linux-kernel - [PATCH v5 5/6] i3c: master: svc: wait for Manual ACK/NACK Done before next step

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Message-Id: <20241001-svc-i3c-hj-v5-5-480ab8aed849@nxp.com>
Date: Tue, 01 Oct 2024 12:02:54 -0400
From: Frank Li <Frank.Li@....com>
To: Miquel Raynal <miquel.raynal@...tlin.com>, 
 Conor Culhane <conor.culhane@...vaco.com>, 
 Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc: linux-i3c@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 imx@...ts.linux.dev, Frank Li <Frank.Li@....com>
Subject: [PATCH v5 5/6] i3c: master: svc: wait for Manual ACK/NACK Done
 before next step

Wait for the controller to complete emitting ACK/NACK, otherwise the next
command may be omitted by the hardware.

A "command done" check in svc_i3c_master_nack(ack)_ibi() and change the
return type to int to flag possible timeouts.

Reviewed-by: Miquel Raynal <miquel.raynal@...tlin.com>
Signed-off-by: Frank Li <Frank.Li@....com>
---
Change from v3 to v4
- rework commit message
- add miquel's review tag
- directly return readl(...)
---
 drivers/i3c/master/svc-i3c-master.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 1ee6ce186195c..3388c9af63fcc 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -388,10 +388,11 @@ static int svc_i3c_master_handle_ibi(struct svc_i3c_master *master,
 	return 0;
 }
 
-static void svc_i3c_master_ack_ibi(struct svc_i3c_master *master,
+static int svc_i3c_master_ack_ibi(struct svc_i3c_master *master,
 				   bool mandatory_byte)
 {
 	unsigned int ibi_ack_nack;
+	u32 reg;
 
 	ibi_ack_nack = SVC_I3C_MCTRL_REQUEST_IBI_ACKNACK;
 	if (mandatory_byte)
@@ -400,18 +401,30 @@ static void svc_i3c_master_ack_ibi(struct svc_i3c_master *master,
 		ibi_ack_nack |= SVC_I3C_MCTRL_IBIRESP_ACK_WITHOUT_BYTE;
 
 	writel(ibi_ack_nack, master->regs + SVC_I3C_MCTRL);
+
+	return readl_poll_timeout_atomic(master->regs + SVC_I3C_MSTATUS, reg,
+					 SVC_I3C_MSTATUS_MCTRLDONE(reg), 1, 1000);
+
 }
 
-static void svc_i3c_master_nack_ibi(struct svc_i3c_master *master)
+static int svc_i3c_master_nack_ibi(struct svc_i3c_master *master)
 {
+	int ret;
+	u32 reg;
+
 	writel(SVC_I3C_MCTRL_REQUEST_IBI_ACKNACK |
 	       SVC_I3C_MCTRL_IBIRESP_NACK,
 	       master->regs + SVC_I3C_MCTRL);
+
+	ret = readl_poll_timeout_atomic(master->regs + SVC_I3C_MSTATUS, reg,
+					SVC_I3C_MSTATUS_MCTRLDONE(reg), 1, 1000);
+	return ret;
 }
 
 static int svc_i3c_master_handle_ibi_won(struct svc_i3c_master *master, u32 mstatus)
 {
 	u32 ibitype;
+	int ret = 0;
 
 	ibitype = SVC_I3C_MSTATUS_IBITYPE(mstatus);
 
@@ -421,10 +434,10 @@ static int svc_i3c_master_handle_ibi_won(struct svc_i3c_master *master, u32 msta
 	switch (ibitype) {
 	case SVC_I3C_MSTATUS_IBITYPE_HOT_JOIN:
 	case SVC_I3C_MSTATUS_IBITYPE_MASTER_REQUEST:
-		svc_i3c_master_nack_ibi(master);
+		ret = svc_i3c_master_nack_ibi(master);
 	}
 
-	return 0;
+	return ret;
 }
 
 static void svc_i3c_master_ibi_work(struct work_struct *work)
@@ -935,7 +948,9 @@ static int svc_i3c_master_do_daa_locked(struct svc_i3c_master *master,
 			if (ret)
 				break;
 		} else if (SVC_I3C_MSTATUS_IBIWON(reg)) {
-			svc_i3c_master_handle_ibi_won(master, reg);
+			ret = svc_i3c_master_handle_ibi_won(master, reg);
+			if (ret)
+				break;
 			continue;
 		} else if (SVC_I3C_MSTATUS_MCTRLDONE(reg)) {
 			if (SVC_I3C_MSTATUS_STATE_IDLE(reg) &&
@@ -1209,7 +1224,9 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
 		 * start.
 		 */
 		if (SVC_I3C_MSTATUS_IBIWON(reg)) {
-			svc_i3c_master_handle_ibi_won(master, reg);
+			ret = svc_i3c_master_handle_ibi_won(master, reg);
+			if (ret)
+				goto emit_stop;
 			continue;
 		}
 

-- 
2.34.1