On Thursday, November 28, 2019, Michael Rolnik <address@hidden> wrote:
On Wed, Nov 27, 2019 at 11:06 PM Aleksandar Markovic <
address@hidden> wrote:
On Wed, Nov 27, 2019 at 6:53 PM Michael Rolnik <address@hidden> wrote:
>
> This series of patches adds 8bit AVR cores to QEMU.
> All instruction, except BREAK/DES/SPM/SPMX, are implemented. Not fully tested yet.
> However I was able to execute simple code with functions. e.g fibonacci calculation.
> This series of patches include a non real, sample board.
> No fuses support yet. PC is set to 0 at reset.
>
I have a couple of general remarks, so I am responding to the cover
letter, not individual patches.
1) The licenses for Sarah devices differ than the rest - shouldn't all
licenses be harmonized?
Sarah,
do you mind if use the same license I use for my code?
2) There is an architectural problem with peripherals. It is possible
that they evolve over time, so, for example, USART could not be the
same for older and newer CPUs (in principle, newer peripheral is
expected to be o sort of "superset" of the older). How do you solve
that problem? Right now, it may not looks serious to you, but if you
don;t think about that right now, from the outset, soon the code will
become so entangled, ti woudl be almost very difficult to fix it.
Please think about that, how would you solve it, is there a way to
pass the information on the currently emulated CPU to the code
covering a peripheral, and provide a different behaviour?
Hi Aleksandar,
Please explain.
My concern is about peripherals inside the chip, together with the core.
If one models, let's say an external (in the sense, it is a separate chip) ADC (analog-to-digital converter), one looks at specs, implement what is resonable possible in QEMU, plug it in in one of machines thst contains it, and that's it. That ADC remains the same, of course, whatever the surrounding system is.
In AVR case, I think we have a phenomenon likes of which we didn't see before (at least I don't know about). Number of AVR microcontrollers is very large, and both cores and peripherals evolved.
For cores, you handle differences with all these AVR_FEATURE macros, and this seems to be working, no significant objection from my side, and btw that was not an easy task to execute, all admiration from me.
But what about peripherals inside the chip? A peripheral with the same name and the same general area of functionality may be differently specified for microcontrollers from 2010 and 2018. By the difference I don't mean starting address, but the difference in behavior. I don't have time right now to spell many examples, but I read three different specs, and there are differences in USART specifications.
I am not clear what is your envisioned solution for these cases. Would you such close, but not the same, flabors of a peripheral treat as if they are two completely separate cases of a peripheral? Or would you have a single peripheral that would somehow configure itself depending on the core it is attached to?
I hope I was clearer this time.
Aleksandar
I don't see any problem from CPU's perspective.
as for the sample board is just a sample, I hope other people will create real models or real hw.
there was no way I could provide a CPU alone, that's why there is sample.
> Following are examples of possible usages, assuming program.elf is compiled for AVR cpu
> 1. Continious non interrupted execution
> run `qemu-system-avr -kernel program.elf`
> 2. Continious non interrupted execution with serial output into telnet window
> run `qemu-system-avr -kernel program.elf -serial tcp::5678,server,nowait -nographic `
> run `telent localhost 5678`
> 3. Continious non interrupted execution with serial output into stdout
> run `qemu-system-avr -kernel program.elf -serial stdio`
> 4. Debugging wit GDB debugger
> run `qemu-system-avr -kernel program.elf -s -S`
> run `avr-gdb program.elf` and then within GDB shell `target remote :1234`
> 5. Print out executed instructions
> run `qemu-system-avr -kernel program.elf -d in_asm`
>
Thank you so much for these examples!
Aleksandar
>
> the patches include the following
> 1. just a basic 8bit AVR CPU, without instruction decoding or translation
> 2. CPU features which allow define the following 8bit AVR cores
> avr1
> avr2 avr25
> avr3 avr31 avr35
> avr4
> avr5 avr51
> avr6
> xmega2 xmega4 xmega5 xmega6 xmega7
> 3. a definition of sample machine with SRAM, FLASH and CPU which allows to execute simple code
> 4. encoding for all AVR instructions
> 5. interrupt handling
> 6. helpers for IN, OUT, SLEEP, WBR & unsupported instructions
> 7. a decoder which given an opcode decides what istruction it is
> 8. translation of AVR instruction into TCG
> 9. all features together
>
> changes since v3
> 1. rampD/X/Y/Z registers are encoded as 0x00ff0000 (instead of 0x000000ff) for faster address manipulaton
> 2. ffs changed to ctz32
> 3. duplicate code removed at avr_cpu_do_interrupt
> 4. using andc instead of not + and
> 5. fixing V flag calculation in varios instructions
> 6. freeing local variables in PUSH
> 7. tcg_const_local_i32 -> tcg_const_i32
> 8. using sextract32 instead of my implementation
> 9. fixing BLD instruction
> 10.xor(r) instead of 0xff - r at COM
> 11.fixing MULS/MULSU not to modify inputs' content
> 12.using SUB for NEG
> 13.fixing tcg_gen_qemu_ld/st call in XCH
>
> changes since v4
> 1. target is now defined as big endian in order to optimize push_ret/pop_ret
> 2. all style warnings are fixed
> 3. adding cpu_set/get_sreg functions
> 4. simplifying gen_goto_tb as there is no real paging
> 5. env->pc -> env->pc_w
> 6. making flag dump more compact
> 7. more spacing
> 8. renaming CODE/DATA_INDEX -> MMU_CODE/DATA_IDX
> 9. removing avr_set_feature
> 10. SPL/SPH set bug fix
> 11. switching stb_phys to cpu_stb_data
> 12. cleaning up avr_decode
> 13. saving sreg, rampD/X/Y/Z, eind in HW format (savevm)
> 14. saving CPU features (savevm)
>
> changes since v5
> 1. BLD bug fix
> 2. decoder generator is added
>
> chages since v6
> 1. using cpu_get_sreg/cpu_set_sreg in avr_cpu_gdb_read_register/avr_cpu_gdb_write_register
> 2. configure the target as little endian because otherwise GDB does not work
> 3. fixing and testing gen_push_ret/gen_pop_ret
>
> changes since v7
> 1. folding back v6
> 2. logging at helper_outb and helper_inb are done for non supported yet registers only
> 3. MAINTAINERS updated
>
> changes since v8
> 1. removing hw/avr from hw/Makefile.obj as it should not be built for all
> 2. making linux compilable
> 3. testing on
> a. Mac, Apple LLVM version 7.0.0
> b. Ubuntu 12.04, gcc 4.9.2
> c. Fedora 23, gcc 5.3.1
> 4. folding back some patches
> 5. translation bug fixes for ORI, CPI, XOR instructions
> 6. propper handling of cpu register writes though memory
>
> changes since v9
> 1. removing forward declarations of static functions
> 2. disabling debug prints
> 3. switching to case range instead of if else if ...
> 4. LD/ST IN/OUT accessing CPU maintainder registers are not routed to any device
> 5. commenst about sample board and sample IO device added
> 6. sample board description is more descriptive now
> 7. memory_region_allocate_system_memory is used to create RAM
> 8. now there are helper_fullrd & helper_fullwr when LD/ST try to access registers
>
> changes since v10
> 1. movig back fullwr & fullrd into the commit where outb and inb were introduced
> 2. changing tlb_fill function signature
> 3. adding empty line between functions
> 4. adding newline on the last line of the file
> 5. using tb->flags to generae full access ST/LD instructions
> 6. fixing SBRC bug
> 7. folding back 10th commit
> 8. whenever a new file is introduced it's added to Makefile.objs
>
> changes since v11
> 1. updating to v2.7.0-rc
> 2. removing assignment to env->fullacc from gen_intermediate_code
>
> changes since v12
> 1. fixing spacing
> 2. fixing get/put_segment functions
> 3. removing target-avr/machine.h file
> 4. VMSTATE_SINGLE_TEST -> VMSTATE_SINGLE
> 5. comment spelling
> 6. removing hw/avr/sample_io.c
> 7. char const* -> const char*
> 8. proper ram allocation
> 9. fixing breakpoint functionality.
> 10.env1 -> env
> 11.fixing avr_cpu_gdb_write_register & avr_cpu_gdb_read_register functions
> 12.any cpu is removed
> 12.feature bits are not saved into vm state
>
> changes since v13
> 1. rebasing to v2.7.0-rc1
>
> changes since v14
> 1. I made self review with git gui tool. (I did not know such a thing exists)
> 2. removing all double/tripple spaces
> 3. removing comment reference to SampleIO
> 4. folding back some changes, so there is not deleted lines in my code
> 5. moving avr configuration, within configure file, before chris
>
> changes since v15
> 1. removing IO registers cache from CPU
> 2. implementing CBI/SBI as read(helper_inb), modify, write(helper_outb)
> 3. implementing CBIC/SBIC as read(helper_inb), check, branch
> 4. adding missing tcg_temp_free_i32 for tcg_const_i32
>
> changes since v16
> 1. removing EXT IO registers knoledge from CPU. These registers are accessible
> by LD/ST only. CPU has no interest in them
>
> changes since v17 (by Richard Henderson)
> This is Michael's v17, with some adjustments of my own:
>
> 1. Fix the whitespace errors reported by "git am",
> 2. Replace the utf-8 characters with normal ascii,
> 3. Ditch the separate compilation of translate.c.
>
> I retained the two separate files that could be regenerated
> from the included cpugen program, but merged in translate-insn.c.
> Not that it matters, but the code generated is about 3k smaller.
>
> changes since v18
> 1. moving target-avr into target/avr
> 2. do not call cpu_exec_initfn function from avr_cpu_initfn
> 3. call cpu_exec_realizefn avr_cpu_realizefn
> 4. do not fail sample machine creation if no rom is suplied
> 5. add tcg_gen_exit_tb(0) for BS_BRANCH in gen_intermediate_code
> 6. fix a register getters/setters in machine.c
> 7. changing QEMU_ARCH_AVR from 1<<17 to 1<<18
>
> changes since v19
> 1. use decodetree.py tool to decode instructions
> 2. adding USART
> 3. adding 16 bit timer peripherals
> 4. changing QEMU_ARCH_AVR from 1<<18 to 1<<20
> 5. renaming tlb_fill to avr_cpu_tlb_fill
>
> changes since v20
> 1. use one CPU naming convention
> 2. merging insn16.decode & insn32.decode files
> 3. modifying skip next instruction mechanizm
> 4. translate BREAK as NOP for now
>
> changes since v21
> 1. Reorganize bstate.
> This will make transition to <exec/translator.h> easier, and fixes a couple of bugs wrt single stepping
> by address@hidden
> 2. Drop cpc and fix page cross condition.
> by address@hidden
> 3. Refactor checking supported/unsupported instructions
> 4. Add gdb-xml/avr-cpu.xml
>
> changes since v22
> 1. Rebase
> 2. Split long comment
>
> changes since v23
> 1. remove avr_cpu_list_compare function
> 2. modify avr_cpu_class_by_name function
> 3. modify avr_cpu_list_entry function
> 4. modify avr_cpu_list function
>
> changes since v24
> 1. remove AVR_CPU_TYPE_NAME macro
>
> changes since v25
> 1. fix patches. every file belong to one patch only
> 2. change copyright year from 2016 to 2019
> 3. create mask device to emulate prr0/prr1
>
> changes since v26
> 1. add avocado acceptence test
> 2. add boot serial test
>
> changes since v27
> 1. list atmel2560 devices as unimplemented
> 2. fix sram base/size
>
> changes since v28
> 1. rebase
> 2. fix includes & build
>
> changes since v29
> 1. fixing ownership
> 2. using 'since' instread of 'added in'
>
> changes since v30
> 1. rebase
>
> changes since v31
> 1. splitting 'Add instruction translation' commit
> 2. fixing typo in qapi/machine.json sicne -> since
> 3. removing unintended changes in configure file
> 4. adding Richard Henderson as a co developer to 'Add instruction translation - CPU main translation funcions' commit
>
> changes since v32
> 1. modify cpu_get_sreg to treat sreg C as other flags, except sreg Z
>
> changes since v33
> 1. ensure flag C is always calculated as one bit
> 2. calculate flag Z as one bit, without using inverse logic
>
> changes since v34
> 1. rebase
>
> changes since v35
> 1. rebase
> 2. use NANOSECONDS_PER_SECOND instead of 1000000000 in avr_timer16.c
> 3. split "target/avr: Register AVR support with the rest of QEMU" into three patches
> 1. "target/avr: Register AVR support with the rest of QEMU"
> 2. "target/avr: Update build system"
> 3. "target/avr: Update MAINTAINERS file"
> 4. split "target/avr: Add tests" patch into two patches
> 1. "target/avr: Add Avocado test"
> 2. "target/avr: Add boot serial test"
> 5. Add instruction disassembly function
> 6. change "since 4.2" to "since 5.0"
>
> changes since v36
> 1. rebase
> 2. tename
> 1. NO_CPU_REGISTERS -> NUMBER_OF_CPU_REGISTERS
> 2. NO_IO_REGISTERS -> NUMBER_OF_IO_REGISTERS
> 3. to_A -> to_regs_16_31_by_one
> 4. to_B -> to_regs_16_23_by_one
> 5. to_C -> to_regs_24_30_by_two
> 6. to_D -> to_regs_00_30_by_two
> 3. add missing licences
> 4. add usage example (see above)
> 5. ass Sarah Harris <address@hidden> as a reviewer to MAINTAINERS
> 7. use git commit sha1 instead of `master`` in avocado test
>
> Michael Rolnik (16):
> target/avr: Add outward facing interfaces and core CPU logic
> target/avr: Add instruction helpers
> target/avr: Add instruction decoding
> target/avr: Add instruction translation - Registers definition
> target/avr: Add instruction translation - Arithmetic and Logic
> Instructions
> target/avr: Add instruction translation - Branch Instructions
> target/avr: Add instruction translation - Bit and Bit-test
> Instructions
> target/avr: Add instruction translation - MCU Control Instructions
> target/avr: Add instruction translation - CPU main translation
> function
> target/avr: Add instruction disassembly function
> target/avr: Add example board configuration
> target/avr: Register AVR support with the rest of QEMU
> target/avr: Update build system
> target/avr: Add boot serial test
> target/avr: Add Avocado test
> target/avr: Update MAINTAINERS file
>
> Sarah Harris (1):
> target/avr: Add limited support for USART and 16 bit timer peripherals
>
> configure | 7 +
> default-configs/avr-softmmu.mak | 5 +
> qapi/machine.json | 3 +-
> include/disas/dis-asm.h | 6 +
> include/hw/char/avr_usart.h | 97 +
> include/hw/misc/avr_mask.h | 47 +
> include/hw/timer/avr_timer16.h | 97 +
> include/sysemu/arch_init.h | 1 +
> target/avr/cpu-param.h | 37 +
> target/avr/cpu-qom.h | 54 +
> target/avr/cpu.h | 254 +++
> target/avr/helper.h | 29 +
> arch_init.c | 2 +
> hw/avr/sample.c | 282 +++
> hw/char/avr_usart.c | 324 ++++
> hw/misc/avr_mask.c | 112 ++
> hw/timer/avr_timer16.c | 605 ++++++
> target/avr/cpu.c | 576 ++++++
> target/avr/disas.c | 228 +++
> target/avr/gdbstub.c | 85 +
> target/avr/helper.c | 354 ++++
> target/avr/machine.c | 121 ++
> target/avr/translate.c | 3052 ++++++++++++++++++++++++++++++
> tests/boot-serial-test.c | 10 +
> tests/machine-none-test.c | 1 +
> MAINTAINERS | 11 +
> gdb-xml/avr-cpu.xml | 49 +
> hw/Kconfig | 1 +
> hw/avr/Kconfig | 6 +
> hw/avr/Makefile.objs | 1 +
> hw/char/Kconfig | 3 +
> hw/char/Makefile.objs | 1 +
> hw/misc/Kconfig | 3 +
> hw/misc/Makefile.objs | 2 +
> hw/timer/Kconfig | 3 +
> hw/timer/Makefile.objs | 2 +
> target/avr/Makefile.objs | 34 +
> target/avr/insn.decode | 194 ++
> tests/Makefile.include | 2 +
> tests/acceptance/machine_avr6.py | 56 +
> 40 files changed, 6756 insertions(+), 1 deletion(-)
> create mode 100644 default-configs/avr-softmmu.mak
> create mode 100644 include/hw/char/avr_usart.h
> create mode 100644 include/hw/misc/avr_mask.h
> create mode 100644 include/hw/timer/avr_timer16.h
> create mode 100644 target/avr/cpu-param.h
> create mode 100644 target/avr/cpu-qom.h
> create mode 100644 target/avr/cpu.h
> create mode 100644 target/avr/helper.h
> create mode 100644 hw/avr/sample.c
> create mode 100644 hw/char/avr_usart.c
> create mode 100644 hw/misc/avr_mask.c
> create mode 100644 hw/timer/avr_timer16.c
> create mode 100644 target/avr/cpu.c
> create mode 100644 target/avr/disas.c
> create mode 100644 target/avr/gdbstub.c
> create mode 100644 target/avr/helper.c
> create mode 100644 target/avr/machine.c
> create mode 100644 target/avr/translate.c
> create mode 100644 gdb-xml/avr-cpu.xml
> create mode 100644 hw/avr/Kconfig
> create mode 100644 hw/avr/Makefile.objs
> create mode 100644 target/avr/Makefile.objs
> create mode 100644 target/avr/insn.decode
> create mode 100644 tests/acceptance/machine_avr6.py
>
> --
> 2.17.2 (Apple Git-113)
>
--
Best Regards,
Michael Rolnik