1 files changed, 76 insertions, 25 deletions

diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
index 645e541a45f6..6824ca7d4d0c 100644
--- a/kernel/pm_qos_params.c
+++ b/kernel/pm_qos_params.c
@@ -40,6 +40,7 @@
 #include <linux/string.h>
 #include <linux/platform_device.h>
 #include <linux/init.h>
+#include <linux/kernel.h>
 
 #include <linux/uaccess.h>
 
@@ -53,11 +54,17 @@ enum pm_qos_type {
         PM_QOS_MIN              /* return the smallest value */
 };
 
+/*
+ * Note: The lockless read path depends on the CPU accessing
+ * target_value atomically.  Atomic access is only guaranteed on all CPU
+ * types linux supports for 32 bit quantites
+ */
 struct pm_qos_object {
         struct plist_head requests;
         struct blocking_notifier_head *notifiers;
         struct miscdevice pm_qos_power_miscdev;
         char *name;
+        s32 target_value;       /* Do not change to 64 bit */
         s32 default_value;
         enum pm_qos_type type;
 };
@@ -70,7 +77,8 @@ static struct pm_qos_object cpu_dma_pm_qos = {
         .requests = PLIST_HEAD_INIT(cpu_dma_pm_qos.requests, pm_qos_lock),
         .notifiers = &cpu_dma_lat_notifier,
         .name = "cpu_dma_latency",
-        .default_value = 2000 * USEC_PER_SEC,
+        .target_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
+        .default_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
         .type = PM_QOS_MIN,
 };
 
@@ -79,7 +87,8 @@ static struct pm_qos_object network_lat_pm_qos = {
         .requests = PLIST_HEAD_INIT(network_lat_pm_qos.requests, pm_qos_lock),
         .notifiers = &network_lat_notifier,
         .name = "network_latency",
-        .default_value = 2000 * USEC_PER_SEC,
+        .target_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
+        .default_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
         .type = PM_QOS_MIN
 };
 
@@ -89,7 +98,8 @@ static struct pm_qos_object network_throughput_pm_qos = {
         .requests = PLIST_HEAD_INIT(network_throughput_pm_qos.requests, pm_qos_lock),
         .notifiers = &network_throughput_notifier,
         .name = "network_throughput",
-        .default_value = 0,
+        .target_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
+        .default_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
         .type = PM_QOS_MAX,
 };
 
@@ -103,13 +113,17 @@ static struct pm_qos_object *pm_qos_array[] = {
 
 static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
                 size_t count, loff_t *f_pos);
+static ssize_t pm_qos_power_read(struct file *filp, char __user *buf,
+                size_t count, loff_t *f_pos);
 static int pm_qos_power_open(struct inode *inode, struct file *filp);
 static int pm_qos_power_release(struct inode *inode, struct file *filp);
 
 static const struct file_operations pm_qos_power_fops = {
         .write = pm_qos_power_write,
+        .read = pm_qos_power_read,
         .open = pm_qos_power_open,
         .release = pm_qos_power_release,
+        .llseek = noop_llseek,
 };
 
 /* unlocked internal variant */
@@ -120,10 +134,10 @@ static inline int pm_qos_get_value(struct pm_qos_object *o)
 
         switch (o->type) {
         case PM_QOS_MIN:
-                return plist_last(&o->requests)->prio;
+                return plist_first(&o->requests)->prio;
 
         case PM_QOS_MAX:
-                return plist_first(&o->requests)->prio;
+                return plist_last(&o->requests)->prio;
 
         default:
                 /* runtime check for not using enum */
@@ -131,6 +145,16 @@ static inline int pm_qos_get_value(struct pm_qos_object *o)
         }
 }
 
+static inline s32 pm_qos_read_value(struct pm_qos_object *o)
+{
+        return o->target_value;
+}
+
+static inline void pm_qos_set_value(struct pm_qos_object *o, s32 value)
+{
+        o->target_value = value;
+}
+
 static void update_target(struct pm_qos_object *o, struct plist_node *node,
                           int del, int value)
 {
@@ -155,6 +179,7 @@ static void update_target(struct pm_qos_object *o, struct plist_node *node,
                 plist_add(node, &o->requests);
         }
         curr_value = pm_qos_get_value(o);
+        pm_qos_set_value(o, curr_value);
         spin_unlock_irqrestore(&pm_qos_lock, flags);
 
         if (prev_value != curr_value)
@@ -189,18 +214,11 @@ static int find_pm_qos_object_by_minor(int minor)
  * pm_qos_request - returns current system wide qos expectation
  * @pm_qos_class: identification of which qos value is requested
  *
- * This function returns the current target value in an atomic manner.
+ * This function returns the current target value.
  */
 int pm_qos_request(int pm_qos_class)
 {
-        unsigned long flags;
-        int value;
-
-        spin_lock_irqsave(&pm_qos_lock, flags);
-        value = pm_qos_get_value(pm_qos_array[pm_qos_class]);
-        spin_unlock_irqrestore(&pm_qos_lock, flags);
-
-        return value;
+        return pm_qos_read_value(pm_qos_array[pm_qos_class]);
 }
 EXPORT_SYMBOL_GPL(pm_qos_request);
 
@@ -375,30 +393,63 @@ static int pm_qos_power_release(struct inode *inode, struct file *filp)
 }
 
 
+static ssize_t pm_qos_power_read(struct file *filp, char __user *buf,
+                size_t count, loff_t *f_pos)
+{
+        s32 value;
+        unsigned long flags;
+        struct pm_qos_object *o;
+        struct pm_qos_request_list *pm_qos_req = filp->private_data;
+
+        if (!pm_qos_req)
+                return -EINVAL;
+        if (!pm_qos_request_active(pm_qos_req))
+                return -EINVAL;
+
+        o = pm_qos_array[pm_qos_req->pm_qos_class];
+        spin_lock_irqsave(&pm_qos_lock, flags);
+        value = pm_qos_get_value(o);
+        spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+        return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32));
+}
+
 static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
                 size_t count, loff_t *f_pos)
 {
         s32 value;
-        int x;
-        char ascii_value[11];
         struct pm_qos_request_list *pm_qos_req;
 
         if (count == sizeof(s32)) {
                 if (copy_from_user(&value, buf, sizeof(s32)))
                         return -EFAULT;
-        } else if (count == 11) { /* len('0x12345678/0') */
-                if (copy_from_user(ascii_value, buf, 11))
+        } else if (count <= 11) { /* ASCII perhaps? */
+                char ascii_value[11];
+                unsigned long int ulval;
+                int ret;
+
+                if (copy_from_user(ascii_value, buf, count))
                         return -EFAULT;
-                if (strlen(ascii_value) != 10)
-                        return -EINVAL;
-                x = sscanf(ascii_value, "%x", &value);
-                if (x != 1)
+
+                if (count > 10) {
+                        if (ascii_value[10] == '\n')
+                                ascii_value[10] = '\0';
+                        else
+                                return -EINVAL;
+                } else {
+                        ascii_value[count] = '\0';
+                }
+                ret = strict_strtoul(ascii_value, 16, &ulval);
+                if (ret) {
+                        pr_debug("%s, 0x%lx, 0x%x\n", ascii_value, ulval, ret);
                         return -EINVAL;
-                pr_debug("%s, %d, 0x%x\n", ascii_value, x, value);
-        } else
+                }
+                value = (s32)lower_32_bits(ulval);
+        } else {
                 return -EINVAL;
+        }
 
-        pm_qos_req = (struct pm_qos_request_list *)filp->private_data;
+        pm_qos_req = filp->private_data;
         pm_qos_update_request(pm_qos_req, value);
 
         return count;