| Message ID | 20130109.134641.1582472136842052082.hdoyu@nvidia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jan 09, 2013 at 11:46:41AM +0000, Hiroshi Doyu wrote: > Hi Lorenzo, > > Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> wrote @ Tue, 8 Jan 2013 18:11:03 +0100: > > > On Tue, Jan 08, 2013 at 04:21:38PM +0000, Mark Rutland wrote: > > > On Tue, Jan 08, 2013 at 02:53:42PM +0000, Hiroshi Doyu wrote: > > > > [...] > > > > > > > > static void __init tegra_smp_init_cpus(void) > > > > > > { > > > > > > - unsigned int i, ncores = scu_get_core_count(scu_base); > > > > > > + unsigned int i, cpu_id, ncores; > > > > > > + u32 l2ctlr; > > > > > > + phys_addr_t pa; > > > > > > + > > > > > > + cpu_id = read_cpuid(CPUID_ID) & CPU_MASK; > > > > > > + switch (cpu_id) { > > > > > > + case CPU_CORTEX_A15: > > > > > > + asm("mrc p15, 1, %0, c9, c0, 2\n" : "=r" (l2ctlr)); > > > > > > + ncores = ((l2ctlr >> 24) & 3) + 1; > > > > > > + break; > > > > > > > > > > [...] > > > > > > > > > > As mentioned last time [1], you should get this information from the dt > > > > > instead. > > > > > > > > Most of platsmp.c:.smp_init_cpus() implementations seem just to > > > > overwrite # of cores by SCU/MRC detection. Is there any implementation > > > > to use the DT's # and skip SCU/MRC detection in .smp_init_cpus()? > > > > > > As far as I can see, there's no other platform which just relies on > > > arm_dt_init_cpu_maps. Until recently, it didn't exist, so that makes some > > > sense. As far as I can see, for the Tegra 114 you only need your smp_init_cpus > > > to call set_smp_cross_call(gic_raise_softirq). Everything else you do seems to > > > be handled by arm_dt_init_cpus. > > > > > > I think the best option would be to have a separate smp_ops for your dt > > > platforms where we know cpu nodes are populated (e.g. Tegra 114), where > > > smp_init_cpus is different to that for non-dt platforms. That way non dt > > > platforms can keep the SCU hack for now, and won't be broken, and the dt > > > platforms are far removed from the SCU hack and just use common infrastructure. > > > > > > Maybe someone else has a better idea? > > > > Have a look at mach-vexpress/platsmp.c (keeping in mind that the > > GENERIC_SCU case will be refactored/removed since arm_dt_init_cpu_maps() is > > doing most of the required steps), please let me know what you think. > > In tegra, we don't support non-DT. What about falling back SCU/MRC > based detection only when arm_dt_init_cpu_maps() fails? > > diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c > index 68e76ef..51d24ae 100644 > --- a/arch/arm/mach-tegra/platsmp.c > +++ b/arch/arm/mach-tegra/platsmp.c > @@ -152,7 +152,7 @@ done: > * Initialise the CPU possible map early - this describes the CPUs > * which may be present or become present in the system. > */ > -static void __init tegra_smp_init_cpus(void) > +static void __init tegra_smp_detect_cores(void) > { > unsigned int i, cpu_id, ncores; > u32 l2ctlr; > @@ -183,6 +183,12 @@ static void __init tegra_smp_init_cpus(void) > > for (i = 0; i < ncores; i++) > set_cpu_possible(i, true); > +} > + > +static void __init tegra_smp_init_cpus(void) > +{ > + if (!num_possible_cpus()) > + tegra_smp_detect_cores(); Thought about this, I would prefer writing an inline function that provides this information (DT missing /cpu information or parsing failure) instead of relying on num_possible_cpus to be == 0 as a way to check that. Lorenzo
diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c index 68e76ef..51d24ae 100644 --- a/arch/arm/mach-tegra/platsmp.c +++ b/arch/arm/mach-tegra/platsmp.c @@ -152,7 +152,7 @@ done: * Initialise the CPU possible map early - this describes the CPUs * which may be present or become present in the system. */ -static void __init tegra_smp_init_cpus(void) +static void __init tegra_smp_detect_cores(void) { unsigned int i, cpu_id, ncores; u32 l2ctlr; @@ -183,6 +183,12 @@ static void __init tegra_smp_init_cpus(void) for (i = 0; i < ncores; i++) set_cpu_possible(i, true); +} + +static void __init tegra_smp_init_cpus(void) +{ + if (!num_possible_cpus()) + tegra_smp_detect_cores(); set_smp_cross_call(gic_raise_softirq); }