| Message ID | 20211201130505.257379-2-stephan@gerhold.net |
|---|---|
| State | Accepted |
| Commit | 0ee30ace67e425ab83a1673bf51f50b577328cf9 |
| Headers | show |
| Series | qcom_scm: Add support for MC boot address API | expand |
On 01/12/2021 14:05, Stephan Gerhold wrote: > At the moment, the "qcom-spm-cpuidle" platform device is always created, > even if none of the CPUs is actually managed by the SPM. On non-qcom > platforms this will result in infinite probe-deferral due to the > failing qcom_scm_is_available() call. > > To avoid this, look through the CPU DT nodes and check if there is > actually any CPU managed by a SPM (as indicated by the qcom,saw property). > It should also be available because e.g. MSM8916 has qcom,saw defined > but it's typically not enabled with ARM64/PSCI firmwares. > > This is needed in preparation of a follow-up change that calls > qcom_scm_set_warm_boot_addr() a single time before registering any > cpuidle drivers. Otherwise this call might be made even on devices > that have this driver enabled but actually make use of PSCI. > > Fixes: 60f3692b5f0b ("cpuidle: qcom_spm: Detach state machine from main SPM handling") > Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> > Link: https://lore.kernel.org/r/86e3e09f-a8d7-3dff-3fc6-ddd7d30c5d78@samsung.com/ > Signed-off-by: Stephan Gerhold <stephan@gerhold.net> > --- > Daniel, would be great if you could ack this patch and PATCH 3/4 > (the cpuidle part) if they look good to you. I think it's easiest if Bjorn > takes them together with the qcom_scm changes through the qcom tree. Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> > Marek had an alternative fix for this [1], the difference in this patch is > that it avoids creating the platform device entirely if no CPU is managed > by a SPM. > > [1]: https://lore.kernel.org/r/20211020120643.28231-1-m.szyprowski@samsung.com/ > --- > drivers/cpuidle/cpuidle-qcom-spm.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/drivers/cpuidle/cpuidle-qcom-spm.c b/drivers/cpuidle/cpuidle-qcom-spm.c > index 01e77913a414..5f27dcc6c110 100644 > --- a/drivers/cpuidle/cpuidle-qcom-spm.c > +++ b/drivers/cpuidle/cpuidle-qcom-spm.c > @@ -155,6 +155,22 @@ static struct platform_driver spm_cpuidle_driver = { > }, > }; > > +static bool __init qcom_spm_find_any_cpu(void) > +{ > + struct device_node *cpu_node, *saw_node; > + > + for_each_of_cpu_node(cpu_node) { > + saw_node = of_parse_phandle(cpu_node, "qcom,saw", 0); > + if (of_device_is_available(saw_node)) { > + of_node_put(saw_node); > + of_node_put(cpu_node); > + return true; > + } > + of_node_put(saw_node); > + } > + return false; > +} > + > static int __init qcom_spm_cpuidle_init(void) > { > struct platform_device *pdev; > @@ -164,6 +180,10 @@ static int __init qcom_spm_cpuidle_init(void) > if (ret) > return ret; > > + /* Make sure there is actually any CPU managed by the SPM */ > + if (!qcom_spm_find_any_cpu()) > + return 0; > + > pdev = platform_device_register_simple("qcom-spm-cpuidle", > -1, NULL, 0); > if (IS_ERR(pdev)) { >
diff --git a/drivers/cpuidle/cpuidle-qcom-spm.c b/drivers/cpuidle/cpuidle-qcom-spm.c index 01e77913a414..5f27dcc6c110 100644 --- a/drivers/cpuidle/cpuidle-qcom-spm.c +++ b/drivers/cpuidle/cpuidle-qcom-spm.c @@ -155,6 +155,22 @@ static struct platform_driver spm_cpuidle_driver = { }, }; +static bool __init qcom_spm_find_any_cpu(void) +{ + struct device_node *cpu_node, *saw_node; + + for_each_of_cpu_node(cpu_node) { + saw_node = of_parse_phandle(cpu_node, "qcom,saw", 0); + if (of_device_is_available(saw_node)) { + of_node_put(saw_node); + of_node_put(cpu_node); + return true; + } + of_node_put(saw_node); + } + return false; +} + static int __init qcom_spm_cpuidle_init(void) { struct platform_device *pdev; @@ -164,6 +180,10 @@ static int __init qcom_spm_cpuidle_init(void) if (ret) return ret; + /* Make sure there is actually any CPU managed by the SPM */ + if (!qcom_spm_find_any_cpu()) + return 0; + pdev = platform_device_register_simple("qcom-spm-cpuidle", -1, NULL, 0); if (IS_ERR(pdev)) {
At the moment, the "qcom-spm-cpuidle" platform device is always created, even if none of the CPUs is actually managed by the SPM. On non-qcom platforms this will result in infinite probe-deferral due to the failing qcom_scm_is_available() call. To avoid this, look through the CPU DT nodes and check if there is actually any CPU managed by a SPM (as indicated by the qcom,saw property). It should also be available because e.g. MSM8916 has qcom,saw defined but it's typically not enabled with ARM64/PSCI firmwares. This is needed in preparation of a follow-up change that calls qcom_scm_set_warm_boot_addr() a single time before registering any cpuidle drivers. Otherwise this call might be made even on devices that have this driver enabled but actually make use of PSCI. Fixes: 60f3692b5f0b ("cpuidle: qcom_spm: Detach state machine from main SPM handling") Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Link: https://lore.kernel.org/r/86e3e09f-a8d7-3dff-3fc6-ddd7d30c5d78@samsung.com/ Signed-off-by: Stephan Gerhold <stephan@gerhold.net> --- Daniel, would be great if you could ack this patch and PATCH 3/4 (the cpuidle part) if they look good to you. I think it's easiest if Bjorn takes them together with the qcom_scm changes through the qcom tree. Marek had an alternative fix for this [1], the difference in this patch is that it avoids creating the platform device entirely if no CPU is managed by a SPM. [1]: https://lore.kernel.org/r/20211020120643.28231-1-m.szyprowski@samsung.com/ --- drivers/cpuidle/cpuidle-qcom-spm.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)