[PATCH v6 2/5] i3c: master: Report actual GET CCC payload length on success

From: Adrian Ng Ho Yin <[email protected]>

Set dests[].payload.actual_len on successful GET CCC transfers in I3C
master drivers so the core can distinguish requested and received
buffer lengths. Switch core GET helpers to use actual_len instead of
len when interpreting GET CCC results.

Signed-off-by: Adrian Ng Ho Yin <[email protected]>
Signed-off-by: Tze Yee Ng <[email protected]>
---
Changes in v6:
- Fix ADI and Cadence GET actual_len: store hardware-reported xfer bytes
  in cmd->rx_len and set actual_len from that, not from payload.len.
- Fix Renesas GET actual_len: drain the response FIFO at rx_buf + rx_count
  in resp_isr, clamp rx_count to data_len before subtracting (avoids
  unsigned underflow when rx_isr reads round up to 32-bit words), and
  report actual_len from cmd->rx_count.

Changes in v5:
- New patch scope: all I3C master drivers (adi, dw, cdns, renesas, svc,
  mipi-hci) set actual_len on successful GET transfers.
- dw_i3c_ccc_get() sets actual_len from cmd->rx_len; dw_i3c_ccc_set()
  does not touch actual_len (fixes v4 regression).
- Initialise actual_len to 0 in i3c_ccc_cmd_dest_init().
- Switch core GET helpers (getmrl, getmwl, getmxds, gethdrcap) to use
  actual_len instead of len when interpreting GET results.

Changes in v4:
- Refactor dw_i3c_ccc_map_err() to return enum i3c_error_code; callers
  assign ccc->err.
- Map I3C_ERROR_M2 only for RESPONSE_ERROR_IBA_NACK (broadcast address
  7'h7E not ACKed). Do not report target-address NACK as M2.
- Keep RESPONSE_ERROR_ADDRESS_NACK returning -EIO in
  dw_i3c_master_end_xfer_locked().
---
 drivers/i3c/master.c                   | 11 ++++++-----
 drivers/i3c/master/adi-i3c-master.c    |  3 +++
 drivers/i3c/master/dw-i3c-master.c     |  5 ++++-
 drivers/i3c/master/i3c-master-cdns.c   |  3 +++
 drivers/i3c/master/mipi-i3c-hci/core.c |  5 +++--
 drivers/i3c/master/renesas-i3c.c       | 16 ++++++++++++----
 drivers/i3c/master/svc-i3c-master.c    |  4 ++--
 7 files changed, 33 insertions(+), 14 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 5cd4e5da2233..037b3b980717 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -901,6 +901,7 @@ static void *i3c_ccc_cmd_dest_init(struct i3c_ccc_cmd_dest *dest, u8 addr,
 {
 	dest->addr = addr;
 	dest->payload.len = payloadlen;
+	dest->payload.actual_len = 0;
 	if (payloadlen)
 		dest->payload.data = kzalloc(payloadlen, GFP_KERNEL);
 	else
@@ -1302,7 +1303,7 @@ static int i3c_master_getmrl_locked(struct i3c_master_controller *master,
 	if (ret)
 		goto out;
 
-	switch (dest.payload.len) {
+	switch (dest.payload.actual_len) {
 	case 3:
 		info->max_ibi_len = mrl->ibi_len;
 		fallthrough;
@@ -1337,7 +1338,7 @@ static int i3c_master_getmwl_locked(struct i3c_master_controller *master,
 	if (ret)
 		goto out;
 
-	if (dest.payload.len != sizeof(*mwl)) {
+	if (dest.payload.actual_len != sizeof(*mwl)) {
 		ret = -EIO;
 		goto out;
 	}
@@ -1376,14 +1377,14 @@ static int i3c_master_getmxds_locked(struct i3c_master_controller *master,
 			goto out;
 	}
 
-	if (dest.payload.len != 2 && dest.payload.len != 5) {
+	if (dest.payload.actual_len != 2 && dest.payload.actual_len != 5) {
 		ret = -EIO;
 		goto out;
 	}
 
 	info->max_read_ds = getmaxds->maxrd;
 	info->max_write_ds = getmaxds->maxwr;
-	if (dest.payload.len == 5)
+	if (dest.payload.actual_len == 5)
 		info->max_read_turnaround = getmaxds->maxrdturn[0] |
 					    ((u32)getmaxds->maxrdturn[1] << 8) |
 					    ((u32)getmaxds->maxrdturn[2] << 16);
@@ -1412,7 +1413,7 @@ static int i3c_master_gethdrcap_locked(struct i3c_master_controller *master,
 	if (ret)
 		goto out;
 
-	if (dest.payload.len != 1) {
+	if (dest.payload.actual_len != 1) {
 		ret = -EIO;
 		goto out;
 	}
diff --git a/drivers/i3c/master/adi-i3c-master.c b/drivers/i3c/master/adi-i3c-master.c
index 047081c9f064..b5ab2e4e5d57 100644
--- a/drivers/i3c/master/adi-i3c-master.c
+++ b/drivers/i3c/master/adi-i3c-master.c
@@ -246,6 +246,7 @@ static void adi_i3c_master_end_xfer_locked(struct adi_i3c_master *master,
 		if (cmd->cmd0 & REG_CMD_FIFO_0_RNW) {
 			rx_len = min_t(u32, REG_CMDR_FIFO_XFER_BYTES(cmdr), cmd->rx_len);
 			adi_i3c_master_rd_from_rx_fifo(master, cmd->rx_buf, rx_len);
+			cmd->rx_len = rx_len;
 		}
 		cmd->error = REG_CMDR_FIFO_ERROR(cmdr);
 	}
@@ -360,6 +361,8 @@ static int adi_i3c_master_send_ccc_cmd(struct i3c_master_controller *m,
 		adi_i3c_master_unqueue_xfer(master, xfer);
 
 	cmd->err = adi_i3c_cmd_get_err(&xfer->cmds[0]);
+	if (!xfer->ret && cmd->rnw)
+		cmd->dests[0].payload.actual_len = ccmd->rx_len;
 
 	return xfer->ret;
 }
diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
index 655693a2187e..6998ffd15f5f 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -780,7 +780,10 @@ static int dw_i3c_ccc_get(struct dw_i3c_master *master, struct i3c_ccc_cmd *ccc)
 		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/drivers/i3c/master/i3c-master-cdns.c b/drivers/i3c/master/i3c-master-cdns.c
index 5cfec6761494..cd6adbcecc26 100644
--- a/drivers/i3c/master/i3c-master-cdns.c
+++ b/drivers/i3c/master/i3c-master-cdns.c
@@ -574,6 +574,7 @@ static void cdns_i3c_master_end_xfer_locked(struct cdns_i3c_master *master,
 		cmd = &xfer->cmds[CMDR_CMDID(cmdr)];
 		rx_len = min_t(u32, CMDR_XFER_BYTES(cmdr), cmd->rx_len);
 		cdns_i3c_master_rd_from_rx_fifo(master, cmd->rx_buf, rx_len);
+		cmd->rx_len = rx_len;
 		cmd->error = CMDR_ERROR(cmdr);
 	}
 
@@ -715,6 +716,8 @@ static int cdns_i3c_master_send_ccc_cmd(struct i3c_master_controller *m,
 
 	ret = xfer->ret;
 	cmd->err = cdns_i3c_cmd_get_err(&xfer->cmds[0]);
+	if (!ret && cmd->rnw)
+		cmd->dests[0].payload.actual_len = ccmd->rx_len;
 	cdns_i3c_master_free_xfer(xfer);
 
 	return ret;
diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
index b781dbed2165..2b215658e093 100644
--- a/drivers/i3c/master/mipi-i3c-hci/core.c
+++ b/drivers/i3c/master/mipi-i3c-hci/core.c
@@ -326,7 +326,7 @@ static int i3c_hci_send_ccc_cmd(struct i3c_master_controller *m,
 		goto out;
 	for (i = prefixed; i < nxfers; i++) {
 		if (ccc->rnw)
-			ccc->dests[i - prefixed].payload.len =
+			ccc->dests[i - prefixed].payload.actual_len =
 				RESP_DATA_LENGTH(xfer[i].response);
 		switch (RESP_STATUS(xfer[i].response)) {
 		case RESP_SUCCESS:
@@ -343,7 +343,8 @@ static int i3c_hci_send_ccc_cmd(struct i3c_master_controller *m,
 
 	if (ccc->rnw)
 		dev_dbg(&hci->master.dev, "got: %*ph",
-			ccc->dests[0].payload.len, ccc->dests[0].payload.data);
+			ccc->dests[0].payload.actual_len,
+			ccc->dests[0].payload.data);
 
 out:
 	hci_free_xfer(xfer, nxfers);
diff --git a/drivers/i3c/master/renesas-i3c.c b/drivers/i3c/master/renesas-i3c.c
index f39c449922ca..25a2b2ed618e 100644
--- a/drivers/i3c/master/renesas-i3c.c
+++ b/drivers/i3c/master/renesas-i3c.c
@@ -805,6 +805,8 @@ static int renesas_i3c_send_ccc_cmd(struct i3c_master_controller *m,
 	ret = xfer->ret;
 	if (ret)
 		ccc->err = I3C_ERROR_M2;
+	else if (ccc->rnw)
+		ccc->dests[0].payload.actual_len = cmd->rx_count;
 
 	return ret;
 }
@@ -1072,10 +1074,16 @@ static irqreturn_t renesas_i3c_resp_isr(int irq, void *data)
 			break;
 		case I3C_INTERNAL_STATE_CONTROLLER_READ:
 		case I3C_INTERNAL_STATE_CONTROLLER_COMMAND_READ:
-			if (NDBSTLV0_RDBLV(renesas_readl(i3c->regs, NDBSTLV0)) && !cmd->err)
-				bytes_remaining = data_len - cmd->rx_count;
-
-			i3c_readl_fifo(i3c->regs + NTDTBP0, cmd->rx_buf, bytes_remaining);
+			if (!cmd->err) {
+				u32 rx_count = min(cmd->rx_count, data_len);
+
+				bytes_remaining = data_len - rx_count;
+				if (bytes_remaining)
+					i3c_readl_fifo(i3c->regs + NTDTBP0,
+						       cmd->rx_buf + rx_count,
+						       bytes_remaining);
+				cmd->rx_count = data_len;
+			}
 			renesas_clear_bit(i3c->regs, NTIE, NTIE_RDBFIE0);
 			break;
 		default:
diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index e2d99a3ac07d..c92d96e6b4d8 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -1706,8 +1706,8 @@ static int svc_i3c_master_send_direct_ccc_cmd(struct svc_i3c_master *master,
 		svc_i3c_master_dequeue_xfer(master, xfer);
 	mutex_unlock(&master->lock);
 
-	if (cmd->actual_len != xfer_len)
-		ccc->dests[0].payload.len = cmd->actual_len;
+	if (ccc->rnw)
+		ccc->dests[0].payload.actual_len = cmd->actual_len;
 
 	ret = xfer->ret;
 	svc_i3c_master_free_xfer(xfer);
-- 
2.43.7


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