[PATCH v1 0/2] Add trng driver to JHB100

[PATCH v1 0/2] Add trng driver to JHB100

[lianfeng.ouyang]

From: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>

for jhb100, While IP assert async reset, it may generate glitch
and propagate to downstream IP. In order to solve RDC issue,
conduct clock gating before asserting reset to prevent generating glitch.

Lianfeng Ouyang (2):
  dt-bindings: Add bindings for StarFive JHB100 SoC trng controller.
  hwrng: starfive: Update clk and reset sequence

 .../bindings/rng/starfive,jh7110-trng.yaml     |  2 +-
 MAINTAINERS                                    |  2 +-
 drivers/char/hw_random/jh7110-trng.c           | 18 ++++++++++++++++--
 3 files changed, 18 insertions(+), 4 deletions(-)

--
2.43.0

[PATCH v1 1/2] dt-bindings: Add bindings for StarFive JHB100 SoC trng controller.

[lianfeng.ouyang]

From: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>

Signed-off-by: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>
---
 Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml b/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
index 4639247e9e51..11346d77b2f6 100644
--- a/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
+++ b/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
@@ -13,8 +13,8 @@ properties:
   compatible:
     oneOf:
       - items:
-          - const: starfive,jh8100-trng
           - const: starfive,jh7110-trng
+          - const: starfive,jhb100-trng
       - const: starfive,jh7110-trng
 
   reg:
-- 
2.43.0

[PATCH v1 2/2] hwrng: starfive: Update clk and reset sequence

[lianfeng.ouyang]

From: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>

for jhb100, While IP assert async reset, it may generate glitch
and propagate to downstream IP. In order to solve RDC issue,
conduct clock gating before asserting reset to prevent generating glitch.

Jia Jie Ho has resigned

Signed-off-by: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>
---
 MAINTAINERS                          |  2 +-
 drivers/char/hw_random/jh7110-trng.c | 18 ++++++++++++++++--
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index d3a6b3f6b6a0..729b20ecc697 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -25280,7 +25280,7 @@ F:	Documentation/devicetree/bindings/perf/starfive,jh8100-starlink-pmu.yaml
 F:	drivers/perf/starfive_starlink_pmu.c

 STARFIVE TRNG DRIVER
-M:	Jia Jie Ho <jiajie.ho@starfivetech.com>
+M:	Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>
 S:	Supported
 F:	Documentation/devicetree/bindings/rng/starfive*
 F:	drivers/char/hw_random/jh7110-trng.c
diff --git a/drivers/char/hw_random/jh7110-trng.c b/drivers/char/hw_random/jh7110-trng.c
index 9776f4daa044..f5eb434c94f5 100644
--- a/drivers/char/hw_random/jh7110-trng.c
+++ b/drivers/char/hw_random/jh7110-trng.c
@@ -234,12 +234,18 @@ static irqreturn_t starfive_trng_irq(int irq, void *priv)
 static void starfive_trng_cleanup(struct hwrng *rng)
 {
 	struct starfive_trng *trng = to_trng(rng);
+	bool is_jhb100 = device_is_compatible(trng->dev, "starfive,jhb100-trng");

 	writel(0, trng->base + STARFIVE_CTRL);

-	reset_control_assert(trng->rst);
+	if (!is_jhb100)
+		reset_control_assert(trng->rst);
+
 	clk_disable_unprepare(trng->hclk);
 	clk_disable_unprepare(trng->ahb);
+
+	if (is_jhb100)
+		reset_control_assert(trng->rst);
 }

 static int starfive_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
@@ -337,12 +343,19 @@ static int starfive_trng_probe(struct platform_device *pdev)

 	ret = devm_hwrng_register(&pdev->dev, &trng->rng);
 	if (ret) {
+		bool is_jhb100 = device_is_compatible(trng->dev, "starfive,jhb100-trng");
+
 		pm_runtime_disable(&pdev->dev);

-		reset_control_assert(trng->rst);
+		if (!is_jhb100)
+			reset_control_assert(trng->rst);
+
 		clk_disable_unprepare(trng->ahb);
 		clk_disable_unprepare(trng->hclk);

+		if (is_jhb100)
+			reset_control_assert(trng->rst);
+
 		return dev_err_probe(&pdev->dev, ret, "Failed to register hwrng\n");
 	}

@@ -378,6 +391,7 @@ static const struct dev_pm_ops starfive_trng_pm_ops = {

 static const struct of_device_id trng_dt_ids[] __maybe_unused = {
 	{ .compatible = "starfive,jh7110-trng" },
+	{ .compatible = "starfive,jhb100-trng" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, trng_dt_ids);
--
2.43.0

Re: [PATCH v1 1/2] dt-bindings: Add bindings for StarFive JHB100 SoC trng controller.

[Conor Dooley]

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On Tue, May 12, 2026 at 02:24:03PM +0800, lianfeng.ouyang wrote:
> From: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>
> 
> Signed-off-by: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>
> ---
>  Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml b/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
> index 4639247e9e51..11346d77b2f6 100644
> --- a/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
> +++ b/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
> @@ -13,8 +13,8 @@ properties:
>    compatible:
>      oneOf:
>        - items:
> -          - const: starfive,jh8100-trng
>            - const: starfive,jh7110-trng
> +          - const: starfive,jhb100-trng

You need to add a commit message here explaining why removing the jh8100
is okay.
pw-bot: changes-requested

>        - const: starfive,jh7110-trng
>  
>    reg:
> -- 
> 2.43.0
> 
> 

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Re: [PATCH v1 1/2] dt-bindings: Add bindings for StarFive JHB100 SoC trng controller.

[Conor Dooley]

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On Tue, May 12, 2026 at 06:15:07PM +0100, Conor Dooley wrote:
> On Tue, May 12, 2026 at 02:24:03PM +0800, lianfeng.ouyang wrote:
> > From: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>
> > 
> > Signed-off-by: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>
> > ---
> >  Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml b/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
> > index 4639247e9e51..11346d77b2f6 100644
> > --- a/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
> > +++ b/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
> > @@ -13,8 +13,8 @@ properties:
> >    compatible:
> >      oneOf:
> >        - items:
> > -          - const: starfive,jh8100-trng
> >            - const: starfive,jh7110-trng
> > +          - const: starfive,jhb100-trng
> 
> You need to add a commit message here explaining why removing the jh8100
> is okay.
> pw-bot: changes-requested

Additionally, given the driver changes, it looks like using a jh7110
fallback is invalid anyway.

> 
> >        - const: starfive,jh7110-trng
> >  
> >    reg:
> > -- 
> > 2.43.0
> > 
> > 



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Re: [PATCH v1 1/2] dt-bindings: Add bindings for StarFive JHB100 SoC trng controller.

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Critical] The commit silently removes the `starfive,jh8100-trng` compatible string, breaking backward ABI compatibility.
- [High] The schema enforces an invalid device tree compatible array order (generic fallback before specific device) for the new JHB100 SoC.
--

commit eafedaf1268d7bf5cd0934352607dcf457417047
Author: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>

dt-bindings: Add bindings for StarFive JHB100 SoC trng controller.

This commit adds device tree bindings for the TRNG controller on the StarFive
JHB100 SoC.

> diff --git a/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml b/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
> index 4639247e9e510..11346d77b2f6d 100644
> --- a/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
> +++ b/Documentation/devicetree/bindings/rng/starfive,jh7110-trng.yaml
> @@ -13,8 +13,8 @@ properties:
>    compatible:
>      oneOf:
>        - items:
> -          - const: starfive,jh8100-trng

Does this break backward ABI compatibility?

Device tree bindings are considered kernel ABI, and removing this line drops
support for any existing device trees that use the starfive,jh8100-trng
compatible string. The commit message doesn't document or justify the removal
of the JH8100 support.

>            - const: starfive,jh7110-trng
> +          - const: starfive,jhb100-trng

Does this enforce an invalid device tree compatible array order?

In YAML binding schemas, the items list enforces the exact sequence required in
the device tree source. By placing starfive,jh7110-trng before
starfive,jhb100-trng, this sequence puts the generic fallback before the
specific hardware variant.

This violates the device tree specification which mandates that the most
specific hardware match must come first.

To support both variants falling back to jh7110, would it be better to use
an enum for the first item containing both specific strings, followed by the
fallback constant?

>        - const: starfive,jh7110-trng

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260512062404.4540-1-lianfeng.ouyang@starfivetech.com?part=1

Re: [PATCH v1 2/2] hwrng: starfive: Update clk and reset sequence

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 4 potential issue(s) to consider:
- [High] The patch fails to guarantee that clocks are physically gated before asserting reset in cleanup(), rendering the glitch prevention ineffective when the device is active.
- [High] Misuse of hwrng cleanup and init callbacks leads to system crashes on RNG toggle.
- [High] Unsafe IRQ handler execution after clocks are gated in cleanup() causes bus faults.
- [High] Broken Runtime PM state initialization causes permanent clock leakage.
--

commit 097b8dfdf62a7320bf5e3edd8a668729f1364217
Author: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>

hwrng: starfive: Update clk and reset sequence

For jhb100, this conducts clock gating before asserting reset to prevent
generating glitches that propagate to downstream IP.

> diff --git a/drivers/char/hw_random/jh7110-trng.c b/drivers/char/hw_random/jh7110-trng.c
> --- a/drivers/char/hw_random/jh7110-trng.c
> +++ b/drivers/char/hw_random/jh7110-trng.c
> @@ -234,12 +234,18 @@ static irqreturn_t starfive_trng_irq(int irq, void *priv)
>  static void starfive_trng_cleanup(struct hwrng *rng)
>  {
>  	struct starfive_trng *trng = to_trng(rng);
> +	bool is_jhb100 = device_is_compatible(trng->dev, "starfive,jhb100-trng");
>  
>  	writel(0, trng->base + STARFIVE_CTRL);
>  
> -	reset_control_assert(trng->rst);
> +	if (!is_jhb100)
> +		reset_control_assert(trng->rst);
> +
>  	clk_disable_unprepare(trng->hclk);
>  	clk_disable_unprepare(trng->ahb);
> +
> +	if (is_jhb100)
> +		reset_control_assert(trng->rst);
>  }

Does this sequence guarantee the clocks are physically gated before asserting
the reset?

Because the probe function manually enables the clocks without calling
pm_runtime_set_active(), the physical clock count starts at 1. If the RNG is
deselected while the device is still active (for example, within the 100ms
autosuspend window after a read), the clk_disable_unprepare() calls here
will only decrement the clock count to 1.

Could the physical clocks remain running when reset_control_assert() is
executed, generating the exact downstream glitch this patch intends to
prevent? The driver may need to synchronize with Runtime PM first.

This isn't a bug introduced by this patch, but does managing hardware states
this way in cleanup() lead to a crash if the RNG is re-selected? The hwrng
core invokes cleanup() when the RNG is deselected via sysfs, which drops the
clock count.

If the user subsequently re-selects the RNG, the core invokes
starfive_trng_init(). Since init() does not re-enable the clocks or call
pm_runtime_get_sync(), wouldn't its immediate writel() to the
STARFIVE_AUTO_AGE register trigger a synchronous external abort?

Also pre-existing, but does gating the clocks here leave the device
vulnerable to a bus fault? The interrupt handler remains fully active
because cleanup() can be executed at runtime via sysfs without unbinding the
driver.

If a spurious interrupt or delayed lockup interrupt fires while the RNG is
deselected, wouldn't starfive_trng_irq() attempt to read registers with the
clocks gated? Should the driver clear the interrupt enable register and
synchronize IRQs before gating the clocks?

[ ... ]

> @@ -337,12 +343,19 @@ static int starfive_trng_probe(struct platform_device *pdev)
>  
>  	ret = devm_hwrng_register(&pdev->dev, &trng->rng);
>  	if (ret) {
> +		bool is_jhb100 = device_is_compatible(trng->dev, "starfive,jhb100-trng");
> +
>  		pm_runtime_disable(&pdev->dev);
>  
> -		reset_control_assert(trng->rst);
> +		if (!is_jhb100)
> +			reset_control_assert(trng->rst);
> +
>  		clk_disable_unprepare(trng->ahb);
>  		clk_disable_unprepare(trng->hclk);
>  
> +		if (is_jhb100)
> +			reset_control_assert(trng->rst);
> +
>  		return dev_err_probe(&pdev->dev, ret, "Failed to register hwrng\n");
>  	}

This isn't a bug in the new error handling, but earlier in the probe sequence,
the driver manually invokes clk_prepare_enable() for both clocks, initializing
their enable counts to 1, but fails to call pm_runtime_set_active().

Doesn't the PM core therefore default the runtime status to RPM_SUSPENDED?

Every time starfive_trng_read() executes, pm_runtime_get_sync() transitions
the device to RPM_ACTIVE, calling starfive_trng_resume() which increments
the clock counts to 2. When the autosuspend timer invokes
starfive_trng_suspend(), it decrements the counts back to 1.

Does this mean the clocks are never physically turned off during normal
operation, completely preventing the hardware from powering down?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260512062404.4540-1-lianfeng.ouyang@starfivetech.com?part=2