linux-kernel - [PATCH 3/6] i3c: master: svc: fix ibi may not return mandatory data byte

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Date:   Mon, 16 Oct 2023 11:32:29 -0400
From:   Frank Li <Frank.Li@....com>
To:     miquel.raynal@...tlin.com, conor.culhane@...vaco.com,
        alexandre.belloni@...tlin.com, joe@...ches.com,
        linux-i3c@...ts.infradead.org, linux-kernel@...r.kernel.org,
        imx@...ts.linux.dev
Subject: [PATCH 3/6] i3c: master: svc: fix ibi may not return mandatory data byte

MSTATUS[RXPEND] is only updated after the data transfer cycle started. This
creates an issue when the I3C clock is slow, and the CPU is running fast
enough that MSTATUS[RXPEND] may not be updated when the code reach checking
point. As a result, mandatory data are being missed.

Add a wait for MSTATUS[COMPLETE] to ensure that all mandatory data already
in FIFO.

Fixes: dd3c52846d59 ("i3c: master: svc: Add Silvaco I3C master driver")
Cc: stable@...r.kernel.org
Signed-off-by: Frank Li <Frank.Li@....com>
---
 drivers/i3c/master/svc-i3c-master.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 0f57a5f75e39..c252446b2bc5 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -331,6 +331,7 @@ static int svc_i3c_master_handle_ibi(struct svc_i3c_master *master,
 	struct i3c_ibi_slot *slot;
 	unsigned int count;
 	u32 mdatactrl;
+	int ret, val;
 	u8 *buf;
 
 	slot = i3c_generic_ibi_get_free_slot(data->ibi_pool);
@@ -340,6 +341,13 @@ static int svc_i3c_master_handle_ibi(struct svc_i3c_master *master,
 	slot->len = 0;
 	buf = slot->data;
 
+	ret = readl_relaxed_poll_timeout(master->regs + SVC_I3C_MSTATUS, val,
+						SVC_I3C_MSTATUS_COMPLETE(val), 0, 1000);
+	if (ret) {
+		dev_err(master->dev, "Timeout when polling for COMPLETE\n");
+		return ret;
+	}
+
 	while (SVC_I3C_MSTATUS_RXPEND(readl(master->regs + SVC_I3C_MSTATUS))  &&
 	       slot->len < SVC_I3C_FIFO_SIZE) {
 		mdatactrl = readl(master->regs + SVC_I3C_MDATACTRL);
-- 
2.34.1