[PATCH V3 0/3] can: flexcan: fixes for freeze mode

Fixes for freeze mode.

---
ChangLogs:
V1->V2:
	* make use of existing functions flexcan_chip_freeze().
	* add patch #1 and #3.
V2->V3:
	* read then write MCR register.

Joakim Zhang (3):
  can: flexcan: assert FRZ bit in flexcan_chip_freeze()
  can: flexcan: enable RX FIFO after FRZ/HALT valid
  can: flexcan: invoke flexcan_chip_freeze() to enter freeze mode

 drivers/net/can/flexcan.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

-- 
2.17.1

Invoke flexcan_chip_freeze() to enter freeze mode, since need poll
freeze mode acknowledge.

Fixes: e955cead03117 ("CAN: Add Flexcan CAN controller driver")
Signed-off-by: Joakim Zhang <redacted>
---
 drivers/net/can/flexcan.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index d6a84b7e06da..bdfb36496d96 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c

@@ -1440,10 +1440,13 @@ static int flexcan_chip_start(struct net_device *dev)
 
 	flexcan_set_bittiming(dev);
 
+	/* set freeze, halt */
+	err = flexcan_chip_freeze(priv);
+	if (err)
+		goto out_chip_disable;
+
 	/* MCR
 	 *
-	 * enable freeze
-	 * halt now
 	 * only supervisor access
 	 * enable warning int
 	 * enable individual RX masking

@@ -1452,9 +1455,8 @@ static int flexcan_chip_start(struct net_device *dev)
 	 */
 	reg_mcr = priv->read(&regs->mcr);
 	reg_mcr &= ~FLEXCAN_MCR_MAXMB(0xff);
-	reg_mcr |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT | FLEXCAN_MCR_SUPV |
-		FLEXCAN_MCR_WRN_EN | FLEXCAN_MCR_IRMQ | FLEXCAN_MCR_IDAM_C |
-		FLEXCAN_MCR_MAXMB(priv->tx_mb_idx);
+	reg_mcr |= FLEXCAN_MCR_SUPV | FLEXCAN_MCR_WRN_EN | FLEXCAN_MCR_IRMQ |
+		FLEXCAN_MCR_IDAM_C | FLEXCAN_MCR_MAXMB(priv->tx_mb_idx);
 
 	/* MCR
 	 *

-- 
2.17.1

RX FIFO enable failed could happen when do system reboot stress test:

[    0.303958] flexcan 5a8d0000.can: 5a8d0000.can supply xceiver not found, using dummy regulator
[    0.304281] flexcan 5a8d0000.can (unnamed net_device) (uninitialized): Could not enable RX FIFO, unsupported core
[    0.314640] flexcan 5a8d0000.can: registering netdev failed
[    0.320728] flexcan 5a8e0000.can: 5a8e0000.can supply xceiver not found, using dummy regulator
[    0.320991] flexcan 5a8e0000.can (unnamed net_device) (uninitialized): Could not enable RX FIFO, unsupported core
[    0.331360] flexcan 5a8e0000.can: registering netdev failed
[    0.337444] flexcan 5a8f0000.can: 5a8f0000.can supply xceiver not found, using dummy regulator
[    0.337716] flexcan 5a8f0000.can (unnamed net_device) (uninitialized): Could not enable RX FIFO, unsupported core
[    0.348117] flexcan 5a8f0000.can: registering netdev failed

RX FIFO should be enabled after the FRZ/HALT are valid. But the current
code enable RX FIFO and FRZ/HALT at the same time.

Fixes: e955cead03117 ("CAN: Add Flexcan CAN controller driver")
Signed-off-by: Joakim Zhang <redacted>
---
 drivers/net/can/flexcan.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 737e594cb12c..d6a84b7e06da 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c

@@ -1825,10 +1825,14 @@ static int register_flexcandev(struct net_device *dev)
 	if (err)
 		goto out_chip_disable;
 
-	/* set freeze, halt and activate FIFO, restrict register access */
+	/* set freeze, halt */
+	err = flexcan_chip_freeze(priv);
+	if (err)
+		goto out_chip_disable;
+
+	/* activate FIFO, restrict register access */
 	reg = priv->read(&regs->mcr);
-	reg |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT |
-		FLEXCAN_MCR_FEN | FLEXCAN_MCR_SUPV;
+	reg |=  FLEXCAN_MCR_FEN | FLEXCAN_MCR_SUPV;
 	priv->write(reg, &regs->mcr);
 
 	/* Currently we only support newer versions of this core

-- 
2.17.1

Assert HALT bit to enter freeze mode, there is a premise that FRZ bit is
asserted. This patch asserts FRZ bit in flexcan_chip_freeze, although
the reset value is 1b'1. This is a prepare patch, later patch will
invoke flexcan_chip_freeze() to enter freeze mode, which polling freeze
mode acknowledge.

Fixes: b1aa1c7a2165b ("can: flexcan: fix transition from and to freeze mode in chip_{,un}freeze")
Signed-off-by: Joakim Zhang <redacted>
---
 drivers/net/can/flexcan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 038fe1036df2..737e594cb12c 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c

@@ -662,7 +662,7 @@ static int flexcan_chip_freeze(struct flexcan_priv *priv)
 	u32 reg;
 
 	reg = priv->read(&regs->mcr);
-	reg |= FLEXCAN_MCR_HALT;
+	reg |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT;
 	priv->write(reg, &regs->mcr);
 
 	while (timeout-- && !(priv->read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK))

-- 
2.17.1

On 18.02.2021 19:00:34, Joakim Zhang wrote:

Fixes for freeze mode.

Applied all to linux-can/testing.

Thanks,
Marc

-- 
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