From 4c64053e0646f66463bded712d7e6975757cf4c2 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Tue, 20 Sep 2022 13:49:10 +0200 Subject: [PATCH] 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: Stephen Boyd Reviewed-by: Florian Fainelli Signed-off-by: Maxime Ripard --- drivers/firmware/raspberrypi.c | 20 +++++++++++++++++ include/soc/bcm2835/raspberrypi-firmware.h | 26 ++++++++++++++++++++++ 2 files changed, 46 insertions(+) --- a/drivers/firmware/raspberrypi.c +++ b/drivers/firmware/raspberrypi.c @@ -342,6 +342,26 @@ static void rpi_register_clk_driver(stru -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, --- a/include/soc/bcm2835/raspberrypi-firmware.h +++ b/include/soc/bcm2835/raspberrypi-firmware.h @@ -181,12 +181,32 @@ enum rpi_firmware_clk_id { #define GET_DISPLAY_SETTINGS_PAYLOAD_SIZE 64 +/** + * 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, @@ -206,6 +226,12 @@ static inline int rpi_firmware_property_ 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;