[v2] drm/vc4: Fix the core clock behaviour

[PATCH v2 3/7] firmware: raspberrypi: Provide a helper to query a clock max rate

Posted by Maxime Ripard 3 years, 6 months ago

The firmware allows to query for its clocks the operating range of a
given clock. We'll need this for some drivers (KMS, in particular) to
infer the state of some configuration options, so let's create a
function to do so.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>

diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
index b916e1e171f8..c4b9ea70f5a7 100644
--- a/drivers/firmware/raspberrypi.c
+++ b/drivers/firmware/raspberrypi.c
@@ -228,6 +228,21 @@ static void rpi_register_clk_driver(struct device *dev)
 						-1, NULL, 0);
 }
 
+unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id)
+{
+	struct rpi_firmware_clk_rate_request msg =
+		RPI_FIRMWARE_CLK_RATE_REQUEST(id);
+	int ret;
+
+	ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
+				    &msg, sizeof(msg));
+	if (ret)
+		return 0;
+
+	return le32_to_cpu(msg.rate);
+}
+EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate);
+
 static void rpi_firmware_delete(struct kref *kref)
 {
 	struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
index 74c7bcc1ac2a..10248c370229 100644
--- a/include/soc/bcm2835/raspberrypi-firmware.h
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -154,12 +154,32 @@ enum rpi_firmware_clk_id {
 	RPI_FIRMWARE_NUM_CLK_ID,
 };
 
+/**
+ * struct rpi_firmware_clk_rate_request - Firmware Request for a rate
+ * @id:	ID of the clock being queried
+ * @rate: Rate in Hertz. Set by the firmware.
+ *
+ * Used by @RPI_FIRMWARE_GET_CLOCK_RATE, @RPI_FIRMWARE_GET_CLOCK_MEASURED,
+ * @RPI_FIRMWARE_GET_MAX_CLOCK_RATE and @RPI_FIRMWARE_GET_MIN_CLOCK_RATE.
+ */
+struct rpi_firmware_clk_rate_request {
+	__le32 id;
+	__le32 rate;
+} __packed;
+
+#define RPI_FIRMWARE_CLK_RATE_REQUEST(_id)	\
+	{					\
+		.id = _id,			\
+	}
+
 #if IS_ENABLED(CONFIG_RASPBERRYPI_FIRMWARE)
 int rpi_firmware_property(struct rpi_firmware *fw,
 			  u32 tag, void *data, size_t len);
 int rpi_firmware_property_list(struct rpi_firmware *fw,
 			       void *data, size_t tag_size);
 void rpi_firmware_put(struct rpi_firmware *fw);
+unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw,
+					   unsigned int id);
 struct device_node *rpi_firmware_find_node(void);
 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node);
 struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
@@ -179,6 +199,12 @@ static inline int rpi_firmware_property_list(struct rpi_firmware *fw,
 
 static inline void rpi_firmware_put(struct rpi_firmware *fw) { }
 
+static inline unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw,
+							 unsigned int id)
+{
+	return UINT_MAX;
+}
+
 static inline struct device_node *rpi_firmware_find_node(void)
 {
 	return NULL;

-- 
b4 0.10.0

Re: [PATCH v2 3/7] firmware: raspberrypi: Provide a helper to query a clock max rate

Posted by Stefan Wahren 3 years, 5 months ago

Hi Maxime,

Am 20.09.22 um 14:50 schrieb Maxime Ripard:
> The firmware allows to query for its clocks the operating range of a
> given clock. We'll need this for some drivers (KMS, in particular) to
> infer the state of some configuration options, so let's create a
> function to do so.
>
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
>
> diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
> index b916e1e171f8..c4b9ea70f5a7 100644
> --- a/drivers/firmware/raspberrypi.c
> +++ b/drivers/firmware/raspberrypi.c
> @@ -228,6 +228,21 @@ static void rpi_register_clk_driver(struct device *dev)
>   						-1, NULL, 0);
>   }
>   
> +unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id)
> +{
> +	struct rpi_firmware_clk_rate_request msg =
> +		RPI_FIRMWARE_CLK_RATE_REQUEST(id);
> +	int ret;
> +
> +	ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
> +				    &msg, sizeof(msg));
> +	if (ret)
> +		return 0;
> +
> +	return le32_to_cpu(msg.rate);
> +}
> +EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate);
> +
>   static void rpi_firmware_delete(struct kref *kref)
>   {
>   	struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
> diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
> index 74c7bcc1ac2a..10248c370229 100644
> --- a/include/soc/bcm2835/raspberrypi-firmware.h
> +++ b/include/soc/bcm2835/raspberrypi-firmware.h
> @@ -154,12 +154,32 @@ enum rpi_firmware_clk_id {
>   	RPI_FIRMWARE_NUM_CLK_ID,
>   };
>   
> +/**
> + * struct rpi_firmware_clk_rate_request - Firmware Request for a rate
> + * @id:	ID of the clock being queried
> + * @rate: Rate in Hertz. Set by the firmware.
> + *
> + * Used by @RPI_FIRMWARE_GET_CLOCK_RATE, @RPI_FIRMWARE_GET_CLOCK_MEASURED,
> + * @RPI_FIRMWARE_GET_MAX_CLOCK_RATE and @RPI_FIRMWARE_GET_MIN_CLOCK_RATE.
> + */
> +struct rpi_firmware_clk_rate_request {
> +	__le32 id;
> +	__le32 rate;
> +} __packed;
> +
> +#define RPI_FIRMWARE_CLK_RATE_REQUEST(_id)	\
> +	{					\
> +		.id = _id,			\
> +	}
> +
>   #if IS_ENABLED(CONFIG_RASPBERRYPI_FIRMWARE)
>   int rpi_firmware_property(struct rpi_firmware *fw,
>   			  u32 tag, void *data, size_t len);
>   int rpi_firmware_property_list(struct rpi_firmware *fw,
>   			       void *data, size_t tag_size);
>   void rpi_firmware_put(struct rpi_firmware *fw);
> +unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw,
> +					   unsigned int id);
>   struct device_node *rpi_firmware_find_node(void);
>   struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node);
>   struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
> @@ -179,6 +199,12 @@ static inline int rpi_firmware_property_list(struct rpi_firmware *fw,
>   
>   static inline void rpi_firmware_put(struct rpi_firmware *fw) { }
>   
> +static inline unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw,
> +							 unsigned int id)
> +{
> +	return UINT_MAX;
In case the driver is disabled the function return UINT_MAX, but in case 
the firmware doesn't support RPI_FIRMWARE_GET_MAX_CLOCK_RATE it returns 
0. This looks a little bit inconsistent to me.
> +}
> +
>   static inline struct device_node *rpi_firmware_find_node(void)
>   {
>   	return NULL;
>

Re: [PATCH v2 3/7] firmware: raspberrypi: Provide a helper to query a clock max rate

Posted by Stephen Boyd 3 years, 6 months ago

Quoting Maxime Ripard (2022-09-20 05:50:22)
> The firmware allows to query for its clocks the operating range of a
> given clock. We'll need this for some drivers (KMS, in particular) to
> infer the state of some configuration options, so let's create a
> function to do so.
> 
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> 
Acked-by: Stephen Boyd <sboyd@kernel.org>

[PATCH v2 1/7] firmware: raspberrypi: Introduce rpi_firmware_find_node()
[PATCH v2 2/7] firmware: raspberrypi: Move the clock IDs to the firmware header
[PATCH v2 3/7] firmware: raspberrypi: Provide a helper to query a clock max rate
[PATCH v2 4/7] drm/vc4: hdmi: Fix hdmi_enable_4kp60 detection
[PATCH v2 5/7] drm/vc4: hdmi: Rework hdmi_enable_4kp60 detection code
[PATCH v2 6/7] drm/vc4: hdmi: Add more checks for 4k resolutions
[PATCH v2 7/7] drm/vc4: Make sure we don't end up with a core clock too high