[01/12] ALSA: hda: Allow to fetch hlink by ID

Commit Message

Cezary Rojewski April 4, 2025, 9:49 a.m. UTC

Starting with LNL platform, Intel HDAudio Links carry IDs specifying
non-HDAudio transfer type they help facilitate e.g.: 0xC0 for I2S as
defined by AZX_REG_ML_LEPTR_ID_INTEL_SSP.

The mechanism accounts for LEPTR register as it is Reserved if
LCAP.ALT for given Link equals 0.

Reviewed-by: Amadeusz Sławiński <[e-mail]>
Signed-off-by: Cezary Rojewski <[e-mail]>
---
 include/sound/hdaudio_ext.h         |  5 +++++
 sound/hda/ext/hdac_ext_controller.c | 18 ++++++++++++++++++
 2 files changed, 23 insertions(+)

Patch

diff --git a/include/sound/hdaudio_ext.h b/include/sound/hdaudio_ext.h
index 4c7a40e149a5..60ec12e3b72f 100644
--- a/include/sound/hdaudio_ext.h
+++ b/include/sound/hdaudio_ext.h
@@ -22,6 +22,7 @@  void snd_hdac_ext_bus_ppcap_enable(struct hdac_bus *chip, bool enable);
 void snd_hdac_ext_bus_ppcap_int_enable(struct hdac_bus *chip, bool enable);
 
 int snd_hdac_ext_bus_get_ml_capabilities(struct hdac_bus *bus);
+struct hdac_ext_link *snd_hdac_ext_bus_get_hlink_by_id(struct hdac_bus *bus, u32 id);
 struct hdac_ext_link *snd_hdac_ext_bus_get_hlink_by_addr(struct hdac_bus *bus, int addr);
 struct hdac_ext_link *snd_hdac_ext_bus_get_hlink_by_name(struct hdac_bus *bus,
 							 const char *codec_name);
@@ -97,12 +98,16 @@  struct hdac_ext_link {
 	void __iomem *ml_addr; /* link output stream reg pointer */
 	u32 lcaps;   /* link capablities */
 	u16 lsdiid;  /* link sdi identifier */
+	u32 id;
 
 	int ref_count;
 
 	struct list_head list;
 };
 
+#define hdac_ext_link_alt(link)		((link)->lcaps & AZX_ML_HDA_LCAP_ALT)
+#define hdac_ext_link_ofls(link)	((link)->lcaps & AZX_ML_HDA_LCAP_OFLS)
+
 int snd_hdac_ext_bus_link_power_up(struct hdac_ext_link *hlink);
 int snd_hdac_ext_bus_link_power_down(struct hdac_ext_link *hlink);
 int snd_hdac_ext_bus_link_power_up_all(struct hdac_bus *bus);
diff --git a/sound/hda/ext/hdac_ext_controller.c b/sound/hda/ext/hdac_ext_controller.c
index 6199bb60ccf0..2ec1531d1c1b 100644
--- a/sound/hda/ext/hdac_ext_controller.c
+++ b/sound/hda/ext/hdac_ext_controller.c
@@ -9,6 +9,7 @@ 
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */
 
+#include <linux/bitfield.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <sound/hda_register.h>
@@ -81,6 +82,7 @@  int snd_hdac_ext_bus_get_ml_capabilities(struct hdac_bus *bus)
 	int idx;
 	u32 link_count;
 	struct hdac_ext_link *hlink;
+	u32 leptr;
 
 	link_count = readl(bus->mlcap + AZX_REG_ML_MLCD) + 1;
 
@@ -97,6 +99,11 @@  int snd_hdac_ext_bus_get_ml_capabilities(struct hdac_bus *bus)
 		hlink->lcaps  = readl(hlink->ml_addr + AZX_REG_ML_LCAP);
 		hlink->lsdiid = readw(hlink->ml_addr + AZX_REG_ML_LSDIID);
 
+		if (hdac_ext_link_alt(hlink)) {
+			leptr = readl(hlink->ml_addr + AZX_REG_ML_LEPTR);
+			hlink->id = FIELD_GET(AZX_REG_ML_LEPTR_ID, leptr);
+		}
+
 		/* since link in On, update the ref */
 		hlink->ref_count = 1;
 
@@ -125,6 +132,17 @@  void snd_hdac_ext_link_free_all(struct hdac_bus *bus)
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_link_free_all);
 
+struct hdac_ext_link *snd_hdac_ext_bus_get_hlink_by_id(struct hdac_bus *bus, u32 id)
+{
+	struct hdac_ext_link *hlink;
+
+	list_for_each_entry(hlink, &bus->hlink_list, list)
+		if (hdac_ext_link_alt(hlink) && hlink->id == id)
+			return hlink;
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_get_hlink_by_id);
+
 /**
  * snd_hdac_ext_bus_get_hlink_by_addr - get hlink at specified address
  * @bus: hlink's parent bus device