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>
diff --git a/drivers/gpu/drm/radeon/Makefile b/drivers/gpu/drm/radeon/Makefile
index 1cc7b93..8e62fe1 100644
--- a/drivers/gpu/drm/radeon/Makefile
+++ b/drivers/gpu/drm/radeon/Makefile
@@ -54,7 +54,8 @@
 	radeon_cs.o radeon_bios.o radeon_benchmark.o r100.o r300.o r420.o \
 	rs400.o rs600.o rs690.o rv515.o r520.o r600.o rv770.o radeon_test.o \
 	r200.o radeon_legacy_tv.o r600_cs.o r600_blit.o r600_blit_shaders.o \
-	r600_blit_kms.o radeon_pm.o atombios_dp.o r600_audio.o r600_hdmi.o
+	r600_blit_kms.o radeon_pm.o atombios_dp.o r600_audio.o r600_hdmi.o \
+	radeon_atpx_handler.o
 
 radeon-$(CONFIG_COMPAT) += radeon_ioc32.o
 
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index c0356bb..a5dfb15 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -118,6 +118,10 @@
 /*
  * BIOS.
  */
+#define ATRM_BIOS_PAGE 4096
+
+bool radeon_atrm_supported(struct pci_dev *pdev);
+int radeon_atrm_get_bios_chunk(uint8_t *bios, int offset, int len);
 bool radeon_get_bios(struct radeon_device *rdev);
 
 
@@ -838,6 +842,8 @@
 	int			audio_bits_per_sample;
 	uint8_t			audio_status_bits;
 	uint8_t			audio_category_code;
+
+	bool powered_down;
 };
 
 int radeon_device_init(struct radeon_device *rdev,
@@ -1042,6 +1048,8 @@
 extern void radeon_atom_set_clock_gating(struct radeon_device *rdev, int enable);
 extern void radeon_ttm_placement_from_domain(struct radeon_bo *rbo, u32 domain);
 extern bool radeon_ttm_bo_is_radeon_bo(struct ttm_buffer_object *bo);
+extern int radeon_resume_kms(struct drm_device *dev);
+extern int radeon_suspend_kms(struct drm_device *dev, pm_message_t state);
 
 /* r100,rv100,rs100,rv200,rs200,r200,rv250,rs300,rv280 */
 struct r100_mc_save {
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 0000000..0ae52f1
--- /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();
+}
diff --git a/drivers/gpu/drm/radeon/radeon_bios.c b/drivers/gpu/drm/radeon/radeon_bios.c
index 9069217..a34b909 100644
--- a/drivers/gpu/drm/radeon/radeon_bios.c
+++ b/drivers/gpu/drm/radeon/radeon_bios.c
@@ -30,6 +30,7 @@
 #include "radeon.h"
 #include "atom.h"
 
+#include <linux/vga_switcheroo.h>
 /*
  * BIOS.
  */
@@ -62,7 +63,7 @@
 		iounmap(bios);
 		return false;
 	}
-	memcpy(rdev->bios, bios, size);
+	memcpy_fromio(rdev->bios, bios, size);
 	iounmap(bios);
 	return true;
 }
@@ -93,6 +94,38 @@
 	return true;
 }
 
+/* ATRM is used to get the BIOS on the discrete cards in
+ * dual-gpu systems.
+ */
+static bool radeon_atrm_get_bios(struct radeon_device *rdev)
+{
+	int ret;
+	int size = 64 * 1024;
+	int i;
+
+	if (!radeon_atrm_supported(rdev->pdev))
+		return false;
+
+	rdev->bios = kmalloc(size, GFP_KERNEL);
+	if (!rdev->bios) {
+		DRM_ERROR("Unable to allocate bios\n");
+		return false;
+	}
+
+	for (i = 0; i < size / ATRM_BIOS_PAGE; i++) {
+		ret = radeon_atrm_get_bios_chunk(rdev->bios,
+						 (i * ATRM_BIOS_PAGE),
+						 ATRM_BIOS_PAGE);
+		if (ret <= 0)
+			break;
+	}
+
+	if (i == 0 || rdev->bios[0] != 0x55 || rdev->bios[1] != 0xaa) {
+		kfree(rdev->bios);
+		return false;
+	}
+	return true;
+}
 static bool r700_read_disabled_bios(struct radeon_device *rdev)
 {
 	uint32_t viph_control;
@@ -388,16 +421,16 @@
 		return legacy_read_disabled_bios(rdev);
 }
 
+
 bool radeon_get_bios(struct radeon_device *rdev)
 {
 	bool r;
 	uint16_t tmp;
 
-	if (rdev->flags & RADEON_IS_IGP) {
+	r = radeon_atrm_get_bios(rdev);
+	if (r == false)
 		r = igp_read_bios_from_vram(rdev);
-		if (r == false)
-			r = radeon_read_bios(rdev);
-	} else
+	if (r == false)
 		r = radeon_read_bios(rdev);
 	if (r == false) {
 		r = radeon_read_disabled_bios(rdev);
@@ -408,6 +441,7 @@
 		return false;
 	}
 	if (rdev->bios[0] != 0x55 || rdev->bios[1] != 0xaa) {
+		printk("BIOS signature incorrect %x %x\n", rdev->bios[0], rdev->bios[1]);
 		goto free_bios;
 	}
 
diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index 768b150..cb8d9a1 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -30,6 +30,7 @@
 #include <drm/drm_crtc_helper.h>
 #include <drm/radeon_drm.h>
 #include <linux/vgaarb.h>
+#include <linux/vga_switcheroo.h>
 #include "radeon_reg.h"
 #include "radeon.h"
 #include "radeon_asic.h"
@@ -613,6 +614,36 @@
 	}
 }
 
+static void radeon_switcheroo_set_state(struct pci_dev *pdev, enum vga_switcheroo_state state)
+{
+	struct drm_device *dev = pci_get_drvdata(pdev);
+	struct radeon_device *rdev = dev->dev_private;
+	pm_message_t pmm = { .event = PM_EVENT_SUSPEND };
+	if (state == VGA_SWITCHEROO_ON) {
+		printk(KERN_INFO "radeon: switched on\n");
+		/* don't suspend or resume card normally */
+		rdev->powered_down = false;
+		radeon_resume_kms(dev);
+	} else {
+		printk(KERN_INFO "radeon: switched off\n");
+		radeon_suspend_kms(dev, pmm);
+		/* don't suspend or resume card normally */
+		rdev->powered_down = true;
+	}
+}
+
+static bool radeon_switcheroo_can_switch(struct pci_dev *pdev)
+{
+	struct drm_device *dev = pci_get_drvdata(pdev);
+	bool can_switch;
+
+	spin_lock(&dev->count_lock);
+	can_switch = (dev->open_count == 0);
+	spin_unlock(&dev->count_lock);
+	return can_switch;
+}
+
+
 int radeon_device_init(struct radeon_device *rdev,
 		       struct drm_device *ddev,
 		       struct pci_dev *pdev,
@@ -692,6 +723,9 @@
 	/* this will fail for cards that aren't VGA class devices, just
 	 * ignore it */
 	vga_client_register(rdev->pdev, rdev, NULL, radeon_vga_set_decode);
+	vga_switcheroo_register_client(rdev->pdev,
+				       radeon_switcheroo_set_state,
+				       radeon_switcheroo_can_switch);
 
 	r = radeon_init(rdev);
 	if (r)
@@ -723,6 +757,7 @@
 	rdev->shutdown = true;
 	radeon_fini(rdev);
 	destroy_workqueue(rdev->wq);
+	vga_switcheroo_unregister_client(rdev->pdev);
 	vga_client_register(rdev->pdev, NULL, NULL, NULL);
 	iounmap(rdev->rmmio);
 	rdev->rmmio = NULL;
@@ -746,6 +781,8 @@
 	}
 	rdev = dev->dev_private;
 
+	if (rdev->powered_down)
+		return 0;
 	/* unpin the front buffers */
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
 		struct radeon_framebuffer *rfb = to_radeon_framebuffer(crtc->fb);
@@ -791,6 +828,9 @@
 {
 	struct radeon_device *rdev = dev->dev_private;
 
+	if (rdev->powered_down)
+		return 0;
+
 	acquire_console_sem();
 	pci_set_power_state(dev->pdev, PCI_D0);
 	pci_restore_state(dev->pdev);
diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 8ba3de7..4ab53aa1 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -339,6 +339,7 @@
 		driver = &kms_driver;
 		driver->driver_features |= DRIVER_MODESET;
 		driver->num_ioctls = radeon_max_kms_ioctl;
+		radeon_register_atpx_handler();
 	}
 	/* if the vga console setting is enabled still
 	 * let modprobe override it */
@@ -348,6 +349,7 @@
 static void __exit radeon_exit(void)
 {
 	drm_exit(driver);
+	radeon_unregister_atpx_handler();
 }
 
 module_init(radeon_init);
diff --git a/drivers/gpu/drm/radeon/radeon_drv.h b/drivers/gpu/drm/radeon/radeon_drv.h
index c57ad60..7362371 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.h
+++ b/drivers/gpu/drm/radeon/radeon_drv.h
@@ -455,6 +455,9 @@
 			   int sx, int sy, int dx, int dy,
 			   int w, int h, int src_pitch, int dst_pitch, int cpp);
 
+/* atpx handler */
+void radeon_register_atpx_handler(void);
+void radeon_unregister_atpx_handler(void);
 /* Flags for stats.boxes
  */
 #define RADEON_BOX_DMA_IDLE      0x1
diff --git a/drivers/gpu/drm/radeon/radeon_fb.c b/drivers/gpu/drm/radeon/radeon_fb.c
index d71e346..5617192 100644
--- a/drivers/gpu/drm/radeon/radeon_fb.c
+++ b/drivers/gpu/drm/radeon/radeon_fb.c
@@ -39,6 +39,8 @@
 
 #include "drm_fb_helper.h"
 
+#include <linux/vga_switcheroo.h>
+
 struct radeon_fb_device {
 	struct drm_fb_helper helper;
 	struct radeon_framebuffer	*rfb;
@@ -291,6 +293,7 @@
 	rfbdev->rdev = rdev;
 
 	mutex_unlock(&rdev->ddev->struct_mutex);
+	vga_switcheroo_client_fb_set(rdev->ddev->pdev, info);
 	return 0;
 
 out_unref:
diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index f23b056..5db7af6 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -30,6 +30,8 @@
 #include "radeon.h"
 #include "radeon_drm.h"
 
+#include <linux/vga_switcheroo.h>
+
 int radeon_driver_unload_kms(struct drm_device *dev)
 {
 	struct radeon_device *rdev = dev->dev_private;
@@ -136,6 +138,7 @@
 
 void radeon_driver_lastclose_kms(struct drm_device *dev)
 {
+	vga_switcheroo_process_delayed_switch();
 }
 
 int radeon_driver_open_kms(struct drm_device *dev, struct drm_file *file_priv)