> -----Original Message----- > From: Stuart Yoder [mailto:stuart.yoder@xxxxxxx] > Sent: Friday, October 21, 2016 9:02 AM > To: gregkh@xxxxxxxxxxxxxxxxxxx > Cc: German Rivera <german.rivera@xxxxxxx>; devel@xxxxxxxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; agraf@xxxxxxx; arnd@xxxxxxxx; Leo Li > <leoyang.li@xxxxxxx>; Roy Pledge <roy.pledge@xxxxxxx>; Roy Pledge > <roy.pledge@xxxxxxx>; Haiying Wang <haiying.wang@xxxxxxx>; Stuart > Yoder <stuart.yoder@xxxxxxx> > Subject: [PATCH 6/9] bus: fsl-mc: dpio: add QBMan portal APIs for DPAA2 > > From: Roy Pledge <Roy.Pledge@xxxxxxx> > > Add QBman APIs for frame queue and buffer pool operations. > > Signed-off-by: Roy Pledge <roy.pledge@xxxxxxx> > Signed-off-by: Haiying Wang <haiying.wang@xxxxxxx> > Signed-off-by: Stuart Yoder <stuart.yoder@xxxxxxx> > --- > drivers/bus/fsl-mc/dpio/Makefile | 2 +- > drivers/bus/fsl-mc/dpio/qbman-portal.c | 1009 > ++++++++++++++++++++++++++++++++ > drivers/bus/fsl-mc/dpio/qbman-portal.h | 464 +++++++++++++++ > 3 files changed, 1474 insertions(+), 1 deletion(-) > create mode 100644 drivers/bus/fsl-mc/dpio/qbman-portal.c > create mode 100644 drivers/bus/fsl-mc/dpio/qbman-portal.h > > diff --git a/drivers/bus/fsl-mc/dpio/Makefile b/drivers/bus/fsl- > mc/dpio/Makefile > index 128befc..6588498 100644 > --- a/drivers/bus/fsl-mc/dpio/Makefile > +++ b/drivers/bus/fsl-mc/dpio/Makefile > @@ -6,4 +6,4 @@ subdir-ccflags-y := -Werror > > obj-$(CONFIG_FSL_MC_DPIO) += fsl-mc-dpio.o > > -fsl-mc-dpio-objs := dpio.o > +fsl-mc-dpio-objs := dpio.o qbman-portal.o > diff --git a/drivers/bus/fsl-mc/dpio/qbman-portal.c b/drivers/bus/fsl- > mc/dpio/qbman-portal.c > new file mode 100644 > index 0000000..1eb3dd9 > --- /dev/null > +++ b/drivers/bus/fsl-mc/dpio/qbman-portal.c [...] > +/** > + * qbman_swp_pull() - Issue the pull dequeue command > + * @s: the software portal object > + * @d: the software portal descriptor which has been configured with > + * the set of qbman_pull_desc_set_*() calls > + * > + * Return 0 for success, and -EBUSY if the software portal is not ready > + * to do pull dequeue. > + */ > +int qbman_swp_pull(struct qbman_swp *s, struct qbman_pull_desc *d) > +{ > + struct qbman_pull_desc *p; > + > + if (!atomic_dec_and_test(&s->vdq.available)) { > + atomic_inc(&s->vdq.available); > + return -EBUSY; > + } > + s->vdq.storage = (void *)d->rsp_addr_virt; > + d->tok = 1; > + p = qbman_get_cmd(s, QBMAN_CENA_SWP_VDQCR); > + *p = *d; > + dma_wmb(); > + > + /* Set the verb byte, have to substitute in the valid-bit */ > + p->verb |= s->vdq.valid_bit; > + s->vdq.valid_bit ^= QB_VALID_BIT; > + > + return 0; > +} > + [...] > + > +/** > + * qbman_result_has_new_result() - Check and get the dequeue response > from the > + * dq storage memory set in pull dequeue command > + * @s: the software portal object > + * @dq: the dequeue result read from the memory > + * > + * Return 1 for getting a valid dequeue result, or 0 for not getting a valid > + * dequeue result. > + * > + * Only used for user-provided storage of dequeue results, not DQRR. For > + * efficiency purposes, the driver will perform any required endianness > + * conversion to ensure that the user's dequeue result storage is in host- > endian > + * format. As such, once the user has called > qbman_result_has_new_result() and > + * been returned a valid dequeue result, they should not call it again on > + * the same memory location (except of course if another dequeue > command has > + * been executed to produce a new result to that location). > + */ > +int qbman_result_has_new_result(struct qbman_swp *s, const struct > dpaa2_dq *dq) > +{ > + if (!dq->dq.tok) > + return 0; While testing the Ethernet driver I discovered that sometimes the above check fails. When we check a store entry for the first time, if the hardware didn't manage to fill it with a valid respose yet, we may find a non-null value in the token field (because the stores have uninitialized memory). So by only checking that token is !=0, we risk processing an uninitialized memory area as a valid dequeue entry. We should always compare the token field against 1, the value that is given to the hardware on the dequeue command. It might also be a good idea to use a define here, to make it clear 1 is a magic value. And I think we should also zero the stores when they are first allocated, since even with the proposed fix there's still a (much smaller) risk of finding our exact token value in an uninitialized memory area. Thanks, Ioana _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
