firmware/psci: Add debugfs support to ease debugging

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@linaro.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20220926110758.666922-1-dmitry.baryshkov@linaro.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index 1628f1e..42cae0b 100644 (file)
--- 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>
@@ -326,12 +327,125 @@ 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 2bf93c0..3511095 100644 (file)
--- 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