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can: fix handling of unmodifiable configuration options

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As described in 'can: m_can: tag current CAN FD controllers as non-ISO'
(6cfda7fbeb) it is possible to define fixed configuration options by
setting the according bit in 'ctrlmode' and clear it in 'ctrlmode_supported'.
This leads to the incovenience that the fixed configuration bits can not be
passed by netlink even when they have the correct values (e.g. non-ISO, FD).

This patch fixes that issue and not only allows fixed set bit values to be set
again but now requires(!) to provide these fixed values at configuration time.
A valid CAN FD configuration consists of a nominal/arbitration bittiming, a
data bittiming and a control mode with CAN_CTRLMODE_FD set - which is now
enforced by a new can_validate() function. This fix additionally removed the
inconsistency that was prohibiting the support of 'CANFD-only' controller
drivers, like the RCar CAN FD.

For this reason a new helper can_set_static_ctrlmode() has been introduced to
provide a proper interface to handle static enabled CAN controller options.

Reported-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Reviewed-by: Ramesh Shanmugasundaram  <ramesh.shanmugasundaram@bp.renesas.com>
Cc: <stable@vger.kernel.org> # >= 3.18
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Oliver Hartkopp 2016-03-21 20:18:21 +01:00 • committed by Marc Kleine-Budde
parent b6fd3aba60
commit bb208f144c
3 changed files with 73 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

56
drivers/net/can/dev.c
View file

@ -696,11 +696,17 @@ int can_change_mtu(struct net_device *dev, int new_mtu)
/* allow change of MTU according to the CANFD ability of the device */
switch (new_mtu) {
case CAN_MTU:
/* 'CANFD-only' controllers can not switch to CAN_MTU */
if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
return -EINVAL;
priv->ctrlmode &= ~CAN_CTRLMODE_FD;
break;
case CANFD_MTU:
if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD))
/* check for potential CANFD ability */
if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
!(priv->ctrlmode_static & CAN_CTRLMODE_FD))
return -EINVAL;
priv->ctrlmode |= CAN_CTRLMODE_FD;
@ -782,6 +788,35 @@ static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
= { .len = sizeof(struct can_bittiming_const) },
};
static int can_validate(struct nlattr *tb[], struct nlattr *data[])
{
bool is_can_fd = false;
/* Make sure that valid CAN FD configurations always consist of
* - nominal/arbitration bittiming
* - data bittiming
* - control mode with CAN_CTRLMODE_FD set
*/
if (data[IFLA_CAN_CTRLMODE]) {
struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
}
if (is_can_fd) {
if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
return -EOPNOTSUPP;
}
if (data[IFLA_CAN_DATA_BITTIMING]) {
if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
return -EOPNOTSUPP;
}
return 0;
}
static int can_changelink(struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[])
{
@ -813,19 +848,31 @@ static int can_changelink(struct net_device *dev,
if (data[IFLA_CAN_CTRLMODE]) {
struct can_ctrlmode *cm;
u32 ctrlstatic;
u32 maskedflags;
/* Do not allow changing controller mode while running */
if (dev->flags & IFF_UP)
return -EBUSY;
cm = nla_data(data[IFLA_CAN_CTRLMODE]);
ctrlstatic = priv->ctrlmode_static;
maskedflags = cm->flags & cm->mask;
/* check whether changed bits are allowed to be modified */
if (cm->mask & ~priv->ctrlmode_supported)
/* check whether provided bits are allowed to be passed */
if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
return -EOPNOTSUPP;
/* do not check for static fd-non-iso if 'fd' is disabled */
if (!(maskedflags & CAN_CTRLMODE_FD))
ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
/* make sure static options are provided by configuration */
if ((maskedflags & ctrlstatic) != ctrlstatic)
return -EOPNOTSUPP;
/* clear bits to be modified and copy the flag values */
priv->ctrlmode &= ~cm->mask;
priv->ctrlmode |= (cm->flags & cm->mask);
priv->ctrlmode |= maskedflags;
/* CAN_CTRLMODE_FD can only be set when driver supports FD */
if (priv->ctrlmode & CAN_CTRLMODE_FD)
@ -966,6 +1013,7 @@ static struct rtnl_link_ops can_link_ops __read_mostly = {
.maxtype = IFLA_CAN_MAX,
.policy = can_policy,
.setup = can_setup,
.validate = can_validate,
.newlink = can_newlink,
.changelink = can_changelink,
.get_size = can_get_size,