pmdomain: apple: Preserve active T6050 control state

Documentation/devicetree/bindings/power/apple,pmgr-pwrstate.yaml

@@ -132,6 +132,15 @@ properties:
       unlike apple,firmware-owned, their registers remain writable.
     type: boolean
 
+  apple,preserve-active-control:
+    description:
+      Firmware hands off this domain with an active control word that must be
+      retained until an actual power transition is requested. Do not enable
+      auto-PM at probe or rewrite a reset-free, non-busy control word whose
+      target and actual state already satisfy an active request. Power-down
+      and requests that require a state change retain the normal sequence.
+    type: boolean
+
   apple,min-state:
     description:
       Specifies the minimum power state for auto-PM.

drivers/pmdomain/apple/pmgr-pwrstate.c

@@ -39,6 +39,11 @@
 #define APPLE_PMGR_RESET_TIME 1
 #define APPLE_PMGR_T8132_RESET_TIME 10
 
+/* Opt-in investigation: normal power transitions do not log. */
+static bool diagnostic_trace;
+module_param(diagnostic_trace, bool, 0444);
+MODULE_PARM_DESC(diagnostic_trace, "Trace native power handoff and register writes (diagnostic)");
+
 struct apple_pmgr_ps {
 	struct device *dev;
 	struct generic_pm_domain genpd;
@@ -58,6 +63,7 @@ struct apple_pmgr_ps {
 	bool needs_reset_idle_wait;
 	bool strict_state;
 	u32 reset_time_us;
+	bool preserve_active_control;
 };
 
 #define genpd_to_apple_pmgr_ps(_genpd) container_of(_genpd, struct apple_pmgr_ps, genpd)
@@ -70,10 +76,27 @@ static int apple_pmgr_ps_set(struct generic_pm_domain *genpd, u32 pstate, bool a
 	u32 reg, cur;
 	u32 timeout = ps->strict_state ? 10000 : APPLE_PMGR_PS_SET_TIMEOUT;
 
+	if (diagnostic_trace)
+		dev_info(ps->dev, "PMGR begin %s offset=%#x requested=%#x auto=%u\n",
+			 genpd->name, ps->offset, pstate, auto_enable);
 	ret = regmap_read(ps->regmap, ps->offset, &reg);
 	if (ret < 0)
 		return ret;
 
+	if (diagnostic_trace)
+		dev_info(ps->dev, "PMGR read %s offset=%#x value=%#x\n",
+			 genpd->name, ps->offset, reg);
+
+	/* Preserve the explicit firmware handoff when the requested active state
+	 * is already satisfied. Real transitions retain the ordinary sequence.
+	 */
+	if (ps->preserve_active_control && pstate == APPLE_PMGR_PS_ACTIVE &&
+	    FIELD_GET(APPLE_PMGR_PS_TARGET, reg) == pstate &&
+	    FIELD_GET(APPLE_PMGR_PS_ACTUAL, reg) == pstate &&
+	    !(reg & (APPLE_PMGR_RESET | APPLE_PMGR_PS_RESET |
+		     APPLE_PMGR_DEV_DISABLE | APPLE_PMGR_BUSY)))
+		return 0;
+
 	/* Resets are synchronous, and only work if the device is powered and clocked. */
 	if (reg & APPLE_PMGR_RESET && pstate != APPLE_PMGR_PS_ACTIVE)
 		dev_err_ratelimited(ps->dev, "PS %s: powering off with RESET active\n",
@@ -88,7 +111,13 @@ static int apple_pmgr_ps_set(struct generic_pm_domain *genpd, u32 pstate, bool a
 		if (ps->force_reset)
 			reg_pre |= APPLE_PMGR_PS_RESET;
 
+		if (diagnostic_trace)
+			dev_info(ps->dev, "PMGR pre-write %s offset=%#x value=%#x begin\n",
+				 genpd->name, ps->offset, reg_pre);
 		regmap_write(ps->regmap, ps->offset, reg_pre);
+		if (diagnostic_trace)
+			dev_info(ps->dev, "PMGR pre-write %s offset=%#x completed\n",
+				 genpd->name, ps->offset);
 
 		ret = regmap_read_poll_timeout_atomic(
 			ps->regmap, ps->offset, cur,
@@ -110,10 +139,16 @@ static int apple_pmgr_ps_set(struct generic_pm_domain *genpd, u32 pstate, bool a
 
 	dev_dbg(ps->dev, "PS %s: pwrstate = 0x%x: 0x%x\n", genpd->name, pstate, reg);
 
+	if (diagnostic_trace)
+		dev_info(ps->dev, "PMGR write %s offset=%#x value=%#x begin\n",
+			 genpd->name, ps->offset, reg);
 	ret = regmap_write(ps->regmap, ps->offset, reg);
 	if (ret && ps->strict_state)
 		return ret;
 	cur = reg;
+	if (diagnostic_trace)
+		dev_info(ps->dev, "PMGR write %s offset=%#x completed\n",
+			 genpd->name, ps->offset);
 
 	if (ps->externally_clocked && pstate == APPLE_PMGR_PS_ACTIVE) {
 		/*
@@ -147,7 +182,13 @@ static int apple_pmgr_ps_set(struct generic_pm_domain *genpd, u32 pstate, bool a
 		reg |= APPLE_PMGR_AUTO_ENABLE;
 		if (ps->strict_state)
 			return regmap_write(ps->regmap, ps->offset, reg);
+		if (diagnostic_trace)
+			dev_info(ps->dev, "PMGR auto-write %s offset=%#x value=%#x begin\n",
+				 genpd->name, ps->offset, reg);
 		regmap_write(ps->regmap, ps->offset, reg);
+		if (diagnostic_trace)
+			dev_info(ps->dev, "PMGR auto-write %s offset=%#x completed\n",
+				 genpd->name, ps->offset);
 	}
 
 	return ret;
@@ -465,6 +506,9 @@ static int apple_pmgr_ps_probe(struct platform_device *pdev)
 	if (of_property_read_bool(node, "apple,externally-clocked"))
 		ps->externally_clocked = true;
 
+	ps->preserve_active_control =
+		of_property_read_bool(node, "apple,preserve-active-control");
+
 	/* A cold-started coprocessor CPU must not be gated behind its firmware. */
 	ps->no_auto_pm = of_property_read_bool(node, "apple,no-auto-pm");
 
@@ -512,7 +556,8 @@ static int apple_pmgr_ps_probe(struct platform_device *pdev)
 	}
 
 	/* Turn on auto-PM if the domain is already on, unless it must stay off */
-	if (active && !ps->firmware_owned && !ps->inherited_on && !ps->no_auto_enable)
+	if (active && !ps->firmware_owned && !ps->inherited_on && !ps->no_auto_enable &&
+	    !ps->preserve_active_control)
 		regmap_update_bits(regmap, ps->offset, APPLE_PMGR_FLAGS | APPLE_PMGR_AUTO_ENABLE,
 				   ps->no_auto_pm ? 0 : APPLE_PMGR_AUTO_ENABLE);
 

tools/testing/selftests/aurora-apif/pmgr.py

@@ -0,0 +1,73 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only
+"""Exercise the production retained-active PMGR contract with a register test double."""
+from pathlib import Path
+import subprocess,tempfile,sys
+root=Path(__file__).resolve().parents[4]
+p=Path(sys.argv[1]) if len(sys.argv)>1 else root/'drivers/pmdomain/apple/pmgr-pwrstate.c'
+s=p.read_text();start=s.index('static int apple_pmgr_ps_set(');brace=s.index('{',start);end=brace+1;depth=1
+while depth:
+ depth+=(s[end]=='{')-(s[end]=='}');end+=1
+fn=s[start:end]
+defines='\n'.join(l for l in s.splitlines() if l.startswith('#define APPLE_PMGR_'))
+code=r'''
+#include <assert.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <stdio.h>
+typedef uint32_t u32;
+#define BIT(n) (1U<<(n))
+#define GENMASK(h,l) ((~0U>>(31-(h)))&(~0U<<(l)))
+#define FIELD_GET(mask,v) (((v)&(mask))>>__builtin_ctz(mask))
+#define FIELD_PREP(mask,v) (((v)<<__builtin_ctz(mask))&(mask))
+#define dev_info(...) ((void)0)
+#define dev_dbg(...) ((void)0)
+#define dev_err(...) ((void)0)
+#define dev_err_ratelimited(...) ((void)0)
+static bool diagnostic_trace;
+''' + defines + r'''
+struct device {};
+struct generic_pm_domain { const char *name; };
+struct regmap { u32 value; unsigned writes; u32 written[8]; int fail_read; };
+struct apple_pmgr_ps { struct device *dev; struct generic_pm_domain genpd; struct regmap *regmap; u32 offset; bool force_disable,force_reset,externally_clocked,preserve_active_control,strict_state; };
+#define genpd_to_apple_pmgr_ps(g) ((struct apple_pmgr_ps *)((char *)(g)-offsetof(struct apple_pmgr_ps,genpd)))
+static int regmap_read(struct regmap *m,u32 offset,u32 *value) {
+ assert(offset==0x180);if(m->fail_read)return m->fail_read;*value=m->value;return 0;
+}
+static int regmap_write(struct regmap *m,u32 offset,u32 value) {
+ assert(offset==0x180&&m->writes<8);m->written[m->writes++]=value;
+ /* Test double: control transitions reach their requested actual state. */
+ m->value=(value&~APPLE_PMGR_PS_ACTUAL)|FIELD_PREP(APPLE_PMGR_PS_ACTUAL,FIELD_GET(APPLE_PMGR_PS_TARGET,value));return 0;
+}
+#define regmap_read_poll_timeout_atomic(map,offset,cur,condition,delay,timeout) \
+ ({ int err=regmap_read(map,offset,&cur);err?err:((condition)?0:-110); })
+''' + fn + r'''
+int main(void) {
+ struct regmap m={.value=0x510302ff};
+ struct apple_pmgr_ps ps={.genpd={.name="retained"},.regmap=&m,.offset=0x180,.preserve_active_control=true};
+ u32 original=m.value;
+ assert(!apple_pmgr_ps_set(&ps.genpd,15,true));assert(m.writes==0&&m.value==original);
+ ps.preserve_active_control=false;m=(struct regmap){.value=original};
+ assert(!apple_pmgr_ps_set(&ps.genpd,15,true));assert(m.writes==2);
+ ps.preserve_active_control=true;m=(struct regmap){.value=0};
+ assert(!apple_pmgr_ps_set(&ps.genpd,15,true));assert(m.writes==2);
+ assert(FIELD_GET(APPLE_PMGR_PS_TARGET,m.written[0])==15);
+ m=(struct regmap){.value=original};
+ assert(!apple_pmgr_ps_set(&ps.genpd,0,false));assert(m.writes==1);
+ assert(FIELD_GET(APPLE_PMGR_PS_TARGET,m.written[0])==0);
+ for(unsigned i=0;i<4;i++) {
+  const u32 invalid[]={APPLE_PMGR_BUSY,APPLE_PMGR_RESET,APPLE_PMGR_PS_RESET,APPLE_PMGR_DEV_DISABLE};
+  m=(struct regmap){.value=original|invalid[i]};
+  assert(!apple_pmgr_ps_set(&ps.genpd,15,true));assert(m.writes==2);
+  assert(!(m.written[0]&(APPLE_PMGR_BUSY|APPLE_PMGR_FLAGS|APPLE_PMGR_AUTO_ENABLE)));
+ }
+ m=(struct regmap){.value=original,.fail_read=-5};
+ assert(apple_pmgr_ps_set(&ps.genpd,15,true)==-5);assert(m.writes==0);
+ puts("PMGR retained-active and real-transition contracts pass");
+}
+'''
+with tempfile.TemporaryDirectory(prefix='m5-pmgr-host-') as tmp:
+ t=Path(tmp);(t/'test.c').write_text(code)
+ subprocess.run(['cc','-std=gnu11','-fsanitize=address,undefined','-fno-omit-frame-pointer',str(t/'test.c'),'-o',str(t/'test')],check=True)
+ subprocess.run([str(t/'test')],check=True)