[RESEND PATCH v2 0/2] i3c: master: svc: improve IBI handling

[RESEND PATCH v2 0/2] i3c: master: svc: improve IBI handling

[Stanley Chu]

Improve IBI handling to prevent certain error conditions.

Stanley Chu (2):
  i3c: master: svc: Use manual response for IBI events
  i3c: master: svc: Recycle unused IBI slot

 drivers/i3c/master/svc-i3c-master.c | 31 ++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

-- 
2.34.1

[RESEND PATCH v2 1/2] i3c: master: svc: Use manual response for IBI events

[Stanley Chu]

From: Stanley Chu <yschu@nuvoton.com>

Driver wants to nack the IBI request when the target is not in the
known address list. In below code, svc_i3c_master_nack_ibi() will
cause undefined behavior when using AUTOIBI with auto response rule,
because hw always auto ack the IBI request.

    switch (ibitype) {
    case SVC_I3C_MSTATUS_IBITYPE_IBI:
            dev = svc_i3c_master_dev_from_addr(master, ibiaddr);
            if (!dev || !is_events_enabled(master, SVC_I3C_EVENT_IBI))
                    svc_i3c_master_nack_ibi(master);
            ...
            break;

AutoIBI has another issue that the controller doesn't quit AutoIBI state
after IBIWON polling timeout when there is a SDA glitch(high->low->high).
1. SDA high->low: raising an interrupt to execute IBI ISR
2. SDA low->high
3. Driver writes an AutoIBI request
4. AutoIBI process does not start because SDA is not low
5. IBIWON polling times out
6. Controller reamins in AutoIBI state and doesn't accept EmitStop request

Emitting broadcast address with IBIRESP_MANUAL avoids both issues.

Fixes: dd3c52846d59 ("i3c: master: svc: Add Silvaco I3C master driver")
Signed-off-by: Stanley Chu <yschu@nuvoton.com>
---
Changes since v1:
 * Specify full fileds in the MCTRL register
 * Add Fixes tag
---
 drivers/i3c/master/svc-i3c-master.c | 30 ++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 701ae165b25b..8e7b4ab919e3 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -517,9 +517,24 @@ static void svc_i3c_master_ibi_isr(struct svc_i3c_master *master)
 	 */
 	writel(SVC_I3C_MINT_IBIWON, master->regs + SVC_I3C_MSTATUS);
 
-	/* Acknowledge the incoming interrupt with the AUTOIBI mechanism */
-	writel(SVC_I3C_MCTRL_REQUEST_AUTO_IBI |
-	       SVC_I3C_MCTRL_IBIRESP_AUTO,
+	/*
+	 * Write REQUEST_START_ADDR request to emit broadcast address for arbitration,
+	 * instend of using AUTO_IBI.
+	 *
+	 * Using AutoIBI request may cause controller to remain in AutoIBI state when
+	 * there is a glitch on SDA line (high->low->high).
+	 * 1. SDA high->low, raising an interrupt to execute IBI isr.
+	 * 2. SDA low->high.
+	 * 3. IBI isr writes an AutoIBI request.
+	 * 4. The controller will not start AutoIBI process because SDA is not low.
+	 * 5. IBIWON polling times out.
+	 * 6. Controller reamins in AutoIBI state and doesn't accept EmitStop request.
+	 */
+	writel(SVC_I3C_MCTRL_REQUEST_START_ADDR |
+	       SVC_I3C_MCTRL_TYPE_I3C |
+	       SVC_I3C_MCTRL_IBIRESP_MANUAL |
+	       SVC_I3C_MCTRL_DIR(SVC_I3C_MCTRL_DIR_WRITE) |
+	       SVC_I3C_MCTRL_ADDR(I3C_BROADCAST_ADDR),
 	       master->regs + SVC_I3C_MCTRL);
 
 	/* Wait for IBIWON, should take approximately 100us */
@@ -539,10 +554,15 @@ static void svc_i3c_master_ibi_isr(struct svc_i3c_master *master)
 	switch (ibitype) {
 	case SVC_I3C_MSTATUS_IBITYPE_IBI:
 		dev = svc_i3c_master_dev_from_addr(master, ibiaddr);
-		if (!dev || !is_events_enabled(master, SVC_I3C_EVENT_IBI))
+		if (!dev || !is_events_enabled(master, SVC_I3C_EVENT_IBI)) {
 			svc_i3c_master_nack_ibi(master);
-		else
+		} else {
+			if (dev->info.bcr & I3C_BCR_IBI_PAYLOAD)
+				svc_i3c_master_ack_ibi(master, true);
+			else
+				svc_i3c_master_ack_ibi(master, false);
 			svc_i3c_master_handle_ibi(master, dev);
+		}
 		break;
 	case SVC_I3C_MSTATUS_IBITYPE_HOT_JOIN:
 		if (is_events_enabled(master, SVC_I3C_EVENT_HOTJOIN))
-- 
2.34.1

[RESEND PATCH v2 2/2] i3c: master: svc: Recycle unused IBI slot

[Stanley Chu]

From: Stanley Chu <yschu@nuvoton.com>

In svc_i3c_master_handle_ibi(), an IBI slot is fetched from the pool
to store the IBI payload. However, when an error condition is encountered,
the function returns without recycling the IBI slot, resulting in an IBI
slot leak.

Fixes: c85e209b799f ("i3c: master: svc: fix ibi may not return mandatory data byte")
Signed-off-by: Stanley Chu <yschu@nuvoton.com>
---
Changes since v1:
 * Add Fixes tag
---
 drivers/i3c/master/svc-i3c-master.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 8e7b4ab919e3..9641e66a4e5f 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -417,6 +417,7 @@ static int svc_i3c_master_handle_ibi(struct svc_i3c_master *master,
 						SVC_I3C_MSTATUS_COMPLETE(val), 0, 1000);
 	if (ret) {
 		dev_err(master->dev, "Timeout when polling for COMPLETE\n");
+		i3c_generic_ibi_recycle_slot(data->ibi_pool, slot);
 		return ret;
 	}
 
-- 
2.34.1