Unverified Commit 40c31955 authored by Maxime Ripard's avatar Maxime Ripard
Browse files

firmware: raspberrypi: Provide a helper to query a clock max rate 



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.

Acked-by: default avatarStephen Boyd <sboyd@kernel.org>
Reviewed-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Acked-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220815-rpi-fix-4k-60-v5-3-fe9e7ac8b111@cerno.tech


Signed-off-by: default avatarMaxime Ripard <maxime@cerno.tech>
parent d0cde9b3

drivers/firmware/raspberrypi.c

+20 −0
Original line number Diff line number Diff line
@@ -228,6 +228,26 @@ 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)

		/*

		 * If our firmware doesn't support that operation, or fails, we

		 * assume the maximum clock rate is absolute maximum we can

		 * store over our type.

		 */

		 return UINT_MAX;



	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,

include/soc/bcm2835/raspberrypi-firmware.h

+26 −0
Original line number Diff line number Diff line
@@ -155,12 +155,32 @@ 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,
@@ -180,6 +200,12 @@ 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;