[efi] Extend efi_locate_device() to allow searching up the device path

Extend the functionality of efi_locate_device() to allow callers to
find instances of the protocol that may exist further up the device
path.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/drivers/net/efi/nii.c b/src/drivers/net/efi/nii.c
index 5d9aea8d569116e29326b8fd108432779fc71e6e..be5bce4b4326ab8cc5c9a1a64cf389086d05735c 100644 (file)
--- a/src/drivers/net/efi/nii.c
+++ b/src/drivers/net/efi/nii.c
@@ -222,7 +222,7 @@ static int nii_pci_open ( struct nii_nic *nii ) {
 
        /* Locate PCI I/O protocol */
        if ( ( rc = efi_locate_device ( device, &efi_pci_io_protocol_guid,
-                                       &pci_device ) ) != 0 ) {
+                                       &pci_device, 0 ) ) != 0 ) {
                DBGC ( nii, "NII %s could not locate PCI I/O protocol: %s\n",
                       nii->dev.name, strerror ( rc ) );
                goto err_locate;

diff --git a/src/drivers/net/efi/snponly.c b/src/drivers/net/efi/snponly.c
index cb7ea1bbc26e23b87c0507c9c617c6b619592912..674e0a0508afa19eb95a473f9c48f525ba5f3115 100644 (file)
--- a/src/drivers/net/efi/snponly.c
+++ b/src/drivers/net/efi/snponly.c
@@ -80,7 +80,7 @@ static int chained_locate ( struct chained_protocol *chained ) {
 
        /* Locate handle supporting this protocol */
        if ( ( rc = efi_locate_device ( device, chained->protocol,
-                                       &parent ) ) != 0 ) {
+                                       &parent, 0 ) ) != 0 ) {
                DBGC ( device, "CHAINED %s does not support %s: %s\n",
                       efi_handle_name ( device ),
                       efi_guid_ntoa ( chained->protocol ), strerror ( rc ) );

diff --git a/src/include/ipxe/efi/efi_utils.h b/src/include/ipxe/efi/efi_utils.h
index 270d38dc8e894eeb5f586f0b094c25abd653a308..98659b1500bbd96f9b95f427f1d956152c15475b 100644 (file)
--- a/src/include/ipxe/efi/efi_utils.h
+++ b/src/include/ipxe/efi/efi_utils.h
@@ -13,7 +13,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 struct device;
 
 extern int efi_locate_device ( EFI_HANDLE device, EFI_GUID *protocol,
-                              EFI_HANDLE *parent );
+                              EFI_HANDLE *parent, unsigned int skip );
 extern int efi_child_add ( EFI_HANDLE parent, EFI_HANDLE child );
 extern void efi_child_del ( EFI_HANDLE parent, EFI_HANDLE child );
 extern void efi_device_info ( EFI_HANDLE device, const char *prefix,

diff --git a/src/interface/efi/efi_utils.c b/src/interface/efi/efi_utils.c
index 8e660e9d7aa45100c1b30c9f91581517998aef1c..53f82bfe47951a66dca080571b0ba713799cbc19 100644 (file)
--- a/src/interface/efi/efi_utils.c
+++ b/src/interface/efi/efi_utils.c
@@ -23,6 +23,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <string.h>
 #include <errno.h>
 #include <ipxe/efi/efi.h>
+#include <ipxe/efi/efi_path.h>
 #include <ipxe/efi/efi_pci.h>
 #include <ipxe/efi/efi_utils.h>
 
@@ -38,23 +39,26 @@ FILE_LICENCE ( GPL2_OR_LATER );
  * @v device           EFI device handle
  * @v protocol         Protocol GUID
  * @v parent           Parent EFI device handle to fill in
+ * @v skip             Number of protocol-supporting parent devices to skip
  * @ret rc             Return status code
  */
 int efi_locate_device ( EFI_HANDLE device, EFI_GUID *protocol,
-                       EFI_HANDLE *parent ) {
+                       EFI_HANDLE *parent, unsigned int skip ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        union {
                EFI_DEVICE_PATH_PROTOCOL *path;
                void *interface;
-       } path;
-       EFI_DEVICE_PATH_PROTOCOL *devpath;
+       } u;
+       EFI_DEVICE_PATH_PROTOCOL *path;
+       EFI_DEVICE_PATH_PROTOCOL *end;
+       size_t len;
        EFI_STATUS efirc;
        int rc;
 
        /* Get device path */
        if ( ( efirc = bs->OpenProtocol ( device,
                                          &efi_device_path_protocol_guid,
-                                         &path.interface,
+                                         &u.interface,
                                          efi_image_handle, device,
                                          EFI_OPEN_PROTOCOL_GET_PROTOCOL ))!=0){
                rc = -EEFI ( efirc );
@@ -62,22 +66,46 @@ int efi_locate_device ( EFI_HANDLE device, EFI_GUID *protocol,
                       efi_handle_name ( device ), strerror ( rc ) );
                goto err_open_device_path;
        }
-       devpath = path.path;
 
-       /* Check for presence of specified protocol */
-       if ( ( efirc = bs->LocateDevicePath ( protocol, &devpath,
-                                             parent ) ) != 0 ) {
-               rc = -EEFI ( efirc );
-               DBGC ( device, "EFIDEV %s has no parent supporting %s: %s\n",
-                      efi_handle_name ( device ),
-                      efi_guid_ntoa ( protocol ), strerror ( rc ) );
-               goto err_locate_protocol;
+       /* Create modifiable copy of device path */
+       len = ( efi_path_len ( u.path ) + sizeof ( EFI_DEVICE_PATH_PROTOCOL ));
+       path = malloc ( len );
+       if ( ! path ) {
+               rc = -ENOMEM;
+               goto err_alloc_path;
+       }
+       memcpy ( path, u.path, len );
+
+       /* Locate parent device(s) */
+       while ( 1 ) {
+
+               /* Check for presence of specified protocol */
+               end = path;
+               if ( ( efirc = bs->LocateDevicePath ( protocol, &end,
+                                                     parent ) ) != 0 ) {
+                       rc = -EEFI ( efirc );
+                       DBGC ( device, "EFIDEV %s has no parent supporting "
+                              "%s: %s\n", efi_devpath_text ( path ),
+                              efi_guid_ntoa ( protocol ), strerror ( rc ) );
+                       goto err_locate_protocol;
+               }
+
+               /* Stop if we have skipped the requested number of devices */
+               if ( ! skip-- )
+                       break;
+
+               /* Trim device path */
+               efi_path_terminate ( end );
+               end = efi_path_prev ( path, end );
+               efi_path_terminate ( end );
        }
 
        /* Success */
        rc = 0;
 
  err_locate_protocol:
+       free ( path );
+ err_alloc_path:
        bs->CloseProtocol ( device, &efi_device_path_protocol_guid,
                            efi_image_handle, device );
  err_open_device_path:
@@ -150,7 +178,7 @@ static int efi_pci_info ( EFI_HANDLE device, const char *prefix,
 
        /* Find parent PCI device */
        if ( ( rc = efi_locate_device ( device, &efi_pci_io_protocol_guid,
-                                       &pci_device ) ) != 0 ) {
+                                       &pci_device, 0 ) ) != 0 ) {
                DBGC ( device, "EFIDEV %s is not a PCI device: %s\n",
                       efi_handle_name ( device ), strerror ( rc ) );
                return rc;