Signed-off-by: Daniel Dadap <ddadap@xxxxxxxxxx>
---
MAINTAINERS | 6 +
drivers/platform/x86/Kconfig | 9 ++
drivers/platform/x86/Makefile | 2 +
drivers/platform/x86/mxds-gmux.c | 265 +++++++++++++++++++++++++++++++
4 files changed, 282 insertions(+)
create mode 100644 drivers/platform/x86/mxds-gmux.c
diff --git a/MAINTAINERS b/MAINTAINERS
index eeff55560759..636c9259b345 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11510,6 +11510,12 @@ L: linux-usb@xxxxxxxxxxxxxxx
S: Maintained
F: drivers/usb/musb/
+MXDS GMUX DRIVER
+M: Daniel Dadap <ddadap@xxxxxxxxxx>
+L: platform-driver-x86@xxxxxxxxxxxxxxx
+S: Supported
+F: drivers/platform/x86/mxds-gmux.c
+
MXL301RF MEDIA DRIVER
M: Akihiro Tsukada <tskd08@xxxxxxxxx>
L: linux-media@xxxxxxxxxxxxxxx
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 0ad7ad8cf8e1..5d00ad1ffc0e 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1368,6 +1368,15 @@ config INTEL_TELEMETRY
directly via debugfs files. Various tools may use
this interface for SoC state monitoring.
+config MXDS_GMUX
+ tristate "ACPI MXDS Gmux Driver"
+ depends on ACPI_WMI
+ depends on ACPI
+ depends on VGA_SWITCHEROO
+ help
+ This driver provides support for ACPI-driven gmux devices which are
+ present on some notebook designs with hybrid graphics.
+
endif # X86_PLATFORM_DEVICES
config PMC_ATOM
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 53408d965874..b79000733fae 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -146,3 +146,5 @@ obj-$(CONFIG_INTEL_TELEMETRY) += intel_telemetry_core.o \
intel_telemetry_pltdrv.o \
intel_telemetry_debugfs.o
obj-$(CONFIG_PMC_ATOM) += pmc_atom.o
+
+obj-$(CONFIG_MXDS_GMUX) += mxds-gmux.o
diff --git a/drivers/platform/x86/mxds-gmux.c b/drivers/platform/x86/mxds-gmux.c
new file mode 100644
index 000000000000..dd7f6edaf0f3
--- /dev/null
+++ b/drivers/platform/x86/mxds-gmux.c
@@ -0,0 +1,265 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * mxds-gmux: vga_switcheroo mux handler for ACPI MXDS muxes
+ *
+ * Copyright (C) 2020 NVIDIA Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses>.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/pci.h>
+#include <linux/vga_switcheroo.h>
+#include <linux/delay.h>
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("vga_switcheroo mux handler for ACPI MXDS muxes");
+MODULE_AUTHOR("Daniel Dadap <ddadap@xxxxxxxxxx>");
+
+/*
+ * The mux doesn't have its own ACPI HID/CID, or WMI wrapper, so key off of
+ * the WMI wrapper for the related WMAA method for backlight control.
+ */
+MODULE_ALIAS("wmi:603E9613-EF25-4338-A3D0-C46177516DB7");
+
+static struct pci_dev *ig_dev, *dg_dev;
+static acpi_handle internal_mux_handle;
+static acpi_handle external_mux_handle;
+
+enum acpi_method {
+ MXDM = 0,
+ MXDS,
+ NUM_ACPI_METHODS
+};
+
+static char *acpi_methods[NUM_ACPI_METHODS] = {
+ [MXDM] = "MXDM",
+ [MXDS] = "MXDS",
+};
+
+enum mux_mode_command {
+ MUX_MODE_GET = 0,
+};
+
+enum mux_mode {
+ MUX_MODE_DGPU_ONLY = 1,
+ MUX_MODE_IGPU_ONLY = 2,
+ MUX_MODE_MSHYBRID = 3, /* Dual GPU, mux switched to iGPU */
+ MUX_MODE_DYNAMIC = 4, /* Dual GPU, dynamic mux switching */
+};
+
+/*
+ * Call MXDS with argument value 0 to read the current state.
+ * When reading, a return value of 1 means iGPU and 2 means dGPU.
+ * Call MXDS with bit 0 set to change the current state.
+ * When changing state, clear bit 4 for iGPU and set bit 4 for dGPU.
+ */
+
+enum mux_state {
+ MUX_STATE_IGPU = 1,
+ MUX_STATE_DGPU = 2,
+};
+
+enum mux_state_command {
+ MUX_STATE_GET = 0,
+ MUX_STATE_SET_IGPU = BIT(0),
+ MUX_STATE_SET_DGPU = BIT(4) | BIT(0),
+};
+
+static acpi_integer acpi_helper(acpi_handle handle, enum acpi_method method,
+ acpi_integer action)
+{
+ union acpi_object arg = {
+ .integer = { .type = ACPI_TYPE_INTEGER, .value = action }
+ };
+ struct acpi_object_list in = {.count = 1, .pointer = &arg};
+ acpi_integer ret;
+ acpi_status status;
+
+ status = acpi_evaluate_integer(handle, acpi_methods[method], &in, &ret);
+
+ if (ACPI_FAILURE(status)) {
+ pr_err("ACPI %s failed: %s\n", acpi_methods[method],
+ acpi_format_exception(status));
+ return 0;
+ }
+
+ return ret;
+}
+
+static acpi_integer get_mux_mode(acpi_handle handle)
+{
+ return acpi_helper(handle, MXDM, MUX_MODE_GET);
+}
+
+static acpi_integer get_mux_state(acpi_handle handle)
+{
+ return acpi_helper(handle, MXDS, MUX_STATE_GET);
+}
+
+static void set_mux_state(acpi_handle handle, enum mux_state state)
+{
+ enum mux_state_command command;
+
+ switch (state) {
+ case MUX_STATE_IGPU:
+ command = MUX_STATE_SET_IGPU;
+ break;
+ case MUX_STATE_DGPU:
+ command = MUX_STATE_SET_DGPU;
+ break;
+ default:
+ return;
+ }
+
+ acpi_helper(handle, MXDS, command);
+}
+
+static int mxds_gmux_switchto(enum vga_switcheroo_client_id id)
+{
+ enum mux_state state;
+
+ switch (id) {
+ case VGA_SWITCHEROO_IGD:
+ state = MUX_STATE_IGPU;
+ break;
+ case VGA_SWITCHEROO_DIS:
+ state = MUX_STATE_DGPU;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (internal_mux_handle) {
+ set_mux_state(internal_mux_handle, state);
+ if (get_mux_state(internal_mux_handle) != state)
+ return -EAGAIN;
+ }
+
+ if (external_mux_handle) {
+ set_mux_state(external_mux_handle, state);
+ if (get_mux_state(external_mux_handle) != state)
+ return -EAGAIN;
+ }
+
+ /* DP AUX can take up to 100ms to settle after mux switch */
+ mdelay(100);
+
+ return 0;
+}
+
+static enum vga_switcheroo_client_id mxds_gmux_get_client_id(
+ struct pci_dev *dev)
+{
+ if (dev == ig_dev)
+ return VGA_SWITCHEROO_IGD;
+ if (dev == dg_dev)
+ return VGA_SWITCHEROO_DIS;
+
+ return VGA_SWITCHEROO_UNKNOWN_ID;
+}
+
+static const struct vga_switcheroo_handler handler = {
+ .switchto = mxds_gmux_switchto,
+ .get_client_id = mxds_gmux_get_client_id,
+};
+
+static acpi_status find_acpi_methods(
+ acpi_handle object, u32 nesting_level, void *context,
+ void **return_value)
+{
+ acpi_handle search;
+
+ /* If either MXDM or MXDS is missing, we can't use this object */
+ if (acpi_get_handle(object, "MXDM", &search))
+ return AE_OK;
+ if (acpi_get_handle(object, "MXDS", &search))
+ return AE_OK;
+
+ /* MXDS only works when MXDM indicates dynamic mode */
+ if (get_mux_mode(object) != MUX_MODE_DYNAMIC)
+ return AE_OK;
+
+ /* Internal display has _BCL; external does not */
+ if (acpi_get_handle(object, "_BCL", &search))
+ external_mux_handle = object;
+ else
+ internal_mux_handle = object;
+
+ return AE_OK;
+}
+
+static int __init mxds_gmux_init(void)
+{
+ int ret = 0;
+ struct pci_dev *dev = NULL;
+
+ /* Currently only supports Intel integrated and NVIDIA discrete GPUs */
+ while ((dev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, dev))) {
+ /* Ignore eGPU */
+ if (pci_is_thunderbolt_attached(dev))
+ continue;
+
+ switch (dev->vendor) {
+ case PCI_VENDOR_ID_INTEL:
+ pci_dev_put(ig_dev);
+ ig_dev = pci_dev_get(dev);
+ break;
+ case PCI_VENDOR_ID_NVIDIA:
+ pci_dev_put(dg_dev);
+ dg_dev = pci_dev_get(dev);
+ break;
+ default:
+ break;
+ }
+ }
+
+ /* Require both integrated and discrete GPUs */
+ if (!ig_dev || !dg_dev) {
+ ret = -ENODEV;
+ goto done;
+ }
+
+ acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX,
+ find_acpi_methods, NULL, NULL, NULL);
+
+ /* Require at least one mux */
+ if (!internal_mux_handle && !external_mux_handle) {
+ ret = -ENODEV;
+ goto done;
+ }
+
+ ret = vga_switcheroo_register_handler(&handler, 0);
+
+done:
+
+ if (ret) {
+ pci_dev_put(ig_dev);
+ pci_dev_put(dg_dev);
+ }
+
+ return ret;
+}
+module_init(mxds_gmux_init);
+
+static void __exit mxds_gmux_exit(void)
+{
+ vga_switcheroo_unregister_handler();
+ pci_dev_put(ig_dev);
+ pci_dev_put(dg_dev);
+}
+module_exit(mxds_gmux_exit);
