In beagleplay beagleconnect setup, the AP is not directly connected to greybus nodes. The SVC and APBridge tasks are moved to cc1352 coprocessor. This means that there is a need to send cport information between linux host and cc1352.
In the initial version of the driver (and the reference implementation gbridge I was using), the greybus header pad bytes were being used. However, this was a violation of greybus spec.
The following patchset creates a wrapper around greybus message to send the cport information without using the pad bytes.
--- V3: - Rebase on char-misc-next V2: https://lists.linaro.org/archives/list/greybus-dev@lists.linaro.org/thread/7... - Add more comments explaining the new greybus hdlc frame payload - Remove msg len warnings. These checks are also performed by `greybus_data_rcvd` and thus no need for it here.
V1: https://lists.linaro.org/archives/list/greybus-dev@lists.linaro.org/thread/Y...
Ayush Singh (1): greybus: gb-beagleplay: Remove use of pad bytes
drivers/greybus/gb-beagleplay.c | 58 ++++++++++++++++++++++++--------- 1 file changed, 43 insertions(+), 15 deletions(-)
base-commit: e909abe885e2f399be7ac0560a010d7429f951e1
Make gb-beagleplay greybus spec compliant by moving cport information to transport layer instead of using `header->pad` bytes.
Greybus HDLC frame now has the following payload: 1. le16 cport 2. gb_operation_msg_hdr msg_header 3. u8 *msg_payload
Fixes: ec558bbfea67 ("greybus: Add BeaglePlay Linux Driver") Signed-off-by: Ayush Singh ayushdevel1325@gmail.com --- drivers/greybus/gb-beagleplay.c | 58 ++++++++++++++++++++++++--------- 1 file changed, 43 insertions(+), 15 deletions(-)
diff --git a/drivers/greybus/gb-beagleplay.c b/drivers/greybus/gb-beagleplay.c index 43318c1993ba..7d98ae1a8263 100644 --- a/drivers/greybus/gb-beagleplay.c +++ b/drivers/greybus/gb-beagleplay.c @@ -85,17 +85,31 @@ struct hdlc_payload { void *buf; };
+/** + * 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 { + __le16 cport; + struct gb_operation_msg_hdr hdr; + u8 payload[]; +} __packed; + 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)); + struct hdlc_greybus_frame *gb_frame = (struct hdlc_greybus_frame *)buf; + u16 cport_id = le16_to_cpu(gb_frame->cport); + u16 gb_msg_len = le16_to_cpu(gb_frame->hdr.size);
dev_dbg(&bg->sd->dev, "Greybus Operation %u type %X cport %u status %u received", - hdr->operation_id, hdr->type, cport_id, hdr->result); + gb_frame->hdr.operation_id, gb_frame->hdr.type, cport_id, gb_frame->hdr.result);
- greybus_data_rcvd(bg->gb_hd, cport_id, buf, len); + greybus_data_rcvd(bg->gb_hd, cport_id, (u8 *)&gb_frame->hdr, gb_msg_len); }
static void hdlc_rx_dbg_frame(const struct gb_beagleplay *bg, const char *buf, u16 len) @@ -336,25 +350,39 @@ static struct serdev_device_ops gb_beagleplay_ops = { .write_wakeup = gb_tty_wakeup, };
+/** + * 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) { struct gb_beagleplay *bg = dev_get_drvdata(&hd->dev); - struct hdlc_payload payloads[2]; + struct hdlc_payload payloads[3]; + __le16 cport_id = cpu_to_le16(cport);
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) + if (le16_to_cpu(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; + payloads[0].buf = &cport_id; + payloads[0].len = sizeof(cport_id); + payloads[1].buf = msg->header; + payloads[1].len = sizeof(*msg->header); + payloads[2].buf = msg->payload; + payloads[2].len = msg->payload_size;
- hdlc_tx_frames(bg, ADDRESS_GREYBUS, 0x03, payloads, 2); + hdlc_tx_frames(bg, ADDRESS_GREYBUS, 0x03, payloads, 3); greybus_message_sent(bg->gb_hd, msg, 0);
return 0;
-
Ayush Singh