@item @code{testee} -- a dummy target for cases without a real CPU, e.g. CPLD.
@item @code{xscale} -- this is actually an architecture,
not a CPU type. It is based on the ARMv5 architecture.
+@item @code{xtensa} -- this is a generic Cadence/Tensilica Xtensa core.
@end itemize
@end deffn
protocol SWIM, @pxref{swimtransport,,SWIM}.
@section Xtensa Architecture
-Xtensa processors are based on a modular, highly flexible 32-bit RISC architecture
-that can easily scale from a tiny, cache-less controller or task engine to a high-performance
-SIMD/VLIW DSP provided by Cadence.
-@url{https://www.cadence.com/en_US/home/tools/ip/tensilica-ip/tensilica-xtensa-controllers-and-extensible-processors.html}.
-OpenOCD supports generic Xtensa processors implementation which can be customized by
-simply providing vendor-specific core configuration which controls every configurable
+Xtensa is a highly-customizable, user-extensible microprocessor and DSP
+architecture for complex embedded systems provided by Cadence Design
+Systems, Inc. See the
+@uref{https://www.cadence.com/en_US/home/tools/ip/tensilica-ip.html, Tensilica IP}
+website for additional information and documentation.
+
+OpenOCD supports generic Xtensa processor implementations which can be customized by
+providing a core-specific configuration file which describes every enabled
Xtensa architecture option, e.g. number of address registers, exceptions, reduced
-size instructions support, memory banks configuration etc. Also OpenOCD supports SMP
-configurations for Xtensa processors with any number of cores and allows to configure
-their debug signals interconnection (so-called "break/stall networks") which control how
-debug signals are distributed among cores. Xtensa "break networks" are compatible with
-ARM's Cross Trigger Interface (CTI). For debugging code on Xtensa chips OpenOCD
-uses JTAG protocol. Currently OpenOCD implements several Epsressif Xtensa-based chips of
+size instructions support, memory banks configuration etc. OpenOCD also supports SMP
+configurations for Xtensa processors with any number of cores and allows configuring
+their debug interconnect (termed "break/stall networks"), which control how debug
+signals are distributed among cores. Xtensa "break networks" are compatible with
+ARM's Cross Trigger Interface (CTI). OpenOCD implements both generic Xtensa targets
+as well as several Espressif Xtensa-based chips from the
@uref{https://www.espressif.com/en/products/socs, ESP32 family}.
-@subsection General Xtensa Commands
+OCD sessions for Xtensa processor and DSP targets are accessed via the Xtensa
+Debug Module (XDM), which provides external connectivity either through a
+traditional JTAG interface or an ARM DAP interface. If used, the DAP interface
+can control Xtensa targets through JTAG or SWD probes.
+
+@subsection Xtensa Core Configuration
+
+Due to the high level of configurability in Xtensa cores, the Xtensa target
+configuration comprises two categories:
+
+@enumerate
+@item Base Xtensa support common to all core configurations, and
+@item Core-specific support as configured for individual cores.
+@end enumerate
+
+All common Xtensa support is built into the OpenOCD Xtensa target layer and
+is enabled through a combination of TCL scripts: the target-specific
+@file{target/xtensa.cfg} and a board-specific @file{board/xtensa-*.cfg},
+similar to other target architectures.
+
+Importantly, core-specific configuration information must be provided by
+the user, and takes the form of an @file{xtensa-core-XXX.cfg} TCL script that
+defines the core's configurable features through a series of Xtensa
+configuration commands (detailed below).
+
+This core-specific @file{xtensa-core-XXX.cfg} file is typically either:
+
+@itemize @bullet
+@item Located within the Xtensa core configuration build as
+@file{src/config/xtensa-core-openocd.cfg}, or
+@item Generated by running the command @code{xt-gdb --dump-oocd-config}
+from the Xtensa processor tool-chain's command-line tools.
+@end itemize
+
+NOTE: @file{xtensa-core-XXX.cfg} must match the target Xtensa hardware
+connected to OpenOCD.
+
+Some example Xtensa configurations are bundled with OpenOCD for reference:
+@itemize @bullet
+@item Cadence Palladium VDebug emulation target. The user can combine their
+@file{xtensa-core-XXX.cfg} with the provided
+@file{board/xtensa-palladium-vdebug.cfg} to debug an emulated Xtensa RTL design.
+@item NXP MIMXRT685-EVK evaluation kit. The relevant configuration files are
+@file{board/xtensa-rt685-jlink.cfg} and @file{board/xtensa-core-nxp_rt600.cfg}.
+Additional information is provided by
+@uref{https://www.nxp.com/design/development-boards/i-mx-evaluation-and-development-boards/i-mx-rt600-evaluation-kit:MIMXRT685-EVK,
+NXP}.
+@end itemize
+
+@subsection Xtensa Configuration Commands
+
+@deffn {Command} {xtensa xtdef} (@option{LX}|@option{NX})
+Configure the Xtensa target architecture. Currently, Xtensa support is limited
+to LX6, LX7, and NX cores.
+@end deffn
+
+@deffn {Command} {xtensa xtopt} option value
+Configure Xtensa target options that are relevant to the debug subsystem.
+@var{option} is one of: @option{arnum}, @option{windowed},
+@option{cpenable}, @option{exceptions}, @option{intnum}, @option{hipriints},
+@option{excmlevel}, @option{intlevels}, @option{debuglevel},
+@option{ibreaknum}, or @option{dbreaknum}. @var{value} is an integer with
+the exact range determined by each particular option.
+
+NOTE: Some options are specific to Xtensa LX or Xtensa NX architecture, while
+others may be common to both but have different valid ranges.
+@end deffn
+
+@deffn {Command} {xtensa xtmem} (@option{iram}|@option{dram}|@option{sram}|@option{irom}|@option{drom}|@option{srom}) baseaddr bytes
+Configure Xtensa target memory. Memory type determines access rights,
+where RAMs are read/write while ROMs are read-only. @var{baseaddr} and
+@var{bytes} are both integers, typically hexadecimal and decimal, respectively.
+@end deffn
+
+@deffn {Command} {xtensa xtmem} (@option{icache}|@option{dcache}) linebytes cachebytes ways [writeback]
+Configure Xtensa processor cache. All parameters are required except for
+the optional @option{writeback} parameter; all are integers.
+@end deffn
+
+@deffn {Command} {xtensa xtmpu} numfgseg minsegsz lockable execonly
+Configure an Xtensa Memory Protection Unit (MPU). MPUs can restrict access
+and/or control cacheability of specific address ranges, but are lighter-weight
+than a full traditional MMU. All parameters are required; all are integers.
+@end deffn
+
+@deffn {Command} {xtensa xtmmu} numirefillentries numdrefillentries
+(Xtensa-LX only) Configure an Xtensa Memory Management Unit (MMU). Both
+parameters are required; both are integers.
+@end deffn
+
+@deffn {Command} {xtensa xtregs} numregs
+Configure the total number of registers for the Xtensa core. Configuration
+logic expects to subsequently process this number of @code{xtensa xtreg}
+definitions. @var{numregs} is an integer.
+@end deffn
+
+@deffn {Command} {xtensa xtregfmt} (@option{sparse}|@option{contiguous}) [general]
+Configure the type of register map used by GDB to access the Xtensa core.
+Generic Xtensa tools (e.g. xt-gdb) require @option{sparse} mapping (default) while
+Espressif tools expect @option{contiguous} mapping. Contiguous mapping takes an
+additional, optional integer parameter @option{numgregs}, which specifies the number
+of general registers used in handling g/G packets.
+@end deffn
+
+@deffn {Command} {xtensa xtreg} name offset
+Configure an Xtensa core register. All core registers are 32 bits wide,
+while TIE and user registers may have variable widths. @var{name} is a
+character string identifier while @var{offset} is a hexadecimal integer.
+@end deffn
+
+@subsection Xtensa Operation Commands
+
+@deffn {Command} {xtensa maskisr} (@option{on}|@option{off})
+(Xtensa-LX only) Mask or unmask Xtensa interrupts during instruction step.
+When masked, an interrupt that occurs during a step operation is handled and
+its ISR is executed, with the user's debug session returning after potentially
+executing many instructions. When unmasked, a triggered interrupt will result
+in execution progressing the requested number of instructions into the relevant
+vector/ISR code.
+@end deffn
@deffn {Command} {xtensa set_permissive} (0|1)
By default accessing memory beyond defined regions is forbidden. This commnd controls memory access address check.
When set to (1), skips access controls and address range check before read/write memory.
@end deffn
-@deffn {Command} {xtensa maskisr} (on|off)
-Selects whether interrupts will be disabled during stepping over single instruction. The default configuration is (off).
-@end deffn
-
@deffn {Command} {xtensa smpbreak} [none|breakinout|runstall] | [BreakIn] [BreakOut] [RunStallIn] [DebugModeOut]
Configures debug signals connection ("break network") for currently selected core.
@itemize @bullet
@end itemize
@end deffn
+@deffn {Command} {xtensa exe} <ascii-encoded hexadecimal instruction bytes>
+Execute arbitrary instruction(s) provided as an ascii string. The string represents an integer
+number of instruction bytes, thus its length must be even.
+@end deffn
+
+@subsection Xtensa Performance Monitor Configuration
+
@deffn {Command} {xtensa perfmon_enable} <counter_id> <select> [mask] [kernelcnt] [tracelevel]
Enable and start performance counter.
@itemize @bullet
Dump performance counter value. If no argument specified, dumps all counters.
@end deffn
+@subsection Xtensa Trace Configuration
+
@deffn {Command} {xtensa tracestart} [pc <pcval>/[<maskbitcount>]] [after <n> [ins|words]]
Set up and start a HW trace. Optionally set PC address range to trigger tracing stop when reached during program execution.
This command also allows to specify the amount of data to capture after stop trigger activation.
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