Diff: test/usb_msd.py

Revision:

0:01f31e923fe2

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/usb_msd.py	Tue Apr 07 12:55:42 2020 +0200
@@ -0,0 +1,387 @@
+#
+# DAPLink Interface Firmware
+# Copyright (c) 2016-2016, ARM Limited, All Rights Reserved
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+import os
+import struct
+import numbers
+import time
+import usb.util
+
+
+class USBMsd(object):
+    """Wrapper class for a MSD usb device"""
+
+    # Bulk only transport documented in
+    #     "Universal Serial Bus Mass Storage Class"
+    # SCSI commands documented in "SCSI Commands Reference Manual" by Seagate
+
+    CLASS_MSD = 0x8
+    # Write 10
+    # Read 10
+    # Test unit ready
+    # Request Sense
+
+    # dCBWSignature
+    # dCBWTag
+    # dCBWDataTransferLength
+    # bmCBWFlags
+    # bCBWLUN
+    # bCBWCBLength
+    FMT_CBW = "<IIIBBB"
+
+    # dCSWSignature
+    # dCSWTag
+    # dCSWDataResidue
+    # bCSWStatus
+    FMT_CSW = "<IIIB"
+
+    CSW_STATUS_PASSED = 0
+    CSW_STATUS_FAILED = 1
+    CSW_STATUS_PHASE_ERROR = 2
+
+    class SCSIError(Exception):
+
+        def __init__(self, error):
+            Exception.__init__(self)
+            self.value = error
+
+    # Some SCSI commands
+    # Value   Keil middleware define         Seagate name
+    # 0x12    SCSI_INQUIRY                   INQUIRY
+    # 0x23    SCSI_READ_FORMAT_CAPACITIES    Missing
+    # 0x25    SCSI_READ_CAPACITY             READ CAPACITY (10)
+    # 0x28    SCSI_READ10                    READ (10)
+    # 0x1A    SCSI_MODE_SENSE6               MODE SENSE (6)
+    # 0x00    SCSI_TEST_UNIT_READY           TEST UNIT READY
+    # 0x2A    SCSI_WRITE10                   WRITE (10)
+    # 0x03    SCSI_REQUEST_SENSE             REQUEST SENSE
+    # 0x1E    SCSI_MEDIA_REMOVAL             Missing
+
+    def __init__(self, device):
+        self._dev = device
+        self._if = None
+        self.ep_in = None
+        self.ep_out = None
+        self._locked = False
+        self._cbw_tag = 0
+        self.timeout = 60 * 1000
+        # delays are for testing only
+        self.delay_cbw_to_data = 0
+        self.delay_data_to_csw = 0
+
+        # Find interface
+        for interface in device.get_active_configuration():
+            if interface.bInterfaceClass == USBMsd.CLASS_MSD:
+                assert self._if is None
+                self._if = interface
+        assert self._if is not None
+
+        # Find endpoints
+        for endpoint in self._if:
+            if endpoint.bEndpointAddress & 0x80:
+                assert self.ep_in is None
+                self.ep_in = endpoint
+            else:
+                assert self.ep_out is None
+                self.ep_out = endpoint
+        assert self.ep_in is not None
+        assert self.ep_out is not None
+
+    def lock(self):
+        """Acquire exclisive access to MSD"""
+        assert not self._locked
+
+        num = self._if.bInterfaceNumber
+        try:
+            if self._dev.is_kernel_driver_active(num):
+                self._dev.detach_kernel_driver(num)
+        except NotImplementedError:
+            pass
+        except usb.core.USBError:
+            pass
+        usb.util.claim_interface(self._dev, num)
+        self._locked = True
+
+    def unlock(self):
+        """Release exclusive access to MSD"""
+        assert self._locked
+
+        num = self._if.bInterfaceNumber
+        usb.util.release_interface(self._dev, num)
+        try:
+            self._dev.attach_kernel_driver(num)
+        except NotImplementedError:
+            pass
+        except usb.core.USBError:
+            pass
+        self._locked = False
+
+    def scsi_read10(self, lba, block_count):
+        """Send the SCSI read 10 command and return the data read"""
+        block_size = 512
+
+        cbwcb = bytearray(10)
+        cbwcb[0] = 0x28
+        cbwcb[2] = (lba >> (8 * 3)) & 0xFF
+        cbwcb[3] = (lba >> (8 * 2)) & 0xFF
+        cbwcb[4] = (lba >> (8 * 1)) & 0xFF
+        cbwcb[5] = (lba >> (8 * 0)) & 0xFF
+        cbwcb[7] = (block_count >> (8 * 1)) & 0xFF
+        cbwcb[8] = (block_count >> (8 * 0)) & 0xFF
+        ret, data = self._msd_transfer(cbwcb, 0, block_count * block_size)
+        if ret != self.CSW_STATUS_PASSED:
+            raise self.SCSIError(ret)
+        return data
+
+    def scsi_write10(self, lba, data):
+        """Send the SCSI write 10 command"""
+        block_size = 512
+
+        assert len(data) % block_size == 0
+        block_count = (len(data) + (block_size - 1)) // block_size
+
+        cbwcb = bytearray(10)
+        cbwcb[0] = 0x2A
+        cbwcb[2] = (lba >> (8 * 3)) & 0xFF
+        cbwcb[3] = (lba >> (8 * 2)) & 0xFF
+        cbwcb[4] = (lba >> (8 * 1)) & 0xFF
+        cbwcb[5] = (lba >> (8 * 0)) & 0xFF
+        cbwcb[7] = (block_count >> (8 * 1)) & 0xFF
+        cbwcb[8] = (block_count >> (8 * 0)) & 0xFF
+        ret, _ = self._msd_transfer(cbwcb, 0, data)
+        if ret != self.CSW_STATUS_PASSED:
+            raise self.SCSIError(ret)
+
+    def scsi_test_unit_ready(self):
+        """Send the SCSI test unit ready command and return status"""
+        cbwcb = bytearray(10)
+        cbwcb[0] = 0
+        ret, _ = self._msd_transfer(cbwcb, 0)
+        return ret
+
+    def _msd_transfer(self, cbwcb, lun, size_or_data=None):
+        """Perform a bulk only transfer"""
+        assert self._locked
+        assert 1 <= len(cbwcb) <= 16
+
+        # Increment packet tag
+        transfer_tag = self._cbw_tag
+        self._cbw_tag = (self._cbw_tag + 1) & 0xFFFFFFFF
+
+        # None means data size of zero
+        if size_or_data is None:
+            size_or_data = 0
+
+        in_transfer = isinstance(size_or_data, numbers.Number)
+        transfer_size = (size_or_data if in_transfer else len(size_or_data))
+        assert in_transfer or len(size_or_data) > 0
+
+        # Phase - Command transport
+        cbw_signature = 0x43425355
+        cbw_tag = transfer_tag
+        cbw_data_transfer_length = transfer_size
+        cbw_flags = (1 << 7) if in_transfer else 0
+        cbw_lun = lun
+        cbw_length = len(cbwcb)
+        params = [cbw_signature, cbw_tag, cbw_data_transfer_length,
+                  cbw_flags, cbw_lun, cbw_length]
+        cbw = struct.pack(self.FMT_CBW, *params)
+        pad_size = 16 - len(cbwcb)
+        payload = cbw + cbwcb + bytearray(pad_size)
+        self.ep_out.write(payload)
+
+        if self.delay_cbw_to_data != 0:
+            time.sleep(self.delay_cbw_to_data)
+
+        # Phase - Data Out or Data In (Optional)
+        data = None
+        if transfer_size > 0:
+            endpoint = self.ep_in if in_transfer else self.ep_out
+            try:
+                if in_transfer:
+                    data = self.ep_in.read(transfer_size, self.timeout)
+                else:
+                    self.ep_out.write(size_or_data, self.timeout)
+            except usb.core.USBError:
+                endpoint.clear_halt()
+
+        if self.delay_data_to_csw != 0:
+            time.sleep(self.delay_data_to_csw)
+
+        # Phase - Status Transport
+        csw = self.ep_in.read(13, self.timeout)
+        csw_signature, csw_tag, csw_data_residue, csw_status = \
+            struct.unpack(self.FMT_CSW, csw)
+        assert csw_signature == 0x53425355
+        assert csw_tag == transfer_tag
+        #TODO - check residue
+        return (csw_status, data)
+
+
+class Struct(object):
+    """Base class for a C structure"""
+
+    def __init__(self, name, structure, data):
+        field_list = [field[0] for field in structure]
+        fmt_list = [field[1] for field in structure]
+        format_str = "<" + "".join(fmt_list)
+        struct_size = struct.calcsize(format_str)
+        value_list = struct.unpack(format_str, data[:struct_size])
+        value_dict = {}
+        for name, value in zip(field_list, value_list):
+            value_dict[name] = value
+        self.name = name
+        self.format_str = format_str
+        self.field_list = field_list
+        self.value_dict = value_dict
+        self.size = struct_size
+
+    def __getitem__(self, key):
+        return self.value_dict[key]
+
+    def __setitem__(self, key, value):
+        self.value_dict[key] = value
+
+    def __str__(self):
+        desc = ""
+        desc += self.name + ":" + os.linesep
+        for field in self.field_list:
+            value = self.value_dict[field]
+            if isinstance(value, bytes):
+                value = list(bytearray(value))
+            desc += ("    %s=%s" + os.linesep) % (field, value)
+        return desc
+
+    def pack(self):
+        """Return a byte representation of this structure"""
+        value_list = []
+        for field in self.field_list:
+            value_list.append(self.value_dict[field])
+        return struct.pack(self.format_str, *value_list)
+
+
+class MBR(Struct):
+    """Wrapper class for a FAT MBR"""
+
+    STRUCTURE = (
+        ("BS_jmpBoot", "3s"),
+        ("BS_OEMName", "8s"),
+        ("BPB_BytsPerSec", "H"),
+        ("BPB_SecPerClus", "B"),
+        ("BPB_RsvdSecCnt", "H"),
+        ("BPB_NumFATs", "B"),
+        ("BPB_RootEntCnt", "H"),
+        ("BPB_TotSec16", "H"),
+        ("BPB_Media", "B"),
+        ("BPB_FATSz16", "H"),
+        ("BPB_SecPerTrk", "H"),
+        ("BPB_NumHeads", "H"),
+        ("BPB_HiddSec", "L"),
+        ("BPB_TotSec32", "L"),
+        )
+
+    def __init__(self, data, sector=None):
+        Struct.__init__(self, "MBR", self.STRUCTURE, data)
+        self.sector = sector
+
+
+class DirectoryEntry(Struct):
+    """Wrapper class for a FAT DirectoryEntry"""
+
+    STRUCTURE = (
+        ("DIR_Name", "11s"),
+        ("DIR_Attr", "B"),
+        ("DIR_NTRes", "B"),
+        ("DIR_CrtTimeTenth", "B"),
+        ("DIR_CrtTime", "H"),
+        ("DIR_CrtDate", "H"),
+        ("DIR_LstAccDate", "H"),
+        ("DIR_FstClusHI", "H"),
+        ("DIR_WrtTime", "H"),
+        ("DIR_WrtDate", "H"),
+        ("DIR_FstClusLO", "H"),
+        ("DIR_FileSize", "L"),
+        )
+
+    def __init__(self, data):
+        Struct.__init__(self, "DirectoryEntry", self.STRUCTURE, data)
+
+
+class Directory(object):
+    """Wrapper class for a FAT Directory"""
+
+    ENTRY_SIZE = 32
+
+    def __init__(self, entry_count, data, sector=None):
+        directory_list = []
+        for i in range(entry_count):
+            start = i * self.ENTRY_SIZE
+            dir_data = data[start:start + self.ENTRY_SIZE]
+            entry = DirectoryEntry(dir_data)
+            directory_list.append(entry)
+        self.directory_list = directory_list
+        self.sector = sector
+
+    def __iter__(self):
+        return iter(self.directory_list)
+
+    def __getitem__(self, key):
+        return self.directory_list[key]
+
+    def find_free_entry_index(self):
+        """Find a free index in this Directory or return None"""
+        for idx, directory in enumerate(self.directory_list):
+            name_data = bytearray(directory["DIR_Name"])
+            if name_data[0] in (0x00, 0xE5):
+                return idx
+        return None
+
+    def pack(self):
+        """Return a byte a Directory"""
+        data = bytearray()
+        for directory in self.directory_list:
+            data.extend(directory.pack())
+        return data
+
+
+class Fat(object):
+    """Wrapper class for a FAT filesystem on a SCSI device"""
+
+    SECTOR_SIZE = 512
+    CLUSTER_SIZE = 4 * 1024
+
+    def __init__(self, msd):
+        self.msd = msd
+        self.reload()
+
+    def reload(self):
+        """Reload all internal data of this Fat filesystem"""
+
+        # Read MBR
+        mbr_data = self.msd.scsi_read10(0, 1)
+        mbr = MBR(mbr_data, 0)
+
+        # Read in the root directory
+        root_dir_sec = (mbr["BPB_RsvdSecCnt"] +
+                        (mbr["BPB_NumFATs"] * mbr["BPB_FATSz16"]))
+        sec_count = (mbr["BPB_RootEntCnt"] * 32 + 512 - 1) // 512
+        root_dir_data = self.msd.scsi_read10(root_dir_sec, sec_count)
+        root_dir = Directory(mbr["BPB_RootEntCnt"], root_dir_data,
+                             root_dir_sec)
+        self.mbr = mbr
+        self.root_dir = root_dir