| Message ID | 200912081056.40210.jbe@pengutronix.de |
|---|---|
| State | New, archived |
| Headers | show |
Hi, ups, forget this patch, does't work as expected (thanks Wolfram!). Will try again later... Juergen Beisert wrote: > When unmounting an mtd filesystem the s3c2410_nand_select_chip() function > gets called again with "chip == -1". In this case the current code disables > the NFC clock at least a second time, so it does not work anymore. > Clock disabling should only happen if it was really enabled. > > Signed-off-by: Juergen Beisert <jbe@pengutronix.de> > > --- > drivers/mtd/nand/s3c2410.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > Index: linux-2.6.32/drivers/mtd/nand/s3c2410.c > =================================================================== > --- linux-2.6.32.orig/drivers/mtd/nand/s3c2410.c > +++ linux-2.6.32/drivers/mtd/nand/s3c2410.c > @@ -329,12 +329,16 @@ static void s3c2410_nand_select_chip(str > struct s3c2410_nand_mtd *nmtd; > struct nand_chip *this = mtd->priv; > unsigned long cur; > + int clock_enabled; > > nmtd = this->priv; > info = nmtd->info; > > - if (chip != -1 && allow_clk_stop(info)) > + if (chip != -1 && allow_clk_stop(info)) { > clk_enable(info->clk); > + clock_enabled = 1; > + } else > + clock_enabled = 0; > > cur = readl(info->sel_reg); > > @@ -356,7 +360,7 @@ static void s3c2410_nand_select_chip(str > > writel(cur, info->sel_reg); > > - if (chip == -1 && allow_clk_stop(info)) > + if (chip == -1 && allow_clk_stop(info) && clock_enabled != 0) > clk_disable(info->clk); > } Juergen
On Dienstag, 8. Dezember 2009, Sergei Shtylyov wrote: > Hello. > > Juergen Beisert wrote: > > When unmounting an mtd filesystem the s3c2410_nand_select_chip() function > > gets called again with "chip == -1". In this case the current code > > disables the NFC clock at least a second time, so it does not work > > anymore. Clock disabling should only happen if it was really enabled. > > > > Signed-off-by: Juergen Beisert <jbe@pengutronix.de> > > > > --- > > drivers/mtd/nand/s3c2410.c | 8 ++++++-- > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > Index: linux-2.6.32/drivers/mtd/nand/s3c2410.c > > =================================================================== > > --- linux-2.6.32.orig/drivers/mtd/nand/s3c2410.c > > +++ linux-2.6.32/drivers/mtd/nand/s3c2410.c > > @@ -329,12 +329,16 @@ static void s3c2410_nand_select_chip(str > > struct s3c2410_nand_mtd *nmtd; > > struct nand_chip *this = mtd->priv; > > unsigned long cur; > > + int clock_enabled; > > Could be *bool*... I'm not sure. When this function is called more than once to disable a NAND device chip select, who knows if it might be called more than once to enable it? Just an idea. jbe
On Tue, Dec 08, 2009 at 01:07:17PM +0100, Juergen Beisert wrote: > On Dienstag, 8. Dezember 2009, Sergei Shtylyov wrote: > > Hello. > > > > Juergen Beisert wrote: > > > When unmounting an mtd filesystem the s3c2410_nand_select_chip() function > > > gets called again with "chip == -1". In this case the current code > > > disables the NFC clock at least a second time, so it does not work > > > anymore. Clock disabling should only happen if it was really enabled. > > > > > > Signed-off-by: Juergen Beisert <jbe@pengutronix.de> > > > > > > --- > > > drivers/mtd/nand/s3c2410.c | 8 ++++++-- > > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > > > Index: linux-2.6.32/drivers/mtd/nand/s3c2410.c > > > =================================================================== > > > --- linux-2.6.32.orig/drivers/mtd/nand/s3c2410.c > > > +++ linux-2.6.32/drivers/mtd/nand/s3c2410.c > > > @@ -329,12 +329,16 @@ static void s3c2410_nand_select_chip(str > > > struct s3c2410_nand_mtd *nmtd; > > > struct nand_chip *this = mtd->priv; > > > unsigned long cur; > > > + int clock_enabled; > > > > Could be *bool*... > > I'm not sure. When this function is called more than once to disable a NAND > device chip select, who knows if it might be called more than once to enable > it? Just an idea. it might be worth tracking the clock state, not only in these case but to ensure that things like suspend/resume cycles don't cause problems too.
Index: linux-2.6.32/drivers/mtd/nand/s3c2410.c =================================================================== --- linux-2.6.32.orig/drivers/mtd/nand/s3c2410.c +++ linux-2.6.32/drivers/mtd/nand/s3c2410.c @@ -329,12 +329,16 @@ static void s3c2410_nand_select_chip(str struct s3c2410_nand_mtd *nmtd; struct nand_chip *this = mtd->priv; unsigned long cur; + int clock_enabled; nmtd = this->priv; info = nmtd->info; - if (chip != -1 && allow_clk_stop(info)) + if (chip != -1 && allow_clk_stop(info)) { clk_enable(info->clk); + clock_enabled = 1; + } else + clock_enabled = 0; cur = readl(info->sel_reg); @@ -356,7 +360,7 @@ static void s3c2410_nand_select_chip(str writel(cur, info->sel_reg); - if (chip == -1 && allow_clk_stop(info)) + if (chip == -1 && allow_clk_stop(info) && clock_enabled != 0) clk_disable(info->clk); }
When unmounting an mtd filesystem the s3c2410_nand_select_chip() function gets called again with "chip == -1". In this case the current code disables the NFC clock at least a second time, so it does not work anymore. Clock disabling should only happen if it was really enabled. Signed-off-by: Juergen Beisert <jbe@pengutronix.de> --- drivers/mtd/nand/s3c2410.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)