radeon_atpx_handler.c

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/*
 * Copyright (c) 2010 Red Hat Inc.
 * Author : Dave Airlie <[email protected]>
 *
 * 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 {
    acpi_handle handle;
    struct radeon_atpx_functions functions;
};

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

struct atpx_power_control {
    u16 size;
    u8 dgpu_state;
} __packed;

struct atpx_mux {
    u16 size;
    u16 mux;
} __packed;

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, NULL, &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;
}

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;
}

static int radeon_atpx_verify_interface(struct radeon_atpx *atpx)
{
    union acpi_object *info;
    struct atpx_verify_interface output;
    size_t size;
    int err = 0;

    info = radeon_atpx_call(atpx->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: %zu\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_set_discrete_state(struct radeon_atpx *atpx, u8 state)
{
    struct acpi_buffer params;
    union acpi_object *info;
    struct atpx_power_control input;

    if (atpx->functions.power_cntl) {
        input.size = 3;
        input.dgpu_state = state;
        params.length = input.size;
        params.pointer = &input;
        info = radeon_atpx_call(atpx->handle,
                    ATPX_FUNCTION_POWER_CONTROL,
                    &params);
        if (!info)
            return -EIO;
        kfree(info);
    }
    return 0;
}

static int radeon_atpx_switch_disp_mux(struct radeon_atpx *atpx, u16 mux_id)
{
    struct acpi_buffer params;
    union acpi_object *info;
    struct atpx_mux input;

    if (atpx->functions.disp_mux_cntl) {
        input.size = 4;
        input.mux = mux_id;
        params.length = input.size;
        params.pointer = &input;
        info = radeon_atpx_call(atpx->handle,
                    ATPX_FUNCTION_DISPLAY_MUX_CONTROL,
                    &params);
        if (!info)
            return -EIO;
        kfree(info);
    }
    return 0;
}

static int radeon_atpx_switch_i2c_mux(struct radeon_atpx *atpx, u16 mux_id)
{
    struct acpi_buffer params;
    union acpi_object *info;
    struct atpx_mux input;

    if (atpx->functions.i2c_mux_cntl) {
        input.size = 4;
        input.mux = mux_id;
        params.length = input.size;
        params.pointer = &input;
        info = radeon_atpx_call(atpx->handle,
                    ATPX_FUNCTION_I2C_MUX_CONTROL,
                    &params);
        if (!info)
            return -EIO;
        kfree(info);
    }
    return 0;
}

static int radeon_atpx_switch_start(struct radeon_atpx *atpx, u16 mux_id)
{
    struct acpi_buffer params;
    union acpi_object *info;
    struct atpx_mux input;

    if (atpx->functions.switch_start) {
        input.size = 4;
        input.mux = mux_id;
        params.length = input.size;
        params.pointer = &input;
        info = radeon_atpx_call(atpx->handle,
                    ATPX_FUNCTION_GRAPHICS_DEVICE_SWITCH_START_NOTIFICATION,
                    &params);
        if (!info)
            return -EIO;
        kfree(info);
    }
    return 0;
}

static int radeon_atpx_switch_end(struct radeon_atpx *atpx, u16 mux_id)
{
    struct acpi_buffer params;
    union acpi_object *info;
    struct atpx_mux input;

    if (atpx->functions.switch_end) {
        input.size = 4;
        input.mux = mux_id;
        params.length = input.size;
        params.pointer = &input;
        info = radeon_atpx_call(atpx->handle,
                    ATPX_FUNCTION_GRAPHICS_DEVICE_SWITCH_END_NOTIFICATION,
                    &params);
        if (!info)
            return -EIO;
        kfree(info);
    }
    return 0;
}

static int radeon_atpx_switchto(enum vga_switcheroo_client_id id)
{
    u16 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, gpu_id);
    radeon_atpx_switch_disp_mux(&radeon_atpx_priv.atpx, gpu_id);
    radeon_atpx_switch_i2c_mux(&radeon_atpx_priv.atpx, gpu_id);
    radeon_atpx_switch_end(&radeon_atpx_priv.atpx, 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, 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);
}

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();
}