On Wed, Mar 22, 2017 at 12:31:14AM +0800, fu....@linaro.org wrote: > From: Fu Wei <fu....@linaro.org> > > When system init with device-tree, we don't know which node will be > initialized first. And the code in arch_timer_common_init should wait > until per-cpu timer and MMIO timer are both initialized. So we need > arch_timer_needs_probing to detect the init status of system. > > But currently the code is dispersed in arch_timer_needs_probing and > arch_timer_common_init. And the function name doesn't specify that > it's only for device-tree. This is somewhat confusing.
Can the following patch help you to solve nicely the situation ? https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1360007.html > This patch move all related code from arch_timer_common_init to > arch_timer_needs_probing, refactor it, and rename it to > arch_timer_needs_of_probing. And make sure that it will be called > only if acpi is disabled. > > Signed-off-by: Fu Wei <fu....@linaro.org> > Reviewed-by: Hanjun Guo <hanjun....@linaro.org> > --- > drivers/clocksource/arm_arch_timer.c | 34 +++++++++++++++++++--------------- > 1 file changed, 19 insertions(+), 15 deletions(-) > > diff --git a/drivers/clocksource/arm_arch_timer.c > b/drivers/clocksource/arm_arch_timer.c > index 29ca7d6..d1a05d9 100644 > --- a/drivers/clocksource/arm_arch_timer.c > +++ b/drivers/clocksource/arm_arch_timer.c > @@ -839,15 +839,28 @@ static const struct of_device_id > arch_timer_mem_of_match[] __initconst = { > {}, > }; > > -static bool __init > -arch_timer_needs_probing(int type, const struct of_device_id *matches) > +static bool __init arch_timer_needs_of_probing(void) > { > struct device_node *dn; > bool needs_probing = false; > + unsigned int mask = ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM; > > - dn = of_find_matching_node(NULL, matches); > - if (dn && of_device_is_available(dn) && !(arch_timers_present & type)) > + /* We have two timers, and both device-tree nodes are probed. */ > + if ((arch_timers_present & mask) == mask) > + return false; > + > + /* > + * Only one type of timer is probed, > + * check if we have another type of timer node in device-tree. > + */ > + if (arch_timers_present & ARCH_TIMER_TYPE_CP15) > + dn = of_find_matching_node(NULL, arch_timer_mem_of_match); > + else > + dn = of_find_matching_node(NULL, arch_timer_of_match); > + > + if (dn && of_device_is_available(dn)) > needs_probing = true; > + > of_node_put(dn); > > return needs_probing; > @@ -855,17 +868,8 @@ arch_timer_needs_probing(int type, const struct > of_device_id *matches) > > static int __init arch_timer_common_init(void) > { > - unsigned mask = ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM; > - > - /* Wait until both nodes are probed if we have two timers */ > - if ((arch_timers_present & mask) != mask) { > - if (arch_timer_needs_probing(ARCH_TIMER_TYPE_MEM, > - arch_timer_mem_of_match)) > - return 0; > - if (arch_timer_needs_probing(ARCH_TIMER_TYPE_CP15, > - arch_timer_of_match)) > - return 0; > - } > + if (acpi_disabled && arch_timer_needs_of_probing()) > + return 0; > > arch_timer_banner(arch_timers_present); > arch_counter_register(arch_timers_present); > -- > 2.9.3 > -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
