Hi Thomas,
On 1/29/20 9:07 AM, Thomas Huth wrote:
> On 28/01/2020 11.34, Eric Auger wrote:
>> Let's link getchar.o to use puts and getchar from the
>> tests.
>>
>> Then allow tests belonging to the migration group to
>> trigger the migration from the test code by putting
>> "migrate" into the uart. Then the code can wait for the
>> migration completion by using getchar().
>>
>> The __getchar implement is minimalist as it just reads the
>> data register. It is just meant to read the single character
>> emitted at the end of the migration by the runner script.
>>
>> It is not meant to read more data (FIFOs are not enabled).
>>
>> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
>>
>> ---
>>
>> v2 -> v3:
>> - take the lock
>> - assert if more than 16 chars
>> - removed Thomas' R-b
>> ---
>> arm/Makefile.common | 2 +-
>> arm/run | 2 +-
>> lib/arm/io.c | 28 ++++++++++++++++++++++++++++
>> 3 files changed, 30 insertions(+), 2 deletions(-)
>>
>> diff --git a/arm/Makefile.common b/arm/Makefile.common
>> index b8988f2..a123e85 100644
>> --- a/arm/Makefile.common
>> +++ b/arm/Makefile.common
>> @@ -32,7 +32,7 @@ CFLAGS += -I $(SRCDIR)/lib -I $(SRCDIR)/lib/libfdt -I lib
>> asm-offsets = lib/$(ARCH)/asm-offsets.h
>> include $(SRCDIR)/scripts/asm-offsets.mak
>>
>> -cflatobjs += lib/util.o
>> +cflatobjs += lib/util.o lib/getchar.o
>> cflatobjs += lib/alloc_phys.o
>> cflatobjs += lib/alloc_page.o
>> cflatobjs += lib/vmalloc.o
>> diff --git a/arm/run b/arm/run
>> index 277db9b..a390ca5 100755
>> --- a/arm/run
>> +++ b/arm/run
>> @@ -61,6 +61,6 @@ fi
>> M+=",accel=$ACCEL"
>> command="$qemu -nodefaults $M -cpu $processor $chr_testdev $pci_testdev"
>> command+=" -display none -serial stdio -kernel"
>> -command="$(timeout_cmd) $command"
>> +command="$(migration_cmd) $(timeout_cmd) $command"
>>
>> run_qemu $command "$@"
>> diff --git a/lib/arm/io.c b/lib/arm/io.c
>> index 99fd315..d8e7745 100644
>> --- a/lib/arm/io.c
>> +++ b/lib/arm/io.c
>> @@ -87,6 +87,34 @@ void puts(const char *s)
>> spin_unlock(&uart_lock);
>> }
>>
>> +static int ____getchar(void)
>
> Three underscores? ... that's quite a lot already. I'd maybe rather name
> the function "do_getchar" or something similar instead. Or simply merge
> the code into the __getchar function below - it's just three lines.
OK
>
>> +{
>> + int c;
>> +
>> + spin_lock(&uart_lock);
>> + c = readb(uart0_base);
>> + spin_unlock(&uart_lock);
>> +
>> + return c ? : -1;
>
> Just a matter of taste, but I prefer the elvis operator without space in
> between.
OK
>
>> +}
>> +
>> +/*
>> + * Minimalist implementation for migration completion detection.
>> + * Without FIFOs enabled on the QEMU UART device we just read
>> + * the data register: we cannot read more than 16 characters.
>
> Where are the 16 bytes buffered if FIFOs are disabled?
I think this is in the PL011 data register (UARTDR), 4 words.
https://developer.arm.com/docs/ddi0183/latest/programmers-model/register-descriptions/data-register-uartdr
>
>> + */
>> +int __getchar(void)
>> +{
>> + int c = ____getchar();
>> + static int count;
>> +
>> + if (c != -1)
>> + ++count;
>> +
>> + assert(count < 16);
>> +
>> + return c;
>> +}
>
> The above comments were only nits ... feel free to ignore them if you
> don't want to respin the series just because of this.
No Problem. Thank you for your time.
Thanks
Eric
>
> Thomas
>
