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Re: [PATCH v4 1/5] char: add goldfish-tty
From: |
Laurent Vivier |
Subject: |
Re: [PATCH v4 1/5] char: add goldfish-tty |
Date: |
Sun, 7 Mar 2021 20:57:27 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 |
Le 07/03/2021 à 20:24, Philippe Mathieu-Daudé a écrit :
> 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);
I agree.
>
> 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.
TARGET_LONG_SIZE depends on CPU, I don't think we can use it here.
>> + 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,
>> +};
OK
>
> With min_access_size:
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>
Thanks,
Laurent