Patch "i3c: master: svc: fix wrong data return when IBI happen during start frame" has been added to the 6.1-stable tree

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This is a note to let you know that I've just added the patch titled

    i3c: master: svc: fix wrong data return when IBI happen during start frame

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     i3c-master-svc-fix-wrong-data-return-when-ibi-happen-during-start-frame.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 5e5e3c92e748a6d859190e123b9193cf4911fcca Mon Sep 17 00:00:00 2001
From: Frank Li <Frank.Li@xxxxxxx>
Date: Mon, 23 Oct 2023 12:16:54 -0400
Subject: i3c: master: svc: fix wrong data return when IBI happen during start frame
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Frank Li <Frank.Li@xxxxxxx>

commit 5e5e3c92e748a6d859190e123b9193cf4911fcca upstream.

     ┌─────┐     ┏──┐  ┏──┐  ┏──┐  ┏──┐  ┏──┐  ┏──┐  ┏──┐  ┏──┐  ┌─────
SCL: ┘     └─────┛  └──┛  └──┛  └──┛  └──┛  └──┛  └──┛  └──┛  └──┘
     ───┐                       ┌─────┐     ┌─────┐     ┌───────────┐
SDA:    └───────────────────────┘     └─────┘     └─────┘           └─────
     xxx╱    ╲╱                                        ╲╱    ╲╱    ╲╱    ╲
   : xxx╲IBI ╱╲               Addr(0x0a)               ╱╲ RW ╱╲NACK╱╲ S  ╱

If an In-Band Interrupt (IBI) occurs and IBI work thread is not immediately
scheduled, when svc_i3c_master_priv_xfers() initiates the I3C transfer and
attempts to send address 0x7e, the target interprets it as an
IBI handler and returns the target address 0x0a.

However, svc_i3c_master_priv_xfers() does not handle this case and proceeds
with other transfers, resulting in incorrect data being returned.

Add IBIWON check in svc_i3c_master_xfer(). In case this situation occurs,
return a failure to the driver.

Fixes: dd3c52846d59 ("i3c: master: svc: Add Silvaco I3C master driver")
Cc:  <stable@xxxxxxxxxxxxxxx>
Reviewed-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
Link: https://lore.kernel.org/r/20231023161658.3890811-3-Frank.Li@xxxxxxx
Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/i3c/master/svc-i3c-master.c |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -1003,6 +1003,9 @@ static int svc_i3c_master_xfer(struct sv
 	u32 reg;
 	int ret;
 
+	/* clean SVC_I3C_MINT_IBIWON w1c bits */
+	writel(SVC_I3C_MINT_IBIWON, master->regs + SVC_I3C_MSTATUS);
+
 	writel(SVC_I3C_MCTRL_REQUEST_START_ADDR |
 	       xfer_type |
 	       SVC_I3C_MCTRL_IBIRESP_NACK |
@@ -1023,6 +1026,23 @@ static int svc_i3c_master_xfer(struct sv
 	if (ret < 0)
 		goto emit_stop;
 
+	/*
+	 * According to I3C spec ver 1.1.1, 5.1.2.2.3 Consequence of Controller Starting a Frame
+	 * with I3C Target Address.
+	 *
+	 * The I3C Controller normally should start a Frame, the Address may be arbitrated, and so
+	 * the Controller shall monitor to see whether an In-Band Interrupt request, a Controller
+	 * Role Request (i.e., Secondary Controller requests to become the Active Controller), or
+	 * a Hot-Join Request has been made.
+	 *
+	 * If missed IBIWON check, the wrong data will be return. When IBIWON happen, return failure
+	 * and yield the above events handler.
+	 */
+	if (SVC_I3C_MSTATUS_IBIWON(reg)) {
+		ret = -ENXIO;
+		goto emit_stop;
+	}
+
 	if (rnw)
 		*read_len = ret;
 


Patches currently in stable-queue which might be from Frank.Li@xxxxxxx are

queue-6.1/i3c-master-svc-fix-wrong-data-return-when-ibi-happen-during-start-frame.patch
queue-6.1/i3c-master-svc-fix-sda-keep-low-when-polling-ibiwon-timeout-happen.patch
queue-6.1/i3c-master-svc-fix-ibi-may-not-return-mandatory-data-byte.patch
queue-6.1/i3c-master-svc-fix-check-wrong-status-register-in-irq-handler.patch
queue-6.1/i3c-master-svc-fix-race-condition-in-ibi-work-thread.patch



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