From cfe4af3aac3bd63e9caf548157805ca46ad7b073 Mon Sep 17 00:00:00 2001 From: Fabio Estevam Date: Tue, 13 Jan 2015 20:14:15 -0200 Subject: [PATCH] mtd: fsl-quadspi: Fix module unbound 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 Acked-by: Huang Shijie Tested-by: Frank Li Acked-by: Allen Xu Signed-off-by: Brian Norris --- 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 9d6080079a45..a46bea33580f 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);