On Thu, 28 Jul 2016, Trent Piepho wrote: > On Thu, 2016-07-28 at 10:21 -0500, atull wrote: > > > > > > > > This isn't going work if more than one bridge is used. Each bridge has > > > > its own priv and thus priv->l3_remap_value. Each bridge's priv will > > > > have just the bit for it's own remap set. The 2nd bridge to be enabled > > > > will turn off the 1st bridge when it re-write the l3 register. > > > > > > I can confirm this is exactly what happens with tag > > > "rel_socfpga-4.1.22-ltsi_16.06.02_pr" of socfpga-4.1.22-ltsi branch > > > from altera-opensource/linux-socfpga which includes more or less the > > > code in this patch. If you have 2 bridges (lw-hps2fpga and hps2fpga) > > > you end up with only one of them being visible. Easily spot by logging > > > l3_remap_value being passed to regmap_write()... > > > > > > > Anatolij kindly provided a patch for this issue. I'll push it > > to my github repo when I can. > > I still think a better solution would be to allow the syscon driver > manage shared access. The purpose of syscon is to manage access to a > shared resource from multiple devices. And regmap already has the > ability to cache a write-only register and allow thread safe access to > modify bits in said register. The problem is just the pain of trying to > do anything to syscon DT bindings. Something like "write-only" in the > syscon binding that sets a couple values in the regmap_config is all > that's necessary. > > Might as well not use syscon at all and have the bridge driver map the > l3regs itself, since it doesn't really use syscon for anything. > I agree. Just need time to do it. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
