From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qc0-x231.google.com ([2607:f8b0:400d:c01::231]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YB9jf-0005He-VC for linux-mtd@lists.infradead.org; Tue, 13 Jan 2015 22:14:52 +0000 Received: by mail-qc0-f177.google.com with SMTP id x3so4653256qcv.8 for ; Tue, 13 Jan 2015 14:14:30 -0800 (PST) From: Fabio Estevam To: computersforpeace@gmail.com Subject: [PATCH RESEND] mtd: fsl-quadspi: Fix module unbound Date: Tue, 13 Jan 2015 20:14:15 -0200 Message-Id: <1421187255-20618-1-git-send-email-festevam@gmail.com> Cc: Fabio Estevam , Frank.Li@freescale.com, shijie8@gmail.com, han.xu@freescale.com, linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Fabio Estevam When removing the fsl-quadspi module and running 'cat /proc/mtd' afterwards, we see garbage data like: $ rmmod fsl-quadspi $ cat /proc/mtd dev: size erasesize name mtd0: 00000000 00000000 "(null)" mtd0: 00000000 00000000 "(null)" mtd0: 00000000 00000000 "(null)" ... mtd0: a22296c6c756e28 00000000 "(null)" mtd0: a22296c6c756e28 3064746d "(null)" If we continue doing multiple module load/unload operations, then it will also lead to a kernel crash. The reason for this is due to the wrong mtd index used in mtd_device_unregister() in the remove function. We need to keep the mtd unregister index aligned with the one used in the probe function, which means we need to take into account the 'has_second_chip' property. By doing so we can guarantee that the mtd index is the same in the registration and unregistration functions. With this patch applied we can load/unload the fsl-quadspi driver several times and it will result in no crash. Signed-off-by: Fabio Estevam --- drivers/mtd/spi-nor/fsl-quadspi.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c b/drivers/mtd/spi-nor/fsl-quadspi.c index 39763b9..4b468a9 100644 --- a/drivers/mtd/spi-nor/fsl-quadspi.c +++ b/drivers/mtd/spi-nor/fsl-quadspi.c @@ -227,6 +227,7 @@ struct fsl_qspi { u32 nor_num; u32 clk_rate; unsigned int chip_base_addr; /* We may support two chips. */ + bool has_second_chip; }; static inline int is_vybrid_qspi(struct fsl_qspi *q) @@ -783,7 +784,6 @@ static int fsl_qspi_probe(struct platform_device *pdev) struct spi_nor *nor; struct mtd_info *mtd; int ret, i = 0; - bool has_second_chip = false; const struct of_device_id *of_id = of_match_device(fsl_qspi_dt_ids, &pdev->dev); @@ -860,14 +860,14 @@ static int fsl_qspi_probe(struct platform_device *pdev) goto irq_failed; if (of_get_property(np, "fsl,qspi-has-second-chip", NULL)) - has_second_chip = true; + q->has_second_chip = true; /* iterate the subnodes. */ for_each_available_child_of_node(dev->of_node, np) { char modalias[40]; /* skip the holes */ - if (!has_second_chip) + if (!q->has_second_chip) i *= 2; nor = &q->nor[i]; @@ -943,9 +943,12 @@ static int fsl_qspi_probe(struct platform_device *pdev) return 0; last_init_failed: - for (i = 0; i < q->nor_num; i++) + for (i = 0; i < q->nor_num; i++) { + /* skip the holes */ + if (!q->has_second_chip) + i *= 2; mtd_device_unregister(&q->mtd[i]); - + } irq_failed: clk_disable_unprepare(q->clk); clk_failed: @@ -960,8 +963,12 @@ static int fsl_qspi_remove(struct platform_device *pdev) struct fsl_qspi *q = platform_get_drvdata(pdev); int i; - for (i = 0; i < q->nor_num; i++) + for (i = 0; i < q->nor_num; i++) { + /* skip the holes */ + if (!q->has_second_chip) + i *= 2; mtd_device_unregister(&q->mtd[i]); + } /* disable the hardware */ writel(QUADSPI_MCR_MDIS_MASK, q->iobase + QUADSPI_MCR); -- 1.9.1