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/ regards Antti -- http://palosaari.fi/ -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
