[RESEND PATCH v2] firmware/psci: Add debugfs support to ease debugging

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

To ease debugging of PSCI supported features, add debugfs file called
'psci' describing PSCI and SMC CC versions, enabled features and
options.

Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
I sketched this while trying to narrow down the particular issue on
the Qualcomm platform (which started as an attempt to implement PSCI
domains, but then led to understanding that while the platform claims
supports OSI, it doesn't support SET_SUSPEND). We were going to use
this to help to narrow down issues with the PSCI support on other
platforms as well.

Changes since v1:
- Extended the table to include MEM_PROTECT functions (noted by Mark
  Brown)
- Switched to seq_puts where possible
- Changed S_IRUGO to 0444

The patch is resent to include soc@kernel.org
---
 drivers/firmware/psci/psci.c | 116 ++++++++++++++++++++++++++++++++++-
 include/uapi/linux/psci.h    |  14 +++++
 2 files changed, 129 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index cfb448eabdaa..9fdcb6bff403 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 +325,125 @@ 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)
 {
 	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),
+	PSCI_ID(1_1, MEM_PROTECT),
+	PSCI_ID_NATIVE(1_1, MEM_PROTECT_CHECK_RANGE),
+};
+
+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_puts(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_puts(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", 0444, 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..3511095c2702 100644
--- a/include/uapi/linux/psci.h
+++ b/include/uapi/linux/psci.h
@@ -48,12 +48,26 @@
 #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_1_FN_MEM_PROTECT			PSCI_0_2_FN(19)
+#define PSCI_1_1_FN_MEM_PROTECT_CHECK_RANGE	PSCI_0_2_FN(19)
 
+#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)
+#define PSCI_1_1_FN64_MEM_PROTECT_CHECK_RANGE	PSCI_0_2_FN64(19)
 
 /* PSCI v0.2 power state encoding for CPU_SUSPEND function */
 #define PSCI_0_2_POWER_STATE_ID_MASK		0xffff
-- 
2.35.1