Re: [PATCH v3 1/3] hw/char: add K230 DW 8250-compatible UART

Hi,

On 8/8/26 04:32, WX Chen wrote:
> Implement a K230 SoC DesignWare 8250-compatible UART controller model for
> QEMU, capable of running the Linux 8250_dw driver and providing an
> interactive shell.
> 
> Implemented:
>    - Standard 16550 registers (RBR/THR/DLL, IER/DLH, IIR/FCR, LCR, MCR,
>      LSR, MSR, SCR) and DesignWare-specific registers (USR, TFL, RFL, SRR,
>      SRTS, SBCR, SDMAM, SFE, SRT, STET, HTX, CPR, UCV, CTR)
>    - DLAB switching; 32-byte TX/RX FIFO; synchronous transmit with
>      backpressure handling
>    - Loopback mode; chardev BREAK routed to LSR.BI/FE via CHR_EVENT_BREAK
>    - Four-level prioritized interrupt scheme (ELSI / RX Data / Timeout /
>      THRE), with edge-triggered THRE
>    - RX Character Timeout interrupt (IID=0xc) with 4-char-time timer that
>      tracks the programmed divisor latch
>    - Busy Detect interrupt (IID=0x7): LCR (and its shadow SBCR) writes
>      while USR.BUSY=1 are rejected and raise IID=0x7, cleared by reading
>      USR; USR.BUSY reflects TX-not-empty / RX-data-ready
>    - Shadow registers alias their underlying fields
>    - SRR (UR/RFR/XFR) self-clearing software reset
> 
> Not implemented:
>    - RS485 transceiver control (TCR/DE_EN/RE_EN/DET/TAT)
>    - 9-bit multidrop (LCR_EXT/RAR/TAR)
>    - Fractional baud rate (DLF)
>    - Auto Flow Control (MCR.AFCE)
>    - IrDA SIR mode (MCR.SIRE)
>    - Low-power divisor latch (LPDLL/LPDLH)
>    - FIFO access test mode (FAR/TFR/RFW)
>    - DMA Software Acknowledge (DMASA)
> 
> Signed-off-by: WX Chen <[email protected]>
> ---
>   hw/char/Kconfig             |   3 +
>   hw/char/k230_uart.c         | 816 ++++++++++++++++++++++++++++++++++++++++++++

How much this diverges of the generic 8250 model we have?

In order to reduce maintenance burden with duplicated code, the
project preference is to use the inheritance pattern of oriented
bject programming, in particular with QOM APIs.

This model could inherit from our generic model with:

   TypeInfo::parent = TYPE_SERIAL

then override its specific methods.

Could you have a look and justify the full rewrite?

Thanks,

Phil.

>   hw/char/meson.build         |   1 +
>   include/hw/char/k230_uart.h | 198 +++++++++++
>   4 files changed, 1018 insertions(+)