Em 25-05-2012 15:32, Mauro Carvalho Chehab escreveu:
> Em 25-05-2012 14:44, Antti Palosaari escreveu:
>> On 21.05.2012 06:50, Mauro Carvalho Chehab wrote:
>>> Em 20-05-2012 17:55, Antti Palosaari escreveu:
>>>> I did some more planning and made alternative RFC.
>>>> As the earlier alternative was more like changing old functionality that new one goes much more deeper.
>>>>
>>>> As a basic rule I designed it to reduce stuff from the current struct dvb_usb_device_properties. Currently there is many nested structs introducing same callbacks. For that one I dropped all frontend and adapter level callbacks to device level. Currently struct contains 2 adapters and 3 frontends - which means we have 2 * 3 = 6 "similar" callbacks and only 1 is used. It wastes some space since devices having more than one adapter or frontend are rather rare. Making callback selection inside individual driver is very trivial even without a designated callback. Here is common example from the use of .frontend_attach() callback in case of only one callback used:
>>>> static int frontend_attach(struct dvb_usb_adapter *adap)
>>>> {
>>>> if (adap->id == 0)
>>>> return frontend_attach_1();
>>>> else
>>>> return frontend_attach_2();
>>>> }
>>>>
>>>> Functionality enhancement mentioned earlier RFC are valid too:
>>>> http://www.mail-archive.com/linux-media@xxxxxxxxxxxxxxx/msg46352.html
>>>>
>>>> As I was a little bit lazy I wrote only quick skeleton code to represent new simplified "struct dvb_usb_device_properties":
>>>>
>>>> struct dvb_usb_device_properties = {
>>>> /* download_firmware() success return values to signal what happens next */
>>>> #define RECONNECTS_USB (1<< 0)
>>>> #define RECONNECTS_USB_USING_NEW_ID (1<< 1)
>>>>
>>>> .size_of_priv = sizeof(struct 'state'),
>>>>
>>>> /* firmware download */
>>>> .identify_state(struct dvb_usb_device *d, int *cold),
>>>> .get_firmware_name(struct dvb_usb_device *d, char *firmware_name),
>>>> .download_firmware(struct dvb_usb_device *d, const struct firmware *fw),
>>>> .allow_dynamic_id = true,
>>>>
>>>> .power_ctrl(struct dvb_usb_device *d, int onoff),
>>>> .read_config(struct dvb_usb_device *d, u8 mac[6]),
>>>> .get_adapter_count(struct dvb_usb_device *d, int *count),
>>>>
>>>> .frontend_attach(struct dvb_usb_adapter *adap),
>>>> .tuner_attach(struct dvb_usb_adapter *adap),
>>>>
>>>> .init(struct dvb_usb_device *d),
>>>>
>>>> .get_rc(struct dvb_rc *),
>>>> .i2c_algo = (struct i2c_algorithm),
>>>>
>>>> .frontend_ctrl(struct dvb_frontend *fe, int onoff),
>>>> .get_stream_props(struct usb_data_stream_properties *),
>>>> .streaming_ctrl(struct dvb_usb_adapter *adap, int onoff),
>>>>
>>>> .generic_bulk_ctrl_endpoint = (int),
>>>> .generic_bulk_ctrl_endpoint_response = (int),
>>>>
>>>> .devices = (struct dvb_usb_device)[],
>>>> };
>>>>
>>>> struct dvb_usb_device dvb_usb_devices {
>>>> char *name = "name",
>>>> .rc_map = RC_MAP_EMPTY,
>>>> .device_id = (struct usb_device_id),
>>>> }
>>>
>>> It looks OK to me. It may make sense to add an optional
>>> per-device field, to allow drivers to add more board-specific
>>> information, if they need, in order to avoid duplicating
>>> things there.
>>>
>>> Another option would be for the drivers to do:
>>>
>>> struct dvb_usb_drive_foo dvb_usb_driver_foo {
>>> struct dvb_usb_device dvb_usb_devices dvb_usb_dev;
>>> int foo;
>>> long bar;
>>> ...
>>> }
>>>
>>> And, inside the core, use the container_of() macro to go from
>>> the device-specific table to struct dvb_usb_device.
>>>
>>> This way, simple drivers can do just:
>>>
>>> struct dvb_usb_drive_foo dvb_usb_driver_foo {
>>> struct dvb_usb_device dvb_usb_devices dvb_usb_dev;
>>> }
>>>
>>> And complex drivers can add more stuff there.
>>
>> I have now implemented some basic stuff. Most interesting is new way of map device id and properties for it. I found that I can use .driver_info field from the (struct usb_device_id) to carry pointer. I used it to carry all the other data to the DVB USB core. Thus that one big issue is now resolved. It reduces something like 8-9 kB of binary size which is huge improvement. Same will happen for every driver using multiple (struct dvb_usb_device_properties) - for more you are used more you save.
>>
>> Here is 3 example drivers I have converted to that new style:
>> http://palosaari.fi/linux/v4l-dvb/dvb-usb-2012-05-25/
>
> It will be better if you inline a diff at the email, instead of pointing
> to the changed files.
>
> Also, instead of doing:
>
> static struct usb_device_id af9015_usb_table[] = {
> { USB_DEVICE(USB_VID_AFATECH, USB_PID_AFATECH_AF9015_9015),
> .driver_info = (kernel_ulong_t) &((struct dvb_usb_driver_info) {
> .name = "Afatech AF9015 reference design",
> .props = &af9015_properties })},
>
> I suggest you to add a macro for it, converting the above to something similar to:
>
> DVB_USB_DRIVER_INFO("Afatech AF9015 reference design", &af9015_properties),
>
> or, even better, to:
>
> DVB_USB_DEVICE(USB_VID_AFATECH,
> USB_PID_AFATECH_AF9015_9015,
> "Afatech AF9015 reference design",
> &af9015_properties),
>
> Btw, I still think that you should move things like RC type to be stored outside
> the properties struct.
Ah, I suggest you to try to convert a driver like dib0700 (with has 83 types of devices
and several options of tuners/demods).
It shold be noticed that dib0700, has two tables (well, there are actually several
different keymaps there - but they ended to be converted into just two tables -
mainly because of my lack of time and device specifics knowledge to break the NEC
and RC5 tables on a per-device table). Any dvb-usb driver newer than RC core that
supports multiple vendors will have a different RC table for each device.
Regards,
Mauro
>
> Regards,
> Mauro
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