target-xtensa: update qemu-doc.texi

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

qemu-doc.texi

@@ -110,6 +110,7 @@ For system emulation, the following hardware targets are supported:
 @item Syborg SVP base model (ARM Cortex-A8).
 @item AXIS-Devboard88 (CRISv32 ETRAX-FS).
 @item Petalogix Spartan 3aDSP1800 MMU ref design (MicroBlaze).
+@item Avnet LX60/LX110/LX200 boards (Xtensa)
 @end itemize
 
 @cindex supported user mode targets
@@ -1446,6 +1447,7 @@ differences are mentioned in the following sections.
 * Cris System emulator::
 * Microblaze System emulator::
 * SH4 System emulator::
+* Xtensa System emulator::
 @end menu
 
 @node PowerPC System emulator
@@ -2124,6 +2126,59 @@ TODO
 
 TODO
 
+@node Xtensa System emulator
+@section Xtensa System emulator
+@cindex system emulation (Xtensa)
+
+Two executables cover simulation of both Xtensa endian options,
+@file{qemu-system-xtensa} and @file{qemu-system-xtensaeb}.
+Two different machine types are emulated:
+
+@itemize @minus
+@item
+Xtensa emulator pseudo board "sim"
+@item
+Avnet LX60/LX110/LX200 board
+@end itemize
+
+The sim pseudo board emulation provides an environment similiar
+to one provided by the proprietary Tensilica ISS.
+It supports:
+
+@itemize @minus
+@item
+A range of Xtensa CPUs, default is the DC232B
+@item
+Console and filesystem access via semihosting calls
+@end itemize
+
+The Avnet LX60/LX110/LX200 emulation supports:
+
+@itemize @minus
+@item
+A range of Xtensa CPUs, default is the DC232B
+@item
+16550 UART
+@item
+OpenCores 10/100 Mbps Ethernet MAC
+@end itemize
+
+@c man begin OPTIONS
+
+The following options are specific to the Xtensa emulation:
+
+@table @option
+
+@item -semihosting
+Enable semihosting syscall emulation.
+
+Xtensa semihosting provides basic file IO calls, such as open/read/write/seek/select.
+Tensilica baremetal libc for ISS and linux platform "sim" use this interface.
+
+Note that this allows guest direct access to the host filesystem,
+so should only be used with trusted guest OS.
+
+@end table
 @node QEMU User space emulator
 @chapter QEMU User space emulator
 

qemu-tech.texi

@@ -42,13 +42,14 @@
 @chapter Introduction
 
 @menu
-* intro_features::        Features
-* intro_x86_emulation::   x86 and x86-64 emulation
-* intro_arm_emulation::   ARM emulation
-* intro_mips_emulation::  MIPS emulation
-* intro_ppc_emulation::   PowerPC emulation
-* intro_sparc_emulation:: Sparc32 and Sparc64 emulation
-* intro_other_emulation:: Other CPU emulation
+* intro_features::         Features
+* intro_x86_emulation::    x86 and x86-64 emulation
+* intro_arm_emulation::    ARM emulation
+* intro_mips_emulation::   MIPS emulation
+* intro_ppc_emulation::    PowerPC emulation
+* intro_sparc_emulation::  Sparc32 and Sparc64 emulation
+* intro_xtensa_emulation:: Xtensa emulation
+* intro_other_emulation::  Other CPU emulation
 @end menu
 
 @node intro_features
@@ -259,6 +260,31 @@ Current QEMU limitations:
 
 @end itemize
 
+@node intro_xtensa_emulation
+@section Xtensa emulation
+
+@itemize
+
+@item Core Xtensa ISA emulation, including most options: code density,
+loop, extended L32R, 16- and 32-bit multiplication, 32-bit division,
+MAC16, miscellaneous operations, boolean, multiprocessor synchronization,
+conditional store, exceptions, relocatable vectors, unaligned exception,
+interrupts (including high priority and timer), hardware alignment,
+region protection, region translation, MMU, windowed registers, thread
+pointer, processor ID.
+
+@item Not implemented options: FP coprocessor, coprocessor context,
+data/instruction cache (including cache prefetch and locking), XLMI,
+processor interface, debug. Also options not covered by the core ISA
+(e.g. FLIX, wide branches) are not implemented.
+
+@item Can run most Xtensa Linux binaries.
+
+@item New core configuration that requires no additional instructions
+may be created from overlay with minimal amount of hand-written code.
+
+@end itemize
+
 @node intro_other_emulation
 @section Other CPU emulation