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authorAlexander Shishkin <alexander.shishkin@linux.intel.com>2016-06-28 11:35:02 +0300
committerAlexander Shishkin <alexander.shishkin@linux.intel.com>2016-07-01 11:00:14 +0300
commit8e0469a4f3e647059c0ef8db961140ee25246fbd (patch)
treee98b5e24ba140a035f3e36243a041788dcd83009 /drivers/hwtracing/stm
parentaf8c34ce6ae32addda3788d54a7e340cad22516b (diff)
downloadlinux-8e0469a4f3e647059c0ef8db961140ee25246fbd.tar.bz2
stm class: Add runtime power management handling
Currently, there's no runtime pm in stm class devices, which makes it harder for the underlying hardware drivers to handle their power management. This patch applies the following runtime pm policy to stm class devices, which their parents can rely on for their power management tracking: * device is in use during character device writes, * delayed autosuspend is used to keep it active between adjacent writes, * device is in use while mmio regions are mapped, * device is is use while any stm_source devices are linked to it. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Chunyan Zhang <zhang.chunyan@linaro.org>
Diffstat (limited to 'drivers/hwtracing/stm')
-rw-r--r--drivers/hwtracing/stm/core.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c
index ff31108b066f..51f81d64ca37 100644
--- a/drivers/hwtracing/stm/core.c
+++ b/drivers/hwtracing/stm/core.c
@@ -15,6 +15,7 @@
* as defined in MIPI STPv2 specification.
*/
+#include <linux/pm_runtime.h>
#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -482,14 +483,40 @@ static ssize_t stm_char_write(struct file *file, const char __user *buf,
return -EFAULT;
}
+ pm_runtime_get_sync(&stm->dev);
+
count = stm_write(stm->data, stmf->output.master, stmf->output.channel,
kbuf, count);
+ pm_runtime_mark_last_busy(&stm->dev);
+ pm_runtime_put_autosuspend(&stm->dev);
kfree(kbuf);
return count;
}
+static void stm_mmap_open(struct vm_area_struct *vma)
+{
+ struct stm_file *stmf = vma->vm_file->private_data;
+ struct stm_device *stm = stmf->stm;
+
+ pm_runtime_get(&stm->dev);
+}
+
+static void stm_mmap_close(struct vm_area_struct *vma)
+{
+ struct stm_file *stmf = vma->vm_file->private_data;
+ struct stm_device *stm = stmf->stm;
+
+ pm_runtime_mark_last_busy(&stm->dev);
+ pm_runtime_put_autosuspend(&stm->dev);
+}
+
+static const struct vm_operations_struct stm_mmap_vmops = {
+ .open = stm_mmap_open,
+ .close = stm_mmap_close,
+};
+
static int stm_char_mmap(struct file *file, struct vm_area_struct *vma)
{
struct stm_file *stmf = file->private_data;
@@ -514,8 +541,11 @@ static int stm_char_mmap(struct file *file, struct vm_area_struct *vma)
if (!phys)
return -EINVAL;
+ pm_runtime_get_sync(&stm->dev);
+
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
+ vma->vm_ops = &stm_mmap_vmops;
vm_iomap_memory(vma, phys, size);
return 0;
@@ -701,6 +731,17 @@ int stm_register_device(struct device *parent, struct stm_data *stm_data,
if (err)
goto err_device;
+ /*
+ * Use delayed autosuspend to avoid bouncing back and forth
+ * on recurring character device writes, with the initial
+ * delay time of 2 seconds.
+ */
+ pm_runtime_no_callbacks(&stm->dev);
+ pm_runtime_use_autosuspend(&stm->dev);
+ pm_runtime_set_autosuspend_delay(&stm->dev, 2000);
+ pm_runtime_set_suspended(&stm->dev);
+ pm_runtime_enable(&stm->dev);
+
return 0;
err_device:
@@ -724,6 +765,9 @@ void stm_unregister_device(struct stm_data *stm_data)
struct stm_source_device *src, *iter;
int i, ret;
+ pm_runtime_dont_use_autosuspend(&stm->dev);
+ pm_runtime_disable(&stm->dev);
+
mutex_lock(&stm->link_mutex);
list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) {
ret = __stm_source_link_drop(src, stm);
@@ -878,6 +922,8 @@ static int __stm_source_link_drop(struct stm_source_device *src,
stm_output_free(link, &src->output);
list_del_init(&src->link_entry);
+ pm_runtime_mark_last_busy(&link->dev);
+ pm_runtime_put_autosuspend(&link->dev);
/* matches stm_find_device() from stm_source_link_store() */
stm_put_device(link);
rcu_assign_pointer(src->link, NULL);
@@ -971,8 +1017,11 @@ static ssize_t stm_source_link_store(struct device *dev,
if (!link)
return -EINVAL;
+ pm_runtime_get(&link->dev);
+
err = stm_source_link_add(src, link);
if (err) {
+ pm_runtime_put_autosuspend(&link->dev);
/* matches the stm_find_device() above */
stm_put_device(link);
}
@@ -1033,6 +1082,9 @@ int stm_source_register_device(struct device *parent,
if (err)
goto err;
+ pm_runtime_no_callbacks(&src->dev);
+ pm_runtime_forbid(&src->dev);
+
err = device_add(&src->dev);
if (err)
goto err;