Commit 5e5e3c92 authored by Frank Li's avatar Frank Li Committed by Alexandre Belloni
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i3c: master: svc: fix wrong data return when IBI happen during start frame 



     ┌─────┐     ┏──┐  ┏──┐  ┏──┐  ┏──┐  ┏──┐  ┏──┐  ┏──┐  ┏──┐  ┌─────
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: dd3c5284 ("i3c: master: svc: Add Silvaco I3C master driver")
Cc:  <stable@vger.kernel.org>
Reviewed-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: default avatarFrank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20231023161658.3890811-3-Frank.Li@nxp.com


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 6bf3fc26

drivers/i3c/master/svc-i3c-master.c

+20 −0
Original line number Diff line number Diff line
@@ -1011,6 +1011,9 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master, 
	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 |
@@ -1029,6 +1032,23 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master, 
		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);

	else