On Mon, Sep 07, 2015 at 01:08:29PM +0200, Gerd Hoffmann wrote: > > It's just simplicity. If you want to read a few times from the same > > field (like in ACPI tables, read the data size and then the data), you > > need a way to enable and disable the selector and manage the current > > offset for that entry. This is already provided with the "old" > > interface. > > Could be handled with a 'select' control bit. Only when set select > entry and reset offset to zero. I think two features would help "round off" the new fw_cfg DMA proposal: add a select bit as you describe (that uses the 16 most significant bits of the "control" field for the "select entry" when the bit is set), and define a static signature (eg, "QEMU CFG") when reading the 64bit MMIO dma register. Both are optional features that don't change the fundamental interface; I was thinking of sending them as two patches on top of Marc's next version of his patch series (if no one else gets to it first). -Kevin -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
