[Skiboot] [PATCH Skiboot v1.2 3/3] Advertise the self-save and self-restore attributes in the device tree

[Pratik Rajesh Sampat]

Support for self save and self restore interface is advertised in the
device tree, along with the list of SPRs it supports for each.

The Special Purpose Register identification is encoded in a 2048 bitmask
structure, where each bit signifies the identification key of that SPR
which is consistent with that of the Linux kernel for that register.

Signed-off-by: Pratik Rajesh Sampat <psampat at linux.ibm.com>
---
 hw/slw.c          | 72 +++++++++++++++++++++++++++++++++++++++++++++++
 include/skiboot.h |  1 +
 2 files changed, 73 insertions(+)

diff --git a/hw/slw.c b/hw/slw.c
index b79aaab3..d9c2d091 100644
--- a/hw/slw.c
+++ b/hw/slw.c
@@ -22,6 +22,7 @@
 #include <opal-api.h>
 #include <nvram.h>
 #include <sbe-p8.h>
+#include <bitmap.h>
 
 #include <p9_stop_api.H>
 #include <p8_pore_table_gen_api.H>
@@ -753,6 +754,70 @@ static void slw_late_init_p9(struct proc_chip *chip)
 	}
 }
 
+/* Add device tree properties to determine self-save | restore */
+void add_cpu_self_save_properties(struct dt_node *power_mgt)
+{
+	int i;
+	struct dt_node *self_restore, *self_save;
+	bitmap_t *self_restore_map, *self_save_map;
+	/* 32 times 64 bits needed to store a 2048 bits bitmask*/
+	const int bits_nr = 32;
+
+	const uint64_t self_restore_regs[] = {
+		0x130, // HSPRG0
+		0x13E, // LPCR
+		0x151, // HMEER
+		0x3F0, // HID0
+		0x3F1, // HID1
+		0x3F4, // HID4
+		0x3F6, // HID5
+		0x7D0, // MSR
+		0x357 // PSCCR
+	};
+
+	const uint64_t self_save_regs[] = {
+		0x130, // HSPRG0
+		0x13E, // LPCR
+		0x151, // HMEER
+		0x7D0, // MSR
+		0x357 // PSCCR
+	};
+	const int self_save_regs_nr	=	ARRAY_SIZE(self_save_regs);
+	const int self_restore_regs_nr	=	ARRAY_SIZE(self_restore_regs);
+
+	self_save_map = zalloc(BITMAP_BYTES(0x800));
+	self_restore_map = zalloc(BITMAP_BYTES(0x800));
+
+	for (i = 0; i < self_save_regs_nr; i++)
+		bitmap_set_bit(*self_save_map, self_save_regs[i]);
+
+	for (i = 0; i < self_restore_regs_nr; i++)
+		bitmap_set_bit(*self_restore_map, self_restore_regs[i]);
+
+	self_restore = dt_new(power_mgt, "self-restore");
+	if (!self_restore) {
+		prerror("OCC: Failed to create self restore node");
+		return;
+	}
+	dt_add_property_cells(self_restore, "active", 0x1);
+
+	dt_add_property(self_restore, "sprn-bitmask", *self_restore_map,
+			bits_nr * sizeof(uint64_t));
+
+	self_save = dt_new(power_mgt, "self-save");
+	if (!self_save) {
+		prerror("OCC: Failed to create self save node");
+		return;
+	}
+	if (proc_gen == proc_gen_p9) {
+		dt_add_property_cells(self_save, "active", 0x1);
+
+		dt_add_property(self_save, "sprn-bitmask", *self_save_map,
+				bits_nr * sizeof(uint64_t));
+	} else
+		dt_add_property_cells(self_save, "active", 0x0);
+}
+
 /* Add device tree properties to describe idle states */
 void add_cpu_idle_state_properties(void)
 {
@@ -1543,6 +1608,7 @@ opal_call(OPAL_SLW_SELF_SAVE_REG, opal_slw_self_save_reg, 2);
 void slw_init(void)
 {
 	struct proc_chip *chip;
+	struct dt_node *power_mgt;
 
 	if (proc_chip_quirks & QUIRK_MAMBO_CALLOUTS) {
 		wakeup_engine_state = WAKEUP_ENGINE_NOT_PRESENT;
@@ -1568,4 +1634,10 @@ void slw_init(void)
 		}
 	}
 	add_cpu_idle_state_properties();
+	power_mgt = dt_find_by_path(dt_root, "/ibm,opal/power-mgt");
+	if (!power_mgt) {
+		prerror("OCC: dt node /ibm,opal/power-mgt not found\n");
+		return;
+	}
+	add_cpu_self_save_properties(power_mgt);
 }
diff --git a/include/skiboot.h b/include/skiboot.h
index 1aa8bf7c..e8f0f755 100644
--- a/include/skiboot.h
+++ b/include/skiboot.h
@@ -202,6 +202,7 @@ extern void early_uart_init(void);
 extern void homer_init(void);
 extern void slw_init(void);
 extern void add_cpu_idle_state_properties(void);
+extern void add_cpu_self_save_properties(struct dt_node *power_mgt);
 extern void lpc_rtc_init(void);
 
 /* flash support */
-- 
2.21.0