Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1421981 > unrolled thread

[PATCH v6 0/5] ACPI / processor_idle: Add ACPI v6.0 LPI support

Back to article view | Back to linux.kernel

Contents

  [PATCH v6 0/5] ACPI / processor_idle: Add ACPI v6.0 LPI support Sudeep Holla <sudeep.holla@arm.com> - 2016-06-14 16:50 +0200
    [PATCH v6 2/5] ACPI / processor_idle: Add support for Low Power Idle(LPI) states Sudeep Holla <sudeep.holla@arm.com> - 2016-06-14 17:00 +0200
      Re: [PATCH v6 2/5] ACPI / processor_idle: Add support for Low Power  Idle(LPI) states Sudeep Holla <sudeep.holla@arm.com> - 2016-06-14 18:50 +0200
      [PATCH v6 2/5][UPDATED] ACPI / processor_idle: Add support for Low Power Idle(LPI) states Sudeep Holla <sudeep.holla@arm.com> - 2016-06-14 19:00 +0200
    Re: [PATCH v6 0/5] ACPI / processor_idle: Add ACPI v6.0 LPI support Sudeep Holla <sudeep.holla@arm.com> - 2016-06-22 19:50 +0200
      Re: [PATCH v6 0/5] ACPI / processor_idle: Add ACPI v6.0 LPI support "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-06-23 02:40 +0200

#1421981 — [PATCH v6 0/5] ACPI / processor_idle: Add ACPI v6.0 LPI support

ACPI 6.0 introduced LPI(Low Power Idle) states that provides an alternate
method to describe processor idle states. It extends the specification
to allow the expression of idle states like C-states selectable by the
OSPM when a processor goes idle, but may affect more than one processor,
and may affect other system components.

LPI extensions leverages the processor container device(again introduced
in ACPI 6.0) allowing to express which parts of the system are affected
by a given LPI state. It defines the local power states for each node
in a hierarchical processor topology. The OSPM can use _LPI object to
select a local power state for each level of processor hierarchy in the
system. They used to produce a composite power state request that is
presented to the platform by the OSPM.

Since multiple processors affect the idle state for any non-leaf hierarchy
node, coordination of idle state requests between the processors is
required. ACPI supports two different coordination schemes: Platform
coordinated and  OS initiated.

This series aims at providing basic and initial support for platform
coordinated LPI states.

v5[5]->v6:
	- Added support for autopromotable state by not flattening them
	- Moved arm_enter_idle_state to cpuidle-arm.h as it can be reused
	  in ARM64 backend for ACPI LPI
	- Other review comments(mainly for ARM64 from Lorenzo)
	- Dropped support for skipping PM notifier as it needs to be fixed
	  in GICv3 code(will be done separately)

v4[4]->v5:
	- Addressed all the comments from Rafael
	- Added support for retention mode(Prashant)
	- Handled acpi_processor_get_power_info return value correctly(Vikas)
	- Dropped __init from arm_cpuidle_init
	- Merged psci prepartory patch into arm64 lpi support

v3[3]->v4:
	- Dropped the preparatory patches that are merged already
	- Added ARM64 arch specific callback implementations
	- Addressed most of the review comments from Rafael

v2[2]->v3:
        - rebased against v4.4-rc3
        - fixed couple of issues reported by Prashanth and review comments
          from Ashwin

v1[1]->v2[2]:
        - Fixed support for ACPI0010 processor container
        - moved sleep state code out of processor_idle

Code is also available @[5]

Regards,
Sudeep

[1] http://marc.info/?l=linux-acpi&m=143871041601132&w=2
[2] http://marc.info/?l=linux-acpi&m=144241209800788&w=2
[3] http://marc.info/?l=linux-acpi&m=144906557814813&w=2
[4] http://marc.info/?l=linux-acpi&m=146106902731359&w=2
[5] http://marc.info/?l=linux-acpi&m=146298107608349&w=2
[6] git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux.git for_review/arm64_lpi

Sudeep Holla (5):
  ACPI / processor_idle: introduce ACPI_PROCESSOR_CSTATE
  ACPI / processor_idle: Add support for Low Power Idle(LPI) states
  arm64: cpuidle: drop __init section marker to arm_cpuidle_init
  arm64: add support for ACPI Low Power Idle(LPI)
  ACPI : enable ACPI_PROCESSOR_IDLE on ARM64

 arch/arm64/kernel/cpuidle.c     |  19 +-
 drivers/acpi/Kconfig            |   6 +-
 drivers/acpi/bus.c              |  14 +-
 drivers/acpi/processor_driver.c |   2 +-
 drivers/acpi/processor_idle.c   | 545 ++++++++++++++++++++++++++++++++++------
 drivers/cpuidle/cpuidle-arm.c   |  23 +-
 drivers/firmware/psci.c         |  56 +++++
 include/acpi/processor.h        |  26 +-
 include/linux/acpi.h            |   4 +
 include/linux/cpuidle-arm.h     |  30 +++
 10 files changed, 616 insertions(+), 109 deletions(-)
 create mode 100644 include/linux/cpuidle-arm.h

-- 
2.7.4

[toc] | [next] | [standalone]

#1421990 — [PATCH v6 2/5] ACPI / processor_idle: Add support for Low Power Idle(LPI) states

ACPI 6.0 introduced an optional object _LPI that provides an alternate
method to describe Low Power Idle states. It defines the local power
states for each node in a hierarchical processor topology. The OSPM can
use _LPI object to select a local power state for each level of processor
hierarchy in the system. They used to produce a composite power state
request that is presented to the platform by the OSPM.

Since multiple processors affect the idle state for any non-leaf hierarchy
node, coordination of idle state requests between the processors is
required. ACPI supports two different coordination schemes: Platform
coordinated and  OS initiated.

This patch adds initial support for Platform coordination scheme of LPI.

Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 drivers/acpi/bus.c              |  14 +-
 drivers/acpi/processor_driver.c |   2 +-
 drivers/acpi/processor_idle.c   | 469 +++++++++++++++++++++++++++++++++++-----
 include/acpi/processor.h        |  24 +-
 include/linux/acpi.h            |   4 +
 5 files changed, 453 insertions(+), 60 deletions(-)

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 262ca31b86d9..80ebb05e387c 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -302,6 +302,14 @@ acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context)
 EXPORT_SYMBOL(acpi_run_osc);
 
 bool osc_sb_apei_support_acked;
+
+/*
+ * ACPI 6.0 Section 8.4.4.2 Idle State Coordination
+ * OSPM supports platform coordinated low power idle(LPI) states
+ */
+bool osc_pc_lpi_support_confirmed;
+EXPORT_SYMBOL_GPL(osc_pc_lpi_support_confirmed);
+
 static u8 sb_uuid_str[] = "0811B06E-4A27-44F9-8D60-3CBBC22E7B48";
 static void acpi_bus_osc_support(void)
 {
@@ -322,6 +330,7 @@ static void acpi_bus_osc_support(void)
 		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PPC_OST_SUPPORT;
 
 	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_HOTPLUG_OST_SUPPORT;
+	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PCLPI_SUPPORT;
 
 	if (!ghes_disable)
 		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_APEI_SUPPORT;
@@ -329,9 +338,12 @@ static void acpi_bus_osc_support(void)
 		return;
 	if (ACPI_SUCCESS(acpi_run_osc(handle, &context))) {
 		u32 *capbuf_ret = context.ret.pointer;
-		if (context.ret.length > OSC_SUPPORT_DWORD)
+		if (context.ret.length > OSC_SUPPORT_DWORD) {
 			osc_sb_apei_support_acked =
 				capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_APEI_SUPPORT;
+			osc_pc_lpi_support_confirmed =
+				capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_PCLPI_SUPPORT;
+		}
 		kfree(context.ret.pointer);
 	}
 	/* do we need to check other returned cap? Sounds no */
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index d2fa8cb82d2b..0ca14ac7bb28 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -90,7 +90,7 @@ static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
 						  pr->performance_platform_limit);
 		break;
 	case ACPI_PROCESSOR_NOTIFY_POWER:
-		acpi_processor_cst_has_changed(pr);
+		acpi_processor_power_state_has_changed(pr);
 		acpi_bus_generate_netlink_event(device->pnp.device_class,
 						  dev_name(&device->dev), event, 0);
 		break;
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index ca0de35d1c3a..cbc99a3b65c7 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -303,7 +303,6 @@ static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 	union acpi_object *cst;
 
-
 	if (nocst)
 		return -ENODEV;
 
@@ -576,7 +575,7 @@ static int acpi_processor_power_verify(struct acpi_processor *pr)
 	return (working);
 }
 
-static int acpi_processor_get_power_info(struct acpi_processor *pr)
+static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 {
 	unsigned int i;
 	int result;
@@ -810,31 +809,12 @@ static void acpi_idle_enter_freeze(struct cpuidle_device *dev,
 	acpi_idle_do_entry(cx);
 }
 
-/**
- * acpi_processor_setup_cpuidle_cx - prepares and configures CPUIDLE
- * device i.e. per-cpu data
- *
- * @pr: the ACPI processor
- * @dev : the cpuidle device
- */
 static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 					   struct cpuidle_device *dev)
 {
 	int i, count = CPUIDLE_DRIVER_STATE_START;
 	struct acpi_processor_cx *cx;
 
-	if (!pr->flags.power_setup_done)
-		return -EINVAL;
-
-	if (pr->flags.power == 0) {
-		return -EINVAL;
-	}
-
-	if (!dev)
-		return -EINVAL;
-
-	dev->cpu = pr->id;
-
 	if (max_cstate == 0)
 		max_cstate = 1;
 
@@ -857,31 +837,13 @@ static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 	return 0;
 }
 
-/**
- * acpi_processor_setup_cpuidle states- prepares and configures cpuidle
- * global state data i.e. idle routines
- *
- * @pr: the ACPI processor
- */
-static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
+static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 {
 	int i, count = CPUIDLE_DRIVER_STATE_START;
 	struct acpi_processor_cx *cx;
 	struct cpuidle_state *state;
 	struct cpuidle_driver *drv = &acpi_idle_driver;
 
-	if (!pr->flags.power_setup_done)
-		return -EINVAL;
-
-	if (pr->flags.power == 0)
-		return -EINVAL;
-
-	drv->safe_state_index = -1;
-	for (i = CPUIDLE_DRIVER_STATE_START; i < CPUIDLE_STATE_MAX; i++) {
-		drv->states[i].name[0] = '\0';
-		drv->states[i].desc[0] = '\0';
-	}
-
 	if (max_cstate == 0)
 		max_cstate = 1;
 
@@ -893,7 +855,7 @@ static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
 
 		state = &drv->states[count];
 		snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
-		strncpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
+		strlcpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
 		state->exit_latency = cx->latency;
 		state->target_residency = cx->latency * latency_factor;
 		state->enter = acpi_idle_enter;
@@ -952,7 +914,7 @@ static inline void acpi_processor_cstate_first_run_checks(void)
 
 static inline int disabled_by_idle_boot_param(void) { return 0; }
 static inline void acpi_processor_cstate_first_run_checks(void) { }
-static int acpi_processor_get_power_info(struct acpi_processor *pr)
+static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 {
 	return -ENODEV;
 }
@@ -963,13 +925,416 @@ static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 	return -EINVAL;
 }
 
-static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
+static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 {
 	return -EINVAL;
 }
 
 #endif /* CONFIG_ACPI_PROCESSOR_CSTATE */
 
+struct acpi_lpi_states_array {
+	unsigned int size;
+	struct acpi_lpi_state *entries;
+};
+
+static int obj_get_integer(union acpi_object *obj, u32 *value)
+{
+	if (obj->type != ACPI_TYPE_INTEGER)
+		return -EINVAL;
+
+	*value = obj->integer.value;
+	return 0;
+}
+
+static int acpi_processor_evaluate_lpi(acpi_handle handle,
+				       struct acpi_lpi_states_array *info)
+{
+	acpi_status status;
+	int ret = 0;
+	int pkg_count, state_idx = 1, loop;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *lpi_data;
+	struct acpi_lpi_state *lpi_state;
+
+	status = acpi_evaluate_object(handle, "_LPI", NULL, &buffer);
+	if (ACPI_FAILURE(status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _LPI, giving up\n"));
+		return -ENODEV;
+	}
+
+	lpi_data = buffer.pointer;
+
+	/* There must be at least 4 elements = 3 elements + 1 package */
+	if (!lpi_data || lpi_data->type != ACPI_TYPE_PACKAGE ||
+	    lpi_data->package.count < 4) {
+		pr_debug("not enough elements in _LPI\n");
+		ret = -ENODATA;
+		goto end;
+	}
+
+	pkg_count = lpi_data->package.elements[2].integer.value;
+
+	/* Validate number of power states. */
+	if (pkg_count < 1 || pkg_count != lpi_data->package.count - 3) {
+		pr_debug("count given by _LPI is not valid\n");
+		ret = -ENODATA;
+		goto end;
+	}
+
+	lpi_state = kcalloc(pkg_count, sizeof(*lpi_state), GFP_KERNEL);
+	if (!lpi_state) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+	info->size = pkg_count;
+	info->entries = lpi_state;
+
+	/* LPI States start at index 3 */
+	for (loop = 3; state_idx <= pkg_count;
+	     loop++, state_idx++, lpi_state++) {
+		union acpi_object *element, *pkg_elem, *obj;
+
+		element = &lpi_data->package.elements[loop];
+		if (element->type != ACPI_TYPE_PACKAGE)
+			continue;
+
+		if (element->package.count < 7)
+			continue;
+
+		pkg_elem = element->package.elements;
+
+		obj = pkg_elem + 6;
+		if (obj->type == ACPI_TYPE_BUFFER) {
+			struct acpi_power_register *reg;
+
+			reg = (struct acpi_power_register *)obj->buffer.pointer;
+			if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
+			    (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
+				continue;
+
+			lpi_state->address = reg->address;
+
+			if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
+				lpi_state->entry_method = ACPI_CSTATE_FFH;
+			else
+				lpi_state->entry_method = ACPI_CSTATE_SYSTEMIO;
+		} else if (obj->type == ACPI_TYPE_INTEGER) {
+			lpi_state->entry_method = ACPI_CSTATE_INTEGER;
+			lpi_state->address = obj->integer.value;
+		} else {
+			continue;
+		}
+
+		/* elements[7,8] skipped for now i.e. Residency/Usage counter*/
+
+		obj = pkg_elem + 9;
+		if (obj->type == ACPI_TYPE_STRING)
+			strlcpy(lpi_state->desc, obj->string.pointer,
+				ACPI_CX_DESC_LEN);
+
+		lpi_state->index = state_idx;
+		if (obj_get_integer(pkg_elem + 0, &lpi_state->min_residency)) {
+			pr_debug("No min. residency found, assuming 10 us\n");
+			lpi_state->min_residency = 10;
+		}
+
+		if (obj_get_integer(pkg_elem + 1, &lpi_state->wake_latency)) {
+			pr_debug("No wakeup residency found, assuming 10 us\n");
+			lpi_state->wake_latency = 10;
+		}
+
+		if (obj_get_integer(pkg_elem + 2, &lpi_state->flags))
+			lpi_state->flags = 0;
+
+		if (obj_get_integer(pkg_elem + 3, &lpi_state->arch_flags))
+			lpi_state->arch_flags = 0;
+
+		if (obj_get_integer(pkg_elem + 4, &lpi_state->res_cnt_freq))
+			lpi_state->res_cnt_freq = 1;
+
+		if (obj_get_integer(pkg_elem + 5, &lpi_state->enable_parent_state))
+			lpi_state->enable_parent_state = 0;
+	}
+
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
+			  state_idx));
+end:
+	kfree(buffer.pointer);
+	return ret;
+}
+
+/*
+ * max_leaf_depth - holds the depth of the processor hierarchy/tree
+ * flat_state_cnt - the number of composite LPI states after the process of flattening
+ */
+static int max_leaf_depth, flat_state_cnt;
+
+/**
+ * combine_lpi_states - combine local and parent LPI states to form a composite LPI state
+ *
+ * @local: local LPI state
+ * @parent: parent LPI state
+ * @result: composite LPI state
+ */
+static bool combine_lpi_states(struct acpi_lpi_state *local,
+			       struct acpi_lpi_state *parent,
+			       struct acpi_lpi_state *result)
+{
+	if (parent->entry_method == ACPI_CSTATE_INTEGER) {
+		if (!parent->address) /* 0 means autopromotable */
+			return false;
+		result->address = local->address + parent->address;
+	} else {
+		result->address = parent->address;
+	}
+
+	result->min_residency = max(local->min_residency, parent->min_residency);
+	result->wake_latency = local->wake_latency + parent->wake_latency;
+	result->enable_parent_state = parent->enable_parent_state;
+	result->entry_method = local->entry_method;
+
+	result->flags = parent->flags;
+	result->arch_flags = parent->arch_flags;
+
+	strlcpy(result->desc, local->desc, ACPI_CX_DESC_LEN);
+	strlcat(result->desc, "+", ACPI_CX_DESC_LEN);
+	strlcat(result->desc, parent->desc, ACPI_CX_DESC_LEN);
+	return true;
+}
+
+#define ACPI_LPI_STATE_FLAGS_ENABLED			BIT(0)
+
+static int flatten_lpi_states(struct acpi_processor *pr,
+			      struct acpi_lpi_states_array *info,
+			      struct acpi_lpi_state *lpi,
+			      uint32_t depth)
+{
+	int j, state_count = info[depth].size;
+	struct acpi_lpi_state *t = info[depth].entries;
+
+	for (j = 0; j < state_count; j++, t++) {
+		struct acpi_lpi_state *flpi;
+		bool valid = false;
+
+		if (!(t->flags & ACPI_LPI_STATE_FLAGS_ENABLED))
+			continue;
+
+		flpi = &pr->power.lpi_states[flat_state_cnt];
+		flpi->index = flat_state_cnt;
+
+		if (depth == max_leaf_depth) { /* leaf/processor node */
+			memcpy(flpi, t, sizeof(*t));
+			flat_state_cnt++;
+			valid = true;
+		} else if (lpi && t->index <= lpi->enable_parent_state) {
+			if (combine_lpi_states(lpi, t, flpi)) {
+				flat_state_cnt++;
+				valid = true;
+			}
+		}
+
+		/*
+		 * flatten recursively from leaf until the highest level
+		 * (e.g. system) is reached
+		 */
+		if (valid && depth)
+			flatten_lpi_states(pr, info, flpi, depth - 1);
+	}
+	return 0;
+}
+
+static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
+{
+	int ret, i;
+	struct acpi_lpi_states_array *info;
+	struct acpi_device *d = NULL;
+	acpi_handle handle = pr->handle, pr_ahandle;
+	acpi_status status;
+
+	if (!osc_pc_lpi_support_confirmed)
+		return -EOPNOTSUPP;
+
+	max_leaf_depth = 0;
+	if (!acpi_has_method(handle, "_LPI"))
+		return -EINVAL;
+	flat_state_cnt = 0;
+
+	while (ACPI_SUCCESS(status = acpi_get_parent(handle, &pr_ahandle))) {
+		acpi_bus_get_device(pr_ahandle, &d);
+		handle = pr_ahandle;
+
+		if (strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))
+			break;
+
+		if (!acpi_has_method(pr_ahandle, "_LPI"))
+			break;
+
+		max_leaf_depth++;
+	}
+
+	info = kcalloc(max_leaf_depth + 1, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	pr_ahandle = pr->handle;
+	for (i = max_leaf_depth; i >= 0 && ACPI_SUCCESS(status); i--) {
+		handle = pr_ahandle;
+		ret = acpi_processor_evaluate_lpi(handle, info + i);
+		if (ret)
+			break;
+
+		status = acpi_get_parent(handle, &pr_ahandle);
+	}
+
+	/* flatten all the LPI states in the entire hierarchy */
+	flatten_lpi_states(pr, info, NULL, max_leaf_depth);
+
+	pr->power.count = flat_state_cnt;
+
+	for (i = 0; i <= max_leaf_depth; i++)
+		kfree(info[i].entries);
+
+	kfree(info);
+
+	/* Tell driver that _LPI is supported. */
+	pr->flags.has_lpi = 1;
+	pr->flags.power = 1;
+
+	return 0;
+}
+
+int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
+{
+	return -ENODEV;
+}
+
+int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi, int idx)
+{
+	return -ENODEV;
+}
+
+/**
+ * acpi_idle_lpi_enter - enters an ACPI any LPI state
+ * @dev: the target CPU
+ * @drv: cpuidle driver containing cpuidle state info
+ * @index: index of target state
+ *
+ * Return: 0 for success or negative value for error
+ */
+static int acpi_idle_lpi_enter(struct cpuidle_device *dev,
+			       struct cpuidle_driver *drv, int index)
+{
+	struct acpi_processor *pr;
+	struct acpi_lpi_state *lpi;
+
+	pr = __this_cpu_read(processors);
+
+	if (unlikely(!pr))
+		return -EINVAL;
+
+	lpi = &pr->power.lpi_states[index];
+	if (lpi->entry_method == ACPI_CSTATE_FFH)
+		return acpi_processor_ffh_lpi_enter(lpi, index);
+
+	return -EINVAL;
+}
+
+static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
+{
+	int i;
+	struct acpi_lpi_state *lpi;
+	struct cpuidle_state *state;
+	struct cpuidle_driver *drv = &acpi_idle_driver;
+
+	if (!pr->flags.has_lpi)
+		return -EOPNOTSUPP;
+
+	for (i = 0; i < flat_state_cnt && i < CPUIDLE_STATE_MAX; i++) {
+		lpi = &pr->power.lpi_states[i];
+
+		state = &drv->states[i];
+		snprintf(state->name, CPUIDLE_NAME_LEN, "LPI-%d", i);
+		strlcpy(state->desc, lpi->desc, CPUIDLE_DESC_LEN);
+		state->exit_latency = lpi->wake_latency;
+		state->target_residency = lpi->min_residency;
+		if (lpi->arch_flags)
+			state->flags |= CPUIDLE_FLAG_TIMER_STOP;
+		state->enter = acpi_idle_lpi_enter;
+		drv->safe_state_index = i;
+	}
+
+	drv->state_count = i;
+
+	return 0;
+}
+
+/**
+ * acpi_processor_setup_cpuidle_states- prepares and configures cpuidle
+ * global state data i.e. idle routines
+ *
+ * @pr: the ACPI processor
+ */
+static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
+{
+	int i;
+	struct cpuidle_driver *drv = &acpi_idle_driver;
+
+	if (!pr->flags.power_setup_done)
+		return -EINVAL;
+
+	if (pr->flags.power == 0)
+		return -EINVAL;
+
+	drv->safe_state_index = -1;
+	for (i = CPUIDLE_DRIVER_STATE_START; i < CPUIDLE_STATE_MAX; i++) {
+		drv->states[i].name[0] = '\0';
+		drv->states[i].desc[0] = '\0';
+	}
+
+	if (pr->flags.has_lpi)
+		return acpi_processor_setup_lpi_states(pr);
+
+	return acpi_processor_setup_cstates(pr);
+}
+
+/**
+ * acpi_processor_setup_cpuidle_dev - prepares and configures CPUIDLE
+ * device i.e. per-cpu data
+ *
+ * @pr: the ACPI processor
+ * @dev : the cpuidle device
+ */
+static int acpi_processor_setup_cpuidle_dev(struct acpi_processor *pr,
+					    struct cpuidle_device *dev)
+{
+	if (!pr->flags.power_setup_done)
+		return -EINVAL;
+
+	if (pr->flags.power == 0)
+		return -EINVAL;
+
+	if (!dev)
+		return -EINVAL;
+
+	dev->cpu = pr->id;
+	if (pr->flags.has_lpi)
+		return acpi_processor_ffh_lpi_probe(pr->id);
+
+	return acpi_processor_setup_cpuidle_cx(pr, dev);
+}
+
+static int acpi_processor_get_power_info(struct acpi_processor *pr)
+{
+	int ret;
+
+	ret = acpi_processor_get_lpi_info(pr);
+	if (ret)
+		ret = acpi_processor_get_cstate_info(pr);
+
+	return ret;
+}
+
 int acpi_processor_hotplug(struct acpi_processor *pr)
 {
 	int ret = 0;
@@ -978,18 +1343,15 @@ int acpi_processor_hotplug(struct acpi_processor *pr)
 	if (disabled_by_idle_boot_param())
 		return 0;
 
-	if (nocst)
-		return -ENODEV;
-
 	if (!pr->flags.power_setup_done)
 		return -ENODEV;
 
 	dev = per_cpu(acpi_cpuidle_device, pr->id);
 	cpuidle_pause_and_lock();
 	cpuidle_disable_device(dev);
-	acpi_processor_get_power_info(pr);
-	if (pr->flags.power) {
-		acpi_processor_setup_cpuidle_cx(pr, dev);
+	ret = acpi_processor_get_power_info(pr);
+	if (!ret && pr->flags.power) {
+		acpi_processor_setup_cpuidle_dev(pr, dev);
 		ret = cpuidle_enable_device(dev);
 	}
 	cpuidle_resume_and_unlock();
@@ -997,7 +1359,7 @@ int acpi_processor_hotplug(struct acpi_processor *pr)
 	return ret;
 }
 
-int acpi_processor_cst_has_changed(struct acpi_processor *pr)
+int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
 {
 	int cpu;
 	struct acpi_processor *_pr;
@@ -1006,9 +1368,6 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr)
 	if (disabled_by_idle_boot_param())
 		return 0;
 
-	if (nocst)
-		return -ENODEV;
-
 	if (!pr->flags.power_setup_done)
 		return -ENODEV;
 
@@ -1045,7 +1404,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr)
 			acpi_processor_get_power_info(_pr);
 			if (_pr->flags.power) {
 				dev = per_cpu(acpi_cpuidle_device, cpu);
-				acpi_processor_setup_cpuidle_cx(_pr, dev);
+				acpi_processor_setup_cpuidle_dev(_pr, dev);
 				cpuidle_enable_device(dev);
 			}
 		}
@@ -1092,7 +1451,7 @@ int acpi_processor_power_init(struct acpi_processor *pr)
 			return -ENOMEM;
 		per_cpu(acpi_cpuidle_device, pr->id) = dev;
 
-		acpi_processor_setup_cpuidle_cx(pr, dev);
+		acpi_processor_setup_cpuidle_dev(pr, dev);
 
 		/* Register per-cpu cpuidle_device. Cpuidle driver
 		 * must already be registered before registering device
diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index 48779d678122..e2dcb0c51554 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -39,6 +39,7 @@
 #define ACPI_CSTATE_SYSTEMIO	0
 #define ACPI_CSTATE_FFH		1
 #define ACPI_CSTATE_HALT	2
+#define ACPI_CSTATE_INTEGER	3
 
 #define ACPI_CX_DESC_LEN	32
 
@@ -67,9 +68,25 @@ struct acpi_processor_cx {
 	char desc[ACPI_CX_DESC_LEN];
 };
 
+struct acpi_lpi_state {
+	u32 min_residency;
+	u32 wake_latency; /* worst case */
+	u32 flags;
+	u32 arch_flags;
+	u32 res_cnt_freq;
+	u32 enable_parent_state;
+	u64 address;
+	u8 index;
+	u8 entry_method;
+	char desc[ACPI_CX_DESC_LEN];
+};
+
 struct acpi_processor_power {
 	int count;
-	struct acpi_processor_cx states[ACPI_PROCESSOR_MAX_POWER];
+	union {
+		struct acpi_processor_cx states[ACPI_PROCESSOR_MAX_POWER];
+		struct acpi_lpi_state lpi_states[ACPI_PROCESSOR_MAX_POWER];
+	};
 	int timer_broadcast_on_state;
 };
 
@@ -189,6 +206,7 @@ struct acpi_processor_flags {
 	u8 bm_control:1;
 	u8 bm_check:1;
 	u8 has_cst:1;
+	u8 has_lpi:1;
 	u8 power_setup_done:1;
 	u8 bm_rld_set:1;
 	u8 need_hotplug_init:1;
@@ -371,7 +389,7 @@ extern struct cpuidle_driver acpi_idle_driver;
 #ifdef CONFIG_ACPI_PROCESSOR_IDLE
 int acpi_processor_power_init(struct acpi_processor *pr);
 int acpi_processor_power_exit(struct acpi_processor *pr);
-int acpi_processor_cst_has_changed(struct acpi_processor *pr);
+int acpi_processor_power_state_has_changed(struct acpi_processor *pr);
 int acpi_processor_hotplug(struct acpi_processor *pr);
 #else
 static inline int acpi_processor_power_init(struct acpi_processor *pr)
@@ -384,7 +402,7 @@ static inline int acpi_processor_power_exit(struct acpi_processor *pr)
 	return -ENODEV;
 }
 
-static inline int acpi_processor_cst_has_changed(struct acpi_processor *pr)
+static inline int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
 {
 	return -ENODEV;
 }
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 288fac5294f5..65754566ae17 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -444,8 +444,12 @@ acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context);
 #define OSC_SB_HOTPLUG_OST_SUPPORT		0x00000008
 #define OSC_SB_APEI_SUPPORT			0x00000010
 #define OSC_SB_CPC_SUPPORT			0x00000020
+#define OSC_SB_CPCV2_SUPPORT			0x00000040
+#define OSC_SB_PCLPI_SUPPORT			0x00000080
+#define OSC_SB_OSLPI_SUPPORT			0x00000100
 
 extern bool osc_sb_apei_support_acked;
+extern bool osc_pc_lpi_support_confirmed;
 
 /* PCI Host Bridge _OSC: Capabilities DWORD 2: Support Field */
 #define OSC_PCI_EXT_CONFIG_SUPPORT		0x00000001
-- 
2.7.4

[toc] | [prev] | [next] | [standalone]

#1422083 — Re: [PATCH v6 2/5] ACPI / processor_idle: Add support for Low Power Idle(LPI) states

On 14/06/16 15:48, Sudeep Holla wrote:
> ACPI 6.0 introduced an optional object _LPI that provides an alternate
> method to describe Low Power Idle states. It defines the local power
> states for each node in a hierarchical processor topology. The OSPM can
> use _LPI object to select a local power state for each level of processor
> hierarchy in the system. They used to produce a composite power state
> request that is presented to the platform by the OSPM.
>
> Since multiple processors affect the idle state for any non-leaf hierarchy
> node, coordination of idle state requests between the processors is
> required. ACPI supports two different coordination schemes: Platform
> coordinated and  OS initiated.
>
> This patch adds initial support for Platform coordination scheme of LPI.
>

I seem to have sent a stale version of this patch, will send an updated
version of this patch alone. Please ignore this one.

-- 
Regards,
Sudeep

[toc] | [prev] | [next] | [standalone]

#1422095 — [PATCH v6 2/5][UPDATED] ACPI / processor_idle: Add support for Low Power Idle(LPI) states

ACPI 6.0 introduced an optional object _LPI that provides an alternate
method to describe Low Power Idle states. It defines the local power
states for each node in a hierarchical processor topology. The OSPM can
use _LPI object to select a local power state for each level of processor
hierarchy in the system. They used to produce a composite power state
request that is presented to the platform by the OSPM.

Since multiple processors affect the idle state for any non-leaf hierarchy
node, coordination of idle state requests between the processors is
required. ACPI supports two different coordination schemes: Platform
coordinated and  OS initiated.

This patch adds initial support for Platform coordination scheme of LPI.

Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 drivers/acpi/bus.c              |  14 +-
 drivers/acpi/processor_driver.c |   2 +-
 drivers/acpi/processor_idle.c   | 468 +++++++++++++++++++++++++++++++++++-----
 include/acpi/processor.h        |  24 ++-
 include/linux/acpi.h            |   4 +
 5 files changed, 452 insertions(+), 60 deletions(-)

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 262ca31b86d9..80ebb05e387c 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -302,6 +302,14 @@ acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context)
 EXPORT_SYMBOL(acpi_run_osc);
 
 bool osc_sb_apei_support_acked;
+
+/*
+ * ACPI 6.0 Section 8.4.4.2 Idle State Coordination
+ * OSPM supports platform coordinated low power idle(LPI) states
+ */
+bool osc_pc_lpi_support_confirmed;
+EXPORT_SYMBOL_GPL(osc_pc_lpi_support_confirmed);
+
 static u8 sb_uuid_str[] = "0811B06E-4A27-44F9-8D60-3CBBC22E7B48";
 static void acpi_bus_osc_support(void)
 {
@@ -322,6 +330,7 @@ static void acpi_bus_osc_support(void)
 		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PPC_OST_SUPPORT;
 
 	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_HOTPLUG_OST_SUPPORT;
+	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PCLPI_SUPPORT;
 
 	if (!ghes_disable)
 		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_APEI_SUPPORT;
@@ -329,9 +338,12 @@ static void acpi_bus_osc_support(void)
 		return;
 	if (ACPI_SUCCESS(acpi_run_osc(handle, &context))) {
 		u32 *capbuf_ret = context.ret.pointer;
-		if (context.ret.length > OSC_SUPPORT_DWORD)
+		if (context.ret.length > OSC_SUPPORT_DWORD) {
 			osc_sb_apei_support_acked =
 				capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_APEI_SUPPORT;
+			osc_pc_lpi_support_confirmed =
+				capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_PCLPI_SUPPORT;
+		}
 		kfree(context.ret.pointer);
 	}
 	/* do we need to check other returned cap? Sounds no */
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index d2fa8cb82d2b..0ca14ac7bb28 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -90,7 +90,7 @@ static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
 						  pr->performance_platform_limit);
 		break;
 	case ACPI_PROCESSOR_NOTIFY_POWER:
-		acpi_processor_cst_has_changed(pr);
+		acpi_processor_power_state_has_changed(pr);
 		acpi_bus_generate_netlink_event(device->pnp.device_class,
 						  dev_name(&device->dev), event, 0);
 		break;
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index ca0de35d1c3a..98e8c62a961c 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -303,7 +303,6 @@ static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 	union acpi_object *cst;
 
-
 	if (nocst)
 		return -ENODEV;
 
@@ -576,7 +575,7 @@ static int acpi_processor_power_verify(struct acpi_processor *pr)
 	return (working);
 }
 
-static int acpi_processor_get_power_info(struct acpi_processor *pr)
+static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 {
 	unsigned int i;
 	int result;
@@ -810,31 +809,12 @@ static void acpi_idle_enter_freeze(struct cpuidle_device *dev,
 	acpi_idle_do_entry(cx);
 }
 
-/**
- * acpi_processor_setup_cpuidle_cx - prepares and configures CPUIDLE
- * device i.e. per-cpu data
- *
- * @pr: the ACPI processor
- * @dev : the cpuidle device
- */
 static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 					   struct cpuidle_device *dev)
 {
 	int i, count = CPUIDLE_DRIVER_STATE_START;
 	struct acpi_processor_cx *cx;
 
-	if (!pr->flags.power_setup_done)
-		return -EINVAL;
-
-	if (pr->flags.power == 0) {
-		return -EINVAL;
-	}
-
-	if (!dev)
-		return -EINVAL;
-
-	dev->cpu = pr->id;
-
 	if (max_cstate == 0)
 		max_cstate = 1;
 
@@ -857,31 +837,13 @@ static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 	return 0;
 }
 
-/**
- * acpi_processor_setup_cpuidle states- prepares and configures cpuidle
- * global state data i.e. idle routines
- *
- * @pr: the ACPI processor
- */
-static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
+static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 {
 	int i, count = CPUIDLE_DRIVER_STATE_START;
 	struct acpi_processor_cx *cx;
 	struct cpuidle_state *state;
 	struct cpuidle_driver *drv = &acpi_idle_driver;
 
-	if (!pr->flags.power_setup_done)
-		return -EINVAL;
-
-	if (pr->flags.power == 0)
-		return -EINVAL;
-
-	drv->safe_state_index = -1;
-	for (i = CPUIDLE_DRIVER_STATE_START; i < CPUIDLE_STATE_MAX; i++) {
-		drv->states[i].name[0] = '\0';
-		drv->states[i].desc[0] = '\0';
-	}
-
 	if (max_cstate == 0)
 		max_cstate = 1;
 
@@ -893,7 +855,7 @@ static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
 
 		state = &drv->states[count];
 		snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
-		strncpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
+		strlcpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
 		state->exit_latency = cx->latency;
 		state->target_residency = cx->latency * latency_factor;
 		state->enter = acpi_idle_enter;
@@ -952,7 +914,7 @@ static inline void acpi_processor_cstate_first_run_checks(void)
 
 static inline int disabled_by_idle_boot_param(void) { return 0; }
 static inline void acpi_processor_cstate_first_run_checks(void) { }
-static int acpi_processor_get_power_info(struct acpi_processor *pr)
+static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
 {
 	return -ENODEV;
 }
@@ -963,13 +925,415 @@ static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
 	return -EINVAL;
 }
 
-static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
+static int acpi_processor_setup_cstates(struct acpi_processor *pr)
 {
 	return -EINVAL;
 }
 
 #endif /* CONFIG_ACPI_PROCESSOR_CSTATE */
 
+struct acpi_lpi_states_array {
+	unsigned int size;
+	struct acpi_lpi_state *entries;
+};
+
+static int obj_get_integer(union acpi_object *obj, u32 *value)
+{
+	if (obj->type != ACPI_TYPE_INTEGER)
+		return -EINVAL;
+
+	*value = obj->integer.value;
+	return 0;
+}
+
+static int acpi_processor_evaluate_lpi(acpi_handle handle,
+				       struct acpi_lpi_states_array *info)
+{
+	acpi_status status;
+	int ret = 0;
+	int pkg_count, state_idx = 1, loop;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *lpi_data;
+	struct acpi_lpi_state *lpi_state;
+
+	status = acpi_evaluate_object(handle, "_LPI", NULL, &buffer);
+	if (ACPI_FAILURE(status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _LPI, giving up\n"));
+		return -ENODEV;
+	}
+
+	lpi_data = buffer.pointer;
+
+	/* There must be at least 4 elements = 3 elements + 1 package */
+	if (!lpi_data || lpi_data->type != ACPI_TYPE_PACKAGE ||
+	    lpi_data->package.count < 4) {
+		pr_debug("not enough elements in _LPI\n");
+		ret = -ENODATA;
+		goto end;
+	}
+
+	pkg_count = lpi_data->package.elements[2].integer.value;
+
+	/* Validate number of power states. */
+	if (pkg_count < 1 || pkg_count != lpi_data->package.count - 3) {
+		pr_debug("count given by _LPI is not valid\n");
+		ret = -ENODATA;
+		goto end;
+	}
+
+	lpi_state = kcalloc(pkg_count, sizeof(*lpi_state), GFP_KERNEL);
+	if (!lpi_state) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+	info->size = pkg_count;
+	info->entries = lpi_state;
+
+	/* LPI States start at index 3 */
+	for (loop = 3; state_idx <= pkg_count;
+	     loop++, state_idx++, lpi_state++) {
+		union acpi_object *element, *pkg_elem, *obj;
+
+		element = &lpi_data->package.elements[loop];
+		if (element->type != ACPI_TYPE_PACKAGE)
+			continue;
+
+		if (element->package.count < 7)
+			continue;
+
+		pkg_elem = element->package.elements;
+
+		obj = pkg_elem + 6;
+		if (obj->type == ACPI_TYPE_BUFFER) {
+			struct acpi_power_register *reg;
+
+			reg = (struct acpi_power_register *)obj->buffer.pointer;
+			if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
+			    (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
+				continue;
+
+			lpi_state->address = reg->address;
+
+			if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
+				lpi_state->entry_method = ACPI_CSTATE_FFH;
+			else
+				lpi_state->entry_method = ACPI_CSTATE_SYSTEMIO;
+		} else if (obj->type == ACPI_TYPE_INTEGER) {
+			lpi_state->entry_method = ACPI_CSTATE_INTEGER;
+			lpi_state->address = obj->integer.value;
+		} else {
+			continue;
+		}
+
+		/* elements[7,8] skipped for now i.e. Residency/Usage counter*/
+
+		obj = pkg_elem + 9;
+		if (obj->type == ACPI_TYPE_STRING)
+			strlcpy(lpi_state->desc, obj->string.pointer,
+				ACPI_CX_DESC_LEN);
+
+		lpi_state->index = state_idx;
+		if (obj_get_integer(pkg_elem + 0, &lpi_state->min_residency)) {
+			pr_debug("No min. residency found, assuming 10 us\n");
+			lpi_state->min_residency = 10;
+		}
+
+		if (obj_get_integer(pkg_elem + 1, &lpi_state->wake_latency)) {
+			pr_debug("No wakeup residency found, assuming 10 us\n");
+			lpi_state->wake_latency = 10;
+		}
+
+		if (obj_get_integer(pkg_elem + 2, &lpi_state->flags))
+			lpi_state->flags = 0;
+
+		if (obj_get_integer(pkg_elem + 3, &lpi_state->arch_flags))
+			lpi_state->arch_flags = 0;
+
+		if (obj_get_integer(pkg_elem + 4, &lpi_state->res_cnt_freq))
+			lpi_state->res_cnt_freq = 1;
+
+		if (obj_get_integer(pkg_elem + 5, &lpi_state->enable_parent_state))
+			lpi_state->enable_parent_state = 0;
+	}
+
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
+			  state_idx));
+end:
+	kfree(buffer.pointer);
+	return ret;
+}
+
+/*
+ * max_leaf_depth - holds the depth of the processor hierarchy/tree
+ * flat_state_cnt - the number of composite LPI states after the process of flattening
+ */
+static int max_leaf_depth, flat_state_cnt;
+
+/**
+ * combine_lpi_states - combine local and parent LPI states to form a composite LPI state
+ *
+ * @local: local LPI state
+ * @parent: parent LPI state
+ * @result: composite LPI state
+ */
+static bool combine_lpi_states(struct acpi_lpi_state *local,
+			       struct acpi_lpi_state *parent,
+			       struct acpi_lpi_state *result)
+{
+	if (parent->entry_method == ACPI_CSTATE_INTEGER) {
+		if (!parent->address) /* 0 means autopromotable */
+			return false;
+		result->address = local->address + parent->address;
+	} else {
+		result->address = parent->address;
+	}
+
+	result->min_residency = max(local->min_residency, parent->min_residency);
+	result->wake_latency = local->wake_latency + parent->wake_latency;
+	result->enable_parent_state = parent->enable_parent_state;
+	result->entry_method = local->entry_method;
+
+	result->flags = parent->flags;
+	result->arch_flags = parent->arch_flags;
+
+	strlcpy(result->desc, local->desc, ACPI_CX_DESC_LEN);
+	strlcat(result->desc, "+", ACPI_CX_DESC_LEN);
+	strlcat(result->desc, parent->desc, ACPI_CX_DESC_LEN);
+	return true;
+}
+
+#define ACPI_LPI_STATE_FLAGS_ENABLED			BIT(0)
+
+static int flatten_lpi_states(struct acpi_processor *pr,
+			      struct acpi_lpi_states_array *info,
+			      struct acpi_lpi_state *lpi,
+			      uint32_t depth)
+{
+	int j, state_count = info[depth].size;
+	struct acpi_lpi_state *t = info[depth].entries;
+
+	for (j = 0; j < state_count; j++, t++) {
+		struct acpi_lpi_state *flpi;
+		bool valid = false;
+
+		if (!(t->flags & ACPI_LPI_STATE_FLAGS_ENABLED))
+			continue;
+
+		flpi = &pr->power.lpi_states[flat_state_cnt];
+
+		if (depth == max_leaf_depth) { /* leaf/processor node */
+			memcpy(flpi, t, sizeof(*t));
+			flpi->index = flat_state_cnt++;
+			valid = true;
+		} else if (lpi && t->index <= lpi->enable_parent_state) {
+			if (combine_lpi_states(lpi, t, flpi)) {
+				flpi->index = flat_state_cnt++;
+				valid = true;
+			}
+		}
+
+		/*
+		 * flatten recursively from leaf until the highest level
+		 * (e.g. system) is reached
+		 */
+		if (valid && depth)
+			flatten_lpi_states(pr, info, flpi, depth - 1);
+	}
+	return 0;
+}
+
+static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
+{
+	int ret, i;
+	struct acpi_lpi_states_array *info;
+	struct acpi_device *d = NULL;
+	acpi_handle handle = pr->handle, pr_ahandle;
+	acpi_status status;
+
+	if (!osc_pc_lpi_support_confirmed)
+		return -EOPNOTSUPP;
+
+	max_leaf_depth = 0;
+	if (!acpi_has_method(handle, "_LPI"))
+		return -EINVAL;
+	flat_state_cnt = 0;
+
+	while (ACPI_SUCCESS(status = acpi_get_parent(handle, &pr_ahandle))) {
+		acpi_bus_get_device(pr_ahandle, &d);
+		handle = pr_ahandle;
+
+		if (strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))
+			break;
+
+		if (!acpi_has_method(pr_ahandle, "_LPI"))
+			break;
+
+		max_leaf_depth++;
+	}
+
+	info = kcalloc(max_leaf_depth + 1, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	pr_ahandle = pr->handle;
+	for (i = max_leaf_depth; i >= 0 && ACPI_SUCCESS(status); i--) {
+		handle = pr_ahandle;
+		ret = acpi_processor_evaluate_lpi(handle, info + i);
+		if (ret)
+			break;
+
+		status = acpi_get_parent(handle, &pr_ahandle);
+	}
+
+	/* flatten all the LPI states in the entire hierarchy */
+	flatten_lpi_states(pr, info, NULL, max_leaf_depth);
+
+	pr->power.count = flat_state_cnt;
+
+	for (i = 0; i <= max_leaf_depth; i++)
+		kfree(info[i].entries);
+
+	kfree(info);
+
+	/* Tell driver that _LPI is supported. */
+	pr->flags.has_lpi = 1;
+	pr->flags.power = 1;
+
+	return 0;
+}
+
+int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
+{
+	return -ENODEV;
+}
+
+int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
+{
+	return -ENODEV;
+}
+
+/**
+ * acpi_idle_lpi_enter - enters an ACPI any LPI state
+ * @dev: the target CPU
+ * @drv: cpuidle driver containing cpuidle state info
+ * @index: index of target state
+ *
+ * Return: 0 for success or negative value for error
+ */
+static int acpi_idle_lpi_enter(struct cpuidle_device *dev,
+			       struct cpuidle_driver *drv, int index)
+{
+	struct acpi_processor *pr;
+	struct acpi_lpi_state *lpi;
+
+	pr = __this_cpu_read(processors);
+
+	if (unlikely(!pr))
+		return -EINVAL;
+
+	lpi = &pr->power.lpi_states[index];
+	if (lpi->entry_method == ACPI_CSTATE_FFH)
+		return acpi_processor_ffh_lpi_enter(lpi);
+
+	return -EINVAL;
+}
+
+static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
+{
+	int i;
+	struct acpi_lpi_state *lpi;
+	struct cpuidle_state *state;
+	struct cpuidle_driver *drv = &acpi_idle_driver;
+
+	if (!pr->flags.has_lpi)
+		return -EOPNOTSUPP;
+
+	for (i = 0; i < flat_state_cnt && i < CPUIDLE_STATE_MAX; i++) {
+		lpi = &pr->power.lpi_states[i];
+
+		state = &drv->states[i];
+		snprintf(state->name, CPUIDLE_NAME_LEN, "LPI-%d", i);
+		strlcpy(state->desc, lpi->desc, CPUIDLE_DESC_LEN);
+		state->exit_latency = lpi->wake_latency;
+		state->target_residency = lpi->min_residency;
+		if (lpi->arch_flags)
+			state->flags |= CPUIDLE_FLAG_TIMER_STOP;
+		state->enter = acpi_idle_lpi_enter;
+		drv->safe_state_index = i;
+	}
+
+	drv->state_count = i;
+
+	return 0;
+}
+
+/**
+ * acpi_processor_setup_cpuidle_states- prepares and configures cpuidle
+ * global state data i.e. idle routines
+ *
+ * @pr: the ACPI processor
+ */
+static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
+{
+	int i;
+	struct cpuidle_driver *drv = &acpi_idle_driver;
+
+	if (!pr->flags.power_setup_done)
+		return -EINVAL;
+
+	if (pr->flags.power == 0)
+		return -EINVAL;
+
+	drv->safe_state_index = -1;
+	for (i = CPUIDLE_DRIVER_STATE_START; i < CPUIDLE_STATE_MAX; i++) {
+		drv->states[i].name[0] = '\0';
+		drv->states[i].desc[0] = '\0';
+	}
+
+	if (pr->flags.has_lpi)
+		return acpi_processor_setup_lpi_states(pr);
+
+	return acpi_processor_setup_cstates(pr);
+}
+
+/**
+ * acpi_processor_setup_cpuidle_dev - prepares and configures CPUIDLE
+ * device i.e. per-cpu data
+ *
+ * @pr: the ACPI processor
+ * @dev : the cpuidle device
+ */
+static int acpi_processor_setup_cpuidle_dev(struct acpi_processor *pr,
+					    struct cpuidle_device *dev)
+{
+	if (!pr->flags.power_setup_done)
+		return -EINVAL;
+
+	if (pr->flags.power == 0)
+		return -EINVAL;
+
+	if (!dev)
+		return -EINVAL;
+
+	dev->cpu = pr->id;
+	if (pr->flags.has_lpi)
+		return acpi_processor_ffh_lpi_probe(pr->id);
+
+	return acpi_processor_setup_cpuidle_cx(pr, dev);
+}
+
+static int acpi_processor_get_power_info(struct acpi_processor *pr)
+{
+	int ret;
+
+	ret = acpi_processor_get_lpi_info(pr);
+	if (ret)
+		ret = acpi_processor_get_cstate_info(pr);
+
+	return ret;
+}
+
 int acpi_processor_hotplug(struct acpi_processor *pr)
 {
 	int ret = 0;
@@ -978,18 +1342,15 @@ int acpi_processor_hotplug(struct acpi_processor *pr)
 	if (disabled_by_idle_boot_param())
 		return 0;
 
-	if (nocst)
-		return -ENODEV;
-
 	if (!pr->flags.power_setup_done)
 		return -ENODEV;
 
 	dev = per_cpu(acpi_cpuidle_device, pr->id);
 	cpuidle_pause_and_lock();
 	cpuidle_disable_device(dev);
-	acpi_processor_get_power_info(pr);
-	if (pr->flags.power) {
-		acpi_processor_setup_cpuidle_cx(pr, dev);
+	ret = acpi_processor_get_power_info(pr);
+	if (!ret && pr->flags.power) {
+		acpi_processor_setup_cpuidle_dev(pr, dev);
 		ret = cpuidle_enable_device(dev);
 	}
 	cpuidle_resume_and_unlock();
@@ -997,7 +1358,7 @@ int acpi_processor_hotplug(struct acpi_processor *pr)
 	return ret;
 }
 
-int acpi_processor_cst_has_changed(struct acpi_processor *pr)
+int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
 {
 	int cpu;
 	struct acpi_processor *_pr;
@@ -1006,9 +1367,6 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr)
 	if (disabled_by_idle_boot_param())
 		return 0;
 
-	if (nocst)
-		return -ENODEV;
-
 	if (!pr->flags.power_setup_done)
 		return -ENODEV;
 
@@ -1045,7 +1403,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr)
 			acpi_processor_get_power_info(_pr);
 			if (_pr->flags.power) {
 				dev = per_cpu(acpi_cpuidle_device, cpu);
-				acpi_processor_setup_cpuidle_cx(_pr, dev);
+				acpi_processor_setup_cpuidle_dev(_pr, dev);
 				cpuidle_enable_device(dev);
 			}
 		}
@@ -1092,7 +1450,7 @@ int acpi_processor_power_init(struct acpi_processor *pr)
 			return -ENOMEM;
 		per_cpu(acpi_cpuidle_device, pr->id) = dev;
 
-		acpi_processor_setup_cpuidle_cx(pr, dev);
+		acpi_processor_setup_cpuidle_dev(pr, dev);
 
 		/* Register per-cpu cpuidle_device. Cpuidle driver
 		 * must already be registered before registering device
diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index 48779d678122..e2dcb0c51554 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -39,6 +39,7 @@
 #define ACPI_CSTATE_SYSTEMIO	0
 #define ACPI_CSTATE_FFH		1
 #define ACPI_CSTATE_HALT	2
+#define ACPI_CSTATE_INTEGER	3
 
 #define ACPI_CX_DESC_LEN	32
 
@@ -67,9 +68,25 @@ struct acpi_processor_cx {
 	char desc[ACPI_CX_DESC_LEN];
 };
 
+struct acpi_lpi_state {
+	u32 min_residency;
+	u32 wake_latency; /* worst case */
+	u32 flags;
+	u32 arch_flags;
+	u32 res_cnt_freq;
+	u32 enable_parent_state;
+	u64 address;
+	u8 index;
+	u8 entry_method;
+	char desc[ACPI_CX_DESC_LEN];
+};
+
 struct acpi_processor_power {
 	int count;
-	struct acpi_processor_cx states[ACPI_PROCESSOR_MAX_POWER];
+	union {
+		struct acpi_processor_cx states[ACPI_PROCESSOR_MAX_POWER];
+		struct acpi_lpi_state lpi_states[ACPI_PROCESSOR_MAX_POWER];
+	};
 	int timer_broadcast_on_state;
 };
 
@@ -189,6 +206,7 @@ struct acpi_processor_flags {
 	u8 bm_control:1;
 	u8 bm_check:1;
 	u8 has_cst:1;
+	u8 has_lpi:1;
 	u8 power_setup_done:1;
 	u8 bm_rld_set:1;
 	u8 need_hotplug_init:1;
@@ -371,7 +389,7 @@ extern struct cpuidle_driver acpi_idle_driver;
 #ifdef CONFIG_ACPI_PROCESSOR_IDLE
 int acpi_processor_power_init(struct acpi_processor *pr);
 int acpi_processor_power_exit(struct acpi_processor *pr);
-int acpi_processor_cst_has_changed(struct acpi_processor *pr);
+int acpi_processor_power_state_has_changed(struct acpi_processor *pr);
 int acpi_processor_hotplug(struct acpi_processor *pr);
 #else
 static inline int acpi_processor_power_init(struct acpi_processor *pr)
@@ -384,7 +402,7 @@ static inline int acpi_processor_power_exit(struct acpi_processor *pr)
 	return -ENODEV;
 }
 
-static inline int acpi_processor_cst_has_changed(struct acpi_processor *pr)
+static inline int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
 {
 	return -ENODEV;
 }
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 288fac5294f5..65754566ae17 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -444,8 +444,12 @@ acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context);
 #define OSC_SB_HOTPLUG_OST_SUPPORT		0x00000008
 #define OSC_SB_APEI_SUPPORT			0x00000010
 #define OSC_SB_CPC_SUPPORT			0x00000020
+#define OSC_SB_CPCV2_SUPPORT			0x00000040
+#define OSC_SB_PCLPI_SUPPORT			0x00000080
+#define OSC_SB_OSLPI_SUPPORT			0x00000100
 
 extern bool osc_sb_apei_support_acked;
+extern bool osc_pc_lpi_support_confirmed;
 
 /* PCI Host Bridge _OSC: Capabilities DWORD 2: Support Field */
 #define OSC_PCI_EXT_CONFIG_SUPPORT		0x00000001
-- 
2.7.4

[toc] | [prev] | [next] | [standalone]

#1429028

Hi Rafael,

On 14/06/16 15:48, Sudeep Holla wrote:
> ACPI 6.0 introduced LPI(Low Power Idle) states that provides an alternate
> method to describe processor idle states. It extends the specification
> to allow the expression of idle states like C-states selectable by the
> OSPM when a processor goes idle, but may affect more than one processor,
> and may affect other system components.
>
> LPI extensions leverages the processor container device(again introduced
> in ACPI 6.0) allowing to express which parts of the system are affected
> by a given LPI state. It defines the local power states for each node
> in a hierarchical processor topology. The OSPM can use _LPI object to
> select a local power state for each level of processor hierarchy in the
> system. They used to produce a composite power state request that is
> presented to the platform by the OSPM.
>
> Since multiple processors affect the idle state for any non-leaf hierarchy
> node, coordination of idle state requests between the processors is
> required. ACPI supports two different coordination schemes: Platform
> coordinated and  OS initiated.
>
> This series aims at providing basic and initial support for platform
> coordinated LPI states.
>

Gentle ping, was hoping to target this series for v4.8

-- 
Regards,
Sudeep

[toc] | [prev] | [next] | [standalone]

#1429368

On Wednesday, June 22, 2016 06:45:15 PM Sudeep Holla wrote:
> Hi Rafael,
> 
> On 14/06/16 15:48, Sudeep Holla wrote:
> > ACPI 6.0 introduced LPI(Low Power Idle) states that provides an alternate
> > method to describe processor idle states. It extends the specification
> > to allow the expression of idle states like C-states selectable by the
> > OSPM when a processor goes idle, but may affect more than one processor,
> > and may affect other system components.
> >
> > LPI extensions leverages the processor container device(again introduced
> > in ACPI 6.0) allowing to express which parts of the system are affected
> > by a given LPI state. It defines the local power states for each node
> > in a hierarchical processor topology. The OSPM can use _LPI object to
> > select a local power state for each level of processor hierarchy in the
> > system. They used to produce a composite power state request that is
> > presented to the platform by the OSPM.
> >
> > Since multiple processors affect the idle state for any non-leaf hierarchy
> > node, coordination of idle state requests between the processors is
> > required. ACPI supports two different coordination schemes: Platform
> > coordinated and  OS initiated.
> >
> > This series aims at providing basic and initial support for platform
> > coordinated LPI states.
> >
> 
> Gentle ping, was hoping to target this series for v4.8

On my list of things to take care of this week.  But this is a long list ...

Thanks,
Rafael

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web