[PATCH v3 0/3] Meson S4 HW RNG Support

[PATCH v3 0/3] Meson S4 HW RNG Support

[Alexey Romanov]

Hello!

This patch series adds hwrng support for Amlogic S4-series.
Now, S4 uses a new random number generation algorithm.
This changes implemnents new algo and also adds description
to meson-s4.dtsi.

V2:

- Use readl_relaxed_poll_timeout_atomic() function instead of loop.
- Use two different functions: meson_rng_read() and meson_s4_rng_read().
- Fix naming in DT schema (meson-s4-hwrng instead of meson-hwrng-s4).
- A little code style fixes.

V3:

- Fix commit message in patch with dt-bindings schema changes.

Alexey Romanov (3):
  drivers: rng: meson: add support for S4
  dt-bindings: rng: meson: add meson-rng-s4 compatible
  arch/arm64: dts: meson-s4: add hwrng node

 .../bindings/rng/amlogic,meson-rng.yaml       |  1 +
 arch/arm64/boot/dts/amlogic/meson-s4.dtsi     |  5 ++
 drivers/char/hw_random/meson-rng.c            | 80 ++++++++++++++++++-
 3 files changed, 83 insertions(+), 3 deletions(-)

-- 
2.25.1

[PATCH v3 1/3] drivers: rng: meson: add support for S4

[Alexey Romanov]

From: Alexey Romanov <avromanov@sberdevices.ru>

For some Amlogic SOC's, mechanism to obtain random number
has been changed. For example, S4 now uses status bit waiting algo.

Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
---
 drivers/char/hw_random/meson-rng.c | 80 ++++++++++++++++++++++++++++--
 1 file changed, 77 insertions(+), 3 deletions(-)

diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c
index a4eb8e35f13d..5e1dee659866 100644
--- a/drivers/char/hw_random/meson-rng.c
+++ b/drivers/char/hw_random/meson-rng.c
@@ -13,12 +13,24 @@
 #include <linux/types.h>
 #include <linux/of.h>
 #include <linux/clk.h>
+#include <linux/iopoll.h>
 
-#define RNG_DATA 0x00
+#define RNG_DATA	0x00
+#define RNG_S4_DATA	0x08
+#define RNG_S4_CFG	0x00
+
+#define RUN_BIT		BIT(0)
+#define SEED_READY_STS_BIT	BIT(31)
+
+struct meson_rng_priv {
+	int (*read)(struct hwrng *rng, void *buf, size_t max, bool wait);
+};
 
 struct meson_rng_data {
 	void __iomem *base;
 	struct hwrng rng;
+	struct device *dev;
+	const struct meson_rng_priv *priv;
 };
 
 static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
@@ -31,6 +43,47 @@ static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
 	return sizeof(u32);
 }
 
+static int meson_rng_wait_status(void __iomem *cfg_addr, int bit)
+{
+	u32 status = 0;
+	int ret;
+
+	ret = readl_relaxed_poll_timeout_atomic(cfg_addr,
+						status, !(status & bit),
+						10, 10000);
+	if (ret)
+		return -EBUSY;
+
+	return 0;
+}
+
+static int meson_s4_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	struct meson_rng_data *data =
+			container_of(rng, struct meson_rng_data, rng);
+
+	void __iomem *cfg_addr = data->base + RNG_S4_CFG;
+	int err;
+
+	writel_relaxed(readl_relaxed(cfg_addr) | SEED_READY_STS_BIT, cfg_addr);
+
+	err = meson_rng_wait_status(cfg_addr, SEED_READY_STS_BIT);
+	if (err) {
+		dev_err(data->dev, "Seed isn't ready, try again\n");
+		return err;
+	}
+
+	err = meson_rng_wait_status(cfg_addr, RUN_BIT);
+	if (err) {
+		dev_err(data->dev, "Can't get random number, try again\n");
+		return err;
+	}
+
+	*(u32 *)buf = readl_relaxed(data->base + RNG_S4_DATA);
+
+	return sizeof(u32);
+}
+
 static int meson_rng_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -41,6 +94,10 @@ static int meson_rng_probe(struct platform_device *pdev)
 	if (!data)
 		return -ENOMEM;
 
+	data->priv = device_get_match_data(&pdev->dev);
+	if (!data->priv)
+		return -ENODEV;
+
 	data->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(data->base))
 		return PTR_ERR(data->base);
@@ -51,13 +108,30 @@ static int meson_rng_probe(struct platform_device *pdev)
 				     "Failed to get core clock\n");
 
 	data->rng.name = pdev->name;
-	data->rng.read = meson_rng_read;
+	data->rng.read = data->priv->read;
+
+	data->dev = &pdev->dev;
 
 	return devm_hwrng_register(dev, &data->rng);
 }
 
+static const struct meson_rng_priv meson_rng_priv = {
+	.read = meson_rng_read,
+};
+
+static const struct meson_rng_priv meson_rng_priv_s4 = {
+	.read = meson_s4_rng_read,
+};
+
 static const struct of_device_id meson_rng_of_match[] = {
-	{ .compatible = "amlogic,meson-rng", },
+	{
+		.compatible = "amlogic,meson-rng",
+		.data = (void *)&meson_rng_priv,
+	},
+	{
+		.compatible = "amlogic,meson-s4-rng",
+		.data = (void *)&meson_rng_priv_s4,
+	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, meson_rng_of_match);
-- 
2.25.1

Re: [PATCH v3 1/3] drivers: rng: meson: add support for S4

[Herbert Xu]

On Mon, Sep 11, 2023 at 01:11:27PM +0300, Alexey Romanov wrote:
>
> +struct meson_rng_priv {
> +	int (*read)(struct hwrng *rng, void *buf, size_t max, bool wait);
> +};
>  
>  struct meson_rng_data {
>  	void __iomem *base;
>  	struct hwrng rng;
> +	struct device *dev;
> +	const struct meson_rng_priv *priv;
>  };

Is data->priv really necessary? It doesn't seem to be used anywhere
after the probe.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH v3 1/3] drivers: rng: meson: add support for S4

[Alexey Romanov]

Hi Herbert,

On Wed, Sep 20, 2023 at 12:55:33PM +0800, Herbert Xu wrote:
> On Mon, Sep 11, 2023 at 01:11:27PM +0300, Alexey Romanov wrote:
> >
> > +struct meson_rng_priv {
> > +	int (*read)(struct hwrng *rng, void *buf, size_t max, bool wait);
> > +};
> >  
> >  struct meson_rng_data {
> >  	void __iomem *base;
> >  	struct hwrng rng;
> > +	struct device *dev;
> > +	const struct meson_rng_priv *priv;
> >  };
> 
> Is data->priv really necessary? It doesn't seem to be used anywhere
> after the probe.
> 

Are you suggesting remove meson_rng_priv and putting a pointer to read
function in meson_rng_data?


> Thanks,
> -- 
> Email: Herbert Xu <herbert@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

-- 
Thank you,
Alexey

Re: [PATCH v3 1/3] drivers: rng: meson: add support for S4

[Herbert Xu]

On Fri, Sep 22, 2023 at 08:15:27AM +0000, Alexey Romanov wrote:
>
> Are you suggesting remove meson_rng_priv and putting a pointer to read
> function in meson_rng_data?

I just thought it was weird that you assign meson_rng_data->priv
and then never use it anywhere else in the driver.  Did I miss
something?

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[PATCH v3 2/3] dt-bindings: rng: meson: add meson-rng-s4 compatible

[Alexey Romanov]

From: Alexey Romanov <avromanov@sberdevices.ru>

Add compatible for hardware number generator node for
Amlogic S4-series.

Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
---
 Documentation/devicetree/bindings/rng/amlogic,meson-rng.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/rng/amlogic,meson-rng.yaml b/Documentation/devicetree/bindings/rng/amlogic,meson-rng.yaml
index 457a6e43d810..afa52af442a7 100644
--- a/Documentation/devicetree/bindings/rng/amlogic,meson-rng.yaml
+++ b/Documentation/devicetree/bindings/rng/amlogic,meson-rng.yaml
@@ -14,6 +14,7 @@ properties:
   compatible:
     enum:
       - amlogic,meson-rng
+      - amlogic,meson-s4-rng
 
   reg:
     maxItems: 1
-- 
2.25.1

[PATCH v3 3/3] arch/arm64: dts: meson-s4: add hwrng node

[Alexey Romanov]

From: Alexey Romanov <avromanov@sberdevices.ru>

Using this node, we can obtain random numbers via
hardware random number generator.

Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
---
 arch/arm64/boot/dts/amlogic/meson-s4.dtsi | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-s4.dtsi b/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
index f24460186d3d..b3a1ecf36467 100644
--- a/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
@@ -133,6 +133,11 @@ reset: reset-controller@2000 {
 				reg = <0x0 0x2000 0x0 0x98>;
 				#reset-cells = <1>;
 			};
+
+			hwrng: rng@440788 {
+				compatible = "amlogic,meson-s4-rng";
+				reg = <0x0 0x440788 0x0 0x0c>;
+			};
 		};
 	};
 };
-- 
2.25.1

Re: [PATCH v3 3/3] arch/arm64: dts: meson-s4: add hwrng node

[neil.armstrong]

On 11/09/2023 12:11, Alexey Romanov wrote:
> From: Alexey Romanov <avromanov@sberdevices.ru>
> 
> Using this node, we can obtain random numbers via
> hardware random number generator.
> 
> Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
> ---
>   arch/arm64/boot/dts/amlogic/meson-s4.dtsi | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/amlogic/meson-s4.dtsi b/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
> index f24460186d3d..b3a1ecf36467 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
> +++ b/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
> @@ -133,6 +133,11 @@ reset: reset-controller@2000 {
>   				reg = <0x0 0x2000 0x0 0x98>;
>   				#reset-cells = <1>;
>   			};
> +
> +			hwrng: rng@440788 {
> +				compatible = "amlogic,meson-s4-rng";
> +				reg = <0x0 0x440788 0x0 0x0c>;
> +			};
>   		};
>   	};
>   };

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>