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[PATCH v2 3/5] clk: renesas: rzv2h-cpg: Add support for enabling PLLs

Prabhakar posted 5 patches 11 months, 1 week ago
[PATCH v2 3/5] clk: renesas: rzv2h-cpg: Add support for enabling PLLs
Posted by Prabhakar 11 months, 1 week ago 
From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Some RZ/V2H(P) SoC variants do not have a GPU, resulting in PLLGPU being
disabled by default in TF-A. Add support for enabling PLL clocks in the
RZ/V2H(P) CPG driver to manage this.

Introduce `is_enabled` and `enable` callbacks to handle PLL state
transitions. With the `enable` callback, PLLGPU will be turned ON only
when the GPU node is enabled; otherwise, it will remain off. Define new
macros for PLL standby and monitor registers to facilitate this process.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
v1->v2
- Updated macros to get PLL offsets
- Switched to readl_poll_timeout_atomic() and updated the timeout
---
 drivers/clk/renesas/rzv2h-cpg.c | 49 +++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/drivers/clk/renesas/rzv2h-cpg.c b/drivers/clk/renesas/rzv2h-cpg.c
index e489ce28ae63..76ad037b4361 100644
--- a/drivers/clk/renesas/rzv2h-cpg.c
+++ b/drivers/clk/renesas/rzv2h-cpg.c
@@ -44,12 +44,18 @@
 #define CPG_BUS_1_MSTOP		(0xd00)
 #define CPG_BUS_MSTOP(m)	(CPG_BUS_1_MSTOP + ((m) - 1) * 4)
 
+#define CPG_PLL_STBY(x)		((x))
+#define CPG_PLL_STBY_RESETB	BIT(0)
+#define CPG_PLL_STBY_RESETB_WEN	BIT(16)
 #define CPG_PLL_CLK1(x)		((x) + 0x004)
 #define KDIV(val)		((s16)FIELD_GET(GENMASK(31, 16), (val)))
 #define MDIV(val)		FIELD_GET(GENMASK(15, 6), (val))
 #define PDIV(val)		FIELD_GET(GENMASK(5, 0), (val))
 #define CPG_PLL_CLK2(x)		((x) + 0x008)
 #define SDIV(val)		FIELD_GET(GENMASK(2, 0), (val))
+#define CPG_PLL_MON(x)		((x) + 0x010)
+#define CPG_PLL_MON_RESETB	BIT(0)
+#define CPG_PLL_MON_LOCK	BIT(4)
 
 #define DDIV_DIVCTL_WEN(shift)		BIT((shift) + 16)
 
@@ -141,6 +147,47 @@ struct ddiv_clk {
 
 #define to_ddiv_clock(_div) container_of(_div, struct ddiv_clk, div)
 
+static int rzv2h_cpg_pll_clk_is_enabled(struct clk_hw *hw)
+{
+	struct pll_clk *pll_clk = to_pll(hw);
+	struct rzv2h_cpg_priv *priv = pll_clk->priv;
+	u32 val = readl(priv->base + CPG_PLL_MON(pll_clk->pll.offset));
+
+	/* Ensure both RESETB and LOCK bits are set */
+	return (val & (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK)) ==
+	       (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK);
+}
+
+static int rzv2h_cpg_pll_clk_enable(struct clk_hw *hw)
+{
+	struct pll_clk *pll_clk = to_pll(hw);
+	struct rzv2h_cpg_priv *priv = pll_clk->priv;
+	struct pll pll = pll_clk->pll;
+	u32 stby_offset;
+	u32 mon_offset;
+	u32 val;
+	int ret;
+
+	if (rzv2h_cpg_pll_clk_is_enabled(hw))
+		return 0;
+
+	stby_offset = CPG_PLL_STBY(pll.offset);
+	mon_offset = CPG_PLL_MON(pll.offset);
+
+	writel(CPG_PLL_STBY_RESETB_WEN | CPG_PLL_STBY_RESETB,
+	       priv->base + stby_offset);
+
+	/* ensure PLL is in normal mode */
+	ret = readl_poll_timeout_atomic(priv->base + mon_offset, val,
+					(val & (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK)) ==
+					(CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK), 10, 100);
+	if (ret)
+		dev_err(priv->dev, "Failed to enable PLL 0x%x/%pC\n",
+			stby_offset, hw->clk);
+
+	return ret;
+}
+
 static unsigned long rzv2h_cpg_pll_clk_recalc_rate(struct clk_hw *hw,
 						   unsigned long parent_rate)
 {
@@ -163,6 +210,8 @@ static unsigned long rzv2h_cpg_pll_clk_recalc_rate(struct clk_hw *hw,
 }
 
 static const struct clk_ops rzv2h_cpg_pll_ops = {
+	.is_enabled = rzv2h_cpg_pll_clk_is_enabled,
+	.enable = rzv2h_cpg_pll_clk_enable,
 	.recalc_rate = rzv2h_cpg_pll_clk_recalc_rate,
 };
 
-- 
2.43.0
Re: [PATCH v2 3/5] clk: renesas: rzv2h-cpg: Add support for enabling PLLs
Posted by Lad, Prabhakar 11 months ago 
Hi Geert,

On Sun, Mar 9, 2025 at 9:14 PM Prabhakar <prabhakar.csengg@gmail.com> wrote:
>
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> Some RZ/V2H(P) SoC variants do not have a GPU, resulting in PLLGPU being
> disabled by default in TF-A. Add support for enabling PLL clocks in the
> RZ/V2H(P) CPG driver to manage this.
>
> Introduce `is_enabled` and `enable` callbacks to handle PLL state
> transitions. With the `enable` callback, PLLGPU will be turned ON only
> when the GPU node is enabled; otherwise, it will remain off. Define new
> macros for PLL standby and monitor registers to facilitate this process.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
> v1->v2
> - Updated macros to get PLL offsets
> - Switched to readl_poll_timeout_atomic() and updated the timeout
> ---
>  drivers/clk/renesas/rzv2h-cpg.c | 49 +++++++++++++++++++++++++++++++++
>  1 file changed, 49 insertions(+)
>
> diff --git a/drivers/clk/renesas/rzv2h-cpg.c b/drivers/clk/renesas/rzv2h-cpg.c
> index e489ce28ae63..76ad037b4361 100644
> --- a/drivers/clk/renesas/rzv2h-cpg.c
> +++ b/drivers/clk/renesas/rzv2h-cpg.c
> @@ -44,12 +44,18 @@
>  #define CPG_BUS_1_MSTOP                (0xd00)
>  #define CPG_BUS_MSTOP(m)       (CPG_BUS_1_MSTOP + ((m) - 1) * 4)
>
> +#define CPG_PLL_STBY(x)                ((x))
> +#define CPG_PLL_STBY_RESETB    BIT(0)
> +#define CPG_PLL_STBY_RESETB_WEN        BIT(16)
>  #define CPG_PLL_CLK1(x)                ((x) + 0x004)
>  #define KDIV(val)              ((s16)FIELD_GET(GENMASK(31, 16), (val)))
>  #define MDIV(val)              FIELD_GET(GENMASK(15, 6), (val))
>  #define PDIV(val)              FIELD_GET(GENMASK(5, 0), (val))
>  #define CPG_PLL_CLK2(x)                ((x) + 0x008)
>  #define SDIV(val)              FIELD_GET(GENMASK(2, 0), (val))
> +#define CPG_PLL_MON(x)         ((x) + 0x010)
> +#define CPG_PLL_MON_RESETB     BIT(0)
> +#define CPG_PLL_MON_LOCK       BIT(4)
>
>  #define DDIV_DIVCTL_WEN(shift)         BIT((shift) + 16)
>
> @@ -141,6 +147,47 @@ struct ddiv_clk {
>
>  #define to_ddiv_clock(_div) container_of(_div, struct ddiv_clk, div)
>
> +static int rzv2h_cpg_pll_clk_is_enabled(struct clk_hw *hw)
> +{
> +       struct pll_clk *pll_clk = to_pll(hw);
> +       struct rzv2h_cpg_priv *priv = pll_clk->priv;
> +       u32 val = readl(priv->base + CPG_PLL_MON(pll_clk->pll.offset));
> +
> +       /* Ensure both RESETB and LOCK bits are set */
> +       return (val & (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK)) ==
> +              (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK);
> +}
> +
> +static int rzv2h_cpg_pll_clk_enable(struct clk_hw *hw)
> +{
> +       struct pll_clk *pll_clk = to_pll(hw);
> +       struct rzv2h_cpg_priv *priv = pll_clk->priv;
> +       struct pll pll = pll_clk->pll;
> +       u32 stby_offset;
> +       u32 mon_offset;
> +       u32 val;
> +       int ret;
> +
> +       if (rzv2h_cpg_pll_clk_is_enabled(hw))
> +               return 0;
> +
> +       stby_offset = CPG_PLL_STBY(pll.offset);
> +       mon_offset = CPG_PLL_MON(pll.offset);
> +
> +       writel(CPG_PLL_STBY_RESETB_WEN | CPG_PLL_STBY_RESETB,
> +              priv->base + stby_offset);
> +
> +       /* ensure PLL is in normal mode */
> +       ret = readl_poll_timeout_atomic(priv->base + mon_offset, val,
> +                                       (val & (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK)) ==
> +                                       (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK), 10, 100);
This timeout didnt work when I power cycled after a complete shutdown overnight.

I will update the timeout as below, this Ive made sure the below delay
works OK after complete shutdown.

/*
* Ensure PLL enters into normal mode
*
* Note: There is no HW information about the worst case latency.
*
* Since this value might be dependent on external xtal rate, pll
* rate or even the other emulation clocks rate, use 2000 as a
* "super" safe value.
*/
ret = readl_poll_timeout_atomic(priv->base + mon_offset, val,
                                                    (val &
(CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK)) ==

(CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK), 200, 2000);

Please let me know shall I send v3 with this change or wait for your review.

Cheers,
Prabhakar
Re: [PATCH v2 3/5] clk: renesas: rzv2h-cpg: Add support for enabling PLLs
Posted by Geert Uytterhoeven 11 months ago 
Hi Prabhakar,

On Mon, 10 Mar 2025 at 19:22, Lad, Prabhakar <prabhakar.csengg@gmail.com> wrote:
> On Sun, Mar 9, 2025 at 9:14 PM Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > Some RZ/V2H(P) SoC variants do not have a GPU, resulting in PLLGPU being
> > disabled by default in TF-A. Add support for enabling PLL clocks in the
> > RZ/V2H(P) CPG driver to manage this.
> >
> > Introduce `is_enabled` and `enable` callbacks to handle PLL state
> > transitions. With the `enable` callback, PLLGPU will be turned ON only
> > when the GPU node is enabled; otherwise, it will remain off. Define new
> > macros for PLL standby and monitor registers to facilitate this process.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > ---
> > v1->v2
> > - Updated macros to get PLL offsets
> > - Switched to readl_poll_timeout_atomic() and updated the timeout

Thanks for the update!

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

> > --- a/drivers/clk/renesas/rzv2h-cpg.c
> > +++ b/drivers/clk/renesas/rzv2h-cpg.c

> > +static int rzv2h_cpg_pll_clk_enable(struct clk_hw *hw)
> > +{
> > +       struct pll_clk *pll_clk = to_pll(hw);
> > +       struct rzv2h_cpg_priv *priv = pll_clk->priv;
> > +       struct pll pll = pll_clk->pll;
> > +       u32 stby_offset;
> > +       u32 mon_offset;
> > +       u32 val;
> > +       int ret;
> > +
> > +       if (rzv2h_cpg_pll_clk_is_enabled(hw))
> > +               return 0;
> > +
> > +       stby_offset = CPG_PLL_STBY(pll.offset);
> > +       mon_offset = CPG_PLL_MON(pll.offset);
> > +
> > +       writel(CPG_PLL_STBY_RESETB_WEN | CPG_PLL_STBY_RESETB,
> > +              priv->base + stby_offset);
> > +
> > +       /* ensure PLL is in normal mode */
> > +       ret = readl_poll_timeout_atomic(priv->base + mon_offset, val,
> > +                                       (val & (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK)) ==
> > +                                       (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK), 10, 100);
> This timeout didnt work when I power cycled after a complete shutdown overnight.
>
> I will update the timeout as below, this Ive made sure the below delay
> works OK after complete shutdown.
>
> /*
> * Ensure PLL enters into normal mode
> *
> * Note: There is no HW information about the worst case latency.
> *
> * Since this value might be dependent on external xtal rate, pll
> * rate or even the other emulation clocks rate, use 2000 as a
> * "super" safe value.
> */
> ret = readl_poll_timeout_atomic(priv->base + mon_offset, val,
>                                                     (val &
> (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK)) ==
>
> (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK), 200, 2000);
>
> Please let me know shall I send v3 with this change or wait for your review.

I can incorporate this fix while queuing in renesas-clk for v6.16.
But, please explain what is "the other emulation clocks rate"?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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
Re: [PATCH v2 3/5] clk: renesas: rzv2h-cpg: Add support for enabling PLLs
Posted by Lad, Prabhakar 11 months ago 
Hi Geert,

Thank you for the review.

On Fri, Mar 14, 2025 at 1:04 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Prabhakar,
>
> On Mon, 10 Mar 2025 at 19:22, Lad, Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > On Sun, Mar 9, 2025 at 9:14 PM Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > >
> > > Some RZ/V2H(P) SoC variants do not have a GPU, resulting in PLLGPU being
> > > disabled by default in TF-A. Add support for enabling PLL clocks in the
> > > RZ/V2H(P) CPG driver to manage this.
> > >
> > > Introduce `is_enabled` and `enable` callbacks to handle PLL state
> > > transitions. With the `enable` callback, PLLGPU will be turned ON only
> > > when the GPU node is enabled; otherwise, it will remain off. Define new
> > > macros for PLL standby and monitor registers to facilitate this process.
> > >
> > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > ---
> > > v1->v2
> > > - Updated macros to get PLL offsets
> > > - Switched to readl_poll_timeout_atomic() and updated the timeout
>
> Thanks for the update!
>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
>
> > > --- a/drivers/clk/renesas/rzv2h-cpg.c
> > > +++ b/drivers/clk/renesas/rzv2h-cpg.c
>
> > > +static int rzv2h_cpg_pll_clk_enable(struct clk_hw *hw)
> > > +{
> > > +       struct pll_clk *pll_clk = to_pll(hw);
> > > +       struct rzv2h_cpg_priv *priv = pll_clk->priv;
> > > +       struct pll pll = pll_clk->pll;
> > > +       u32 stby_offset;
> > > +       u32 mon_offset;
> > > +       u32 val;
> > > +       int ret;
> > > +
> > > +       if (rzv2h_cpg_pll_clk_is_enabled(hw))
> > > +               return 0;
> > > +
> > > +       stby_offset = CPG_PLL_STBY(pll.offset);
> > > +       mon_offset = CPG_PLL_MON(pll.offset);
> > > +
> > > +       writel(CPG_PLL_STBY_RESETB_WEN | CPG_PLL_STBY_RESETB,
> > > +              priv->base + stby_offset);
> > > +
> > > +       /* ensure PLL is in normal mode */
> > > +       ret = readl_poll_timeout_atomic(priv->base + mon_offset, val,
> > > +                                       (val & (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK)) ==
> > > +                                       (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK), 10, 100);
> > This timeout didnt work when I power cycled after a complete shutdown overnight.
> >
> > I will update the timeout as below, this Ive made sure the below delay
> > works OK after complete shutdown.
> >
> > /*
> > * Ensure PLL enters into normal mode
> > *
> > * Note: There is no HW information about the worst case latency.
> > *
> > * Since this value might be dependent on external xtal rate, pll
> > * rate or even the other emulation clocks rate, use 2000 as a
> > * "super" safe value.
> > */
> > ret = readl_poll_timeout_atomic(priv->base + mon_offset, val,
> >                                                     (val &
> > (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK)) ==
> >
> > (CPG_PLL_MON_RESETB | CPG_PLL_MON_LOCK), 200, 2000);
> >
> > Please let me know shall I send v3 with this change or wait for your review.
>
> I can incorporate this fix while queuing in renesas-clk for v6.16.
> But, please explain what is "the other emulation clocks rate"?
>
I got carried away referring to R-Car code, let's drop the `or even
the other emulation clocks rate`. Thank you for taking care of it.

Cheers,
Prabhakar

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