Hi Biju,
On Fri, 12 Sept 2025 at 09:54, Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > -----Original Message-----
> > From: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> > Sent: 22 August 2025 10:51
> > Subject: [PATCH/RFC 6/6] can: rcar_canfd: Add suspend/resume support
> >
> > On R-Car Gen3 using PSCI, s2ram powers down the SoC. After resume, the CAN-FD interface no longer
> > works. Trying to bring it up again fails:
> >
> > # ip link set can0 up
> > RTNETLINK answers: Connection timed out
> >
> > # dmesg
> > ...
> > channel 0 communication state failed
> >
> > Fix this by populating the (currently empty) suspend and resume callbacks, to stop/start the individual
> > CAN-FD channels, and (de)initialize the CAN-FD controller.
> >
> > Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
>
> Tested-by: Reviewed-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
>
> With adaption to RZ/G3E for ram_clk [1]
Thanks!
> > --- a/drivers/net/can/rcar/rcar_canfd.c
> > +++ b/drivers/net/can/rcar/rcar_canfd.c
> >
> > static int rcar_canfd_resume(struct device *dev) {
> > + struct rcar_canfd_global *gpriv = dev_get_drvdata(dev);
> > + int err;
> > + u32 ch;
> > +
> > + err = rcar_canfd_global_init(gpriv);
> > + if (err) {
> > + dev_err(dev, "rcar_canfd_open() failed %pe\n", ERR_PTR(err));
>
> Typo: rcar_canfd_global_init
Oops...
> [1]
>
> biju@biju:~/linux-work/linux$ git diff
> diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
> index 57ac90e57f11..cb358a4e49d0 100644
> --- a/drivers/net/can/rcar/rcar_canfd.c
> +++ b/drivers/net/can/rcar/rcar_canfd.c
> @@ -468,6 +468,7 @@ struct rcar_canfd_global {
> struct platform_device *pdev; /* Respective platform device */
> struct clk *clkp; /* Peripheral clock */
> struct clk *can_clk; /* fCAN clock */
> + struct clk *clk_ram; /* Clock RAM */
> unsigned long channels_mask; /* Enabled channels mask */
> bool extclk; /* CANFD or Ext clock */
> bool fdmode; /* CAN FD or Classical CAN only mode */
> @@ -1983,10 +1984,18 @@ static int rcar_canfd_global_init(struct rcar_canfd_global *gpriv)
> goto fail_reset2;
> }
>
> + /* Enable RAM clock */
> + err = clk_prepare_enable(gpriv->clk_ram);
> + if (err) {
> + dev_err(dev,
> + "failed to enable ram clock, error %d\n", err);
> + goto fail_clk;
> + }
> +
> err = rcar_canfd_reset_controller(gpriv);
> if (err) {
> dev_err(dev, "reset controller failed: %pe\n", ERR_PTR(err));
> - goto fail_clk;
> + goto fail_ram_clk;
> }
>
> /* Controller in Global reset & Channel reset mode */
> @@ -2026,6 +2035,8 @@ static int rcar_canfd_global_init(struct rcar_canfd_global *gpriv)
> rcar_canfd_disable_global_interrupts(gpriv);
> fail_clk:
> clk_disable_unprepare(gpriv->clkp);
> +fail_ram_clk:
> + clk_disable_unprepare(gpriv->clk_ram);
> fail_reset2:
> reset_control_assert(gpriv->rstc2);
> fail_reset1:
> @@ -2045,6 +2056,7 @@ static void rcar_canfd_global_deinit(struct rcar_canfd_global *gpriv, bool full)
> }
>
> clk_disable_unprepare(gpriv->clkp);
> + clk_disable_unprepare(gpriv->clk_ram);
> reset_control_assert(gpriv->rstc2);
> reset_control_assert(gpriv->rstc1);
> }
> @@ -2153,10 +2165,10 @@ static int rcar_canfd_probe(struct platform_device *pdev)
> gpriv->extclk = gpriv->info->external_clk;
> }
>
> - clk_ram = devm_clk_get_optional_enabled(dev, "ram_clk");
> + gpriv->clk_ram = devm_clk_get_optional(dev, "ram_clk");
> if (IS_ERR(clk_ram))
> return dev_err_probe(dev, PTR_ERR(clk_ram),
> - "cannot get enabled ram clock\n");
> + "cannot get ram clock\n");
I guess this should be folded into "[PATCH 3/6] can: rcar_canfd:
Extract rcar_canfd_global_{,de}init()", or even better, inserted as
a new patch before that?
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
