@@ -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/net/ti,cc1352p7.yaml
+F: drivers/greybus/gb-beagleplay.c
GREYBUS SUBSYSTEM
M: Johan Hovold <johan@kernel.org>
@@ -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
@@ -18,6 +18,8 @@ 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
new file mode 100644
@@ -0,0 +1,495 @@
+// 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 256
+#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 GB_MAX_CPORTS 32
+
+/**
+ * BeaglePlay Greybus driver
+ *
+ * @sd: underlying serdev device
+ *
+ * @gb_hd: greybus host device of this driver
+ *
+ * @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 serdev_device *sd;
+
+ struct gb_host_device *gb_hd;
+
+ struct work_struct tx_work;
+ spinlock_t tx_producer_lock;
+ spinlock_t tx_consumer_lock;
+ struct circ_buf tx_circ_buf;
+ u16 tx_crc;
+
+ u16 rx_buffer_len;
+ bool rx_in_esc;
+ u8 rx_buffer[MAX_RX_HDLC];
+};
+
+/**
+ * Structure to represent part of HDCL frame payload data.
+ *
+ * @len: buffer length in bytes
+ * @buf: payload buffer
+ */
+struct hdlc_payload {
+ u16 len;
+ void *buf;
+};
+
+static void hdlc_rx_greybus_frame(struct gb_beagleplay *bg, u8 *buf, u16 len)
+{
+ u16 cport_id;
+ struct gb_operation_msg_hdr *hdr = (struct gb_operation_msg_hdr *)buf;
+
+ memcpy(&cport_id, hdr->pad, sizeof(cport_id));
+
+ dev_dbg(&bg->sd->dev, "Greybus Operation %u type %X cport %u status %u received",
+ hdr->operation_id, hdr->type, cport_id, hdr->result);
+
+ greybus_data_rcvd(bg->gb_hd, cport_id, buf, len);
+}
+
+static void hdlc_rx_dbg_frame(const struct gb_beagleplay *bg, const char *buf, u16 len)
+{
+ dev_dbg(&bg->sd->dev, "CC1352 Log: %.*s", (int)len, buf);
+}
+
+/**
+ * Consume HDLC Buffer. This function assumes that consumer lock has been acquired.
+ */
+static void hdlc_write(struct gb_beagleplay *bg)
+{
+ int written;
+ /* Start consuming 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];
+
+ if (count > 0) {
+ written = serdev_device_write_buf(bg->sd, 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->sd->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_buf(struct gb_beagleplay *bg, const u8 *buf, u16 len)
+{
+ size_t i;
+
+ for (i = 0; i < len; i++)
+ hdlc_append_tx_u8(bg, buf[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_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_tx_frames(struct gb_beagleplay *bg, u8 address, u8 control,
+ const struct hdlc_payload payloads[], size_t count)
+{
+ size_t i;
+
+ 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_buf(bg, payloads[i].buf, payloads[i].len);
+
+ hdlc_append_tx_crc(bg);
+ hdlc_append_tx_frame(bg);
+
+ spin_unlock(&bg->tx_producer_lock);
+
+ schedule_work(&bg->tx_work);
+}
+
+static void hdlc_tx_s_frame_ack(struct gb_beagleplay *bg)
+{
+ hdlc_tx_frames(bg, bg->rx_buffer[0], (bg->rx_buffer[1] >> 1) & 0x7, NULL, 0);
+}
+
+static void hdlc_rx_frame(struct gb_beagleplay *bg)
+{
+ u16 crc, len;
+ u8 ctrl, *buf;
+ u8 address = bg->rx_buffer[0];
+
+ crc = crc_ccitt(0xffff, bg->rx_buffer, bg->rx_buffer_len);
+ if (crc != 0xf0b8) {
+ dev_warn_ratelimited(&bg->sd->dev, "CRC failed from %02x: 0x%04x", address, crc);
+ return;
+ }
+
+ ctrl = bg->rx_buffer[1];
+ buf = &bg->rx_buffer[2];
+ len = bg->rx_buffer_len - 4;
+
+ /* I-Frame, send S-Frame ACK */
+ if ((ctrl & 1) == 0)
+ hdlc_tx_s_frame_ack(bg);
+
+ switch (address) {
+ case ADDRESS_DBG:
+ hdlc_rx_dbg_frame(bg, buf, len);
+ break;
+ case ADDRESS_GREYBUS:
+ hdlc_rx_greybus_frame(bg, buf, len);
+ break;
+ default:
+ dev_warn_ratelimited(&bg->sd->dev, "unknown frame %u", address);
+ }
+}
+
+static int hdlc_rx(struct gb_beagleplay *bg, const u8 *data, size_t count)
+{
+ size_t i;
+ u8 c;
+
+ for (i = 0; i < count; ++i) {
+ c = data[i];
+
+ switch (c) {
+ case HDLC_FRAME:
+ if (bg->rx_buffer_len)
+ hdlc_rx_frame(bg);
+
+ bg->rx_buffer_len = 0;
+ break;
+ case HDLC_ESC:
+ bg->rx_in_esc = true;
+ break;
+ default:
+ if (bg->rx_in_esc) {
+ c ^= 0x20;
+ bg->rx_in_esc = false;
+ }
+
+ 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->sd->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->sd->dev, TX_CIRC_BUF_SIZE, GFP_KERNEL);
+ if (!bg->tx_circ_buf.buf)
+ return -ENOMEM;
+
+ bg->rx_buffer_len = 0;
+ bg->rx_in_esc = false;
+
+ return 0;
+}
+
+static void hdlc_deinit(struct gb_beagleplay *bg)
+{
+ flush_work(&bg->tx_work);
+}
+
+static int gb_tty_receive(struct serdev_device *sd, const unsigned char *data, size_t count)
+{
+ struct gb_beagleplay *bg = serdev_device_get_drvdata(sd);
+
+ return hdlc_rx(bg, data, count);
+}
+
+static void gb_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_tty_receive,
+ .write_wakeup = gb_tty_wakeup,
+};
+
+static int gb_message_send(struct gb_host_device *hd, u16 cport, struct gb_message *msg, gfp_t 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);
+
+ if (msg->header->size > RX_HDLC_PAYLOAD)
+ return dev_err_probe(&hd->dev, -E2BIG, "Greybus message too big");
+
+ memcpy(msg->header->pad, &cport, sizeof(cport));
+
+ payloads[0].buf = msg->header;
+ payloads[0].len = sizeof(*msg->header);
+ payloads[1].buf = msg->payload;
+ payloads[1].len = msg->payload_size;
+
+ hdlc_tx_frames(bg, ADDRESS_GREYBUS, 0x03, payloads, 2);
+ greybus_message_sent(bg->gb_hd, 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 = { .len = 1, .buf = (void *)&command };
+
+ hdlc_tx_frames(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 = { .len = 1, .buf = (void *)&command };
+
+ hdlc_tx_frames(bg, ADDRESS_CONTROL, 0x03, &payload, 1);
+}
+
+static void gb_greybus_deinit(struct gb_beagleplay *bg)
+{
+ gb_hd_del(bg->gb_hd);
+ gb_hd_put(bg->gb_hd);
+}
+
+static int gb_greybus_init(struct gb_beagleplay *bg)
+{
+ int ret;
+
+ bg->gb_hd = gb_hd_create(&gb_hdlc_driver, &bg->sd->dev, TX_CIRC_BUF_SIZE, GB_MAX_CPORTS);
+ if (IS_ERR(bg->gb_hd)) {
+ dev_err(&bg->sd->dev, "Failed to create greybus host device");
+ return PTR_ERR(bg->gb_hd);
+ }
+
+ ret = gb_hd_add(bg->gb_hd);
+ if (ret) {
+ dev_err(&bg->sd->dev, "Failed to add greybus host device");
+ goto free_gb_hd;
+ }
+ dev_set_drvdata(&bg->gb_hd->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->sd);
+}
+
+static int gb_serdev_init(struct gb_beagleplay *bg)
+{
+ u32 speed = 115200;
+ int ret;
+
+ serdev_device_set_drvdata(bg->sd, bg);
+ serdev_device_set_client_ops(bg->sd, &gb_beagleplay_ops);
+ ret = serdev_device_open(bg->sd);
+ if (ret)
+ return dev_err_probe(&bg->sd->dev, ret, "Unable to open serial device");
+
+ speed = serdev_device_set_baudrate(bg->sd, speed);
+ serdev_device_set_flow_control(bg->sd, false);
+
+ return 0;
+}
+
+static int gb_beagleplay_probe(struct serdev_device *serdev)
+{
+ int ret = 0;
+ struct gb_beagleplay *bg;
+
+ bg = devm_kmalloc(&serdev->dev, sizeof(*bg), GFP_KERNEL);
+ if (!bg)
+ return -ENOMEM;
+
+ bg->sd = 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 = "ti,cc1352p7",
+ },
+ {},
+};
+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");