ACPI: Add support for native USB4 control _OSC

ACPI 6.4 introduced a new _OSC capability that is used negotiate native
connection manager support. Connection manager is the entity that is
responsible for tunneling over the USB4 fabric. If the platform rejects
the native access then firmware based connection manager is used.

The new _OSC also includes a set of bits that can be used to disable
certain tunnel types such as PCIe for security reasons for instance.

This implements the new USB4 _OSC so that we try to negotiate native
USB4 support if the Thunderbolt/USB4 (CONFIG_USB4) driver is enabled.
Drivers can determine what was negotiated by checking two new variables
exposed in this patch.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 76 insertions, 0 deletions

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index a52cb28c40d8..9c3fe08e8f18 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -281,6 +281,12 @@ bool osc_sb_apei_support_acked;
 bool osc_pc_lpi_support_confirmed;
 EXPORT_SYMBOL_GPL(osc_pc_lpi_support_confirmed);
 
+/*
+ * ACPI 6.4 Operating System Capabilities for USB.
+ */
+bool osc_sb_native_usb4_support_confirmed;
+EXPORT_SYMBOL_GPL(osc_sb_native_usb4_support_confirmed);
+
 static u8 sb_uuid_str[] = "0811B06E-4A27-44F9-8D60-3CBBC22E7B48";
 static void acpi_bus_osc_negotiate_platform_control(void)
 {
@@ -317,6 +323,9 @@ static void acpi_bus_osc_negotiate_platform_control(void)
 	if (IS_ENABLED(CONFIG_SCHED_MC_PRIO))
 		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_CPC_DIVERSE_HIGH_SUPPORT;
 
+	if (IS_ENABLED(CONFIG_USB4))
+		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_NATIVE_USB4_SUPPORT;
+
 	if (!ghes_disable)
 		capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_APEI_SUPPORT;
 	if (ACPI_FAILURE(acpi_get_handle(NULL, "\\_SB", &handle)))
@@ -348,8 +357,74 @@ static void acpi_bus_osc_negotiate_platform_control(void)
 			capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_APEI_SUPPORT;
 		osc_pc_lpi_support_confirmed =
 			capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_PCLPI_SUPPORT;
+		osc_sb_native_usb4_support_confirmed =
+			capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_NATIVE_USB4_SUPPORT;
+	}
+
+	kfree(context.ret.pointer);
+}
+
+/*
+ * Native control of USB4 capabilities. If any of the tunneling bits is
+ * set it means OS is in control and we use software based connection
+ * manager.
+ */
+u32 osc_sb_native_usb4_control;
+EXPORT_SYMBOL_GPL(osc_sb_native_usb4_control);
+
+static void acpi_bus_decode_usb_osc(const char *msg, u32 bits)
+{
+	printk(KERN_INFO PREFIX "%s USB3%c DisplayPort%c PCIe%c XDomain%c\n", msg,
+	       (bits & OSC_USB_USB3_TUNNELING) ? '+' : '-',
+	       (bits & OSC_USB_DP_TUNNELING) ? '+' : '-',
+	       (bits & OSC_USB_PCIE_TUNNELING) ? '+' : '-',
+	       (bits & OSC_USB_XDOMAIN) ? '+' : '-');
+}
+
+static u8 sb_usb_uuid_str[] = "23A0D13A-26AB-486C-9C5F-0FFA525A575A";
+static void acpi_bus_osc_negotiate_usb_control(void)
+{
+	u32 capbuf[3];
+	struct acpi_osc_context context = {
+		.uuid_str = sb_usb_uuid_str,
+		.rev = 1,
+		.cap.length = sizeof(capbuf),
+		.cap.pointer = capbuf,
+	};
+	acpi_handle handle;
+	acpi_status status;
+	u32 control;
+
+	if (!osc_sb_native_usb4_support_confirmed)
+		return;
+
+	if (ACPI_FAILURE(acpi_get_handle(NULL, "\\_SB", &handle)))
+		return;
+
+	control = OSC_USB_USB3_TUNNELING | OSC_USB_DP_TUNNELING |
+		  OSC_USB_PCIE_TUNNELING | OSC_USB_XDOMAIN;
+
+	capbuf[OSC_QUERY_DWORD] = 0;
+	capbuf[OSC_SUPPORT_DWORD] = 0;
+	capbuf[OSC_CONTROL_DWORD] = control;
+
+	status = acpi_run_osc(handle, &context);
+	if (ACPI_FAILURE(status))
+		return;
+
+	if (context.ret.length != sizeof(capbuf)) {
+		printk(KERN_INFO PREFIX "USB4 _OSC: returned invalid length buffer\n");
+		goto out_free;
 	}
 
+	osc_sb_native_usb4_control =
+		control & ((u32 *)context.ret.pointer)[OSC_CONTROL_DWORD];
+
+	acpi_bus_decode_usb_osc("USB4 _OSC: OS supports", control);
+	acpi_bus_decode_usb_osc("USB4 _OSC: OS controls",
+				osc_sb_native_usb4_control);
+
+out_free:
 	kfree(context.ret.pointer);
 }
 
@@ -1188,6 +1263,7 @@ static int __init acpi_bus_init(void)
 	 * so it must be run after ACPI_FULL_INITIALIZATION
 	 */
 	acpi_bus_osc_negotiate_platform_control();
+	acpi_bus_osc_negotiate_usb_control();
 
 	/*
 	 * _PDC control method may load dynamic SSDT tables,