ASoC: SOF: Intel: hda-mlink: add helper to get sublink LSDIID register

We need to retrieve the current value to deal with the HDAudio
WAKEEN/WAKESTS setup.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Link: https://lore.kernel.org/r/20230807210959.506849-18-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

include/sound/hda-mlink.h

@@ -42,6 +42,7 @@ int hdac_bus_eml_power_down_unlocked(struct hdac_bus *bus, bool alt, int elid, i
 int hdac_bus_eml_sdw_power_up_unlocked(struct hdac_bus *bus, int sublink);
 int hdac_bus_eml_sdw_power_down_unlocked(struct hdac_bus *bus, int sublink);
 
+int hdac_bus_eml_sdw_get_lsdiid_unlocked(struct hdac_bus *bus, int sublink, u16 *lsdiid);
 int hdac_bus_eml_sdw_set_lsdiid(struct hdac_bus *bus, int sublink, int dev_num);
 
 int hdac_bus_eml_sdw_map_stream_ch(struct hdac_bus *bus, int sublink, int y,
@@ -145,6 +146,9 @@ hdac_bus_eml_sdw_power_up_unlocked(struct hdac_bus *bus, int sublink) { return 0
 static inline int
 hdac_bus_eml_sdw_power_down_unlocked(struct hdac_bus *bus, int sublink) { return 0; }
 
+static inline int
+hdac_bus_eml_sdw_get_lsdiid_unlocked(struct hdac_bus *bus, int sublink, u16 *lsdiid) { return 0; }
+
 static inline int
 hdac_bus_eml_sdw_set_lsdiid(struct hdac_bus *bus, int sublink, int dev_num) { return 0; }
 

sound/soc/sof/intel/hda-mlink.c

@@ -331,6 +331,11 @@ static bool hdaml_link_check_cmdsync(u32 __iomem *lsync, u32 cmdsync_mask)
 	return !!(val & cmdsync_mask);
 }
 
+static u16 hdaml_link_get_lsdiid(u16 __iomem *lsdiid)
+{
+	return readw(lsdiid);
+}
+
 static void hdaml_link_set_lsdiid(u16 __iomem *lsdiid, int dev_num)
 {
 	u16 val;
@@ -752,6 +757,22 @@ int hdac_bus_eml_sdw_power_down_unlocked(struct hdac_bus *bus, int sublink)
 }
 EXPORT_SYMBOL_NS(hdac_bus_eml_sdw_power_down_unlocked, SND_SOC_SOF_HDA_MLINK);
 
+int hdac_bus_eml_sdw_get_lsdiid_unlocked(struct hdac_bus *bus, int sublink, u16 *lsdiid)
+{
+	struct hdac_ext2_link *h2link;
+	struct hdac_ext_link *hlink;
+
+	h2link = find_ext2_link(bus, true, AZX_REG_ML_LEPTR_ID_SDW);
+	if (!h2link)
+		return -ENODEV;
+
+	hlink = &h2link->hext_link;
+
+	*lsdiid = hdaml_link_get_lsdiid(hlink->ml_addr + AZX_REG_ML_LSDIID_OFFSET(sublink));
+
+	return 0;
+} EXPORT_SYMBOL_NS(hdac_bus_eml_sdw_get_lsdiid_unlocked, SND_SOC_SOF_HDA_MLINK);
+
 int hdac_bus_eml_sdw_set_lsdiid(struct hdac_bus *bus, int sublink, int dev_num)
 {
 	struct hdac_ext2_link *h2link;