[PATCH 6.5 358/491] i3c: master: svc: fix wrong data return when IBI happen during start frame

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

6.5-stable review patch.  If anyone has any objections, please let me know.

------------------

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
@@ -1011,6 +1011,9 @@ 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 |
@@ -1028,6 +1031,23 @@ static int svc_i3c_master_xfer(struct sv
 		ret = -ENXIO;
 		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)
 		ret = svc_i3c_master_read(master, in, xfer_len);