Re: [Qemu-devel] [PATCH 02/10] hw/sd/sd.c: QOMify

[Peter Maydell <peter.maydell@linaro.org>]

On 17 December 2015 at 21:45, Alistair Francis
<alistair.francis@xilinx.com> wrote:
> On Fri, Dec 11, 2015 at 8:37 AM, Peter Maydell <peter.maydell@linaro.org> wrote:
>> Turn the SD card into a QOM device.
>> This conversion only changes the device itself; the various
>> functions which are effectively methods on the device are not
>> touched at this point.
>>
>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

>> @@ -472,34 +476,26 @@ static const VMStateDescription sd_vmstate = {
>>      }
>>  };
>>
>> -/* We do not model the chip select pin, so allow the board to select
>> -   whether card should be in SSI or MMC/SD mode.  It is also up to the
>> -   board to ensure that ssi transfers only occur when the chip select
>> -   is asserted.  */
>> +/* Legacy initialization function for use by non-qdevified callers */
>>  SDState *sd_init(BlockBackend *blk, bool is_spi)
>>  {
>> -    SDState *sd;
>> +    DeviceState *dev;
>> +    Error *err = NULL;
>>
>> -    if (blk && blk_is_read_only(blk)) {
>> -        fprintf(stderr, "sd_init: Cannot use read-only drive\n");
>> +    dev = qdev_create(NULL, TYPE_SD);
>> +    qdev_prop_set_drive(dev, "drive", blk, &err);
>> +    if (err) {
>> +        error_report("sd_init failed: %s", error_get_pretty(err));
>>          return NULL;
>>      }
>> -
>> -    sd = (SDState *) g_malloc0(sizeof(SDState));
>> -    sd->buf = blk_blockalign(blk, 512);
>> -    sd->spi = is_spi;
>> -    sd->enable = true;
>> -    sd->blk = blk;
>> -    sd_reset(sd);
>> -    if (sd->blk) {
>> -        /* Attach dev if not already attached.  (This call ignores an
>> -         * error return code if sd->blk is already attached.) */
>> -        /* FIXME ignoring blk_attach_dev() failure is dangerously brittle */
>> -        blk_attach_dev(sd->blk, sd);
>
> This functionality is removed with this patch. If the block is not
> already attached won't this cause errors?

The block backend is attached when we set the "drive" property
(which we do in this function in the new code just above).
[the actual call to blk_attach_dev() is in parse_drive() in
hw/core/qdev-properties-system.c.]

The blk_set_dev_ops() moves in this patch to sd_realize().

There is incidentally no longer any case where the block backend
could be already attached when we call sd_init(), because the
only case there was when it had been attached to the sdhci
controller device because of the x-drive property on that device,
and we removed the property in the previous patch. It's exactly
because setting a drive property does an implicit blk_attach_dev
that this code previously had to have special casing for
"attach of an already attached blk".

>> -        blk_set_dev_ops(sd->blk, &sd_block_ops, sd);
>> +    qdev_prop_set_bit(dev, "spi", is_spi);
>> +    object_property_set_bool(OBJECT(dev), true, "realized", &err);
>> +    if (err) {
>> +        error_report("sd_init failed: %s", error_get_pretty(err));
>> +        return NULL;
>>      }
>> -    vmstate_register(NULL, -1, &sd_vmstate, sd);
>> -    return sd;
>> +
>> +    return SD(dev);
>>  }
>>
>>  void sd_set_cb(SDState *sd, qemu_irq readonly, qemu_irq insert)
>> @@ -1765,3 +1761,62 @@ void sd_enable(SDState *sd, bool enable)
>>  {
>>      sd->enable = enable;
>>  }
>> +
>> +static void sd_instance_init(Object *obj)
>> +{
>> +    SDState *sd = SD(obj);
>> +
>> +    sd->enable = true;
>> +}
>> +
>> +static void sd_realize(DeviceState *dev, Error ** errp)
>
> You have one too many spaces here.

Yep, will fix.

thanks
-- PMM