On Thu, 19 Mar 2015, Stephen Warren wrote:
On 03/19/2015 09:26 AM, Paul Walmsley wrote:
On Tue, 17 Mar 2015, Russell King - ARM Linux wrote:
On Tue, Mar 17, 2015 at 01:32:21AM -0700, Paul Walmsley wrote:
- compatible : For Tegra20, must contain "nvidia,tegra20-ahb". For
- Tegra30, must contain "nvidia,tegra30-ahb". Otherwise, must contain
- '"nvidia,<chip>-ahb", "nvidia,tegra30-ahb"' where <chip> is tegra124,
- tegra132, or tegra210.
-- reg : Should contain 1 register ranges(address and length)
+ Tegra30, must contain "nvidia,tegra30-ahb". For Tegra114 and
+ contain '"nvidia,<chip>-ahb", "nvidia,tegra30-ahb"' where <chip> is
+ or tegra124. For Tegra132, the compatible string must contain
+- reg : Should contain 1 register ranges(address and length). On
+ Tegra30, Tegra114, and Tegra124 chips, the low byte of the physical
+ address of the IP block must end in 0x04. On DT files for later
+ actual hardware base address of the IP block should be used.
You could check that in the driver. If you can check it in the driver,
you can also decide to ignore it if it were offset by 0x04 (possibly
printing a warning.) That opens up the ability to fix the older Tegra
DT files going forward while still remaining compatible with existing
DT files, and avoiding the need for a complex note about this.
That's fine, I'll do that and drop this patch.
Don't we still want to update the DT binding documentation to state what the
preferred base address (or at least set of legal base addresses) is/are?
As far as I know, the DT binding documents are intended to be a
reference for IP block integration data like base addresses. At least,
that is not how they've been used in the past, in the cases that I'm
I can see some marginal utility in changing the base address in the
example. But since the worst possible outcome of using the old address is
a warning message at boot, that margin seems quite small indeed. Anyone
who would blindly use the base address from the example to create a DT
file for a new Tegra SoC isn't doing it correctly.