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Re: [PATCH v4 1/5] char: add goldfish-tty
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [PATCH v4 1/5] char: add goldfish-tty |
Date: |
Sun, 7 Mar 2021 20:24:04 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 |
On 3/7/21 5:48 PM, Laurent Vivier wrote:
> Implement the goldfish tty device as defined in
>
> https://android.googlesource.com/platform/external/qemu/+/master/docs/GOLDFISH-VIRTUAL-HARDWARE.TXT
>
> and based on the kernel driver code:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/tty/goldfish.c
>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
> include/hw/char/goldfish_tty.h | 35 +++++
> hw/char/goldfish_tty.c | 272 +++++++++++++++++++++++++++++++++
> hw/char/Kconfig | 3 +
> hw/char/meson.build | 2 +
> hw/char/trace-events | 10 ++
> 5 files changed, 322 insertions(+)
> create mode 100644 include/hw/char/goldfish_tty.h
> create mode 100644 hw/char/goldfish_tty.c
> +static void goldfish_tty_write(void *opaque, hwaddr addr,
> + uint64_t value, unsigned size)
> +{
> + GoldfishTTYState *s = opaque;
> + unsigned char c;
> +
> + trace_goldfish_tty_write(s, addr, size, value);
> +
> + switch (addr) {
> + case REG_PUT_CHAR:
> + c = value;
> + qemu_chr_fe_write_all(&s->chr, &c, sizeof(c));
No IRQ here described in the spec... So this is correct.
> + break;
> + case REG_CMD:
> + goldfish_tty_cmd(s, value);
> + break;
> + case REG_DATA_PTR:
> + s->data_ptr = value;
> + break;
> + case REG_DATA_PTR_HIGH:
> + s->data_ptr = (value << 32) | (uint32_t)s->data_ptr;
Matter of taste, I find it easier to review as:
s->data_ptr = deposit64(s->data_ptr, value, 32, 32);
The spec says this register is only available on 64-bit targets.
Should we restrict this "#if TARGET_LONG_SIZE == 8"?
else log_mask(GUEST_ERROR)...
This seems overkill to me but that would respect the spec.
> + break;
> + case REG_DATA_LEN:
> + s->data_len = value;
> + break;
> + default:
> + qemu_log_mask(LOG_UNIMP,
> + "%s: unimplemented register write
> 0x%02"HWADDR_PRIx"\n",
> + __func__, addr);
> + break;
> + }
> +}
> +
> +static const MemoryRegionOps goldfish_tty_ops = {
> + .read = goldfish_tty_read,
> + .write = goldfish_tty_write,
> + .endianness = DEVICE_NATIVE_ENDIAN,
> + .valid.max_access_size = 4,
Again, I think you also want:
.impl.min_access_size = 4,
> + .impl.max_access_size = 4,
> +};
With min_access_size:
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>