[PATCH 0/8] intel_idle: Assorted cleanups

[PATCH 0/8] intel_idle: Assorted cleanups

[Rafael J. Wysocki]

Hi All,

The intel_idle driver can be cleaned up somewhat after the recent changes
made to it (present in linux-next at this time).

This series of patches goes in that direction and none of the patches in
it is expected to alter the functionality of the driver.

The series applies on top of linux-next from yesterday.

Thanks,
Rafael

[PATCH 1/8] intel_idle: Eliminate __setup_broadcast_timer()

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The __setup_broadcast_timer() static function is only called in one
place and "true" is passed to it as the argument in there, so
effectively it is a wrapper arround tick_broadcast_enable().

To simplify the code, call tick_broadcast_enable() directly instead
of __setup_broadcast_timer() and drop the latter.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/idle/intel_idle.c |   10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

Index: linux-pm/drivers/idle/intel_idle.c
===================================================================
--- linux-pm.orig/drivers/idle/intel_idle.c
+++ linux-pm/drivers/idle/intel_idle.c
@@ -967,14 +967,6 @@ static bool intel_idle_verify_cstate(uns
 	return true;
 }
 
-static void __setup_broadcast_timer(bool on)
-{
-	if (on)
-		tick_broadcast_enable();
-	else
-		tick_broadcast_disable();
-}
-
 static void auto_demotion_disable(void)
 {
 	unsigned long long msr_bits;
@@ -1624,7 +1616,7 @@ static int intel_idle_cpu_online(unsigne
 	struct cpuidle_device *dev;
 
 	if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
-		__setup_broadcast_timer(true);
+		tick_broadcast_enable();
 
 	/*
 	 * Some systems can hotplug a cpu at runtime after

[PATCH 2/8] intel_idle: Fold intel_idle_probe() into intel_idle_init()

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

There is no particular reason why intel_idle_probe() needs to be
a separate function and folding it into intel_idle_init() causes
the code to be somewhat easier to follow, so do just that.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/idle/intel_idle.c |   97 +++++++++++++++++++---------------------------
 1 file changed, 42 insertions(+), 55 deletions(-)

Index: linux-pm/drivers/idle/intel_idle.c
===================================================================
--- linux-pm.orig/drivers/idle/intel_idle.c
+++ linux-pm/drivers/idle/intel_idle.c
@@ -1297,58 +1297,6 @@ static inline bool intel_idle_off_by_def
 #endif /* !CONFIG_ACPI_PROCESSOR_CSTATE */
 
 /*
- * intel_idle_probe()
- */
-static int __init intel_idle_probe(void)
-{
-	unsigned int eax, ebx, ecx;
-	const struct x86_cpu_id *id;
-
-	if (max_cstate == 0) {
-		pr_debug("disabled\n");
-		return -EPERM;
-	}
-
-	id = x86_match_cpu(intel_idle_ids);
-	if (id) {
-		if (!boot_cpu_has(X86_FEATURE_MWAIT)) {
-			pr_debug("Please enable MWAIT in BIOS SETUP\n");
-			return -ENODEV;
-		}
-	} else {
-		id = x86_match_cpu(intel_mwait_ids);
-		if (!id)
-			return -ENODEV;
-	}
-
-	if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
-		return -ENODEV;
-
-	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);
-
-	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
-	    !(ecx & CPUID5_ECX_INTERRUPT_BREAK) ||
-	    !mwait_substates)
-			return -ENODEV;
-
-	pr_debug("MWAIT substates: 0x%x\n", mwait_substates);
-
-	icpu = (const struct idle_cpu *)id->driver_data;
-	if (icpu) {
-		cpuidle_state_table = icpu->state_table;
-		if (icpu->use_acpi)
-			intel_idle_acpi_cst_extract();
-	} else if (!intel_idle_acpi_cst_extract()) {
-		return -ENODEV;
-	}
-
-	pr_debug("v" INTEL_IDLE_VERSION " model 0x%X\n",
-		 boot_cpu_data.x86_model);
-
-	return 0;
-}
-
-/*
  * intel_idle_cpuidle_devices_uninit()
  * Unregisters the cpuidle devices.
  */
@@ -1632,15 +1580,54 @@ static int intel_idle_cpu_online(unsigne
 
 static int __init intel_idle_init(void)
 {
+	const struct x86_cpu_id *id;
+	unsigned int eax, ebx, ecx;
 	int retval;
 
 	/* Do not load intel_idle at all for now if idle= is passed */
 	if (boot_option_idle_override != IDLE_NO_OVERRIDE)
 		return -ENODEV;
 
-	retval = intel_idle_probe();
-	if (retval)
-		return retval;
+	if (max_cstate == 0) {
+		pr_debug("disabled\n");
+		return -EPERM;
+	}
+
+	id = x86_match_cpu(intel_idle_ids);
+	if (id) {
+		if (!boot_cpu_has(X86_FEATURE_MWAIT)) {
+			pr_debug("Please enable MWAIT in BIOS SETUP\n");
+			return -ENODEV;
+		}
+	} else {
+		id = x86_match_cpu(intel_mwait_ids);
+		if (!id)
+			return -ENODEV;
+	}
+
+	if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
+		return -ENODEV;
+
+	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);
+
+	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
+	    !(ecx & CPUID5_ECX_INTERRUPT_BREAK) ||
+	    !mwait_substates)
+			return -ENODEV;
+
+	pr_debug("MWAIT substates: 0x%x\n", mwait_substates);
+
+	icpu = (const struct idle_cpu *)id->driver_data;
+	if (icpu) {
+		cpuidle_state_table = icpu->state_table;
+		if (icpu->use_acpi)
+			intel_idle_acpi_cst_extract();
+	} else if (!intel_idle_acpi_cst_extract()) {
+		return -ENODEV;
+	}
+
+	pr_debug("v" INTEL_IDLE_VERSION " model 0x%X\n",
+		 boot_cpu_data.x86_model);
 
 	intel_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
 	if (intel_idle_cpuidle_devices == NULL)

[PATCH 3/8] intel_idle: Clean up NULL pointer check in intel_idle_init()

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Instead of comparing intel_idle_cpuidle_devices with NULL apply
the "!" (not) operator to it when checking it against NULL.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/idle/intel_idle.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-pm/drivers/idle/intel_idle.c
===================================================================
--- linux-pm.orig/drivers/idle/intel_idle.c
+++ linux-pm/drivers/idle/intel_idle.c
@@ -1630,7 +1630,7 @@ static int __init intel_idle_init(void)
 		 boot_cpu_data.x86_model);
 
 	intel_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
-	if (intel_idle_cpuidle_devices == NULL)
+	if (!intel_idle_cpuidle_devices)
 		return -ENOMEM;
 
 	intel_idle_cpuidle_driver_init();

[PATCH 4/8] intel_idle: Rearrange intel_idle_cpuidle_driver_init()

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Notice that intel_idle_state_table_update() only needs to be called
if icpu is not NULL, so fold it into intel_idle_init_cstates_icpu(),
and pass a pointer to the driver object to
intel_idle_cpuidle_driver_init() as an argument instead of
referencing it locally in there.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/idle/intel_idle.c |   24 ++++++------------------
 1 file changed, 6 insertions(+), 18 deletions(-)

Index: linux-pm/drivers/idle/intel_idle.c
===================================================================
--- linux-pm.orig/drivers/idle/intel_idle.c
+++ linux-pm/drivers/idle/intel_idle.c
@@ -1447,16 +1447,12 @@ static void sklh_idle_state_table_update
 	skl_cstates[5].flags |= CPUIDLE_FLAG_UNUSABLE;	/* C8-SKL */
 	skl_cstates[6].flags |= CPUIDLE_FLAG_UNUSABLE;	/* C9-SKL */
 }
-/*
- * intel_idle_state_table_update()
- *
- * Update the default state_table for this CPU-id
- */
 
-static void intel_idle_state_table_update(void)
+static void intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
 {
-	switch (boot_cpu_data.x86_model) {
+	int cstate;
 
+	switch (boot_cpu_data.x86_model) {
 	case INTEL_FAM6_IVYBRIDGE_X:
 		ivt_idle_state_table_update();
 		break;
@@ -1468,11 +1464,6 @@ static void intel_idle_state_table_updat
 		sklh_idle_state_table_update();
 		break;
 	}
-}
-
-static void intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
-{
-	int cstate;
 
 	for (cstate = 0; cstate < CPUIDLE_STATE_MAX; ++cstate) {
 		unsigned int mwait_hint;
@@ -1515,12 +1506,8 @@ static void intel_idle_init_cstates_icpu
  * intel_idle_cpuidle_driver_init()
  * allocate, initialize cpuidle_states
  */
-static void __init intel_idle_cpuidle_driver_init(void)
+static void __init intel_idle_cpuidle_driver_init(struct cpuidle_driver *drv)
 {
-	struct cpuidle_driver *drv = &intel_idle_driver;
-
-	intel_idle_state_table_update();
-
 	cpuidle_poll_state_init(drv);
 	drv->state_count = 1;
 
@@ -1633,7 +1620,8 @@ static int __init intel_idle_init(void)
 	if (!intel_idle_cpuidle_devices)
 		return -ENOMEM;
 
-	intel_idle_cpuidle_driver_init();
+	intel_idle_cpuidle_driver_init(&intel_idle_driver);
+
 	retval = cpuidle_register_driver(&intel_idle_driver);
 	if (retval) {
 		struct cpuidle_driver *drv = cpuidle_get_driver();

[PATCH 5/8] intel_idle: Move and clean up intel_idle_cpuidle_devices_uninit()

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Move intel_idle_cpuidle_devices_uninit() closer to its caller,
intel_idle_init(), add the __init modifier to its header, drop a
redundant local variable from it and fix up its kerneldoc comment.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/idle/intel_idle.c |   26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

Index: linux-pm/drivers/idle/intel_idle.c
===================================================================
--- linux-pm.orig/drivers/idle/intel_idle.c
+++ linux-pm/drivers/idle/intel_idle.c
@@ -1297,21 +1297,6 @@ static inline bool intel_idle_off_by_def
 #endif /* !CONFIG_ACPI_PROCESSOR_CSTATE */
 
 /*
- * intel_idle_cpuidle_devices_uninit()
- * Unregisters the cpuidle devices.
- */
-static void intel_idle_cpuidle_devices_uninit(void)
-{
-	int i;
-	struct cpuidle_device *dev;
-
-	for_each_online_cpu(i) {
-		dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
-		cpuidle_unregister_device(dev);
-	}
-}
-
-/*
  * ivt_idle_state_table_update(void)
  *
  * Tune IVT multi-socket targets
@@ -1565,6 +1550,17 @@ static int intel_idle_cpu_online(unsigne
 	return 0;
 }
 
+/**
+ * intel_idle_cpuidle_devices_uninit - Unregister all cpuidle devices.
+ */
+static void __init intel_idle_cpuidle_devices_uninit(void)
+{
+	int i;
+
+	for_each_online_cpu(i)
+		cpuidle_unregister_device(per_cpu_ptr(intel_idle_cpuidle_devices, i));
+}
+
 static int __init intel_idle_init(void)
 {
 	const struct x86_cpu_id *id;

[PATCH 6/8] intel_idle: Annotate initialization code and data structures

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Annotate the functions that are only used at the initialization time
with __init and the data structures used by them with __initdata or
__initconst.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/idle/intel_idle.c |   27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

Index: linux-pm/drivers/idle/intel_idle.c
===================================================================
--- linux-pm.orig/drivers/idle/intel_idle.c
+++ linux-pm/drivers/idle/intel_idle.c
@@ -1148,7 +1148,7 @@ static const struct x86_cpu_id intel_mwa
 	{}
 };
 
-static bool intel_idle_max_cstate_reached(int cstate)
+static bool __init intel_idle_max_cstate_reached(int cstate)
 {
 	if (cstate + 1 > max_cstate) {
 		pr_info("max_cstate %d reached\n", max_cstate);
@@ -1164,7 +1164,7 @@ static bool no_acpi __read_mostly;
 module_param(no_acpi, bool, 0444);
 MODULE_PARM_DESC(no_acpi, "Do not use ACPI _CST for building the idle states list");
 
-static struct acpi_processor_power acpi_state_table;
+static struct acpi_processor_power acpi_state_table __initdata;
 
 /**
  * intel_idle_cst_usable - Check if the _CST information can be used.
@@ -1172,7 +1172,7 @@ static struct acpi_processor_power acpi_
  * Check if all of the C-states listed by _CST in the max_cstate range are
  * ACPI_CSTATE_FFH, which means that they should be entered via MWAIT.
  */
-static bool intel_idle_cst_usable(void)
+static bool __init intel_idle_cst_usable(void)
 {
 	int cstate, limit;
 
@@ -1189,7 +1189,7 @@ static bool intel_idle_cst_usable(void)
 	return true;
 }
 
-static bool intel_idle_acpi_cst_extract(void)
+static bool __init intel_idle_acpi_cst_extract(void)
 {
 	unsigned int cpu;
 
@@ -1224,7 +1224,7 @@ static bool intel_idle_acpi_cst_extract(
 	return false;
 }
 
-static void intel_idle_init_cstates_acpi(struct cpuidle_driver *drv)
+static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv)
 {
 	int cstate, limit = min_t(int, CPUIDLE_STATE_MAX, acpi_state_table.count);
 
@@ -1268,7 +1268,7 @@ static void intel_idle_init_cstates_acpi
 	}
 }
 
-static bool intel_idle_off_by_default(u32 mwait_hint)
+static bool __init intel_idle_off_by_default(u32 mwait_hint)
 {
 	int cstate, limit;
 
@@ -1302,7 +1302,7 @@ static inline bool intel_idle_off_by_def
  * Tune IVT multi-socket targets
  * Assumption: num_sockets == (max_package_num + 1)
  */
-static void ivt_idle_state_table_update(void)
+static void __init ivt_idle_state_table_update(void)
 {
 	/* IVT uses a different table for 1-2, 3-4, and > 4 sockets */
 	int cpu, package_num, num_sockets = 1;
@@ -1329,10 +1329,11 @@ static void ivt_idle_state_table_update(
  * Translate IRTL (Interrupt Response Time Limit) MSR to usec
  */
 
-static unsigned int irtl_ns_units[] = {
-	1, 32, 1024, 32768, 1048576, 33554432, 0, 0 };
+static const unsigned int irtl_ns_units[] __initconst = {
+	1, 32, 1024, 32768, 1048576, 33554432, 0, 0
+};
 
-static unsigned long long irtl_2_usec(unsigned long long irtl)
+static unsigned long long __init irtl_2_usec(unsigned long long irtl)
 {
 	unsigned long long ns;
 
@@ -1349,7 +1350,7 @@ static unsigned long long irtl_2_usec(un
  * On BXT, we trust the IRTL to show the definitive maximum latency
  * We use the same value for target_residency.
  */
-static void bxt_idle_state_table_update(void)
+static void __init bxt_idle_state_table_update(void)
 {
 	unsigned long long msr;
 	unsigned int usec;
@@ -1396,7 +1397,7 @@ static void bxt_idle_state_table_update(
  * On SKL-H (model 0x5e) disable C8 and C9 if:
  * C10 is enabled and SGX disabled
  */
-static void sklh_idle_state_table_update(void)
+static void __init sklh_idle_state_table_update(void)
 {
 	unsigned long long msr;
 	unsigned int eax, ebx, ecx, edx;
@@ -1433,7 +1434,7 @@ static void sklh_idle_state_table_update
 	skl_cstates[6].flags |= CPUIDLE_FLAG_UNUSABLE;	/* C9-SKL */
 }
 
-static void intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
+static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
 {
 	int cstate;
 

[PATCH 7/8] intel_idle: Move 3 functions closer to their callers

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Move intel_idle_verify_cstate(), auto_demotion_disable() and
c1e_promotion_disable() closer to their callers.

While at it, annotate intel_idle_verify_cstate() with __init,
as it is only used during the initialization of the driver.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/idle/intel_idle.c |   67 +++++++++++++++++++++++-----------------------
 1 file changed, 34 insertions(+), 33 deletions(-)

Index: linux-pm/drivers/idle/intel_idle.c
===================================================================
--- linux-pm.orig/drivers/idle/intel_idle.c
+++ linux-pm/drivers/idle/intel_idle.c
@@ -951,39 +951,6 @@ static void intel_idle_s2idle(struct cpu
 	mwait_idle_with_hints(eax, ecx);
 }
 
-static bool intel_idle_verify_cstate(unsigned int mwait_hint)
-{
-	unsigned int mwait_cstate = MWAIT_HINT2CSTATE(mwait_hint) + 1;
-	unsigned int num_substates = (mwait_substates >> mwait_cstate * 4) &
-					MWAIT_SUBSTATE_MASK;
-
-	/* Ignore the C-state if there are NO sub-states in CPUID for it. */
-	if (num_substates == 0)
-		return false;
-
-	if (mwait_cstate > 2 && !boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
-		mark_tsc_unstable("TSC halts in idle states deeper than C2");
-
-	return true;
-}
-
-static void auto_demotion_disable(void)
-{
-	unsigned long long msr_bits;
-
-	rdmsrl(MSR_PKG_CST_CONFIG_CONTROL, msr_bits);
-	msr_bits &= ~(icpu->auto_demotion_disable_flags);
-	wrmsrl(MSR_PKG_CST_CONFIG_CONTROL, msr_bits);
-}
-static void c1e_promotion_disable(void)
-{
-	unsigned long long msr_bits;
-
-	rdmsrl(MSR_IA32_POWER_CTL, msr_bits);
-	msr_bits &= ~0x2;
-	wrmsrl(MSR_IA32_POWER_CTL, msr_bits);
-}
-
 static const struct idle_cpu idle_cpu_nehalem = {
 	.state_table = nehalem_cstates,
 	.auto_demotion_disable_flags = NHM_C1_AUTO_DEMOTE | NHM_C3_AUTO_DEMOTE,
@@ -1434,6 +1401,22 @@ static void __init sklh_idle_state_table
 	skl_cstates[6].flags |= CPUIDLE_FLAG_UNUSABLE;	/* C9-SKL */
 }
 
+static bool __init intel_idle_verify_cstate(unsigned int mwait_hint)
+{
+	unsigned int mwait_cstate = MWAIT_HINT2CSTATE(mwait_hint) + 1;
+	unsigned int num_substates = (mwait_substates >> mwait_cstate * 4) &
+					MWAIT_SUBSTATE_MASK;
+
+	/* Ignore the C-state if there are NO sub-states in CPUID for it. */
+	if (num_substates == 0)
+		return false;
+
+	if (mwait_cstate > 2 && !boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
+		mark_tsc_unstable("TSC halts in idle states deeper than C2");
+
+	return true;
+}
+
 static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
 {
 	int cstate;
@@ -1503,6 +1486,24 @@ static void __init intel_idle_cpuidle_dr
 		intel_idle_init_cstates_acpi(drv);
 }
 
+static void auto_demotion_disable(void)
+{
+	unsigned long long msr_bits;
+
+	rdmsrl(MSR_PKG_CST_CONFIG_CONTROL, msr_bits);
+	msr_bits &= ~(icpu->auto_demotion_disable_flags);
+	wrmsrl(MSR_PKG_CST_CONFIG_CONTROL, msr_bits);
+}
+
+static void c1e_promotion_disable(void)
+{
+	unsigned long long msr_bits;
+
+	rdmsrl(MSR_IA32_POWER_CTL, msr_bits);
+	msr_bits &= ~0x2;
+	wrmsrl(MSR_IA32_POWER_CTL, msr_bits);
+}
+
 /*
  * intel_idle_cpu_init()
  * allocate, initialize, register cpuidle_devices

[PATCH 8/8] intel_idle: Clean up irtl_2_usec()

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Move the irtl_ns_units[] definition into irtl_2_usec() which is the
only user of it, drop the ns local variable from irtl_2_usec() as it
is not really necessary in there, use div_u64() for the division in
there as the divisor is small enough and use the NSEC_PER_USEC symbol
for the divisor.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/idle/intel_idle.c |   21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

Index: linux-pm/drivers/idle/intel_idle.c
===================================================================
--- linux-pm.orig/drivers/idle/intel_idle.c
+++ linux-pm/drivers/idle/intel_idle.c
@@ -1292,25 +1292,24 @@ static void __init ivt_idle_state_table_
 	/* else, 1 and 2 socket systems use default ivt_cstates */
 }
 
-/*
- * Translate IRTL (Interrupt Response Time Limit) MSR to usec
+/**
+ * irtl_2_usec - IRTL to microseconds conversion.
+ *
+ * Translate the IRTL (Interrupt Response Time Limit) MSR value to microseconds.
  */
-
-static const unsigned int irtl_ns_units[] __initconst = {
-	1, 32, 1024, 32768, 1048576, 33554432, 0, 0
-};
-
 static unsigned long long __init irtl_2_usec(unsigned long long irtl)
 {
-	unsigned long long ns;
+	static const unsigned int irtl_ns_units[] __initconst = {
+		1, 32, 1024, 32768, 1048576, 33554432, 0, 0
+	};
 
 	if (!irtl)
 		return 0;
 
-	ns = irtl_ns_units[(irtl >> 10) & 0x7];
-
-	return div64_u64((irtl & 0x3FF) * ns, 1000);
+	return div_u64((irtl & 0x3FF) * irtl_ns_units[(irtl >> 10) & 0x7],
+		       NSEC_PER_USEC);
 }
+
 /*
  * bxt_idle_state_table_update(void)
  *

[PATCH 8/8][update] intel_idle: Clean up irtl_2_usec()

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Move the irtl_ns_units[] definition into irtl_2_usec() which is the
only user of it, use div_u64() for the division in there (as the
divisor is small enough) and use the NSEC_PER_USEC symbol for the
divisor.  Also convert the irtl_2_usec() comment to a proper
kerneldo one.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

The original patch went a bit too far with dropping the local variable
in irtl_2_usec(), so retain it and also document the function argument
in the kerneldoc.

---
 drivers/idle/intel_idle.c |   18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

Index: linux-pm/drivers/idle/intel_idle.c
===================================================================
--- linux-pm.orig/drivers/idle/intel_idle.c
+++ linux-pm/drivers/idle/intel_idle.c
@@ -1292,16 +1292,17 @@ static void __init ivt_idle_state_table_
 	/* else, 1 and 2 socket systems use default ivt_cstates */
 }
 
-/*
- * Translate IRTL (Interrupt Response Time Limit) MSR to usec
+/**
+ * irtl_2_usec - IRTL to microseconds conversion.
+ * @irtl: IRTL MSR value.
+ *
+ * Translate the IRTL (Interrupt Response Time Limit) MSR value to microseconds.
  */
-
-static const unsigned int irtl_ns_units[] __initconst = {
-	1, 32, 1024, 32768, 1048576, 33554432, 0, 0
-};
-
 static unsigned long long __init irtl_2_usec(unsigned long long irtl)
 {
+	static const unsigned int irtl_ns_units[] __initconst = {
+		1, 32, 1024, 32768, 1048576, 33554432, 0, 0
+	};
 	unsigned long long ns;
 
 	if (!irtl)
@@ -1309,8 +1310,9 @@ static unsigned long long __init irtl_2_
 
 	ns = irtl_ns_units[(irtl >> 10) & 0x7];
 
-	return div64_u64((irtl & 0x3FF) * ns, 1000);
+	return div_u64((irtl & 0x3FF) * ns, NSEC_PER_USEC);
 }
+
 /*
  * bxt_idle_state_table_update(void)
  *