| Message ID | 1415174326-6623-2-git-send-email-b29396@freescale.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 11/05/2014 08:58 AM, Dong Aisheng wrote: > At least on the i.MX6SX with M_CAN IP version 3.0.x, an issue with Can you add the imx mask revision, too and the exact m_can version (is available). > the Message RAM was discovered. Sending CAN frames with dlc less > than 4 bytes will lead to bit errors, when the first 8 bytes of > the Message RAM have not been initialized (i.e. written to). > To work around this issue, the first 8 bytes are initialized in open() > function. > > Without the workaround, we can easily see the following errors: > root@imx6qdlsolo:~# ip link set can0 up type can bitrate 1000000 > [ 66.882520] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready > root@imx6qdlsolo:~# cansend can0 123#112233 > [ 66.935640] m_can 20e8000.can can0: Bit Error Uncorrected > > Signed-off-by: Dong Aisheng <b29396@freescale.com> > --- > ChangeLog since v1: > * initialize the first 8 bytes of Tx Buffer of Message RAM in open() > to workaround the issue > --- > drivers/net/can/m_can/m_can.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c > index 664fe30..f47c200 100644 > --- a/drivers/net/can/m_can/m_can.c > +++ b/drivers/net/can/m_can/m_can.c > @@ -902,6 +902,15 @@ static void m_can_chip_config(struct net_device *dev) > /* set bittiming params */ > m_can_set_bittiming(dev); > > + /* At least on the i.MX6SX with M_CAN IP version 3.0.x, an issue with > + * the Message RAM was discovered. Sending CAN frames with dlc less > + * than 4 bytes will lead to bit errors, when the first 8 bytes of > + * the Message RAM have not been initialized (i.e. written to). > + * To work around this issue, the first 8 bytes are initialized here. > + */ > + m_can_fifo_write(priv, 0, M_CAN_FIFO_DATA(0), 0x0); > + m_can_fifo_write(priv, 0, M_CAN_FIFO_DATA(1), 0x0); > + > m_can_config_endisable(priv, false); > } > > Marc
On Wed, Nov 05, 2014 at 11:17:48AM +0100, Marc Kleine-Budde wrote: > On 11/05/2014 08:58 AM, Dong Aisheng wrote: > > At least on the i.MX6SX with M_CAN IP version 3.0.x, an issue with > > Can you add the imx mask revision, too and the exact m_can version (is > available). > What do you mean imx mask revision? By reading the Core Release Register (CREL), it seems the exact m_can version is 3.0.1. (CREL = 30130506). So what about changing to as follows? "At least on the i.MX6SX with M_CAN IP version 3.0.1 (CREL = 30130506), an issue with" Regards Dong Aisheng > > the Message RAM was discovered. Sending CAN frames with dlc less > > than 4 bytes will lead to bit errors, when the first 8 bytes of > > the Message RAM have not been initialized (i.e. written to). > > To work around this issue, the first 8 bytes are initialized in open() > > function. > > > > Without the workaround, we can easily see the following errors: > > root@imx6qdlsolo:~# ip link set can0 up type can bitrate 1000000 > > [ 66.882520] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready > > root@imx6qdlsolo:~# cansend can0 123#112233 > > [ 66.935640] m_can 20e8000.can can0: Bit Error Uncorrected > > > > Signed-off-by: Dong Aisheng <b29396@freescale.com> > > --- > > ChangeLog since v1: > > * initialize the first 8 bytes of Tx Buffer of Message RAM in open() > > to workaround the issue > > --- > > drivers/net/can/m_can/m_can.c | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > > > diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c > > index 664fe30..f47c200 100644 > > --- a/drivers/net/can/m_can/m_can.c > > +++ b/drivers/net/can/m_can/m_can.c > > @@ -902,6 +902,15 @@ static void m_can_chip_config(struct net_device *dev) > > /* set bittiming params */ > > m_can_set_bittiming(dev); > > > > + /* At least on the i.MX6SX with M_CAN IP version 3.0.x, an issue with > > + * the Message RAM was discovered. Sending CAN frames with dlc less > > + * than 4 bytes will lead to bit errors, when the first 8 bytes of > > + * the Message RAM have not been initialized (i.e. written to). > > + * To work around this issue, the first 8 bytes are initialized here. > > + */ > > + m_can_fifo_write(priv, 0, M_CAN_FIFO_DATA(0), 0x0); > > + m_can_fifo_write(priv, 0, M_CAN_FIFO_DATA(1), 0x0); > > + > > m_can_config_endisable(priv, false); > > } > > > > > > Marc > > -- > Pengutronix e.K. | Marc Kleine-Budde | > Industrial Linux Solutions | Phone: +49-231-2826-924 | > Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | > Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de | >
On Wed, Nov 05, 2014 at 12:32:21PM +0100, Marc Kleine-Budde wrote: > On 11/05/2014 11:33 AM, Dong Aisheng wrote: > > On Wed, Nov 05, 2014 at 11:17:48AM +0100, Marc Kleine-Budde wrote: > >> On 11/05/2014 08:58 AM, Dong Aisheng wrote: > >>> At least on the i.MX6SX with M_CAN IP version 3.0.x, an issue with > >> > >> Can you add the imx mask revision, too and the exact m_can version (is > >> available). > >> > > > > What do you mean imx mask revision? > > In my imx6sdl/imx6q data sheet it's called: Chip Silicon Version > (USB_ANALOG_DIGPROG), I expect that the imx6sx has a the same register. > > > By reading the Core Release Register (CREL), it seems the exact m_can > > version is 3.0.1. (CREL = 30130506). > > > > So what about changing to as follows? > > "At least on the i.MX6SX with M_CAN IP version 3.0.1 (CREL = 30130506), > > an issue with" > > Yes, please ass the imx silicon revision, too. > Okay, it's i.MX6SX TO1.2. Will add it. Regards Dong Aisheng > Marc > > -- > Pengutronix e.K. | Marc Kleine-Budde | > Industrial Linux Solutions | Phone: +49-231-2826-924 | > Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | > Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de | >
On 11/05/2014 11:33 AM, Dong Aisheng wrote: > On Wed, Nov 05, 2014 at 11:17:48AM +0100, Marc Kleine-Budde wrote: >> On 11/05/2014 08:58 AM, Dong Aisheng wrote: >>> At least on the i.MX6SX with M_CAN IP version 3.0.x, an issue with >> >> Can you add the imx mask revision, too and the exact m_can version (is >> available). >> > > What do you mean imx mask revision? In my imx6sdl/imx6q data sheet it's called: Chip Silicon Version (USB_ANALOG_DIGPROG), I expect that the imx6sx has a the same register. > By reading the Core Release Register (CREL), it seems the exact m_can > version is 3.0.1. (CREL = 30130506). > > So what about changing to as follows? > "At least on the i.MX6SX with M_CAN IP version 3.0.1 (CREL = 30130506), > an issue with" Yes, please ass the imx silicon revision, too. Marc
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index 664fe30..f47c200 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -902,6 +902,15 @@ static void m_can_chip_config(struct net_device *dev) /* set bittiming params */ m_can_set_bittiming(dev); + /* At least on the i.MX6SX with M_CAN IP version 3.0.x, an issue with + * the Message RAM was discovered. Sending CAN frames with dlc less + * than 4 bytes will lead to bit errors, when the first 8 bytes of + * the Message RAM have not been initialized (i.e. written to). + * To work around this issue, the first 8 bytes are initialized here. + */ + m_can_fifo_write(priv, 0, M_CAN_FIFO_DATA(0), 0x0); + m_can_fifo_write(priv, 0, M_CAN_FIFO_DATA(1), 0x0); + m_can_config_endisable(priv, false); }
At least on the i.MX6SX with M_CAN IP version 3.0.x, an issue with the Message RAM was discovered. Sending CAN frames with dlc less than 4 bytes will lead to bit errors, when the first 8 bytes of the Message RAM have not been initialized (i.e. written to). To work around this issue, the first 8 bytes are initialized in open() function. Without the workaround, we can easily see the following errors: root@imx6qdlsolo:~# ip link set can0 up type can bitrate 1000000 [ 66.882520] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready root@imx6qdlsolo:~# cansend can0 123#112233 [ 66.935640] m_can 20e8000.can can0: Bit Error Uncorrected Signed-off-by: Dong Aisheng <b29396@freescale.com> --- ChangeLog since v1: * initialize the first 8 bytes of Tx Buffer of Message RAM in open() to workaround the issue --- drivers/net/can/m_can/m_can.c | 9 +++++++++ 1 file changed, 9 insertions(+)