Re: [PATCH 00/50] pinctrl: renesas: Reserved field optimizations

[Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>]

On Wed, Apr 13, 2022 at 7:24 PM Geert Uytterhoeven
<geert+renesas@xxxxxxxxx> wrote:
> Lots of register in pin control subdrivers for Renesas SoCs contain
> reserved or unused fields.  As the macros for describing these registers
> (PINMUX_CFG_REG() and PINMUX_CFG_REG_VAR() for registers with
> fixed-width resp. variable-width fields) require describing all fields,
> the resulting data structures contain lots of dummy (zero) values: 2^N
> values for a field of N-bits wide.  To reduce data size, reserved bit
> fields wider than 3 bits were typically split in multiple 2-bit fields.
> This patch series aims to improve this by introducing a shorthand for
> describing reserved variable-width register fields without dummy values.
>
>   - Patch 1 converts a few register definitions for registers with
>     fixed-width fields that accidentally used the equivalent but larger
>     description format intended for registers with variable-width
>     fields,
>   - Patch 2 introduces a shorthand for describing reserved register
>     fields,
>   - Patches 3-22 convert reserved field descriptions in the various
>     SoC-specific pin control subdrivers to the new shorthands,
>   - Patches 23-49 convert register definitions for registers with
>     reserved fixed-width fields to the equivalent definitions with
>     variable-width fields where it makes sense,
>   - Patch 50 updates the checker to flag possible conversions to
>     variable-width reserved fields.
>
> The total kernel size reduction due to patches 3-49 is:
>   - 12685 bytes on ARM32 SoCs (multi-platform),
>   - 5416 bytes on ARM64 SoCs (multi-platform),
>   - 2575 bytes on SH SoCs (sum of mutually-exclusive single platforms).
>
> I've been running with these changes on R-Mobile APE6 and A1, R-Car
> M2-W, H3 ES1.x, H3 ES2.0, M3-W, M3-N, V3M, E3, D3, V3U, and S4, and
> SH-Mobile AG5 during the past six weeks, without any issues.
>
> I plan to queue these in renesas-pinctrl-for-v5.19.

Done.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds