drivers/gpu/drm/radeon/radeon_atpx_handler.c

/*
 * 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 <linux/slab.h>
#include <acpi/acpi.h>
#include <acpi/acpi_bus.h>
#include <linux/pci.h>

#include "radeon_acpi.h"

struct radeon_atpx_functions {
	bool px_params;
	bool power_cntl;
	bool disp_mux_cntl;
	bool i2c_mux_cntl;
	bool switch_start;
	bool switch_end;
	bool disp_connectors_mapping;
	bool disp_detetion_ports;
};

struct radeon_atpx {
	struct radeon_atpx_functions functions;
};

static struct radeon_atpx_priv {
	bool atpx_detected;
	/* handle for device - and atpx */
	acpi_handle dhandle;
	acpi_handle atpx_handle;
	struct radeon_atpx atpx;
} radeon_atpx_priv;

struct atpx_verify_interface {
	u16 size;		/* structure size in bytes (includes size field) */
	u16 version;		/* version */
	u32 function_bits;	/* supported functions bit vector */
} __packed;

/**
 * radeon_atpx_call - call an ATPX method
 *
 * @handle: acpi handle
 * @function: the ATPX function to execute
 * @params: ATPX function params
 *
 * Executes the requested ATPX function (all asics).
 * Returns a pointer to the acpi output buffer.
 */
static union acpi_object *radeon_atpx_call(acpi_handle handle, int function,
					   struct acpi_buffer *params)
{
	acpi_status status;
	union acpi_object atpx_arg_elements[2];
	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 = function;

	if (params) {
		atpx_arg_elements[1].type = ACPI_TYPE_BUFFER;
		atpx_arg_elements[1].buffer.length = params->length;
		atpx_arg_elements[1].buffer.pointer = params->pointer;
	} else {
		/* We need a second fake parameter */
		atpx_arg_elements[1].type = ACPI_TYPE_INTEGER;
		atpx_arg_elements[1].integer.value = 0;
	}

	status = acpi_evaluate_object(handle, "ATPX", &atpx_arg, &buffer);

	/* Fail only if calling the method fails and ATPX is supported */
	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
		printk("failed to evaluate ATPX got %s\n",
		       acpi_format_exception(status));
		kfree(buffer.pointer);
		return NULL;
	}

	return buffer.pointer;
}

/**
 * radeon_atpx_parse_functions - parse supported functions
 *
 * @f: supported functions struct
 * @mask: supported functions mask from ATPX
 *
 * Use the supported functions mask from ATPX function
 * ATPX_FUNCTION_VERIFY_INTERFACE to determine what functions
 * are supported (all asics).
 */
static void radeon_atpx_parse_functions(struct radeon_atpx_functions *f, u32 mask)
{
	f->px_params = mask & ATPX_GET_PX_PARAMETERS_SUPPORTED;
	f->power_cntl = mask & ATPX_POWER_CONTROL_SUPPORTED;
	f->disp_mux_cntl = mask & ATPX_DISPLAY_MUX_CONTROL_SUPPORTED;
	f->i2c_mux_cntl = mask & ATPX_I2C_MUX_CONTROL_SUPPORTED;
	f->switch_start = mask & ATPX_GRAPHICS_DEVICE_SWITCH_START_NOTIFICATION_SUPPORTED;
	f->switch_end = mask & ATPX_GRAPHICS_DEVICE_SWITCH_END_NOTIFICATION_SUPPORTED;
	f->disp_connectors_mapping = mask & ATPX_GET_DISPLAY_CONNECTORS_MAPPING_SUPPORTED;
	f->disp_detetion_ports = mask & ATPX_GET_DISPLAY_DETECTION_PORTS_SUPPORTED;
}

/**
 * radeon_atpx_verify_interface - verify ATPX
 *
 * @handle: acpi handle
 * @atpx: radeon atpx struct
 *
 * Execute the ATPX_FUNCTION_VERIFY_INTERFACE ATPX function
 * to initialize ATPX and determine what features are supported
 * (all asics).
 * returns 0 on success, error on failure.
 */
static int radeon_atpx_verify_interface(acpi_handle handle,
					struct radeon_atpx *atpx)
{
	union acpi_object *info;
	struct atpx_verify_interface output;
	size_t size;
	int err = 0;

	info = radeon_atpx_call(handle, ATPX_FUNCTION_VERIFY_INTERFACE, NULL);
	if (!info)
		return -EIO;

	memset(&output, 0, sizeof(output));

	size = *(u16 *) info->buffer.pointer;
	if (size < 8) {
		printk("ATPX buffer is too small: %lu\n", size);
		err = -EINVAL;
		goto out;
	}
	size = min(sizeof(output), size);

	memcpy(&output, info->buffer.pointer, size);

	/* TODO: check version? */
	printk("ATPX version %u\n", output.version);

	radeon_atpx_parse_functions(&atpx->functions, output.function_bits);

out:
	kfree(info);
	return err;
}

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_FUNCTION_POWER_CONTROL, state);
}

static int radeon_atpx_switch_mux(acpi_handle handle, int mux_id)
{
	return radeon_atpx_execute(handle, ATPX_FUNCTION_DISPLAY_MUX_CONTROL, mux_id);
}

static int radeon_atpx_switch_i2c_mux(acpi_handle handle, int mux_id)
{
	return radeon_atpx_execute(handle, ATPX_FUNCTION_I2C_MUX_CONTROL, mux_id);
}

static int radeon_atpx_switch_start(acpi_handle handle, int gpu_id)
{
	return radeon_atpx_execute(handle,
				   ATPX_FUNCTION_GRAPHICS_DEVICE_SWITCH_START_NOTIFICATION,
				   gpu_id);
}

static int radeon_atpx_switch_end(acpi_handle handle, int gpu_id)
{
	return radeon_atpx_execute(handle,
				   ATPX_FUNCTION_GRAPHICS_DEVICE_SWITCH_END_NOTIFICATION,
				   gpu_id);
}

static int radeon_atpx_switchto(enum vga_switcheroo_client_id id)
{
	int gpu_id;

	if (id == VGA_SWITCHEROO_IGD)
		gpu_id = ATPX_INTEGRATED_GPU;
	else
		gpu_id = ATPX_DISCRETE_GPU;

	radeon_atpx_switch_start(radeon_atpx_priv.atpx_handle, gpu_id);
	radeon_atpx_switch_mux(radeon_atpx_priv.atpx_handle, gpu_id);
	radeon_atpx_switch_i2c_mux(radeon_atpx_priv.atpx_handle, gpu_id);
	radeon_atpx_switch_end(radeon_atpx_priv.atpx_handle, gpu_id);

	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;
	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;

	radeon_atpx_priv.dhandle = dhandle;
	radeon_atpx_priv.atpx_handle = atpx_handle;
	return true;
}

static int radeon_atpx_init(void)
{
	/* set up the ATPX handle */
	return radeon_atpx_verify_interface(radeon_atpx_priv.atpx_handle,
					    &radeon_atpx_priv.atpx);
}

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();
}