* [PATCH] ARM: kernel: respect device tree status of cpu nodes @ 2014-02-24 11:22 ` Jürg Billeter 0 siblings, 0 replies; 9+ messages in thread From: Jürg Billeter @ 2014-02-24 11:22 UTC (permalink / raw) To: linux-arm-kernel Skip 'disabled' cpu nodes when building the cpu logical map. This avoids booting cpus that have been disabled in the device tree. Signed-off-by: J?rg Billeter <j@bitron.ch> Reviewed-by: Ben Dooks <ben.dooks@codethink.co.uk> --- arch/arm/kernel/devtree.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c index 739c3df..9aed299 100644 --- a/arch/arm/kernel/devtree.c +++ b/arch/arm/kernel/devtree.c @@ -95,6 +95,10 @@ void __init arm_dt_init_cpu_maps(void) if (of_node_cmp(cpu->type, "cpu")) continue; + /* Check if CPU is enabled */ + if (!of_device_is_available(cpu)) + continue; + pr_debug(" * %s...\n", cpu->full_name); /* * A device tree containing CPU nodes with missing "reg" -- 1.9.0 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH] ARM: kernel: respect device tree status of cpu nodes @ 2014-02-24 11:22 ` Jürg Billeter 0 siblings, 0 replies; 9+ messages in thread From: Jürg Billeter @ 2014-02-24 11:22 UTC (permalink / raw) To: linux-arm-kernel Cc: linux-kernel, devicetree, linux-kernel, Jürg Billeter Skip 'disabled' cpu nodes when building the cpu logical map. This avoids booting cpus that have been disabled in the device tree. Signed-off-by: Jürg Billeter <j@bitron.ch> Reviewed-by: Ben Dooks <ben.dooks@codethink.co.uk> --- arch/arm/kernel/devtree.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c index 739c3df..9aed299 100644 --- a/arch/arm/kernel/devtree.c +++ b/arch/arm/kernel/devtree.c @@ -95,6 +95,10 @@ void __init arm_dt_init_cpu_maps(void) if (of_node_cmp(cpu->type, "cpu")) continue; + /* Check if CPU is enabled */ + if (!of_device_is_available(cpu)) + continue; + pr_debug(" * %s...\n", cpu->full_name); /* * A device tree containing CPU nodes with missing "reg" -- 1.9.0 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH] ARM: kernel: respect device tree status of cpu nodes @ 2014-02-24 11:22 ` Jürg Billeter 0 siblings, 0 replies; 9+ messages in thread From: Jürg Billeter @ 2014-02-24 11:22 UTC (permalink / raw) To: linux-arm-kernel Cc: linux-kernel, devicetree, Jürg Billeter, linux-kernel Skip 'disabled' cpu nodes when building the cpu logical map. This avoids booting cpus that have been disabled in the device tree. Signed-off-by: Jürg Billeter <j@bitron.ch> Reviewed-by: Ben Dooks <ben.dooks@codethink.co.uk> --- arch/arm/kernel/devtree.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c index 739c3df..9aed299 100644 --- a/arch/arm/kernel/devtree.c +++ b/arch/arm/kernel/devtree.c @@ -95,6 +95,10 @@ void __init arm_dt_init_cpu_maps(void) if (of_node_cmp(cpu->type, "cpu")) continue; + /* Check if CPU is enabled */ + if (!of_device_is_available(cpu)) + continue; + pr_debug(" * %s...\n", cpu->full_name); /* * A device tree containing CPU nodes with missing "reg" -- 1.9.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH] ARM: kernel: respect device tree status of cpu nodes 2014-02-24 11:22 ` Jürg Billeter @ 2014-03-05 20:33 ` Stephen Boyd -1 siblings, 0 replies; 9+ messages in thread From: Stephen Boyd @ 2014-03-05 20:33 UTC (permalink / raw) To: linux-arm-kernel +Lorenzo On 02/24/14 03:22, J?rg Billeter wrote: > Skip 'disabled' cpu nodes when building the cpu logical map. This avoids > booting cpus that have been disabled in the device tree. > > Signed-off-by: J?rg Billeter <j@bitron.ch> > Reviewed-by: Ben Dooks <ben.dooks@codethink.co.uk> > --- > arch/arm/kernel/devtree.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c > index 739c3df..9aed299 100644 > --- a/arch/arm/kernel/devtree.c > +++ b/arch/arm/kernel/devtree.c > @@ -95,6 +95,10 @@ void __init arm_dt_init_cpu_maps(void) > if (of_node_cmp(cpu->type, "cpu")) > continue; > > + /* Check if CPU is enabled */ > + if (!of_device_is_available(cpu)) > + continue; > + > pr_debug(" * %s...\n", cpu->full_name); > /* > * A device tree containing CPU nodes with missing "reg" This doesn't follow the ePAPR spec. According to ePAPR status="disabled" in a cpu node means "the cpu is in a quiescent state" and one can enable it by using the "enable-method". At the least, we should document this in bindings/arm/cpus.txt if we can all agree that we want this definition of disabled. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] ARM: kernel: respect device tree status of cpu nodes @ 2014-03-05 20:33 ` Stephen Boyd 0 siblings, 0 replies; 9+ messages in thread From: Stephen Boyd @ 2014-03-05 20:33 UTC (permalink / raw) To: Jürg Billeter Cc: linux-arm-kernel, linux-kernel, devicetree, Linux Kernel Mailing List, Lorenzo Pieralisi +Lorenzo On 02/24/14 03:22, Jürg Billeter wrote: > Skip 'disabled' cpu nodes when building the cpu logical map. This avoids > booting cpus that have been disabled in the device tree. > > Signed-off-by: Jürg Billeter <j@bitron.ch> > Reviewed-by: Ben Dooks <ben.dooks@codethink.co.uk> > --- > arch/arm/kernel/devtree.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c > index 739c3df..9aed299 100644 > --- a/arch/arm/kernel/devtree.c > +++ b/arch/arm/kernel/devtree.c > @@ -95,6 +95,10 @@ void __init arm_dt_init_cpu_maps(void) > if (of_node_cmp(cpu->type, "cpu")) > continue; > > + /* Check if CPU is enabled */ > + if (!of_device_is_available(cpu)) > + continue; > + > pr_debug(" * %s...\n", cpu->full_name); > /* > * A device tree containing CPU nodes with missing "reg" This doesn't follow the ePAPR spec. According to ePAPR status="disabled" in a cpu node means "the cpu is in a quiescent state" and one can enable it by using the "enable-method". At the least, we should document this in bindings/arm/cpus.txt if we can all agree that we want this definition of disabled. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation ^ permalink raw reply [flat|nested] 9+ messages in thread
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* Re: [Linux-kernel] [PATCH] ARM: kernel: respect device tree status of cpu nodes 2014-03-05 20:33 ` Stephen Boyd @ 2014-03-06 10:00 ` Ben Dooks -1 siblings, 0 replies; 9+ messages in thread From: Ben Dooks @ 2014-03-06 10:00 UTC (permalink / raw) To: linux-kernel-81qHHgoATdFT9dQujB1mzip2UmYkHbXO, open list:OPEN FIRMWARE AND..., Lorenzon Pieralisi, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On 05/03/14 20:33, Stephen Boyd wrote: > +Lorenzo > > On 02/24/14 03:22, Jürg Billeter wrote: >> Skip 'disabled' cpu nodes when building the cpu logical map. This avoids >> booting cpus that have been disabled in the device tree. >> >> Signed-off-by: Jürg Billeter <j@bitron.ch> >> Reviewed-by: Ben Dooks <ben.dooks-4yDnlxn2s6sWdaTGBSpHTA@public.gmane.org> >> --- >> arch/arm/kernel/devtree.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c >> index 739c3df..9aed299 100644 >> --- a/arch/arm/kernel/devtree.c >> +++ b/arch/arm/kernel/devtree.c >> @@ -95,6 +95,10 @@ void __init arm_dt_init_cpu_maps(void) >> if (of_node_cmp(cpu->type, "cpu")) >> continue; >> >> + /* Check if CPU is enabled */ >> + if (!of_device_is_available(cpu)) >> + continue; >> + >> pr_debug(" * %s...\n", cpu->full_name); >> /* >> * A device tree containing CPU nodes with missing "reg" > > This doesn't follow the ePAPR spec. According to ePAPR status="disabled" > in a cpu node means "the cpu is in a quiescent state" and one can enable > it by using the "enable-method". At the least, we should document this > in bindings/arm/cpus.txt if we can all agree that we want this > definition of disabled. My view was that disabled should be the same as for the device case as it makes sense that way. We have a position where we want to use the .dtsi files but not all cpus are available to the Linux. If we cannot use disabled then we need some other method to say this cpu node is not available, so please do not try and bring it online (saves boot time waiting for CPU nodes that cannot online) -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Linux-kernel] [PATCH] ARM: kernel: respect device tree status of cpu nodes @ 2014-03-06 10:00 ` Ben Dooks 0 siblings, 0 replies; 9+ messages in thread From: Ben Dooks @ 2014-03-06 10:00 UTC (permalink / raw) To: linux-kernel, open list:OPEN FIRMWARE AND..., Lorenzon Pieralisi, linux-kernel@vger.kernel.org On 05/03/14 20:33, Stephen Boyd wrote: > +Lorenzo > > On 02/24/14 03:22, Jürg Billeter wrote: >> Skip 'disabled' cpu nodes when building the cpu logical map. This avoids >> booting cpus that have been disabled in the device tree. >> >> Signed-off-by: Jürg Billeter <j@bitron.ch> >> Reviewed-by: Ben Dooks <ben.dooks@codethink.co.uk> >> --- >> arch/arm/kernel/devtree.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c >> index 739c3df..9aed299 100644 >> --- a/arch/arm/kernel/devtree.c >> +++ b/arch/arm/kernel/devtree.c >> @@ -95,6 +95,10 @@ void __init arm_dt_init_cpu_maps(void) >> if (of_node_cmp(cpu->type, "cpu")) >> continue; >> >> + /* Check if CPU is enabled */ >> + if (!of_device_is_available(cpu)) >> + continue; >> + >> pr_debug(" * %s...\n", cpu->full_name); >> /* >> * A device tree containing CPU nodes with missing "reg" > > This doesn't follow the ePAPR spec. According to ePAPR status="disabled" > in a cpu node means "the cpu is in a quiescent state" and one can enable > it by using the "enable-method". At the least, we should document this > in bindings/arm/cpus.txt if we can all agree that we want this > definition of disabled. My view was that disabled should be the same as for the device case as it makes sense that way. We have a position where we want to use the .dtsi files but not all cpus are available to the Linux. If we cannot use disabled then we need some other method to say this cpu node is not available, so please do not try and bring it online (saves boot time waiting for CPU nodes that cannot online) -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius ^ permalink raw reply [flat|nested] 9+ messages in thread
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* Re: [Linux-kernel] [PATCH] ARM: kernel: respect device tree status of cpu nodes 2014-03-06 10:00 ` Ben Dooks @ 2014-03-06 16:51 ` Lorenzo Pieralisi -1 siblings, 0 replies; 9+ messages in thread From: Lorenzo Pieralisi @ 2014-03-06 16:51 UTC (permalink / raw) To: Ben Dooks Cc: linux-kernel-81qHHgoATdFT9dQujB1mzip2UmYkHbXO@public.gmane.org, open list:OPEN FIRMWARE AND..., linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r, grant.likely-QSEj5FYQhm4dnm+yROfE0A, robh+dt-DgEjT+Ai2ygdnm+yROfE0A [CC'in BenH and Grant to check how this is handled in powerPC] On Thu, Mar 06, 2014 at 10:00:10AM +0000, Ben Dooks wrote: > On 05/03/14 20:33, Stephen Boyd wrote: > > +Lorenzo > > > > On 02/24/14 03:22, Jürg Billeter wrote: > >> Skip 'disabled' cpu nodes when building the cpu logical map. This avoids > >> booting cpus that have been disabled in the device tree. > >> > >> Signed-off-by: Jürg Billeter <j@bitron.ch> > >> Reviewed-by: Ben Dooks <ben.dooks-4yDnlxn2s6sWdaTGBSpHTA@public.gmane.org> > >> --- > >> arch/arm/kernel/devtree.c | 4 ++++ > >> 1 file changed, 4 insertions(+) > >> > >> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c > >> index 739c3df..9aed299 100644 > >> --- a/arch/arm/kernel/devtree.c > >> +++ b/arch/arm/kernel/devtree.c > >> @@ -95,6 +95,10 @@ void __init arm_dt_init_cpu_maps(void) > >> if (of_node_cmp(cpu->type, "cpu")) > >> continue; > >> > >> + /* Check if CPU is enabled */ > >> + if (!of_device_is_available(cpu)) > >> + continue; > >> + > >> pr_debug(" * %s...\n", cpu->full_name); > >> /* > >> * A device tree containing CPU nodes with missing "reg" > > > > This doesn't follow the ePAPR spec. According to ePAPR status="disabled" > > in a cpu node means "the cpu is in a quiescent state" and one can enable > > it by using the "enable-method". At the least, we should document this > > in bindings/arm/cpus.txt if we can all agree that we want this > > definition of disabled. > > My view was that disabled should be the same as for the device case > as it makes sense that way. Ok, it has been brought up before. ePAPR v1.1, 2.3.4 "status" "disabled" - Indicates that the device is not presently operational, but it might become operational in the future (for example, something is not plugged in, or switched off). Refer to the device binding for details on what disabled means for a given device. So "disabled" for devices does not read that different to me to what Stephen mentioned for a CPU. After all you just want the CPU node to be ignored, and that's not a CPU status, it is a DT trick to use one .dtsi for multiple boot scenarios. I wonder how the status property has been used on powerPC. By grepping the sources, it is checked in arch/powerpc/kernel/prom_init.c and that's just to check CPU that are already in status =="okay", so they can be put in a holding loop (I guess). It should be fine to deviate from the ePAPR and consider using: status = "disabled" for your aim (it has been ignored so far on all ARM platforms I am aware of, so this should not break the kernel). We need to update cpus.txt accordingly and override it for ARM. > We have a position where we want to use the .dtsi files but not all > cpus are available to the Linux. If we cannot use disabled then we > need some other method to say this cpu node is not available, so > please do not try and bring it online (saves boot time waiting for > CPU nodes that cannot online) Understood, see above. Lorenzo -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Linux-kernel] [PATCH] ARM: kernel: respect device tree status of cpu nodes @ 2014-03-06 16:51 ` Lorenzo Pieralisi 0 siblings, 0 replies; 9+ messages in thread From: Lorenzo Pieralisi @ 2014-03-06 16:51 UTC (permalink / raw) To: Ben Dooks Cc: linux-kernel@lists.codethink.co.uk, open list:OPEN FIRMWARE AND..., linux-kernel@vger.kernel.org, benh, grant.likely, robh+dt [CC'in BenH and Grant to check how this is handled in powerPC] On Thu, Mar 06, 2014 at 10:00:10AM +0000, Ben Dooks wrote: > On 05/03/14 20:33, Stephen Boyd wrote: > > +Lorenzo > > > > On 02/24/14 03:22, Jürg Billeter wrote: > >> Skip 'disabled' cpu nodes when building the cpu logical map. This avoids > >> booting cpus that have been disabled in the device tree. > >> > >> Signed-off-by: Jürg Billeter <j@bitron.ch> > >> Reviewed-by: Ben Dooks <ben.dooks@codethink.co.uk> > >> --- > >> arch/arm/kernel/devtree.c | 4 ++++ > >> 1 file changed, 4 insertions(+) > >> > >> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c > >> index 739c3df..9aed299 100644 > >> --- a/arch/arm/kernel/devtree.c > >> +++ b/arch/arm/kernel/devtree.c > >> @@ -95,6 +95,10 @@ void __init arm_dt_init_cpu_maps(void) > >> if (of_node_cmp(cpu->type, "cpu")) > >> continue; > >> > >> + /* Check if CPU is enabled */ > >> + if (!of_device_is_available(cpu)) > >> + continue; > >> + > >> pr_debug(" * %s...\n", cpu->full_name); > >> /* > >> * A device tree containing CPU nodes with missing "reg" > > > > This doesn't follow the ePAPR spec. According to ePAPR status="disabled" > > in a cpu node means "the cpu is in a quiescent state" and one can enable > > it by using the "enable-method". At the least, we should document this > > in bindings/arm/cpus.txt if we can all agree that we want this > > definition of disabled. > > My view was that disabled should be the same as for the device case > as it makes sense that way. Ok, it has been brought up before. ePAPR v1.1, 2.3.4 "status" "disabled" - Indicates that the device is not presently operational, but it might become operational in the future (for example, something is not plugged in, or switched off). Refer to the device binding for details on what disabled means for a given device. So "disabled" for devices does not read that different to me to what Stephen mentioned for a CPU. After all you just want the CPU node to be ignored, and that's not a CPU status, it is a DT trick to use one .dtsi for multiple boot scenarios. I wonder how the status property has been used on powerPC. By grepping the sources, it is checked in arch/powerpc/kernel/prom_init.c and that's just to check CPU that are already in status =="okay", so they can be put in a holding loop (I guess). It should be fine to deviate from the ePAPR and consider using: status = "disabled" for your aim (it has been ignored so far on all ARM platforms I am aware of, so this should not break the kernel). We need to update cpus.txt accordingly and override it for ARM. > We have a position where we want to use the .dtsi files but not all > cpus are available to the Linux. If we cannot use disabled then we > need some other method to say this cpu node is not available, so > please do not try and bring it online (saves boot time waiting for > CPU nodes that cannot online) Understood, see above. Lorenzo ^ permalink raw reply [flat|nested] 9+ messages in thread
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2014-02-24 11:22 [PATCH] ARM: kernel: respect device tree status of cpu nodes Jürg Billeter
2014-02-24 11:22 ` Jürg Billeter
2014-02-24 11:22 ` Jürg Billeter
2014-03-05 20:33 ` Stephen Boyd
2014-03-05 20:33 ` Stephen Boyd
[not found] ` <53178A03.3090004-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2014-03-06 10:00 ` [Linux-kernel] " Ben Dooks
2014-03-06 10:00 ` Ben Dooks
[not found] ` <5318472A.5060700-4yDnlxn2s6sWdaTGBSpHTA@public.gmane.org>
2014-03-06 16:51 ` Lorenzo Pieralisi
2014-03-06 16:51 ` Lorenzo Pieralisi
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