From a75508c93da2d0ca1290a83be1580aec5bfefeb3 Mon Sep 17 00:00:00 2001
From: Petteri Aimonen <jpa@git.mail.kapsi.fi>
Date: Mon, 22 May 2023 19:13:36 +0300
Subject: [PATCH] More tape command implementations: Erase, Seek and
 ReadPosition

---
 src/BlueSCSI_log_trace.cpp |  5 +--
 src/BlueSCSI_tape.cpp      | 72 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+), 2 deletions(-)

diff --git a/src/BlueSCSI_log_trace.cpp b/src/BlueSCSI_log_trace.cpp
index ba308342..b1255aea 100644
--- a/src/BlueSCSI_log_trace.cpp
+++ b/src/BlueSCSI_log_trace.cpp
@@ -20,7 +20,7 @@ static const char *getCommandName(uint8_t cmd)
     switch (cmd)
     {
         case 0x00: return "TestUnitReady";
-        case 0x01: return "RezeroUnit";
+        case 0x01: return "RezeroUnit/Rewind";
         case 0x03: return "RequestSense";
         case 0x04: return "FormatUnit";
         case 0x05: return "ReadBlockLimits";
@@ -35,6 +35,7 @@ static const char *getCommandName(uint8_t cmd)
         case 0x15: return "ModeSelect6";
         case 0x16: return "Reserve";
         case 0x17: return "Release";
+        case 0x19: return "Erase";
         case 0x1A: return "ModeSense";
         case 0x1B: return "StartStopUnit";
         case 0x1C: return "ReceiveDiagnostic";
@@ -47,7 +48,7 @@ static const char *getCommandName(uint8_t cmd)
         case 0x2C: return "Erase10";
         case 0x2E: return "WriteVerify";
         case 0x2F: return "Verify";
-        case 0x34: return "PreFetch";
+        case 0x34: return "PreFetch/ReadPosition";
         case 0x35: return "SynchronizeCache";
         case 0x36: return "LockUnlockCache";
         case 0x37: return "ReadDefectData";
diff --git a/src/BlueSCSI_tape.cpp b/src/BlueSCSI_tape.cpp
index b68f1fd5..7c0bde43 100644
--- a/src/BlueSCSI_tape.cpp
+++ b/src/BlueSCSI_tape.cpp
@@ -31,6 +31,31 @@ extern "C" {
 #include <scsi.h>
 }
 
+static void doSeek(uint32_t lba)
+{
+    image_config_t &img = *(image_config_t*)scsiDev.target->cfg;
+    uint32_t bytesPerSector = scsiDev.target->liveCfg.bytesPerSector;
+    uint32_t capacity = img.file.size() / bytesPerSector;
+
+    debuglog("------ Locate tape to LBA ", (int)lba);
+
+    if (lba >= capacity)
+    {
+        scsiDev.status = CHECK_CONDITION;
+        scsiDev.target->sense.code = ILLEGAL_REQUEST;
+        scsiDev.target->sense.asc = LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+        scsiDev.phase = STATUS;
+    }
+    else
+    {
+        delay(10);
+        img.tape_pos = lba;
+
+        scsiDev.status = GOOD;
+        scsiDev.phase = STATUS;
+    }
+}
+
 extern "C" int scsiTapeCommand()
 {
     image_config_t &img = *(image_config_t*)scsiDev.target->cfg;
@@ -158,6 +183,12 @@ extern "C" int scsiTapeCommand()
             img.tape_pos += length;
         }
     }
+    else if (command == 0x19)
+    {
+        // Erase
+        // Just a stub implementation, fake erase to end of tape
+        img.tape_pos = img.scsiSectors;
+    }
     else if (command == 0x01)
     {
         // REWIND
@@ -230,6 +261,47 @@ extern "C" int scsiTapeCommand()
             scsiDev.phase = STATUS;
         }
     }
+    else if (command == 0x2B)
+    {
+        // Seek/Locate 10
+        uint32_t lba =
+            (((uint32_t) scsiDev.cdb[3]) << 24) +
+            (((uint32_t) scsiDev.cdb[4]) << 16) +
+            (((uint32_t) scsiDev.cdb[5]) << 8) +
+            scsiDev.cdb[6];
+
+        doSeek(lba);
+    }
+    else if (command == 0x34)
+    {
+        // ReadPosition
+        uint32_t lba = img.tape_pos;
+        scsiDev.data[0] = 0x00;
+        if (lba == 0) scsiDev.data[0] |= 0x80;
+        if (lba >= img.scsiSectors) scsiDev.data[0] |= 0x40;
+        scsiDev.data[1] = 0x00;
+        scsiDev.data[2] = 0x00;
+        scsiDev.data[3] = 0x00;
+        scsiDev.data[4] = (lba >> 24) & 0xFF; // Next block on tape
+        scsiDev.data[5] = (lba >> 16) & 0xFF;
+        scsiDev.data[6] = (lba >>  8) & 0xFF;
+        scsiDev.data[7] = (lba >>  0) & 0xFF;
+        scsiDev.data[8] = (lba >> 24) & 0xFF; // Last block in buffer
+        scsiDev.data[9] = (lba >> 16) & 0xFF;
+        scsiDev.data[10] = (lba >>  8) & 0xFF;
+        scsiDev.data[11] = (lba >>  0) & 0xFF;
+        scsiDev.data[12] = 0x00;
+        scsiDev.data[13] = 0x00;
+        scsiDev.data[14] = 0x00;
+        scsiDev.data[15] = 0x00;
+        scsiDev.data[16] = 0x00;
+        scsiDev.data[17] = 0x00;
+        scsiDev.data[18] = 0x00;
+        scsiDev.data[19] = 0x00;
+
+        scsiDev.phase = DATA_IN;
+        scsiDev.dataLen = 20;
+    }
     else
     {
         commandHandled = 0;