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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 <fabio.estevam@freescale.com>
Acked-by: Huang Shijie <shijie.huang@intel.com>
Tested-by: Frank Li <Frank.Li@freescale.com>
Acked-by: Allen Xu <han.xu@freescale.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
This commit is contained in:
Fabio Estevam 2015-01-13 20:14:15 -02:00 committed by Brian Norris
parent fcc87a9519
commit cfe4af3aac
1 changed files with 13 additions and 6 deletions
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19
drivers/mtd/spi-nor/fsl-quadspi.c
View File

@ -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);