Hi Seth,
On Thu, 24 Apr 2008, Seth Forshee wrote:
> On my OMAP2430 board I was seeing the contents of DRAM become corrupted
> shortly after the kernel started. I tracked this down to
> omap2_enable_osc_ck(). I think this function is intended to only clear
> the bits in OMAP_AUTOEXTCLKMODE_MASK, but it has the side-effect of
> setting all of the other bits in the register. This includes setting
> some fields to reserved values.
>
> I'm not 100% sure whether the problem is with omap2_enable_osc_ck() or
> prm_rmw_reg_bits() (maybe this should be masking off any bits not set in
> mask), but based on what I see elsewhere I think that
> omap2_enable_osc_ck() is to blame. If this is the case, the patch below
> fixes the problem.
>
> ----------
> From: Seth Forshee <seth.forshee@xxxxxxxxx>
> Subject: [PATCH] ARM: OMAP2: Set PRCM_CLKSRC_CTRL correctly in omap2_enable_osc_ck
>
> This patch fixes an incorrect use of prm_rmw_reg_bits() in
> omap2_enable_osc_ck() which is changing bits in PRCM_CLKSRC_CTRL
> that are unrelated to the function it is performing.
>
> Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxx>
Indeed, you have found a bug - thanks for the patch!
Acked-by: Paul Walmsley <paul@xxxxxxxxx>
> ---
> arch/arm/mach-omap2/clock24xx.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/clock24xx.c b/arch/arm/mach-omap2/clock24xx.c
> index 9b7fd15..e7968e7 100644
> --- a/arch/arm/mach-omap2/clock24xx.c
> +++ b/arch/arm/mach-omap2/clock24xx.c
> @@ -78,7 +78,7 @@ static u32 omap2_get_dpll_rate_24xx(struct clk *tclk)
> static int omap2_enable_osc_ck(struct clk *clk)
> {
>
> - prm_rmw_reg_bits(OMAP_AUTOEXTCLKMODE_MASK, ~OMAP_AUTOEXTCLKMODE_MASK,
> + prm_rmw_reg_bits(OMAP_AUTOEXTCLKMODE_MASK, 0,
> OMAP24XX_PRCM_CLKSRC_CTRL);
>
> return 0;
> --
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- Paul
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