efi_driver.c

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/*
 * Copyright (C) 2011 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <ipxe/version.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/Protocol/DriverBinding.h>
#include <ipxe/efi/Protocol/ComponentName2.h>
#include <ipxe/efi/Protocol/DevicePath.h>
#include <ipxe/efi/efi_strings.h>
#include <ipxe/efi/efi_path.h>
#include <ipxe/efi/efi_driver.h>

/** @file
 *
 * EFI driver interface
 *
 */

/* Disambiguate the various error causes */
#define EINFO_EEFI_CONNECT                                              \
        __einfo_uniqify ( EINFO_EPLATFORM, 0x01,                        \
                          "Could not connect controllers" )
#define EINFO_EEFI_CONNECT_PROHIBITED                                   \
        __einfo_platformify ( EINFO_EEFI_CONNECT,                       \
                              EFI_SECURITY_VIOLATION,                   \
                              "Connecting controllers prohibited by "   \
                              "security policy" )
#define EEFI_CONNECT_PROHIBITED                                         \
        __einfo_error ( EINFO_EEFI_CONNECT_PROHIBITED )
#define EEFI_CONNECT( efirc ) EPLATFORM ( EINFO_EEFI_CONNECT, efirc,    \
                                          EEFI_CONNECT_PROHIBITED )

static EFI_DRIVER_BINDING_PROTOCOL efi_driver_binding;

/** List of controlled EFI devices */
static LIST_HEAD ( efi_devices );

/** We are currently disconnecting drivers */
static int efi_driver_disconnecting;

/**
 * Allocate new EFI device
 *
 * @v device            EFI device handle
 * @ret efidev          EFI device, or NULL on error
 */
struct efi_device * efidev_alloc ( EFI_HANDLE device ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        struct efi_device *efidev = NULL;
        union {
                EFI_DEVICE_PATH_PROTOCOL *path;
                void *interface;
        } path;
        EFI_DEVICE_PATH_PROTOCOL *path_end;
        size_t path_len;
        EFI_STATUS efirc;
        int rc;

        /* Open device path */
        if ( ( efirc = bs->OpenProtocol ( device,
                                          &efi_device_path_protocol_guid,
                                          &path.interface, efi_image_handle,
                                          device,
                                          EFI_OPEN_PROTOCOL_GET_PROTOCOL ))!=0){
                rc = -EEFI ( efirc );
                DBGC ( device, "EFIDRV %s could not open device path: %s\n",
                       efi_handle_name ( device ), strerror ( rc ) );
                goto err_open_path;
        }
        path_len = ( efi_path_len ( path.path ) + sizeof ( *path_end ) );

        /* Allocate and initialise structure */
        efidev = zalloc ( sizeof ( *efidev ) + path_len );
        if ( ! efidev )
                goto err_alloc;
        efidev->device = device;
        efidev->dev.desc.bus_type = BUS_TYPE_EFI;
        efidev->path = ( ( ( void * ) efidev ) + sizeof ( *efidev ) );
        memcpy ( efidev->path, path.path, path_len );
        INIT_LIST_HEAD ( &efidev->dev.children );
        list_add ( &efidev->dev.siblings, &efi_devices );

 err_alloc:
        bs->CloseProtocol ( device, &efi_device_path_protocol_guid,
                            efi_image_handle, device );
 err_open_path:
        return efidev;
}

/**
 * Free EFI device
 *
 * @v efidev            EFI device
 */
void efidev_free ( struct efi_device *efidev ) {

        assert ( list_empty ( &efidev->dev.children ) );
        list_del ( &efidev->dev.siblings );
        free ( efidev );
}

/**
 * Find EFI device
 *
 * @v device            EFI device handle (or child handle)
 * @ret efidev          EFI device, or NULL if not found
 */
static struct efi_device * efidev_find ( EFI_HANDLE device ) {
        struct efi_device *efidev;

        /* Avoid false positive matches against NULL children */
        if ( ! device )
                return NULL;

        /* Look for an existing EFI device */
        list_for_each_entry ( efidev, &efi_devices, dev.siblings ) {
                if ( ( device == efidev->device ) ||
                     ( device == efidev->child ) ) {
                        return efidev;
                }
        }

        return NULL;
}

/**
 * Get parent EFI device
 *
 * @v dev               Generic device
 * @ret efidev          Parent EFI device, or NULL
 */
struct efi_device * efidev_parent ( struct device *dev ) {
        struct device *parent;
        struct efi_device *efidev;

        /* Walk upwards until we find a registered EFI device */
        while ( ( parent = dev->parent ) ) {
                list_for_each_entry ( efidev, &efi_devices, dev.siblings ) {
                        if ( parent == &efidev->dev )
                                return efidev;
                }
                dev = parent;
        }

        return NULL;
}

/**
 * Check to see if driver supports a device
 *
 * @v driver            EFI driver
 * @v device            EFI device
 * @v child             Path to child device, if any
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_driver_supported ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
                       EFI_HANDLE device, EFI_DEVICE_PATH_PROTOCOL *child ) {
        struct efi_driver *efidrv;
        int rc;

        DBGCP ( device, "EFIDRV %s DRIVER_SUPPORTED",
                efi_handle_name ( device ) );
        if ( child )
                DBGCP ( device, " (child %s)", efi_devpath_text ( child ) );
        DBGCP ( device, "\n" );

        /* Do nothing if we are already driving this device */
        if ( efidev_find ( device ) != NULL ) {
                DBGCP ( device, "EFIDRV %s is already started\n",
                        efi_handle_name ( device ) );
                return EFI_ALREADY_STARTED;
        }

        /* Look for a driver claiming to support this device */
        for_each_table_entry ( efidrv, EFI_DRIVERS ) {
                if ( ( rc = efidrv->supported ( device ) ) == 0 ) {
                        DBGC ( device, "EFIDRV %s has driver \"%s\"\n",
                               efi_handle_name ( device ), efidrv->name );
                        return 0;
                }
        }
        DBGCP ( device, "EFIDRV %s has no driver\n",
                efi_handle_name ( device ) );

        return EFI_UNSUPPORTED;
}

/**
 * Attach driver to device
 *
 * @v driver            EFI driver
 * @v device            EFI device
 * @v child             Path to child device, if any
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_driver_start ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
                   EFI_HANDLE device, EFI_DEVICE_PATH_PROTOCOL *child ) {
        struct efi_driver *efidrv;
        struct efi_device *efidev;
        struct efi_saved_tpl tpl;
        EFI_STATUS efirc;
        int rc;

        DBGC ( device, "EFIDRV %s DRIVER_START", efi_handle_name ( device ) );
        if ( child )
                DBGC ( device, " (child %s)", efi_devpath_text ( child ) );
        DBGC ( device, "\n" );

        /* Do nothing if we are already driving this device */
        efidev = efidev_find ( device );
        if ( efidev ) {
                DBGCP ( device, "EFIDRV %s is already started\n",
                        efi_handle_name ( device ) );
                efirc = EFI_ALREADY_STARTED;
                goto err_already_started;
        }

        /* Raise TPL */
        efi_raise_tpl ( &tpl );

        /* Do nothing if we are currently disconnecting drivers */
        if ( efi_driver_disconnecting ) {
                DBGC ( device, "EFIDRV %s refusing to start during "
                       "disconnection\n", efi_handle_name ( device ) );
                efirc = EFI_NOT_READY;
                goto err_disconnecting;
        }

        /* Add new device */
        efidev = efidev_alloc ( device );
        if ( ! efidev ) {
                efirc = EFI_OUT_OF_RESOURCES;
                goto err_alloc;
        }

        /* Try to start this device */
        for_each_table_entry ( efidrv, EFI_DRIVERS ) {
                if ( ( rc = efidrv->supported ( device ) ) != 0 ) {
                        DBGC ( device, "EFIDRV %s is not supported by driver "
                               "\"%s\": %s\n", efi_handle_name ( device ),
                               efidrv->name,
                               strerror ( rc ) );
                        continue;
                }
                if ( ( rc = efidrv->start ( efidev ) ) == 0 ) {
                        efidev->driver = efidrv;
                        DBGC ( device, "EFIDRV %s using driver \"%s\"\n",
                               efi_handle_name ( device ),
                               efidev->driver->name );
                        efi_restore_tpl ( &tpl );
                        return 0;
                }
                DBGC ( device, "EFIDRV %s could not start driver \"%s\": %s\n",
                       efi_handle_name ( device ), efidrv->name,
                       strerror ( rc ) );
        }
        efirc = EFI_UNSUPPORTED;

        efidev_free ( efidev );
 err_alloc:
 err_disconnecting:
        efi_restore_tpl ( &tpl );
 err_already_started:
        return efirc;
}

/**
 * Detach driver from device
 *
 * @v driver            EFI driver
 * @v device            EFI device
 * @v pci               PCI device
 * @v num_children      Number of child devices
 * @v children          List of child devices
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_driver_stop ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
                  EFI_HANDLE device, UINTN num_children,
                  EFI_HANDLE *children ) {
        struct efi_driver *efidrv;
        struct efi_device *efidev;
        struct efi_saved_tpl tpl;
        UINTN i;

        DBGC ( device, "EFIDRV %s DRIVER_STOP", efi_handle_name ( device ) );
        for ( i = 0 ; i < num_children ; i++ ) {
                DBGC ( device, "%s%s", ( i ? ", " : " child " ),
                       efi_handle_name ( children[i] ) );
        }
        DBGC ( device, "\n" );

        /* Do nothing unless we are driving this device */
        efidev = efidev_find ( device );
        if ( ! efidev ) {
                DBGCP ( device, "EFIDRV %s is not started\n",
                        efi_handle_name ( device ) );
                return EFI_DEVICE_ERROR;
        }

        /* Raise TPL */
        efi_raise_tpl ( &tpl );

        /* Stop this device */
        efidrv = efidev->driver;
        assert ( efidrv != NULL );
        efidrv->stop ( efidev );
        efidev_free ( efidev );

        efi_restore_tpl ( &tpl );
        return 0;
}

/** EFI driver binding protocol */
static EFI_DRIVER_BINDING_PROTOCOL efi_driver_binding = {
        .Supported = efi_driver_supported,
        .Start = efi_driver_start,
        .Stop = efi_driver_stop,
};

/**
 * Look up driver name
 *
 * @v wtf               Component name protocol
 * @v language          Language to use
 * @v driver_name       Driver name to fill in
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_driver_name ( EFI_COMPONENT_NAME2_PROTOCOL *wtf __unused,
                  CHAR8 *language __unused, CHAR16 **driver_name ) {
        const wchar_t *name;

        name = ( product_wname[0] ? product_wname : build_wname );
        *driver_name = ( ( wchar_t * ) name );
        return 0;
}

/**
 * Look up controller name
 *
 * @v wtf               Component name protocol
 * @v device            Device
 * @v child             Child device, or NULL
 * @v language          Language to use
 * @v driver_name       Device name to fill in
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_driver_controller_name ( EFI_COMPONENT_NAME2_PROTOCOL *wtf __unused,
                             EFI_HANDLE device, EFI_HANDLE child,
                             CHAR8 *language, CHAR16 **controller_name ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        union {
                EFI_COMPONENT_NAME2_PROTOCOL *name2;
                void *interface;
        } name2;
        EFI_STATUS efirc;

        /* Delegate to the EFI_COMPONENT_NAME2_PROTOCOL instance
         * installed on child handle, if present.
         */
        if ( ( child != NULL ) &&
             ( ( efirc = bs->OpenProtocol (
                          child, &efi_component_name2_protocol_guid,
                          &name2.interface, NULL, NULL,
                          EFI_OPEN_PROTOCOL_GET_PROTOCOL ) ) == 0 ) ) {
                return name2.name2->GetControllerName ( name2.name2, device,
                                                        child, language,
                                                        controller_name );
        }

        /* Otherwise, let EFI use the default Device Path Name */
        return EFI_UNSUPPORTED;
}

/** EFI component name protocol */
static EFI_COMPONENT_NAME2_PROTOCOL efi_wtf = {
        .GetDriverName = efi_driver_name,
        .GetControllerName = efi_driver_controller_name,
        .SupportedLanguages = "en",
};

/**
 * Install EFI driver
 *
 * @ret rc              Return status code
 */
int efi_driver_install ( void ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        EFI_STATUS efirc;
        int rc;

        /* Calculate driver version number.  We use the build
         * timestamp (in seconds since the Epoch) shifted right by six
         * bits: this gives us an approximately one-minute resolution
         * and a scheme which will last until the year 10680.
         */
        efi_driver_binding.Version = ( build_timestamp >> 6 );

        /* Install protocols on image handle */
        efi_driver_binding.ImageHandle = efi_image_handle;
        efi_driver_binding.DriverBindingHandle = efi_image_handle;
        if ( ( efirc = bs->InstallMultipleProtocolInterfaces (
                        &efi_image_handle,
                        &efi_driver_binding_protocol_guid, &efi_driver_binding,
                        &efi_component_name2_protocol_guid, &efi_wtf,
                        NULL ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( &efi_driver_binding, "EFIDRV could not install "
                       "protocols: %s\n", strerror ( rc ) );
                return rc;
        }

        return 0;
}

/**
 * Uninstall EFI driver
 *
 */
void efi_driver_uninstall ( void ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;

        /* Uninstall protocols */
        bs->UninstallMultipleProtocolInterfaces (
                efi_image_handle,
                &efi_driver_binding_protocol_guid, &efi_driver_binding,
                &efi_component_name2_protocol_guid, &efi_wtf, NULL );
}

/**
 * Try to connect EFI driver
 *
 * @v device            EFI device
 * @ret rc              Return status code
 */
static int efi_driver_connect ( EFI_HANDLE device ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        EFI_HANDLE drivers[2] =
                { efi_driver_binding.DriverBindingHandle, NULL };
        EFI_STATUS efirc;
        int rc;

        /* Check if we want to drive this device */
        if ( ( efirc = efi_driver_supported ( &efi_driver_binding, device,
                                              NULL ) ) != 0 ) {
                /* Not supported; not an error */
                return 0;
        }

        /* Disconnect any existing drivers */
        DBGC2 ( device, "EFIDRV %s before disconnecting:\n",
                efi_handle_name ( device ) );
        DBGC2_EFI_PROTOCOLS ( device, device );
        DBGC ( device, "EFIDRV %s disconnecting existing drivers\n",
               efi_handle_name ( device ) );
        efi_driver_disconnecting = 1;
        if ( ( efirc = bs->DisconnectController ( device, NULL,
                                                  NULL ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( device, "EFIDRV %s could not disconnect existing "
                       "drivers: %s\n", efi_handle_name ( device ),
                       strerror ( rc ) );
                /* Ignore the error and attempt to connect our drivers */
        }
        efi_driver_disconnecting = 0;
        DBGC2 ( device, "EFIDRV %s after disconnecting:\n",
                efi_handle_name ( device ) );
        DBGC2_EFI_PROTOCOLS ( device, device );

        /* Connect our driver */
        DBGC ( device, "EFIDRV %s connecting new drivers\n",
               efi_handle_name ( device ) );
        if ( ( efirc = bs->ConnectController ( device, drivers, NULL,
                                               TRUE ) ) != 0 ) {
                rc = -EEFI_CONNECT ( efirc );
                DBGC ( device, "EFIDRV %s could not connect new drivers: "
                       "%s\n", efi_handle_name ( device ), strerror ( rc ) );
                DBGC ( device, "EFIDRV %s connecting driver directly\n",
                       efi_handle_name ( device ) );
                if ( ( efirc = efi_driver_start ( &efi_driver_binding, device,
                                                  NULL ) ) != 0 ) {
                        rc = -EEFI_CONNECT ( efirc );
                        DBGC ( device, "EFIDRV %s could not connect driver "
                               "directly: %s\n", efi_handle_name ( device ),
                               strerror ( rc ) );
                        return rc;
                }
        }
        DBGC2 ( device, "EFIDRV %s after connecting:\n",
                efi_handle_name ( device ) );
        DBGC2_EFI_PROTOCOLS ( device, device );

        return 0;
}

/**
 * Try to disconnect EFI driver
 *
 * @v device            EFI device
 * @ret rc              Return status code
 */
static int efi_driver_disconnect ( EFI_HANDLE device ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;

        /* Disconnect our driver */
        efi_driver_disconnecting = 1;
        bs->DisconnectController ( device,
                                   efi_driver_binding.DriverBindingHandle,
                                   NULL );
        efi_driver_disconnecting = 0;
        return 0;
}

/**
 * Reconnect original EFI driver
 *
 * @v device            EFI device
 * @ret rc              Return status code
 */
static int efi_driver_reconnect ( EFI_HANDLE device ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;

        /* Reconnect any available driver */
        bs->ConnectController ( device, NULL, NULL, TRUE );

        return 0;
}

/**
 * Connect/disconnect EFI driver from all handles
 *
 * @v method            Connect/disconnect method
 * @ret rc              Return status code
 */
static int efi_driver_handles ( int ( * method ) ( EFI_HANDLE handle ) ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        EFI_HANDLE *handles;
        UINTN num_handles;
        EFI_STATUS efirc;
        UINTN i;
        int rc;

        /* Enumerate all handles */
        if ( ( efirc = bs->LocateHandleBuffer ( AllHandles, NULL, NULL,
                                                &num_handles,
                                                &handles ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( &efi_driver_binding, "EFIDRV could not list handles: "
                       "%s\n", strerror ( rc ) );
                goto err_locate;
        }

        /* Connect/disconnect driver from all handles */
        for ( i = 0 ; i < num_handles ; i++ ) {
                if ( ( rc = method ( handles[i] ) ) != 0 ) {
                        /* Ignore errors and continue to process
                         * remaining handles.
                         */
                }
        }

        /* Success */
        rc = 0;

        bs->FreePool ( handles );
 err_locate:
        return rc;
}

/**
 * Connect EFI driver to all possible devices
 *
 * @ret rc              Return status code
 */
int efi_driver_connect_all ( void ) {

        DBGC ( &efi_driver_binding, "EFIDRV connecting our drivers\n" );
        return efi_driver_handles ( efi_driver_connect );
}

/**
 * Disconnect EFI driver from all possible devices
 *
 * @ret rc              Return status code
 */
void efi_driver_disconnect_all ( void ) {

        DBGC ( &efi_driver_binding, "EFIDRV disconnecting our drivers\n" );
        efi_driver_handles ( efi_driver_disconnect );
}

/**
 * Reconnect original EFI drivers to all possible devices
 *
 * @ret rc              Return status code
 */
void efi_driver_reconnect_all ( void ) {

        DBGC ( &efi_driver_binding, "EFIDRV reconnecting old drivers\n" );
        efi_driver_handles ( efi_driver_reconnect );
}