// SPDX-License-Identifier: GPL-2.0 /* * Beagleplay Linux Driver for Greybus * * Copyright (c) 2023 Ayush Singh <[email protected]> * Copyright (c) 2023 BeagleBoard.org Foundation */ #include <linux/gfp.h> #include <linux/greybus.h> #include <linux/module.h> #include <linux/of.h> #include <linux/printk.h> #include <linux/serdev.h> #include <linux/tty.h> #include <linux/tty_driver.h> #include <linux/greybus/hd.h> #include <linux/init.h> #include <linux/device.h> #include <linux/crc-ccitt.h> #include <linux/circ_buf.h> #include <linux/types.h> #include <linux/workqueue.h> #define RX_HDLC_PAYLOAD … #define CRC_LEN … #define MAX_RX_HDLC … #define TX_CIRC_BUF_SIZE … #define ADDRESS_GREYBUS … #define ADDRESS_DBG … #define ADDRESS_CONTROL … #define HDLC_FRAME … #define HDLC_ESC … #define HDLC_XOR … #define CONTROL_SVC_START … #define CONTROL_SVC_STOP … /* The maximum number of CPorts supported by Greybus Host Device */ #define GB_MAX_CPORTS … /** * struct gb_beagleplay - BeaglePlay Greybus driver * * @sd: underlying serdev device * * @gb_hd: greybus host device * * @tx_work: hdlc transmit work * @tx_producer_lock: hdlc transmit data producer lock. acquired when appending data to buffer. * @tx_consumer_lock: hdlc transmit data consumer lock. acquired when sending data over uart. * @tx_circ_buf: hdlc transmit circular buffer. * @tx_crc: hdlc transmit crc-ccitt fcs * * @rx_buffer_len: length of receive buffer filled. * @rx_buffer: hdlc frame receive buffer * @rx_in_esc: hdlc rx flag to indicate ESC frame */ struct gb_beagleplay { … }; /** * struct hdlc_payload - Structure to represent part of HDCL frame payload data. * * @len: buffer length in bytes * @buf: payload buffer */ struct hdlc_payload { … }; /** * struct hdlc_greybus_frame - Structure to represent greybus HDLC frame payload * * @cport: cport id * @hdr: greybus operation header * @payload: greybus message payload * * The HDLC payload sent over UART for greybus address has cport preappended to greybus message */ struct hdlc_greybus_frame { … } __packed; static void hdlc_rx_greybus_frame(struct gb_beagleplay *bg, u8 *buf, u16 len) { … } static void hdlc_rx_dbg_frame(const struct gb_beagleplay *bg, const char *buf, u16 len) { … } /** * hdlc_write() - Consume HDLC Buffer. * @bg: beagleplay greybus driver * * Assumes that consumer lock has been acquired. */ static void hdlc_write(struct gb_beagleplay *bg) { … } /** * hdlc_append() - Queue HDLC data for sending. * @bg: beagleplay greybus driver * @value: hdlc byte to transmit * * Assumes that producer lock as been acquired. */ static void hdlc_append(struct gb_beagleplay *bg, u8 value) { … } static void hdlc_append_escaped(struct gb_beagleplay *bg, u8 value) { … } static void hdlc_append_tx_frame(struct gb_beagleplay *bg) { … } static void hdlc_append_tx_u8(struct gb_beagleplay *bg, u8 value) { … } static void hdlc_append_tx_buf(struct gb_beagleplay *bg, const u8 *buf, u16 len) { … } static void hdlc_append_tx_crc(struct gb_beagleplay *bg) { … } static void hdlc_transmit(struct work_struct *work) { … } static void hdlc_tx_frames(struct gb_beagleplay *bg, u8 address, u8 control, const struct hdlc_payload payloads[], size_t count) { … } static void hdlc_tx_s_frame_ack(struct gb_beagleplay *bg) { … } static void hdlc_rx_frame(struct gb_beagleplay *bg) { … } static size_t hdlc_rx(struct gb_beagleplay *bg, const u8 *data, size_t count) { … } static int hdlc_init(struct gb_beagleplay *bg) { … } static void hdlc_deinit(struct gb_beagleplay *bg) { … } static size_t gb_tty_receive(struct serdev_device *sd, const u8 *data, size_t count) { … } static void gb_tty_wakeup(struct serdev_device *serdev) { … } static struct serdev_device_ops gb_beagleplay_ops = …; /** * gb_message_send() - Send greybus message using HDLC over UART * * @hd: pointer to greybus host device * @cport: AP cport where message originates * @msg: greybus message to send * @mask: gfp mask * * Greybus HDLC frame has the following payload: * 1. le16 cport * 2. gb_operation_msg_hdr msg_header * 3. u8 *msg_payload */ static int gb_message_send(struct gb_host_device *hd, u16 cport, struct gb_message *msg, gfp_t mask) { … } static void gb_message_cancel(struct gb_message *message) { … } static struct gb_hd_driver gb_hdlc_driver = …; static void gb_beagleplay_start_svc(struct gb_beagleplay *bg) { … } static void gb_beagleplay_stop_svc(struct gb_beagleplay *bg) { … } static void gb_greybus_deinit(struct gb_beagleplay *bg) { … } static int gb_greybus_init(struct gb_beagleplay *bg) { … } static void gb_serdev_deinit(struct gb_beagleplay *bg) { … } static int gb_serdev_init(struct gb_beagleplay *bg) { … } static int gb_beagleplay_probe(struct serdev_device *serdev) { … } static void gb_beagleplay_remove(struct serdev_device *serdev) { … } static const struct of_device_id gb_beagleplay_of_match[] = …; MODULE_DEVICE_TABLE(of, gb_beagleplay_of_match); static struct serdev_device_driver gb_beagleplay_driver = …; module_serdev_device_driver(…) …; MODULE_LICENSE(…) …; MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …;
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