[PATCH 1/2] soundwire: slave: introduce DMI quirks for HP Spectre x360 Convertible

[Pierre-Louis Bossart]

HP Spectre x360 Convertible devices expose invalid _ADR fields in the
DSDT, which prevents codec drivers from probing. A possible solution
is to override the DSDT, but that's just too painful for users.

This patch suggests a simple DMI-based quirk to remap the existing
invalid ADR information into valid ones.

BugLink: https://github.com/thesofproject/linux/issues/2700
Co-developed-by: Bard Liao <yung-chuan.liao at linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao at linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>
Reviewed-by: Bard Liao <bard.liao at intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski at intel.com>
---
 drivers/soundwire/slave.c | 50 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c
index 180f38bd003b..abdc1ae94e9c 100644
--- a/drivers/soundwire/slave.c
+++ b/drivers/soundwire/slave.c
@@ -2,6 +2,7 @@
 // Copyright(c) 2015-17 Intel Corporation.
 
 #include <linux/acpi.h>
+#include <linux/dmi.h>
 #include <linux/of.h>
 #include <linux/soundwire/sdw.h>
 #include <linux/soundwire/sdw_type.h>
@@ -91,10 +92,44 @@ int sdw_slave_add(struct sdw_bus *bus,
 
 #if IS_ENABLED(CONFIG_ACPI)
 
+struct adr_remap {
+	u64 adr;
+	u64 remapped_adr;
+};
+
+/*
+ * HP Spectre 360 Convertible devices do not expose the correct _ADR
+ * in the DSDT.
+ * Remap the bad _ADR values to the ones reported by hardware
+ */
+static const struct adr_remap hp_spectre_360[] = {
+	{
+		0x000010025D070100,
+		0x000020025D071100
+	},
+	{
+		0x000110025d070100,
+		0x000120025D130800
+	},
+	{}
+};
+
+static const struct dmi_system_id adr_remap_quirk_table[] = {
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "HP Spectre x360 Convertible"),
+		},
+		.driver_data = (void *)hp_spectre_360,
+	},
+	{}
+};
+
 static bool find_slave(struct sdw_bus *bus,
 		       struct acpi_device *adev,
 		       struct sdw_slave_id *id)
 {
+	const struct dmi_system_id *dmi_id;
 	unsigned long long addr;
 	unsigned int link_id;
 	acpi_status status;
@@ -108,6 +143,21 @@ static bool find_slave(struct sdw_bus *bus,
 		return false;
 	}
 
+	/* check if any address remap quirk applies */
+	dmi_id = dmi_first_match(adr_remap_quirk_table);
+	if (dmi_id) {
+		struct adr_remap *map = dmi_id->driver_data;
+
+		for (map = dmi_id->driver_data; map->adr; map++) {
+			if (map->adr == addr) {
+				dev_dbg(bus->dev, "remapped _ADR 0x%llx as 0x%llx\n",
+					addr, map->remapped_adr);
+				addr = map->remapped_adr;
+				break;
+			}
+		}
+	}
+
 	/* Extract link id from ADR, Bit 51 to 48 (included) */
 	link_id = SDW_DISCO_LINK_ID(addr);
 
-- 
2.25.1