Re: [Qemu-devel] [PATCH 14/22] nvram/ds1225y: Convert sysbus init function to realize function

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Hi Peter,

On 20/11/18 15:51, Peter Maydell wrote:
> On 19 November 2018 at 12:08, Mao Zhongyi
> <maozhongyi@cmss.chinamobile.com> wrote:
>> Use DeviceClass rather than SysBusDeviceClass in
>> nvram_sysbus_class_init().
>>
>> Cc: pbonzini@redhat.com
>> Cc: marcandre.lureau@redhat.com
>>
>> Signed-off-by: Mao Zhongyi <maozhongyi@cmss.chinamobile.com>
>> Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
>> ---
>>   hw/nvram/ds1225y.c | 12 +++++-------
>>   1 file changed, 5 insertions(+), 7 deletions(-)
>>
>> diff --git a/hw/nvram/ds1225y.c b/hw/nvram/ds1225y.c
>> index ad7345f288..b6ef463db0 100644
>> --- a/hw/nvram/ds1225y.c
>> +++ b/hw/nvram/ds1225y.c
>> @@ -25,6 +25,7 @@
>>   #include "qemu/osdep.h"
>>   #include "hw/sysbus.h"
>>   #include "trace.h"
>> +#include "qemu/error-report.h"
>>
>>   typedef struct {
>>       MemoryRegion iomem;
>> @@ -113,7 +114,7 @@ typedef struct {
>>       NvRamState nvram;
>>   } SysBusNvRamState;
>>
>> -static int nvram_sysbus_initfn(SysBusDevice *dev)
>> +static void nvram_sysbus_realize(DeviceState *dev, Error **errp)
>>   {
>>       SysBusNvRamState *sys = DS1225Y(dev);
>>       NvRamState *s = &sys->nvram;
>> @@ -123,20 +124,18 @@ static int nvram_sysbus_initfn(SysBusDevice *dev)
>>
>>       memory_region_init_io(&s->iomem, OBJECT(s), &nvram_ops, s,
>>                             "nvram", s->chip_size);
>> -    sysbus_init_mmio(dev, &s->iomem);
>> +    sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
>>
>>       /* Read current file */
>>       file = s->filename ? fopen(s->filename, "rb") : NULL;
>>       if (file) {
>>           /* Read nvram contents */
>>           if (fread(s->contents, s->chip_size, 1, file) != 1) {
>> -            printf("nvram_sysbus_initfn: short read\n");
>> +            error_report("nvram_sysbus_realize: short read");
> 
> It seems a bit odd that we don't make this cause the
> device to fail its realize method, though I suppose
> it was not previously.

I think the case where the file length is <= chip_size is OK, since the 
contents buffer is zero-allocated.

Now for the other case when length > chip_size, you are right we 
shouldn't ignore it and throw an error.

However this is not related to this patch and should be addressed in a 
different patch, so for this patch:
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

This file is named ds1225y but is rather a generic way to byte-access a 
file (except the default chip_size which is 8kB for the DS1225Y).
Is there a more up-to-date way to do that nowaday?

> 
>>           }
>>           fclose(file);
>>       }
>>       nvram_post_load(s, 0);
>> -
>> -    return 0;
>>   }
>>
>>   static Property nvram_sysbus_properties[] = {
>> @@ -148,9 +147,8 @@ static Property nvram_sysbus_properties[] = {
>>   static void nvram_sysbus_class_init(ObjectClass *klass, void *data)
>>   {
>>       DeviceClass *dc = DEVICE_CLASS(klass);
>> -    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
>>
>> -    k->init = nvram_sysbus_initfn;
>> +    dc->realize = nvram_sysbus_realize;
>>       dc->vmsd = &vmstate_nvram;
>>       dc->props = nvram_sysbus_properties;
>>   }
>> --
>> 2.17.1
>>
> 
> thanks
> -- PMM
>