On Tue, May 26, 2015 at 11:10:51AM +0200, Boris Brezillon wrote: > On Tue, 26 May 2015 09:06:29 +0000 > Jason Cooper <jason@xxxxxxxxxxxxxx> wrote: > > > On Mon, May 25, 2015 at 08:43:02PM +0200, Boris Brezillon wrote: > > > Jason, Gregory, > > > > > > On Mon, 25 May 2015 16:46:51 +0000 > > > Jason Cooper <jason@xxxxxxxxxxxxxx> wrote: > > > > > > > On Mon, May 25, 2015 at 05:39:13PM +0200, Gregory CLEMENT wrote: > > > > > Hi Boris, Arnaud, > > > > > > > > > > On 22/05/2015 15:34, Boris Brezillon wrote: > > > > > > From: Arnaud Ebalard <arno@xxxxxxxxxxxx> > > > > > > > > > > > > Add crypto related nodes to kirkwood.dtsi. > > > > > > > > > > Here you use a new compatible string but with an old binding > > > > > to let the user chose between the old and the new driver. Am I right? > > > > > > That was not the intention, but you're right, that's exactly what's > > > happening here. > > > > > > > > > > > I thought we had settled on the user choosing by module load/ which driver is > > > > compiled in? The DT should be describing the hardware, not which driver the > > > > user chooses to use. > > > > > > Right, but I didn't want to add new compatible strings to the old > > > driver in the first place, neither I wanted to support the new way of > > > defining/referencing the crypto SRAMs. > > > > > > > ITOH, if we want to benefit from the TDMA optimization on Kirkwood SoCs, > > > we have to add a new compatible (unlike Orion SoCs, Kirkwood ones embed > > > a TDMA engine). > > > > Ah, there's the HW difference I must have missed in my previous thousand-foot > > overview scans :-/ > > > > So "marvell,orion-crypto" matches IP blocks without the TDMA engine, > > "marvell,kirkwood-crypto" matches IP blocks *with* the TDMA engine. > > > > > This leaves the following solutions: > > > - avoid changing the compatible in existing orion and kirkwood dtsi > > > files > > > > no, in light of the above HW difference, it makes sense to change these. > > > > > - adding kirkwood compatible string support to the existing CESA > > > driver (and I think supporting the new approach to retrieve SRAM > > > memory region would make sense too) > > > > Or, old driver matches "marvell,orion-crypto", and the new driver matches > > either compatible string. If dt has "marvell,kirkwood-crypto" then new driver > > enables TDMA with the provided properties. > > > > We then update the dtsi for all but orion to "marvell,kirkwood-crypto". > > > > This may be what you are already doing. If so, please ignore my rambling. ;-) > > Yes, that's what I'm doing :-). But this means we're forcing kirkwood > users to switch to the new driver, which is not really what you > suggested in the first place. well, I suppose I'm still clinging to the DT-as-stable-abi fantasy where the dtb isn't locked to the kernel version. :-P If you're comfortable with the change adding "marvell,kirkwood-crypto" to the old driver, then go ahead. It would indeed make everyone's lives easier. thx, Jason. > > > -- > Boris Brezillon, Free Electrons > Embedded Linux and Kernel engineering > http://free-electrons.com -- 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
