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Commit cfe4af3a authored by Fabio Estevam's avatar Fabio Estevam Committed by Brian Norris
Browse files

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: default avatarFabio Estevam <fabio.estevam@freescale.com>
Acked-by: default avatarHuang Shijie <shijie.huang@intel.com>
Tested-by: default avatarFrank Li <Frank.Li@freescale.com>
Acked-by: default avatarAllen Xu <han.xu@freescale.com>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
parent fcc87a95

drivers/mtd/spi-nor/fsl-quadspi.c

+13 −6
Original line number Diff line number Diff line
@@ -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);