* Mika Westerberg <[email protected]> [100503 05:52]: > If we are softbooting another kernel using kexec, DMA controller state is not > known when we are performing omap_init_dma(). It is possible that some DMA > channels are already active. For example after kexec we get: > > <4>IRQ 0020 for non-allocated DMAchannel 5 > <4>IRQ 0020 for non-allocated DMAchannel 5 > <4>IRQ 0020 for non-allocated DMAchannel 5 > <4>IRQ 0020 for non-allocated DMAchannel 5 > <4>IRQ 0020 for non-allocated DMAchannel 5 > > To prevent any weird things happening, we perform soft reset for the > controller > and disable all per channel interrupts. > > Signed-off-by: Mika Westerberg <[email protected]> > --- > arch/arm/plat-omap/dma.c | 32 ++++++++++++++++++++++++++++++++ > arch/arm/plat-omap/include/plat/dma.h | 4 ++++ > 2 files changed, 36 insertions(+), 0 deletions(-) > > diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c > index 1d95996..24cbb97 100644 > --- a/arch/arm/plat-omap/dma.c > +++ b/arch/arm/plat-omap/dma.c > @@ -2024,6 +2024,31 @@ void omap_dma_global_context_restore(void) > > > /*----------------------------------------------------------------------------*/ > > +/** > + * omap_dma_reset() - perform software reset for the DMA controller > + */ > +static void omap_dma_reset(void) > +{ > + u32 v; > + > + if (cpu_class_is_omap1()) > + return; > + > + v = dma_read(OCP_SYSCONFIG); > + v |= 0x2; /* software reset */ > + dma_write(v, OCP_SYSCONFIG); > + > + /* wait until reset is complete */ > + while ((dma_read(SYSSTATUS) & 0x1) == 0) > + cpu_relax();
This reset part seems to be mach-omap2 specific. > + /* disable per channel interrupts */ > + dma_write(0, IRQENABLE_L0); > + dma_write(0, IRQENABLE_L1); > + dma_write(0, IRQENABLE_L2); > + dma_write(0, IRQENABLE_L3); > +} For a minimal fix, how about just disable the interrupt in omap_clear_dma()? We are already calling that from omap_init_dma(). Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
