Re: [PATCH 1/2] mtd: spi-nor: Add support of sst26wf* flash ICs protection ops

From: kbuild test robot
Date: Thu Sep 06 2018 - 12:35:07 EST


Hi Eugeniy,

I love your patch! Perhaps something to improve:

[auto build test WARNING on mtd/spi-nor/next]
[also build test WARNING on v4.19-rc2 next-20180906]
[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/Eugeniy-Paltsev/MTD-spi-nor-add-support-for-sst26wf016-sst26wf032/20180907-001236
base: git://git.infradead.org/linux-mtd.git spi-nor/next
config: x86_64-randconfig-x015-201835 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64

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/mtd/spi-nor/spi-nor.c: In function 'sst26_lock_ctl':
>> drivers/mtd/spi-nor/spi-nor.c:671:5: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
if (ret < 0) {
^

vim +/ret +671 drivers/mtd/spi-nor/spi-nor.c

637
638 /*
639 * Lock, unlock or check lock status of the flash region of the flash (depending
640 * on the lock_ctl value)
641 */
642 static int sst26_lock_ctl(struct spi_nor *nor, loff_t ofs, uint64_t len, enum lock_ctl ctl)
643 {
644 struct mtd_info *mtd = &nor->mtd;
645 u32 i, bpr_ptr, rptr_64k, lptr_64k, bpr_size;
646 bool lower_64k = false, upper_64k = false;
647 u8 bpr_buff[SST26_MAX_BPR_REG_LEN] = {};
648 int ret;
649
650 /* Check length and offset for 64k alignment */
651 if ((ofs & (SZ_64K - 1)) || (len & (SZ_64K - 1))) {
652 dev_err(nor->dev, "length or offset is not 64KiB allighned\n");
653 return -EINVAL;
654 }
655
656 if (ofs + len > mtd->size) {
657 dev_err(nor->dev, "range is more than device size: %#llx + %#llx > %#llx\n",
658 ofs, len, mtd->size);
659 return -EINVAL;
660 }
661
662 /* SST26 family has only 16 Mbit, 32 Mbit and 64 Mbit IC */
663 if (mtd->size != SZ_2M &&
664 mtd->size != SZ_4M &&
665 mtd->size != SZ_8M)
666 return -EINVAL;
667
668 bpr_size = 2 + (mtd->size / SZ_64K / 8);
669
670 nor->read_reg(nor, SPINOR_OP_READ_BPR, bpr_buff, bpr_size);
> 671 if (ret < 0) {
672 dev_err(nor->dev, "fail to read block-protection register\n");
673 return ret;
674 }
675
676 rptr_64k = min_t(u32, ofs + len, mtd->size - SST26_BOUND_REG_SIZE);
677 lptr_64k = max_t(u32, ofs, SST26_BOUND_REG_SIZE);
678
679 upper_64k = ((ofs + len) > (mtd->size - SST26_BOUND_REG_SIZE));
680 lower_64k = (ofs < SST26_BOUND_REG_SIZE);
681
682 /* Lower bits in block-protection register are about 64k region */
683 bpr_ptr = lptr_64k / SZ_64K - 1;
684
685 /* Process 64K blocks region */
686 while (lptr_64k < rptr_64k) {
687 if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
688 return EACCES;
689
690 bpr_ptr++;
691 lptr_64k += SZ_64K;
692 }
693
694 /* 32K and 8K region bits in BPR are after 64k region bits */
695 bpr_ptr = (mtd->size - 2 * SST26_BOUND_REG_SIZE) / SZ_64K;
696
697 /* Process lower 32K block region */
698 if (lower_64k)
699 if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
700 return EACCES;
701
702 bpr_ptr++;
703
704 /* Process upper 32K block region */
705 if (upper_64k)
706 if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
707 return EACCES;
708
709 bpr_ptr++;
710
711 /* Process lower 8K block regions */
712 for (i = 0; i < SST26_BPR_8K_NUM; i++) {
713 if (lower_64k)
714 if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
715 return EACCES;
716
717 /* In 8K area BPR has both read and write protection bits */
718 bpr_ptr += 2;
719 }
720
721 /* Process upper 8K block regions */
722 for (i = 0; i < SST26_BPR_8K_NUM; i++) {
723 if (upper_64k)
724 if (sst26_process_bpr(bpr_size, bpr_buff, bpr_ptr, ctl))
725 return EACCES;
726
727 /* In 8K area BPR has both read and write protection bits */
728 bpr_ptr += 2;
729 }
730
731 /* If we check region status we don't need to write BPR back */
732 if (ctl == SST26_CTL_CHECK)
733 return 0;
734
735 nor->write_reg(nor, SPINOR_OP_WRITE_BPR, bpr_buff, bpr_size);
736 if (ret < 0) {
737 dev_err(nor->dev, "fail to write block-protection register\n");
738 return ret;
739 }
740
741 return 0;
742 }
743

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