Am 2020-06-30 18:15, schrieb Oliver Hartkopp:
On 30.06.20 07:53, Michael Walle wrote:
[+ Oliver]
Hi Joakim,
Am 2020-06-30 04:42, schrieb Joakim Zhang:
-----Original Message-----
From: Michael Walle <mich...@walle.cc>
Sent: 2020年6月30日 2:18
To: linux-...@vger.kernel.org; netdev@vger.kernel.org;
linux-ker...@vger.kernel.org
Cc: Wolfgang Grandegger <w...@grandegger.com>; Marc Kleine-Budde
<m...@pengutronix.de>; David S . Miller <da...@davemloft.net>; Jakub
Kicinski <k...@kernel.org>; Joakim Zhang <qiangqing.zh...@nxp.com>;
dl-linux-imx <linux-...@nxp.com>; Michael Walle <mich...@walle.cc>
Subject: [PATCH 2/2] can: flexcan: add support for ISO CAN-FD
Up until now, the controller used non-ISO CAN-FD mode, although it
supports it.
Add support for ISO mode, too. By default the hardware is in non-ISO
mode and
an enable bit has to be explicitly set.
Signed-off-by: Michael Walle <mich...@walle.cc>
---
drivers/net/can/flexcan.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)
diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index
183e094f8d66..a92d3cdf4195 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -94,6 +94,7 @@
#define FLEXCAN_CTRL2_MRP BIT(18)
#define FLEXCAN_CTRL2_RRS BIT(17)
#define FLEXCAN_CTRL2_EACEN BIT(16)
+#define FLEXCAN_CTRL2_ISOCANFDEN BIT(12)
/* FLEXCAN memory error control register (MECR) bits */
#define FLEXCAN_MECR_ECRWRDIS BIT(31)
@@ -1344,14 +1345,25 @@ static int flexcan_chip_start(struct
net_device
*dev)
else
reg_mcr |= FLEXCAN_MCR_SRX_DIS;
- /* MCR - CAN-FD */
- if (priv->can.ctrlmode & CAN_CTRLMODE_FD)
+ /* MCR, CTRL2
+ *
+ * CAN-FD mode
+ * ISO CAN-FD mode
+ */
+ reg_ctrl2 = priv->read(®s->ctrl2);
+ if (priv->can.ctrlmode & CAN_CTRLMODE_FD) {
reg_mcr |= FLEXCAN_MCR_FDEN;
- else
+ reg_ctrl2 |= FLEXCAN_CTRL2_ISOCANFDEN;
+ } else {
reg_mcr &= ~FLEXCAN_MCR_FDEN;
+ }
+
+ if (priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO)
+ reg_ctrl2 &= ~FLEXCAN_CTRL2_ISOCANFDEN;
[1]
[..]
ip link set can0 up type can bitrate 1000000 dbitrate 5000000 fd on
ip link set can0 up type can bitrate 1000000 dbitrate 5000000 fd on \
fd-non-iso on
vs.
ip link set can0 up type can bitrate 1000000 dbitrate 5000000
fd-non-iso on
I haven't found anything if CAN_CTRLMODE_FD_NON_ISO depends on
CAN_CTRLMODE_FD. I.e. wether CAN_CTRLMODE_FD_NON_ISO can only be set
if
CAN_CTRLMODE_FD is also set.
Only the following piece of code, which might be a hint that you
have to set CAN_CTRLMODE_FD if you wan't to use
CAN_CTRLMODE_FD_NON_ISO:
drivers/net/can/dev.c:
/* do not check for static fd-non-iso if 'fd' is disabled */
if (!(maskedflags & CAN_CTRLMODE_FD))
ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
If CAN_CTRLMODE_FD_NON_ISO can be set without CAN_CTRLMODE_FD, what
should be the mode if both are set at the same time?
CAN_CTRLMODE_FD_NON_ISO is only relevant when CAN_CTRLMODE_FD is set.
So in the example from above
ip link set can0 up type can bitrate 1000000 dbitrate 5000000
fd-non-iso on
either the setting of 'dbitrate 5000000' and 'fd-non-iso on' is
pointless.
When switching to FD-mode with 'fd on' the FD relevant settings need
to be applied.
FD ISO is the default.
Did this help or did I get anything wrong?
Thanks for the explanation. Yes this helped a great deal and this
patch should be correct; it sets ISO mode if CAN_CTRLMODE_FD is set
and masks it again if CAN_CTRLMODE_FD_NON_ISO is set. See [1].
-michael
