EVT_FEAT_C3STOP flag. + Example: twd-timer at 2c000600 { diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c index e8f6d241881f..0ca825e24d9c 100644 --- a/arch/arm/kernel/smp_twd.c +++ b/arch/arm/kernel/smp_twd.c @@ -33,6 +33,7 @@ static unsigned long twd_timer_rate; static DEFINE_PER_CPU(bool, percpu_setup_called); static struct clock_event_device __percpu *twd_evt; +static int feat_c3stop; static int twd_ppi; static void twd_set_mode(enum clock_event_mode mode, @@ -293,7 +294,7 @@ static void twd_timer_setup(void) clk->name = "local_timer"; clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT | - CLOCK_EVT_FEAT_C3STOP; + feat_c3stop; clk->rating = 350; clk->set_mode = twd_set_mode; clk->set_next_event = twd_set_next_event; @@ -345,6 +346,8 @@ static int __init twd_local_timer_common_register(struct device_node *np) goto out_irq; twd_get_clock(np); + if (!of_property_read_bool(np, "twd_never_stops")) + feat_c3stop = CLOCK_EVT_FEAT_C3STOP; /* * Immediately configure the timer on the boot CPU, unless we need -- 2.4.5