vga_switcheroo: initial implementation (v15)

Many new laptops now come with 2 gpus, one to be used for low power
modes and one for gaming/on-ac applications. These GPUs are typically
wired to the laptop panel and VGA ports via a multiplexer unit which
is controlled via ACPI methods.

4 combinations of systems typically exist - with 2 ACPI methods.
Intel/ATI - Lenovo W500/T500 - use ATPX ACPI method
ATI/ATI - some ASUS - use ATPX ACPI Method
Intel/Nvidia - - use _DSM ACPI method
Nvidia/Nvidia -  - use _DSM ACPI method.

TODO:
This patch adds support for the ATPX method and initial bits
for the _DSM methods that need to written by someone with
access to the hardware.
Add a proper non-debugfs interface - need to get some proper
testing first.

v2: add power up/down support for both devices
on W500 puts i915/radeon into D3 and cuts power to radeon.

v3: redo probing methods, no DMI list, drm devices call to
register with switcheroo, it tries to find an ATPX method on
any device and once there is two devices + ATPX it inits the
switcher.

v4: ATPX msg handling using buffers - should work on more machines

v5: rearchitect after more mjg59 discussion - move ATPX handling to
    radeon driver.

v6: add file headers + initial nouveau bits (to be filled out).

v7: merge delayed switcher code.

v8: avoid suspend/resume of gpu that is off

v9: rearchitect - mjg59 is always right. - move all ATPX code to
radeon, should allow simpler DSM also proper ATRM handling

v10: add ATRM support for radeon BIOS, add mutex to lock vgasr_priv

v11: fix bug in resuming Intel for 2nd time.

v12: start fixing up nvidia code blindly.

v13: blindly guess at finishing nvidia code

v14: remove radeon audio hacks - fix up intel resume more like upstream

v15: clean up printks + remove unnecessary igd/dis pointers

mount debugfs

/sys/kernel/debug/vgaswitcheroo/switch - should exist if ATPX detected
 + 2 cards.

DIS - immediate change to discrete
IGD - immediate change to IGD
DDIS - delayed change to discrete
DIGD - delayed change to IGD
ON - turn on not in use
OFF - turn off not in use

Tested on W500 (Intel/ATI) and T500 (Intel/ATI)

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 258 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_atpx_handler.c b/drivers/gpu/drm/radeon/radeon_atpx_handler.c
new file mode 100644
index 000000000000..0ae52f19071d
--- /dev/null
+++ b/drivers/gpu/drm/radeon/radeon_atpx_handler.c
@@ -0,0 +1,258 @@
+/*
+ * Copyright (c) 2010 Red Hat Inc.
+ * Author : Dave Airlie <airlied@redhat.com>
+ *
+ * Licensed under GPLv2
+ *
+ * ATPX support for both Intel/ATI
+ */
+
+#include <linux/vga_switcheroo.h>
+#include <acpi/acpi.h>
+#include <acpi/acpi_bus.h>
+#include <linux/pci.h>
+
+#define ATPX_VERSION 0
+#define ATPX_GPU_PWR 2
+#define ATPX_MUX_SELECT 3
+
+#define ATPX_INTEGRATED 0
+#define ATPX_DISCRETE 1
+
+#define ATPX_MUX_IGD 0
+#define ATPX_MUX_DISCRETE 1
+
+static struct radeon_atpx_priv {
+	bool atpx_detected;
+	/* handle for device - and atpx */
+	acpi_handle dhandle;
+	acpi_handle atpx_handle;
+	acpi_handle atrm_handle;
+} radeon_atpx_priv;
+
+/* retrieve the ROM in 4k blocks */
+static int radeon_atrm_call(acpi_handle atrm_handle, uint8_t *bios,
+			    int offset, int len)
+{
+	acpi_status status;
+	union acpi_object atrm_arg_elements[2], *obj;
+	struct acpi_object_list atrm_arg;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL};
+
+	atrm_arg.count = 2;
+	atrm_arg.pointer = &atrm_arg_elements[0];
+
+	atrm_arg_elements[0].type = ACPI_TYPE_INTEGER;
+	atrm_arg_elements[0].integer.value = offset;
+
+	atrm_arg_elements[1].type = ACPI_TYPE_INTEGER;
+	atrm_arg_elements[1].integer.value = len;
+
+	status = acpi_evaluate_object(atrm_handle, NULL, &atrm_arg, &buffer);
+	if (ACPI_FAILURE(status)) {
+		printk("failed to evaluate ATRM got %s\n", acpi_format_exception(status));
+		return -ENODEV;
+	}
+
+	obj = (union acpi_object *)buffer.pointer;
+	memcpy(bios+offset, obj->buffer.pointer, len);
+	kfree(buffer.pointer);
+	return len;
+}
+
+bool radeon_atrm_supported(struct pci_dev *pdev)
+{
+	/* get the discrete ROM only via ATRM */
+	if (!radeon_atpx_priv.atpx_detected)
+		return false;
+
+	if (radeon_atpx_priv.dhandle == DEVICE_ACPI_HANDLE(&pdev->dev))
+		return false;
+	return true;
+}
+
+
+int radeon_atrm_get_bios_chunk(uint8_t *bios, int offset, int len)
+{
+	return radeon_atrm_call(radeon_atpx_priv.atrm_handle, bios, offset, len);
+}
+
+static int radeon_atpx_get_version(acpi_handle handle)
+{
+	acpi_status status;
+	union acpi_object atpx_arg_elements[2], *obj;
+	struct acpi_object_list atpx_arg;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+
+	atpx_arg.count = 2;
+	atpx_arg.pointer = &atpx_arg_elements[0];
+
+	atpx_arg_elements[0].type = ACPI_TYPE_INTEGER;
+	atpx_arg_elements[0].integer.value = ATPX_VERSION;
+
+	atpx_arg_elements[1].type = ACPI_TYPE_INTEGER;
+	atpx_arg_elements[1].integer.value = ATPX_VERSION;
+
+	status = acpi_evaluate_object(handle, NULL, &atpx_arg, &buffer);
+	if (ACPI_FAILURE(status)) {
+		printk("%s: failed to call ATPX: %s\n", __func__, acpi_format_exception(status));
+		return -ENOSYS;
+	}
+	obj = (union acpi_object *)buffer.pointer;
+	if (obj && (obj->type == ACPI_TYPE_BUFFER))
+		printk(KERN_INFO "radeon atpx: version is %d\n", *((u8 *)(obj->buffer.pointer) + 2));
+	kfree(buffer.pointer);
+	return 0;
+}
+
+static int radeon_atpx_execute(acpi_handle handle, int cmd_id, u16 value)
+{
+	acpi_status status;
+	union acpi_object atpx_arg_elements[2];
+	struct acpi_object_list atpx_arg;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	uint8_t buf[4] = {0};
+
+	if (!handle)
+		return -EINVAL;
+
+	atpx_arg.count = 2;
+	atpx_arg.pointer = &atpx_arg_elements[0];
+
+	atpx_arg_elements[0].type = ACPI_TYPE_INTEGER;
+	atpx_arg_elements[0].integer.value = cmd_id;
+
+	buf[2] = value & 0xff;
+	buf[3] = (value >> 8) & 0xff;
+
+	atpx_arg_elements[1].type = ACPI_TYPE_BUFFER;
+	atpx_arg_elements[1].buffer.length = 4;
+	atpx_arg_elements[1].buffer.pointer = buf;
+
+	status = acpi_evaluate_object(handle, NULL, &atpx_arg, &buffer);
+	if (ACPI_FAILURE(status)) {
+		printk("%s: failed to call ATPX: %s\n", __func__, acpi_format_exception(status));
+		return -ENOSYS;
+	}
+	kfree(buffer.pointer);
+
+	return 0;
+}
+
+static int radeon_atpx_set_discrete_state(acpi_handle handle, int state)
+{
+	return radeon_atpx_execute(handle, ATPX_GPU_PWR, state);
+}
+
+static int radeon_atpx_switch_mux(acpi_handle handle, int mux_id)
+{
+	return radeon_atpx_execute(handle, ATPX_MUX_SELECT, mux_id);
+}
+
+
+static int radeon_atpx_switchto(enum vga_switcheroo_client_id id)
+{
+	if (id == VGA_SWITCHEROO_IGD)
+		radeon_atpx_switch_mux(radeon_atpx_priv.atpx_handle, 0);
+	else
+		radeon_atpx_switch_mux(radeon_atpx_priv.atpx_handle, 1);
+	return 0;
+}
+
+static int radeon_atpx_power_state(enum vga_switcheroo_client_id id,
+				   enum vga_switcheroo_state state)
+{
+	/* on w500 ACPI can't change intel gpu state */
+	if (id == VGA_SWITCHEROO_IGD)
+		return 0;
+
+	radeon_atpx_set_discrete_state(radeon_atpx_priv.atpx_handle, state);
+	return 0;
+}
+
+static bool radeon_atpx_pci_probe_handle(struct pci_dev *pdev)
+{
+	acpi_handle dhandle, atpx_handle, atrm_handle;
+	acpi_status status;
+
+	dhandle = DEVICE_ACPI_HANDLE(&pdev->dev);
+	if (!dhandle)
+		return false;
+
+	status = acpi_get_handle(dhandle, "ATPX", &atpx_handle);
+	if (ACPI_FAILURE(status))
+		return false;
+
+	status = acpi_get_handle(dhandle, "ATRM", &atrm_handle);
+	if (ACPI_FAILURE(status))
+		return false;
+
+	radeon_atpx_priv.dhandle = dhandle;
+	radeon_atpx_priv.atpx_handle = atpx_handle;
+	radeon_atpx_priv.atrm_handle = atrm_handle;
+	return true;
+}
+
+static int radeon_atpx_init(void)
+{
+	/* set up the ATPX handle */
+
+	radeon_atpx_get_version(radeon_atpx_priv.atpx_handle);
+	return 0;
+}
+
+static int radeon_atpx_get_client_id(struct pci_dev *pdev)
+{
+	if (radeon_atpx_priv.dhandle == DEVICE_ACPI_HANDLE(&pdev->dev))
+		return VGA_SWITCHEROO_IGD;
+	else
+		return VGA_SWITCHEROO_DIS;
+}
+
+static struct vga_switcheroo_handler radeon_atpx_handler = {
+	.switchto = radeon_atpx_switchto,
+	.power_state = radeon_atpx_power_state,
+	.init = radeon_atpx_init,
+	.get_client_id = radeon_atpx_get_client_id,
+};
+
+static bool radeon_atpx_detect(void)
+{
+	char acpi_method_name[255] = { 0 };
+	struct acpi_buffer buffer = {sizeof(acpi_method_name), acpi_method_name};
+	struct pci_dev *pdev = NULL;
+	bool has_atpx = false;
+	int vga_count = 0;
+
+	while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev)) != NULL) {
+		vga_count++;
+
+		has_atpx |= (radeon_atpx_pci_probe_handle(pdev) == true);
+	}
+
+	if (has_atpx && vga_count == 2) {
+		acpi_get_name(radeon_atpx_priv.atpx_handle, ACPI_FULL_PATHNAME, &buffer);
+		printk(KERN_INFO "VGA switcheroo: detected switching method %s handle\n",
+		       acpi_method_name);
+		radeon_atpx_priv.atpx_detected = true;
+		return true;
+	}
+	return false;
+}
+
+void radeon_register_atpx_handler(void)
+{
+	bool r;
+
+	/* detect if we have any ATPX + 2 VGA in the system */
+	r = radeon_atpx_detect();
+	if (!r)
+		return;
+
+	vga_switcheroo_register_handler(&radeon_atpx_handler);
+}
+
+void radeon_unregister_atpx_handler(void)
+{
+	vga_switcheroo_unregister_handler();
+}