Re: can: kvaser_usb: Add support for Kvaser CAN/USB devices

[Marc Kleine-Budde <mkl@pengutronix.de>]

[-- Attachment #1: Type: text/plain, Size: 2695 bytes --]

On 11/19/2015 01:42 PM, Dan Carpenter wrote:
> Hello Olivier Sobrie,
> 
> The patch 080f40a6fa28: "can: kvaser_usb: Add support for Kvaser
> CAN/USB devices" from Nov 21, 2012, leads to the following static
> checker warning:
> 
> 	drivers/net/can/usb/kvaser_usb.c:949 kvaser_usb_rx_error()
> 	0x08 | 0x18 has 0x08 set on both sides
> 
> drivers/net/can/usb/kvaser_usb.c
>    941          switch (dev->family) {
>    942          case KVASER_LEAF:
>    943                  if (es->leaf.error_factor) {
>    944                          cf->can_id |= CAN_ERR_BUSERROR | CAN_ERR_PROT;
>    945  
>    946                          if (es->leaf.error_factor & M16C_EF_ACKE)
>    947                                  cf->data[3] |= (CAN_ERR_PROT_LOC_ACK);
>    948                          if (es->leaf.error_factor & M16C_EF_CRCE)
>    949                                  cf->data[3] |= (CAN_ERR_PROT_LOC_CRC_SEQ |
>    950                                                  CAN_ERR_PROT_LOC_CRC_DEL);
> 
> CAN_ERR_PROT_LOC_CRC_SEQ is 0x08
> CAN_ERR_PROT_LOC_CRC_DEL is 0x18
> 
> It's weird that the bits overlap.  Was that intentional?  Why isn't it
> enough to just say?:
> 					cf->data[3] |= CAN_ERR_PROT_LOC_CRC_DEL;

Looking at include/uapi/linux/can/error.h I'd say, they are not meant to
be used bitwise. Oliver?

> The static checker complains about most places where
> CAN_ERR_PROT_LOC_CRC_SEQ is used.  I see us setting the flag but not I
> don't see where we test for this so I'm not sure.
> 
>    951                          if (es->leaf.error_factor & M16C_EF_FORME)
>    952                                  cf->data[2] |= CAN_ERR_PROT_FORM;
>    953                          if (es->leaf.error_factor & M16C_EF_STFE)
>    954                                  cf->data[2] |= CAN_ERR_PROT_STUFF;
>    955                          if (es->leaf.error_factor & M16C_EF_BITE0)
>    956                                  cf->data[2] |= CAN_ERR_PROT_BIT0;
>    957                          if (es->leaf.error_factor & M16C_EF_BITE1)
>    958                                  cf->data[2] |= CAN_ERR_PROT_BIT1;
>    959                          if (es->leaf.error_factor & M16C_EF_TRE)
>    960                                  cf->data[2] |= CAN_ERR_PROT_TX;
>    961                  }
>    962                  break;
>    963          case KVASER_USBCAN:

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   |


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 455 bytes --]