QoS: Enhance framework to support cpu/irq specific QoS requests

QoS request for CPU_DMA_LATENCY can be better optimized if the request
can be set only for the required cpus and not all cpus. This helps save
power on other cores, while still gauranteeing the quality of service.

Enhance the QoS constraints data structures to support target value for
each core. Requests specify if the QoS is applicable to all cores
(default) or to a selective subset of the cores or to a core(s), that the
IRQ is affine to.

QoS requests that need to track an IRQ can be set to apply only on the
cpus to which the IRQ's smp_affinity attribute is set to. The QoS
framework will automatically track IRQ migration between the cores. The
QoS is updated to be applied only to the core(s) that the IRQ has been
migrated to.

Idle and interested drivers can request a PM QoS value for a constraint
across all cpus, or a specific cpu or a set of cpus. Separate APIs have
been added to request for individual cpu or a cpumask.  The default
behaviour of PM QoS is maintained i.e, requests that do not specify a
type of the request will continue to be effected on all cores.  Requests
that want to specify an affinity of cpu(s) or an irq, can modify the PM
QoS request data structures by specifying the type of the request and
either the mask of the cpus or the IRQ number depending on the type.
Updating the request does not reset the type of the request.

The userspace sysfs interface does not support CPU/IRQ affinity.

Change-Id: I09ae85a1e8585d44440e86d63504ad734e8e3e36
Signed-off-by: Praveen Chidambaram <pchidamb@codeaurora.org>

Conflicts:
	kernel/power/qos.c

1 files changed, 20 insertions, 0 deletions

diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index a0d82e44c898..ff49ab3516b1 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -9,6 +9,8 @@
 #include <linux/miscdevice.h>
 #include <linux/device.h>
 #include <linux/workqueue.h>
+#include <linux/cpumask.h>
+#include <linux/interrupt.h>
 
 enum {
 	PM_QOS_RESERVED = 0,
@@ -42,7 +44,22 @@ enum pm_qos_flags_status {
 #define PM_QOS_FLAG_NO_POWER_OFF	(1 << 0)
 #define PM_QOS_FLAG_REMOTE_WAKEUP	(1 << 1)
 
+enum pm_qos_req_type {
+	PM_QOS_REQ_ALL_CORES = 0,
+	PM_QOS_REQ_AFFINE_CORES,
+#ifdef CONFIG_SMP
+	PM_QOS_REQ_AFFINE_IRQ,
+#endif
+};
+
 struct pm_qos_request {
+	enum pm_qos_req_type type;
+	struct cpumask cpus_affine;
+#ifdef CONFIG_SMP
+	uint32_t irq;
+	/* Internal structure members */
+	struct irq_affinity_notify irq_notify;
+#endif
 	struct plist_node node;
 	int pm_qos_class;
 	struct delayed_work work; /* for pm_qos_update_request_timeout */
@@ -83,6 +100,7 @@ enum pm_qos_type {
 struct pm_qos_constraints {
 	struct plist_head list;
 	s32 target_value;	/* Do not change to 64 bit */
+	s32 target_per_cpu[NR_CPUS];
 	s32 default_value;
 	s32 no_constraint_value;
 	enum pm_qos_type type;
@@ -130,6 +148,8 @@ void pm_qos_update_request_timeout(struct pm_qos_request *req,
 void pm_qos_remove_request(struct pm_qos_request *req);
 
 int pm_qos_request(int pm_qos_class);
+int pm_qos_request_for_cpu(int pm_qos_class, int cpu);
+int pm_qos_request_for_cpumask(int pm_qos_class, struct cpumask *mask);
 int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier);
 int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier);
 int pm_qos_request_active(struct pm_qos_request *req);