[PATCH v4 1/3] i3c: master: dw: Report actual GET CCC payload length on success

[tze.yee.ng@altera.com]

From: Adrian Ng Ho Yin <adrian.ho.yin.ng@altera.com>

On successful GET CCC transfers, set dests[0].payload.actual_len from
RESPONSE_PORT_DATA_LEN so the I3C core receives the number of bytes
actually read. Add actual_len to struct i3c_ccc_cmd_payload to keep
the requested buffer size in len.

Signed-off-by: Adrian Ng Ho Yin <adrian.ho.yin.ng@altera.com>
Signed-off-by: Tze Yee Ng <tze.yee.ng@altera.com>
---
 drivers/i3c/master/dw-i3c-master.c | 5 ++++-
 include/linux/i3c/ccc.h            | 4 +++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
index 655693a2187e..856961da1827 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -742,7 +742,10 @@ static int dw_i3c_ccc_set(struct dw_i3c_master *master,
 		dw_i3c_master_dequeue_xfer(master, xfer);
 
 	ret = xfer->ret;
-	if (xfer->cmds[0].error == RESPONSE_ERROR_IBA_NACK)
+	cmd = &xfer->cmds[0];
+	if (!ret)
+		ccc->dests[0].payload.actual_len = cmd->rx_len;
+	if (cmd->error == RESPONSE_ERROR_IBA_NACK)
 		ccc->err = I3C_ERROR_M2;
 
 	return ret;
diff --git a/include/linux/i3c/ccc.h b/include/linux/i3c/ccc.h
index ad59a4ae60d1..d8052949e57e 100644
--- a/include/linux/i3c/ccc.h
+++ b/include/linux/i3c/ccc.h
@@ -343,11 +343,13 @@ struct i3c_ccc_getxtime {
 /**
  * struct i3c_ccc_cmd_payload - CCC payload
  *
- * @len: payload length
+ * @len: requested payload length
+ * @actual_len: number of bytes received on a GET CCC (filled by the driver)
  * @data: payload data. This buffer must be DMA-able
  */
 struct i3c_ccc_cmd_payload {
 	u16 len;
+	u16 actual_len;
 	void *data;
 };
 
-- 
2.43.7