Re: [PATCH v6 05/18] dmaengine: st_fdma: Add STMicroelectronics FDMA engine driver support

From: kbuild test robot
Date: Wed Jul 06 2016 - 12:33:15 EST


Hi,

[auto build test WARNING on robh/for-next]
[also build test WARNING on v4.7-rc6 next-20160706]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/Peter-Griffin/Add-support-for-FDMA-DMA-controller-and-slim-core-rproc-found-on-STi-chipsets/20160706-170304
base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
config: arm-allyesconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 5.3.1-8) 5.3.1 20160205
reproduce:
wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=arm

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

drivers/dma/st_fdma.c: In function 'st_fdma_prep_slave_sg':
>> drivers/dma/st_fdma.c:550:19: warning: 'hw_node' may be used uninitialized in this function [-Wmaybe-uninitialized]
hw_node->control |= FDMA_NODE_CTRL_INT_EON;
^
drivers/dma/st_fdma.c: In function 'st_fdma_probe':
drivers/dma/st_fdma.c:759:5: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
if (ret) {
^

vim +/hw_node +550 drivers/dma/st_fdma.c

534
535 hw_node->next = fdesc->node[(i + 1) % sg_len].pdesc;
536 hw_node->control = FDMA_NODE_CTRL_REQ_MAP_DREQ(fchan->dreq_line);
537
538 fill_hw_node(hw_node, fchan, direction);
539
540 if (direction == DMA_MEM_TO_DEV)
541 hw_node->saddr = sg_dma_address(sg);
542 else
543 hw_node->daddr = sg_dma_address(sg);
544
545 hw_node->nbytes = sg_dma_len(sg);
546 hw_node->generic.length = sg_dma_len(sg);
547 }
548
549 /* interrupt at end of last node */
> 550 hw_node->control |= FDMA_NODE_CTRL_INT_EON;
551
552 return vchan_tx_prep(&fchan->vchan, &fdesc->vdesc, flags);
553 }
554
555 static size_t st_fdma_desc_residue(struct st_fdma_chan *fchan,
556 struct virt_dma_desc *vdesc,
557 bool in_progress)
558 {

---
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