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greybus: gb-beagleplay: propagate hdlc_tx_frames() errors to callers

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Now that hdlc_tx_frames() can drop frames when the circular buffer is
full, make the failure visible to callers:

 - Change hdlc_tx_frames() return type from void to int (-EAGAIN on
   buffer full).
 - Change gb_beagleplay_start_svc() / gb_beagleplay_stop_svc() to
   return int so probe and firmware-upload paths can detect failures.
 - gb_message_send(): propagate the error so the greybus core can
   handle the transport failure.
 - hdlc_tx_s_frame_ack(): log with dev_warn_ratelimited on failure
   (ACK loss is recoverable by HDLC retransmission).
 - Probe path: propagate start_svc failure via new free_greybus label.
 - Firmware upload paths: return FW_UPLOAD_ERR_RW_ERROR when SVC
   restart fails instead of silently continuing.
 - Remove path: best-effort stop_svc, ignore failure.

Cc: Ayush Singh <ayushdevel1325@gmail.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Alex Elder <elder@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Weigang He <geoffreyhe2@gmail.com>
Link: https://patch.msgid.link/20260330120801.981506-2-geoffreyhe2@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Weigang He 2026-03-30 12:08:01 +00:00 committed by Greg Kroah-Hartman
parent 6b526dca09
commit 58fa2357f5
1 changed files with 44 additions and 20 deletions
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64
drivers/greybus/gb-beagleplay.c
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@ -314,6 +314,9 @@ static void hdlc_transmit(struct work_struct *work)
* @payloads: array of payload buffers
* @count: number of payloads
*
* Every data byte may need HDLC escaping (doubling its size).
* Frame layout: flag(1) + address(1-2) + control(1-2) + payload + CRC(2-4) + flag(1).
*
* Returns the maximum number of bytes needed in the circular buffer.
*/
static size_t hdlc_encoded_length(const struct hdlc_payload payloads[],
@ -348,8 +351,10 @@ static size_t hdlc_encoded_length(const struct hdlc_payload payloads[],
* available, then verifies space under the lock and writes the entire
* frame atomically. Either a complete frame is enqueued or nothing is
* written, avoiding both sleeping in atomic context and partial frames.
*
* Returns 0 on success, -EAGAIN if the buffer remains full after retries.
*/
static void hdlc_tx_frames(struct gb_beagleplay *bg, u8 address, u8 control,
static int hdlc_tx_frames(struct gb_beagleplay *bg, u8 address, u8 control,
const struct hdlc_payload payloads[], size_t count)
{
size_t needed = hdlc_encoded_length(payloads, count);
@ -372,25 +377,24 @@ static void hdlc_tx_frames(struct gb_beagleplay *bg, u8 address, u8 control,
}
if (retries < 0) {
dev_warn_ratelimited(&bg->sd->dev,
"Tx circ buf full, dropping frame\n");
return;
dev_warn_ratelimited(&bg->sd->dev, "Tx circ buf full, dropping frame\n");
return -EAGAIN;
}
spin_lock(&bg->tx_producer_lock);
/*
* Re-check under the lock. Should not fail since
* tx_producer_lock serialises all producers and the
* consumer only frees space, but guard against it.
* Re-check space under the lock to close the TOCTOU window.
* This should be rare since tx_producer_lock serialises all
* producers and the consumer only frees space. If it fires,
* the caller is expected to handle -EAGAIN (retry or report).
*/
head = bg->tx_circ_buf.head;
tail = READ_ONCE(bg->tx_circ_buf.tail);
if (unlikely(CIRC_SPACE(head, tail, TX_CIRC_BUF_SIZE) < needed)) {
spin_unlock(&bg->tx_producer_lock);
dev_warn_ratelimited(&bg->sd->dev,
"Tx circ buf space lost, dropping frame\n");
return;
dev_warn_ratelimited(&bg->sd->dev, "Tx circ buf space lost, dropping frame\n");
return -EAGAIN;
}
hdlc_append_tx_frame(bg);
@ -406,11 +410,16 @@ static void hdlc_tx_frames(struct gb_beagleplay *bg, u8 address, u8 control,
spin_unlock(&bg->tx_producer_lock);
schedule_work(&bg->tx_work);
return 0;
}
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);
int ret;
ret = hdlc_tx_frames(bg, bg->rx_buffer[0], (bg->rx_buffer[1] >> 1) & 0x7, NULL, 0);
if (ret)
dev_warn_ratelimited(&bg->sd->dev, "Failed to send HDLC ACK: %d\n", ret);
}
static void hdlc_rx_frame(struct gb_beagleplay *bg)
@ -674,6 +683,7 @@ static int gb_message_send(struct gb_host_device *hd, u16 cport, struct gb_messa
struct gb_beagleplay *bg = dev_get_drvdata(&hd->dev);
struct hdlc_payload payloads[3];
__le16 cport_id = cpu_to_le16(cport);
int ret;
dev_dbg(&hd->dev, "Sending greybus message with Operation %u, Type: %X on Cport %u",
msg->header->operation_id, msg->header->type, cport);
@ -688,7 +698,10 @@ static int gb_message_send(struct gb_host_device *hd, u16 cport, struct gb_messa
payloads[2].buf = msg->payload;
payloads[2].len = msg->payload_size;
hdlc_tx_frames(bg, ADDRESS_GREYBUS, 0x03, payloads, 3);
ret = hdlc_tx_frames(bg, ADDRESS_GREYBUS, 0x03, payloads, 3);
if (ret)
return ret;
greybus_message_sent(bg->gb_hd, msg, 0);
return 0;
@ -701,20 +714,20 @@ 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)
static int 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);
return hdlc_tx_frames(bg, ADDRESS_CONTROL, 0x03, &payload, 1);
}
static void gb_beagleplay_stop_svc(struct gb_beagleplay *bg)
static int 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);
return hdlc_tx_frames(bg, ADDRESS_CONTROL, 0x03, &payload, 1);
}
static int cc1352_bootloader_wait_for_ack(struct gb_beagleplay *bg)
@ -952,7 +965,9 @@ static enum fw_upload_err cc1352_prepare(struct fw_upload *fw_upload,
gb_greybus_deinit(bg);
msleep(5 * MSEC_PER_SEC);
gb_beagleplay_stop_svc(bg);
/* Best effort — device is entering bootloader mode regardless. */
if (gb_beagleplay_stop_svc(bg))
dev_warn(&bg->sd->dev, "Failed to send SVC stop before flashing\n");
msleep(200);
flush_work(&bg->tx_work);
@ -994,7 +1009,9 @@ static enum fw_upload_err cc1352_prepare(struct fw_upload *fw_upload,
if (gb_greybus_init(bg) < 0)
return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_RW_ERROR,
"Failed to initialize greybus");
gb_beagleplay_start_svc(bg);
if (gb_beagleplay_start_svc(bg))
return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_RW_ERROR,
"Failed to restart SVC after skip");
return FW_UPLOAD_ERR_FW_INVALID;
}
@ -1075,7 +1092,9 @@ static enum fw_upload_err cc1352_poll_complete(struct fw_upload *fw_upload)
return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_RW_ERROR,
"Failed to initialize greybus");
gb_beagleplay_start_svc(bg);
if (gb_beagleplay_start_svc(bg) < 0)
return dev_err_probe(&bg->sd->dev, FW_UPLOAD_ERR_RW_ERROR,
"Failed to start SVC");
return FW_UPLOAD_ERR_NONE;
}
@ -1186,10 +1205,14 @@ static int gb_beagleplay_probe(struct serdev_device *serdev)
if (ret)
goto free_fw;
gb_beagleplay_start_svc(bg);
ret = gb_beagleplay_start_svc(bg);
if (ret)
goto free_greybus;
return 0;
free_greybus:
gb_greybus_deinit(bg);
free_fw:
gb_fw_deinit(bg);
free_hdlc:
@ -1205,6 +1228,7 @@ static void gb_beagleplay_remove(struct serdev_device *serdev)
gb_fw_deinit(bg);
gb_greybus_deinit(bg);
/* Best effort — device is being removed. */
gb_beagleplay_stop_svc(bg);
hdlc_deinit(bg);
gb_serdev_deinit(bg);