Hi Laurent,
On Mon, Jun 14, 2021 at 8:38 PM Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
> On Thu, Jun 10, 2021 at 11:37:16AM +0200, Geert Uytterhoeven wrote:
> > As R-Car H3 ES1.x (R8A77950) and R-Car ES2.0+ (R8A77951) use the same
> > compatible value, the pin control driver relies on soc_device_match()
> > with soc_id = "r8a7795" and the (non)matching of revision = "ES1.*" to
> > match with and distinguish between the two SoC variants. The
> > corresponding entries in the normal of_match_table are present only to
> > make the optional sanity checks work.
> >
> > The R-Car H3e-2G (R8A779M1) SoC is a different grading of the R-Car H3
> > ES3.0 (R8A77951) SoC. It uses the same compatible values for individual
> > devices, but has an additional compatible value for the root node.
> > When running on an R-Car H3e-2G SoC, soc_device_match() with soc_id =
> > "r8a7795" does not return a match. Hence the pin control driver falls
> > back to the normal of_match_table, and, as the R8A77950 entry is listed
> > first, incorrectly uses the sub-driver for R-Car H3 ES1.x.
> >
> > Fix this by moving the entry for R8A77951 before the entry for R8A77950.
> >
> > Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Thanks!
> I wonder if this means we could drop the second entry in the quirks
> array, in sh_pfc_quirk_match().
As both R-Car H3 ES1.x and ES2.0+ use the same compatible value,
that function is designed (with the help of the __weak
r8a7795[01]_pinmux_info symbols) to fail, when booting a kernel
that lacks the right pin control driver. It's less likely to happen
nowadays, since we gained separate Kconfig symbols.
Note that if you enable CONFIG_ARCH_R8A77950 but not
CONFIG_ARCH_R8A77951, you can still trick a kernel running on R-Car
H3e-2G into using the wrong pin control driver, which will usually
cause something to fail during boot. Perhaps the time is ripe to
drop the safety net; need to thing about that with a fresh mind,
after a morning coffee...
> > --- a/drivers/pinctrl/renesas/core.c
> > +++ b/drivers/pinctrl/renesas/core.c
> > @@ -571,17 +571,21 @@ static const struct of_device_id sh_pfc_of_table[] = {
> > .data = &r8a7794_pinmux_info,
> > },
> > #endif
> > -/* Both r8a7795 entries must be present to make sanity checks work */
> > -#ifdef CONFIG_PINCTRL_PFC_R8A77950
> > +/*
> > + * Both r8a7795 entries must be present to make sanity checks work, but only
> > + * the first entry is actually used, for R-Car H3e.
> > + * R-Car H3 ES1.x and ES2.0+ are matched using soc_device_match() instead.
> > + */
> > +#ifdef CONFIG_PINCTRL_PFC_R8A77951
> > {
> > .compatible = "renesas,pfc-r8a7795",
> > - .data = &r8a77950_pinmux_info,
> > + .data = &r8a77951_pinmux_info,
> > },
> > #endif
> > -#ifdef CONFIG_PINCTRL_PFC_R8A77951
> > +#ifdef CONFIG_PINCTRL_PFC_R8A77950
> > {
> > .compatible = "renesas,pfc-r8a7795",
> > - .data = &r8a77951_pinmux_info,
> > + .data = &r8a77950_pinmux_info,
> > },
> > #endif
> > #ifdef CONFIG_PINCTRL_PFC_R8A77960
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
