On Tue, Mar 30, 2010 at 10:22:03AM +0200, Christian Pellegrin wrote:
> Option CONFIG_MTD_NAND_S3C2410_CLKSTOP was broken by higher MTD layers
> calling select_chip with -1 twice in a row. This patch fixes the problem
> by making sure that clk_disable is not called too many times.
>
> Signed-off-by: Christian Pellegrin <chripell@xxxxxxxx>
> ---
> drivers/mtd/nand/s3c2410.c | 10 ++++++++--
> 1 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/nand/s3c2410.c b/drivers/mtd/nand/s3c2410.c
> index fa6e9c7..9adecc6 100644
> --- a/drivers/mtd/nand/s3c2410.c
> +++ b/drivers/mtd/nand/s3c2410.c
> @@ -37,6 +37,7 @@
> #include <linux/slab.h>
> #include <linux/clk.h>
> #include <linux/cpufreq.h>
> +#include <linux/bitops.h>
>
> #include <linux/mtd/mtd.h>
> #include <linux/mtd/nand.h>
> @@ -135,6 +136,9 @@ struct s3c2410_nand_info {
> #ifdef CONFIG_CPU_FREQ
> struct notifier_block freq_transition;
> #endif
> +#ifdef CONFIG_MTD_NAND_S3C2410_CLKSTOP
> + unsigned long clk_running;
> +#endif
> };
>
> /* conversion functions */
> @@ -333,7 +337,8 @@ static void s3c2410_nand_select_chip(struct mtd_info *mtd, int chip)
> nmtd = this->priv;
> info = nmtd->info;
>
> - if (chip != -1 && allow_clk_stop(info))
> + if (chip != -1 && allow_clk_stop(info) &&
> + !test_and_set_bit(0, &info->clk_running))
> clk_enable(info->clk);
please let me know why you feel the need to use test_and_set_bit on
a variable that is single use.
> cur = readl(info->sel_reg);
> @@ -356,7 +361,8 @@ static void s3c2410_nand_select_chip(struct mtd_info *mtd, int chip)
>
> writel(cur, info->sel_reg);
>
> - if (chip == -1 && allow_clk_stop(info))
> + if (chip == -1 && allow_clk_stop(info) &&
> + test_and_clear_bit(0, &info->clk_running))
> clk_disable(info->clk);
> }
>
> --
> 1.5.6.5
>
> --
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--
--
Ben
Q: What's a light-year?
A: One-third less calories than a regular year.
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