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ALSA: hdac: add link pm and ref counting

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The HDA links can be switched off when not is use, similarly
command DMA can be stopped as well. This calls for a reference
counting mechanism on the link by it's users to manage the link
power. The DMA can be turned off when all links are off

For this we add two APIs
	snd_hdac_ext_bus_link_get
	snd_hdac_ext_bus_link_put

They help users to turn up/down link and manage the DMA as well

Signed-off-by: Jeeja KP <jeeja.kp@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Vinod Koul
2016-05-12 08:58:53 +05:30
committed by Mark Brown
parent bfb7802a06
commit 4446085d21
3 changed files with 82 additions and 0 deletions
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3
sound/hda/ext/hdac_ext_bus.c
View File

@@ -105,6 +105,9 @@ int snd_hdac_ext_bus_init(struct hdac_ext_bus *ebus, struct device *dev,
INIT_LIST_HEAD(&ebus->hlink_list);
ebus->idx = idx++;
mutex_init(&ebus->lock);
ebus->cmd_dma_state = true;
return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_init);

66
sound/hda/ext/hdac_ext_controller.c
View File

@@ -186,6 +186,9 @@ int snd_hdac_ext_bus_get_ml_capabilities(struct hdac_ext_bus *ebus)
hlink->lcaps = readl(hlink->ml_addr + AZX_REG_ML_LCAP);
hlink->lsdiid = readw(hlink->ml_addr + AZX_REG_ML_LSDIID);
/* since link in On, update the ref */
hlink->ref_count = 1;
list_add_tail(&hlink->list, &ebus->hlink_list);
}
@@ -327,3 +330,66 @@ int snd_hdac_ext_bus_link_power_down_all(struct hdac_ext_bus *ebus)
return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_down_all);
int snd_hdac_ext_bus_link_get(struct hdac_ext_bus *ebus,
struct hdac_ext_link *link)
{
int ret = 0;
mutex_lock(&ebus->lock);
/*
* if we move from 0 to 1, count will be 1 so power up this link
* as well, also check the dma status and trigger that
*/
if (++link->ref_count == 1) {
if (!ebus->cmd_dma_state) {
snd_hdac_bus_init_cmd_io(&ebus->bus);
ebus->cmd_dma_state = true;
}
ret = snd_hdac_ext_bus_link_power_up(link);
}
mutex_unlock(&ebus->lock);
return ret;
}
EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_get);
int snd_hdac_ext_bus_link_put(struct hdac_ext_bus *ebus,
struct hdac_ext_link *link)
{
int ret = 0;
struct hdac_ext_link *hlink;
bool link_up = false;
mutex_lock(&ebus->lock);
/*
* if we move from 1 to 0, count will be 0
* so power down this link as well
*/
if (--link->ref_count == 0) {
ret = snd_hdac_ext_bus_link_power_down(link);
/*
* now check if all links are off, if so turn off
* cmd dma as well
*/
list_for_each_entry(hlink, &ebus->hlink_list, list) {
if (hlink->ref_count) {
link_up = true;
break;
}
}
if (!link_up) {
snd_hdac_bus_stop_cmd_io(&ebus->bus);
ebus->cmd_dma_state = false;
}
}
mutex_unlock(&ebus->lock);
return ret;
}
EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_put);