Add the Greybus host driver for BeaglePlay board by BeagleBoard.org.
Current beagleconnect setup involves running SVC in a user-space application (GBridge) and using netlink to communicate with kernel space. GBridge itself uses wpanusb kernel driver for communication with CC1325, so the greybus messages travel from kernel space (gb_netlink) to user-space (GBridge) and then back to kernel space (wpanusb) before reaching CC1352.
gb-beagleplay directly communicates with CC1352 (running Zephyr application). Thus, it simplifies the complete beagleconnect setup eliminating user-space GBridge.
This driver is responsible for the following: - Start SVC (CC1352) on driver load. - Send/Receive Greybus messages to/from CC1352 using HDLC over UART. - Print Logs from CC1352. - Stop SVC (CC1352) on driver load.
Signed-off-by: Ayush Singh ayushdevel1325@gmail.com --- MAINTAINERS | 1 + drivers/greybus/Kconfig | 10 + drivers/greybus/Makefile | 4 +- drivers/greybus/gb-beagleplay.c | 526 ++++++++++++++++++++++++++++++++ 4 files changed, 539 insertions(+), 2 deletions(-) create mode 100644 drivers/greybus/gb-beagleplay.c
diff --git a/MAINTAINERS b/MAINTAINERS index 9d1b49a6dfad..3cbf2c87fb14 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -8974,6 +8974,7 @@ M: Ayush Singh ayushdevel1325@gmail.com L: greybus-dev@lists.linaro.org (moderated for non-subscribers) S: Maintained F: Documentation/devicetree/bindings/serial/beaglecc1352.yaml +F: drivers/greybus/gb-beagleplay.c
GREYBUS SUBSYSTEM M: Johan Hovold johan@kernel.org diff --git a/drivers/greybus/Kconfig b/drivers/greybus/Kconfig index 78ba3c3083d5..07e3119e2faa 100644 --- a/drivers/greybus/Kconfig +++ b/drivers/greybus/Kconfig @@ -17,6 +17,16 @@ menuconfig GREYBUS
if GREYBUS
+config GREYBUS_BEAGLEPLAY + tristate "Greybus BeaglePlay driver" + depends on TTY + help + Select this option if you have a BeaglePlay where CC1352 + co-processor acts as Greybus SVC. + + To compile this code as a module, chose M here: the module + will be called gb-beagleplay.ko + config GREYBUS_ES2 tristate "Greybus ES3 USB host controller" depends on USB diff --git a/drivers/greybus/Makefile b/drivers/greybus/Makefile index 9bccdd229aa2..15a84a83788d 100644 --- a/drivers/greybus/Makefile +++ b/drivers/greybus/Makefile @@ -18,9 +18,9 @@ obj-$(CONFIG_GREYBUS) += greybus.o # needed for trace events ccflags-y += -I$(src)
+obj-$(CONFIG_GREYBUS_BEAGLEPLAY) += gb-beagleplay.o + # Greybus Host controller drivers gb-es2-y := es2.o
obj-$(CONFIG_GREYBUS_ES2) += gb-es2.o - - diff --git a/drivers/greybus/gb-beagleplay.c b/drivers/greybus/gb-beagleplay.c new file mode 100644 index 000000000000..39d87ef3b8fc --- /dev/null +++ b/drivers/greybus/gb-beagleplay.c @@ -0,0 +1,526 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Beagleplay Linux Driver for Greybus + * + * Copyright (c) 2023 Ayush Singh ayushdevel1325@gmail.com + * 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 1024 +#define CRC_LEN 2 +#define MAX_RX_HDLC (1 + RX_HDLC_PAYLOAD + CRC_LEN) +#define TX_CIRC_BUF_SIZE 1024 + +#define ADDRESS_GREYBUS 0x01 +#define ADDRESS_DBG 0x02 +#define ADDRESS_CONTROL 0x03 + +#define HDLC_FRAME 0x7E +#define HDLC_ESC 0x7D +#define HDLC_XOR 0x20 + +#define CONTROL_SVC_START 0x01 +#define CONTROL_SVC_STOP 0x02 + +/* The maximum number of CPorts supported by Greybus Host Device */ +#define BEAGLEPLAY_GB_MAX_CPORTS 32 + +/* + * BeaglePlay Greybus driver + * + * @serdev: Serdev device + * + * @gb_host_device: greybud host device + * + * @tx_work: transmit work + * @tx_producer_lock: transmit producer lock + * @tx_consumer_lock: transmit consumer lock + * @tx_circ_buf: transmit circular buffer + * @tx_crc: HDCL CRC + * @tx_ack_seq: current TX ACK sequence number + * + * @rx_buffer_len: Rx buffer length + * @rx_in_esc: Rx Flag to indicate if ESC + * @rx_buffer: Rx buffer + */ +struct gb_beagleplay { + struct serdev_device *serdev; + + struct gb_host_device *gb_host_device; + + struct work_struct tx_work; + /* tx_producer_lock: HDLC producer lock */ + spinlock_t tx_producer_lock; + /* tx_consumer_lock: HDLC consumer lock */ + spinlock_t tx_consumer_lock; + struct circ_buf tx_circ_buf; + u16 tx_crc; + u8 tx_ack_seq; + + u16 rx_buffer_len; + u8 rx_in_esc; + u8 rx_buffer[MAX_RX_HDLC]; +}; + +struct hdlc_payload { + u16 length; + void *payload; +}; + +static void hdlc_handle_greybus_frame(struct gb_beagleplay *bg, u8 *buffer, + size_t buffer_len) +{ + u16 cport_id; + struct gb_operation_msg_hdr *hdr = + (struct gb_operation_msg_hdr *)buffer; + + memcpy(&cport_id, hdr->pad, sizeof(cport_id)); + + dev_dbg(&bg->serdev->dev, + "Greybus Operation %u of Type %X on CPort %u with Status %u Received", + hdr->operation_id, hdr->type, cport_id, hdr->result); + + greybus_data_rcvd(bg->gb_host_device, cport_id, buffer, buffer_len); +} + +static void hdlc_handle_dbg_frame(struct gb_beagleplay *bg, const char *buffer, + size_t buffer_len) +{ + dev_dbg(&bg->serdev->dev, "CC1352 Debug: %.*s", (int)buffer_len, + buffer); +} + +/* + * Consume HDLC Buffer. This function assumes that consumer lock has been acquired. + */ +static void hdlc_write(struct gb_beagleplay *bg) +{ + /* Start consuning HDLC data */ + int head = smp_load_acquire(&bg->tx_circ_buf.head); + int tail = bg->tx_circ_buf.tail; + int count = CIRC_CNT_TO_END(head, tail, TX_CIRC_BUF_SIZE); + const unsigned char *buf = &bg->tx_circ_buf.buf[tail]; + int written; + + if (count > 0) { + written = serdev_device_write_buf(bg->serdev, buf, count); + + /* Finish consuming HDLC data */ + smp_store_release(&bg->tx_circ_buf.tail, + (tail + written) & (TX_CIRC_BUF_SIZE - 1)); + } +} + +/* + * Queue HDLC data for sending. This function assumes that producer lock as been acquired. + */ +static void hdlc_append(struct gb_beagleplay *bg, u8 value) +{ + int tail, head = bg->tx_circ_buf.head; + + while (true) { + tail = READ_ONCE(bg->tx_circ_buf.tail); + + if (CIRC_SPACE(head, tail, TX_CIRC_BUF_SIZE) >= 1) { + bg->tx_circ_buf.buf[head] = value; + + /* Finish producing HDLC byte */ + smp_store_release(&bg->tx_circ_buf.head, + (head + 1) & (TX_CIRC_BUF_SIZE - 1)); + return; + } + dev_warn(&bg->serdev->dev, "Tx circ buf full"); + usleep_range(3000, 5000); + } +} + +static void hdlc_append_escaped(struct gb_beagleplay *bg, u8 value) +{ + if (value == HDLC_FRAME || value == HDLC_ESC) { + hdlc_append(bg, HDLC_ESC); + value ^= HDLC_XOR; + } + hdlc_append(bg, value); +} + +static void hdlc_append_tx_frame(struct gb_beagleplay *bg) +{ + bg->tx_crc = 0xFFFF; + hdlc_append(bg, HDLC_FRAME); +} + +static void hdlc_append_tx_u8(struct gb_beagleplay *bg, u8 value) +{ + bg->tx_crc = crc_ccitt(bg->tx_crc, &value, 1); + hdlc_append_escaped(bg, value); +} + +static void hdlc_append_tx_buffer(struct gb_beagleplay *bg, const u8 *buffer, + size_t len) +{ + size_t i; + + for (i = 0; i < len; i++) + hdlc_append_tx_u8(bg, buffer[i]); +} + +static void hdlc_append_tx_crc(struct gb_beagleplay *bg) +{ + bg->tx_crc ^= 0xffff; + hdlc_append_escaped(bg, bg->tx_crc & 0xff); + hdlc_append_escaped(bg, (bg->tx_crc >> 8) & 0xff); +} + +static void hdlc_handle_rx_frame(struct gb_beagleplay *bg) +{ + u8 address = bg->rx_buffer[0]; + char *buffer = &bg->rx_buffer[2]; + size_t buffer_len = bg->rx_buffer_len - 4; + + switch (address) { + case ADDRESS_DBG: + hdlc_handle_dbg_frame(bg, buffer, buffer_len); + break; + case ADDRESS_GREYBUS: + hdlc_handle_greybus_frame(bg, buffer, buffer_len); + break; + default: + dev_warn_ratelimited(&bg->serdev->dev, "Got Unknown Frame %u", + address); + } +} + +static void hdlc_transmit(struct work_struct *work) +{ + struct gb_beagleplay *bg = + container_of(work, struct gb_beagleplay, tx_work); + + spin_lock_bh(&bg->tx_consumer_lock); + hdlc_write(bg); + spin_unlock_bh(&bg->tx_consumer_lock); +} + +static void hdlc_send_async(struct gb_beagleplay *bg, u8 address, u8 control, + const struct hdlc_payload payloads[], size_t count) +{ + size_t i; + + /* + * HDLC_FRAME + * 0 address : 0x01 + * 1 control : 0x03 + * contents + * x/y crc + * HDLC_FRAME + */ + + spin_lock(&bg->tx_producer_lock); + + hdlc_append_tx_frame(bg); + hdlc_append_tx_u8(bg, address); + hdlc_append_tx_u8(bg, control); + for (i = 0; i < count; ++i) { + hdlc_append_tx_buffer(bg, payloads[i].payload, + payloads[i].length); + } + hdlc_append_tx_crc(bg); + hdlc_append_tx_frame(bg); + + spin_unlock(&bg->tx_producer_lock); + + schedule_work(&bg->tx_work); +} + +static void hdlc_send_s_frame_ack(struct gb_beagleplay *bg) +{ + hdlc_send_async(bg, bg->rx_buffer[0], (bg->rx_buffer[1] >> 1) & 0x7, + NULL, 0); +} + +static int hdlc_rx(struct gb_beagleplay *bg, const u8 *data, size_t count) +{ + u16 crc_check; + size_t i; + u8 c, ctrl; + + for (i = 0; i < count; ++i) { + c = data[i]; + + switch (c) { + case HDLC_FRAME: + if (bg->rx_buffer_len) { + crc_check = crc_ccitt(0xffff, bg->rx_buffer, + bg->rx_buffer_len); + if (crc_check == 0xf0b8) { + ctrl = bg->rx_buffer[1]; + if ((ctrl & 1) == 0) { + /* I-Frame, send S-Frame ACK */ + hdlc_send_s_frame_ack(bg); + } + hdlc_handle_rx_frame(bg); + } else { + dev_warn_ratelimited( + &bg->serdev->dev, + "CRC Failed from %02x: 0x%04x", + bg->rx_buffer[0], crc_check); + } + } + bg->rx_buffer_len = 0; + break; + case HDLC_ESC: + bg->rx_in_esc = 1; + break; + default: + if (bg->rx_in_esc) { + c ^= 0x20; + bg->rx_in_esc = 0; + } + + if (bg->rx_buffer_len < MAX_RX_HDLC) { + bg->rx_buffer[bg->rx_buffer_len] = c; + bg->rx_buffer_len++; + } else { + dev_err_ratelimited(&bg->serdev->dev, + "RX Buffer Overflow"); + bg->rx_buffer_len = 0; + } + } + } + + return count; +} + +static int hdlc_init(struct gb_beagleplay *bg) +{ + INIT_WORK(&bg->tx_work, hdlc_transmit); + spin_lock_init(&bg->tx_producer_lock); + spin_lock_init(&bg->tx_consumer_lock); + bg->tx_circ_buf.head = 0; + bg->tx_circ_buf.tail = 0; + + bg->tx_circ_buf.buf = + devm_kmalloc(&bg->serdev->dev, TX_CIRC_BUF_SIZE, GFP_KERNEL); + if (!bg->tx_circ_buf.buf) + return -ENOMEM; + + bg->rx_buffer_len = 0; + bg->rx_in_esc = 0; + + return 0; +} + +static void hdlc_deinit(struct gb_beagleplay *bg) +{ + flush_work(&bg->tx_work); +} + +static int gb_beagleplay_tty_receive(struct serdev_device *serdev, + const unsigned char *data, size_t count) +{ + struct gb_beagleplay *bg = serdev_device_get_drvdata(serdev); + + return hdlc_rx(bg, data, count); +} + +static void beagleplay_greybus_tty_wakeup(struct serdev_device *serdev) +{ + struct gb_beagleplay *bg = serdev_device_get_drvdata(serdev); + + schedule_work(&bg->tx_work); +} + +static struct serdev_device_ops gb_beagleplay_ops = { + .receive_buf = gb_beagleplay_tty_receive, + .write_wakeup = beagleplay_greybus_tty_wakeup, +}; + +static int gb_message_send(struct gb_host_device *hd, u16 cport_id, + struct gb_message *msg, gfp_t gfp_mask) +{ + struct gb_beagleplay *bg = dev_get_drvdata(&hd->dev); + struct hdlc_payload payloads[2]; + + dev_dbg(&hd->dev, + "Sending Greybus message with Operation %u, Type: %X on Cport %u", + msg->header->operation_id, msg->header->type, cport_id); + + if (msg->header->size > RX_HDLC_PAYLOAD) { + dev_err(&hd->dev, "Greybus message too big"); + return -E2BIG; + } + + memcpy(msg->header->pad, &cport_id, sizeof(cport_id)); + + payloads[0].payload = msg->header; + payloads[0].length = sizeof(*msg->header); + payloads[1].payload = msg->payload; + payloads[1].length = msg->payload_size; + + hdlc_send_async(bg, ADDRESS_GREYBUS, 0x03, payloads, 2); + greybus_message_sent(bg->gb_host_device, msg, 0); + + return 0; +} + +static void gb_message_cancel(struct gb_message *message) +{ +} + +static struct gb_hd_driver gb_hdlc_driver = { .message_send = gb_message_send, + .message_cancel = + gb_message_cancel }; + +static void gb_beagleplay_start_svc(struct gb_beagleplay *bg) +{ + const u8 command = CONTROL_SVC_START; + const struct hdlc_payload payload = { .length = 1, + .payload = (void *)&command }; + + hdlc_send_async(bg, ADDRESS_CONTROL, 0x03, &payload, 1); +} + +static void gb_beagleplay_stop_svc(struct gb_beagleplay *bg) +{ + const u8 command = CONTROL_SVC_STOP; + const struct hdlc_payload payload = { .length = 1, + .payload = (void *)&command }; + + hdlc_send_async(bg, ADDRESS_CONTROL, 0x03, &payload, 1); +} + +static void gb_greybus_deinit(struct gb_beagleplay *bg) +{ + gb_hd_del(bg->gb_host_device); + gb_hd_put(bg->gb_host_device); +} + +static int gb_greybus_init(struct gb_beagleplay *bg) +{ + int ret; + + bg->gb_host_device = gb_hd_create(&gb_hdlc_driver, &bg->serdev->dev, + TX_CIRC_BUF_SIZE, + BEAGLEPLAY_GB_MAX_CPORTS); + if (IS_ERR(bg->gb_host_device)) { + return dev_err_probe(&bg->serdev->dev, + PTR_ERR(bg->gb_host_device), + "Unable to create Greybus Host Device"); + } + ret = gb_hd_add(bg->gb_host_device); + if (ret) { + dev_err(&bg->serdev->dev, "Failed to add Greybus Host Device"); + goto free_gb_hd; + } + dev_set_drvdata(&bg->gb_host_device->dev, bg); + + return 0; + +free_gb_hd: + gb_greybus_deinit(bg); + return ret; +} + +static void gb_serdev_deinit(struct gb_beagleplay *bg) +{ + serdev_device_close(bg->serdev); +} + +static int gb_serdev_init(struct gb_beagleplay *bg) +{ + u32 speed = 115200; + int ret; + + serdev_device_set_drvdata(bg->serdev, bg); + serdev_device_set_client_ops(bg->serdev, &gb_beagleplay_ops); + ret = serdev_device_open(bg->serdev); + if (ret) { + return dev_err_probe(&bg->serdev->dev, ret, + "Unable to Open Serial Device"); + } + speed = serdev_device_set_baudrate(bg->serdev, speed); + serdev_device_set_flow_control(bg->serdev, false); + + return 0; +} + +static int gb_beagleplay_probe(struct serdev_device *serdev) +{ + int ret = 0; + struct gb_beagleplay *bg = + devm_kmalloc(&serdev->dev, sizeof(*bg), GFP_KERNEL); + + if (!bg) + return -ENOMEM; + + bg->serdev = serdev; + ret = gb_serdev_init(bg); + if (ret) + return ret; + + ret = hdlc_init(bg); + if (ret) + goto free_serdev; + + ret = gb_greybus_init(bg); + if (ret) + goto free_hdlc; + + gb_beagleplay_start_svc(bg); + + return 0; + +free_hdlc: + hdlc_deinit(bg); +free_serdev: + gb_serdev_deinit(bg); + return ret; +} + +static void gb_beagleplay_remove(struct serdev_device *serdev) +{ + struct gb_beagleplay *bg = serdev_device_get_drvdata(serdev); + + gb_greybus_deinit(bg); + gb_beagleplay_stop_svc(bg); + hdlc_deinit(bg); + gb_serdev_deinit(bg); +} + +static const struct of_device_id gb_beagleplay_of_match[] = { + { + .compatible = "beagle,play-cc1352", + }, + {}, +}; +MODULE_DEVICE_TABLE(of, gb_beagleplay_of_match); + +static struct serdev_device_driver gb_beagleplay_driver = { + .probe = gb_beagleplay_probe, + .remove = gb_beagleplay_remove, + .driver = { + .name = "gb_beagleplay", + .of_match_table = gb_beagleplay_of_match, + }, +}; + +module_serdev_device_driver(gb_beagleplay_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Ayush Singh ayushdevel1325@gmail.com"); +MODULE_DESCRIPTION("A Greybus driver for BeaglePlay");