[PATCH] firmware/psci: Add debugfs support to ease debugging
Dmitry Baryshkov
dmitry.baryshkov at linaro.org
Wed Jul 27 13:53:24 PDT 2022
On Wed, 27 Jul 2022 at 23:15, Bhupesh Sharma <bhupesh.sharma at linaro.org> wrote:
>
> Hi Dmitry,
>
> On 7/28/22 1:39 AM, Dmitry Baryshkov wrote:
> > To ease debugging of PSCI supported features, add debugfs file called
> > 'psci' describing PSCI and SMC CC versions, enabled features and
> > options.
> >
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> > ---
> > drivers/firmware/psci/psci.c | 112 ++++++++++++++++++++++++++++++++++-
> > include/uapi/linux/psci.h | 9 +++
> > 2 files changed, 120 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> > index b907768eea01..6595cc964635 100644
> > --- a/drivers/firmware/psci/psci.c
> > +++ b/drivers/firmware/psci/psci.c
> > @@ -9,6 +9,7 @@
> > #include <linux/acpi.h>
> > #include <linux/arm-smccc.h>
> > #include <linux/cpuidle.h>
> > +#include <linux/debugfs.h>
> > #include <linux/errno.h>
> > #include <linux/linkage.h>
> > #include <linux/of.h>
> > @@ -324,12 +325,121 @@ static void psci_sys_poweroff(void)
> > invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
> > }
> >
> > -static int __init psci_features(u32 psci_func_id)
> > +static int psci_features(u32 psci_func_id)
>
> This change doesn't seem related to the patch $SUBJECT.
> Also is it really needed? If yes, probably this should be a separate patch.
It is related and I don't think it should be moved to a separate
patch. Removing the __init annotation from psci_features() is
necessary to allow using psci_features() from psci_debufs_read(),
which is definitely not an __init code. Otherwise reading from
debugfs/psci would cause null pointer exceptions.
>
> Thanks,
> Bhupesh
>
> > {
> > return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES,
> > psci_func_id, 0, 0);
> > }
> >
> > +#ifdef CONFIG_DEBUG_FS
> > +
> > +#define PSCI_ID(ver, _name) \
> > + { .fn = PSCI_##ver##_FN_##_name, .name = #_name, }
> > +#define PSCI_ID_NATIVE(ver, _name) \
> > + { .fn = PSCI_FN_NATIVE(ver, _name), .name = #_name, }
> > +
> > +/* A table of all optional functions */
> > +static const struct {
> > + u32 fn;
> > + const char *name;
> > +} psci_fn_ids[] = {
> > + PSCI_ID_NATIVE(0_2, MIGRATE),
> > + PSCI_ID(0_2, MIGRATE_INFO_TYPE),
> > + PSCI_ID_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
> > + PSCI_ID(1_0, CPU_FREEZE),
> > + PSCI_ID_NATIVE(1_0, CPU_DEFAULT_SUSPEND),
> > + PSCI_ID_NATIVE(1_0, NODE_HW_STATE),
> > + PSCI_ID_NATIVE(1_0, SYSTEM_SUSPEND),
> > + PSCI_ID(1_0, SET_SUSPEND_MODE),
> > + PSCI_ID_NATIVE(1_0, STAT_RESIDENCY),
> > + PSCI_ID_NATIVE(1_0, STAT_COUNT),
> > + PSCI_ID_NATIVE(1_1, SYSTEM_RESET2),
> > +};
> > +
> > +static int psci_debugfs_read(struct seq_file *s, void *data)
> > +{
> > + int feature, type, i;
> > + u32 ver;
> > +
> > + ver = psci_ops.get_version();
> > + seq_printf(s, "PSCIv%d.%d\n",
> > + PSCI_VERSION_MAJOR(ver),
> > + PSCI_VERSION_MINOR(ver));
> > +
> > + /* PSCI_FEATURES is available only starting from 1.0 */
> > + if (PSCI_VERSION_MAJOR(ver) < 1)
> > + return 0;
> > +
> > + feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
> > + if (feature != PSCI_RET_NOT_SUPPORTED) {
> > + ver = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
> > + seq_printf(s, "SMC Calling Convention v%d.%d\n",
> > + PSCI_VERSION_MAJOR(ver),
> > + PSCI_VERSION_MINOR(ver));
> > + } else {
> > + seq_printf(s, "SMC Calling Convention v1.0 is assumed\n");
> > + }
> > +
> > + feature = psci_features(PSCI_FN_NATIVE(0_2, CPU_SUSPEND));
> > + if (feature < 0) {
> > + seq_printf(s, "PSCI_FEATURES(CPU_SUSPEND) error (%d)\n", feature);
> > + } else {
> > + seq_printf(s, "OSI is %ssupported\n",
> > + (feature & BIT(0)) ? "" : "not ");
> > + seq_printf(s, "%s StateID format is used\n",
> > + (feature & BIT(1)) ? "Extended" : "Original");
> > + }
> > +
> > + type = psci_ops.migrate_info_type();
> > + if (type == PSCI_0_2_TOS_UP_MIGRATE ||
> > + type == PSCI_0_2_TOS_UP_NO_MIGRATE) {
> > + unsigned long cpuid;
> > +
> > + seq_printf(s, "Trusted OS %smigrate capable\n",
> > + type == PSCI_0_2_TOS_UP_NO_MIGRATE ? "not " : "");
> > + cpuid = psci_migrate_info_up_cpu();
> > + seq_printf(s, "Trusted OS resident on physical CPU 0x%lx (#%d)\n", cpuid, resident_cpu);
> > + } else if (type == PSCI_0_2_TOS_MP) {
> > + seq_printf(s, "Trusted OS migration not required\n");
> > + } else {
> > + if (type != PSCI_RET_NOT_SUPPORTED)
> > + seq_printf(s, "MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
> > + }
> > +
> > + for (i = 0; i < ARRAY_SIZE(psci_fn_ids); i++) {
> > + feature = psci_features(psci_fn_ids[i].fn);
> > + if (feature == PSCI_RET_NOT_SUPPORTED)
> > + continue;
> > + if (feature < 0)
> > + seq_printf(s, "PSCI_FEATURES(%s) error (%d)\n", psci_fn_ids[i].name, feature);
> > + else
> > + seq_printf(s, "%s is supported\n", psci_fn_ids[i].name);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int psci_debugfs_open(struct inode *inode, struct file *f)
> > +{
> > + return single_open(f, psci_debugfs_read, NULL);
> > +}
> > +
> > +static const struct file_operations psci_debugfs_ops = {
> > + .owner = THIS_MODULE,
> > + .open = psci_debugfs_open,
> > + .release = single_release,
> > + .read = seq_read,
> > + .llseek = seq_lseek
> > +};
> > +
> > +static int __init psci_debugfs_init(void)
> > +{
> > + return PTR_ERR_OR_ZERO(debugfs_create_file("psci", S_IRUGO, NULL, NULL,
> > + &psci_debugfs_ops));
> > +}
> > +late_initcall(psci_debugfs_init)
> > +#endif
> > +
> > #ifdef CONFIG_CPU_IDLE
> > static int psci_suspend_finisher(unsigned long state)
> > {
> > diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
> > index 2bf93c0d6354..f6f0bad5858b 100644
> > --- a/include/uapi/linux/psci.h
> > +++ b/include/uapi/linux/psci.h
> > @@ -48,11 +48,20 @@
> > #define PSCI_0_2_FN64_MIGRATE_INFO_UP_CPU PSCI_0_2_FN64(7)
> >
> > #define PSCI_1_0_FN_PSCI_FEATURES PSCI_0_2_FN(10)
> > +#define PSCI_1_0_FN_CPU_FREEZE PSCI_0_2_FN(11)
> > +#define PSCI_1_0_FN_CPU_DEFAULT_SUSPEND PSCI_0_2_FN(12)
> > +#define PSCI_1_0_FN_NODE_HW_STATE PSCI_0_2_FN(13)
> > #define PSCI_1_0_FN_SYSTEM_SUSPEND PSCI_0_2_FN(14)
> > #define PSCI_1_0_FN_SET_SUSPEND_MODE PSCI_0_2_FN(15)
> > +#define PSCI_1_0_FN_STAT_RESIDENCY PSCI_0_2_FN(16)
> > +#define PSCI_1_0_FN_STAT_COUNT PSCI_0_2_FN(17)
> > #define PSCI_1_1_FN_SYSTEM_RESET2 PSCI_0_2_FN(18)
> >
> > +#define PSCI_1_0_FN64_CPU_DEFAULT_SUSPEND PSCI_0_2_FN64(12)
> > +#define PSCI_1_0_FN64_NODE_HW_STATE PSCI_0_2_FN64(13)
> > #define PSCI_1_0_FN64_SYSTEM_SUSPEND PSCI_0_2_FN64(14)
> > +#define PSCI_1_0_FN64_STAT_RESIDENCY PSCI_0_2_FN64(16)
> > +#define PSCI_1_0_FN64_STAT_COUNT PSCI_0_2_FN64(17)
> > #define PSCI_1_1_FN64_SYSTEM_RESET2 PSCI_0_2_FN64(18)
> >
> > /* PSCI v0.2 power state encoding for CPU_SUSPEND function */
--
With best wishes
Dmitry
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