From: Karicheri, Muralidharan > Sent: 09 February 2016 16:19 > >... > >> >In reality the 'pad' fields ought to be renamed - since they aren't pads. > >> >Perhaps they should be a union? > > > >> No. At the end of the descriptor, host software can add scratchpad > >> which is not modified by the hardware, but is used by the driver. So > >> please don't rename. > > > >So comment in the definition that the hardware doesn't modify them. > >The driver is defining these fields and they are definitely NOT padding. > > > It is scratch pad, not padding. Looks like pad is a confusing name. Can be > renamed to sw_data to be in sync with spec below. > > The hardware spec from > http://www.ti.com/lit/ug/sprugr9h/sprugr9h.pdf > > The other SW data portion of the descriptor exists after all of the defined > words and is reserved for use by the host software to store completely > private data. This region is not used in any way by the DMA or queue manager > modules in a Multicore Navigator system and these modules will not modify > any bytes within this region.
Right, so comment that the hardware doesn't look at the fields. But name/type the structure fields to indicate what they contain. Maybe sw_buf_len etc - but I suspect there are much more meaningful names. David