From: Sugar Zhang sugar.zhang@rock-chips.com
[ Upstream commit 2da254cc7908105a60a6bb219d18e8dced03dcb9 ]
This patch kill instructs the DMAC to immediately terminate execution of a thread. and then clear the interrupt status, at last, stop generating interrupts for DMA_SEV. to guarantee the next dma start is clean. otherwise, one interrupt maybe leave to next start and make some mistake.
we can reporduce the problem as follows:
DMASEV: modify the event-interrupt resource, and if the INTEN sets function as interrupt, the DMAC will set irq<event_num> HIGH to generate interrupt. write INTCLR to clear interrupt.
DMA EXECUTING INSTRUCTS DMA TERMINATE | | | | ... _stop | | | spin_lock_irqsave DMASEV | | | | mask INTEN | | | DMAKILL | | | spin_unlock_irqrestore
in above case, a interrupt was left, and if we unmask INTEN, the DMAC will set irq<event_num> HIGH to generate interrupt.
to fix this, do as follows:
DMA EXECUTING INSTRUCTS DMA TERMINATE | | | | ... _stop | | | spin_lock_irqsave DMASEV | | | | DMAKILL | | | clear INTCLR | mask INTEN | | | spin_unlock_irqrestore
Signed-off-by: Sugar Zhang sugar.zhang@rock-chips.com Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/dma/pl330.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 95619ee33112c..799c182c3eacc 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -1006,6 +1006,7 @@ static void _stop(struct pl330_thread *thrd) { void __iomem *regs = thrd->dmac->base; u8 insn[6] = {0, 0, 0, 0, 0, 0}; + u32 inten = readl(regs + INTEN);
if (_state(thrd) == PL330_STATE_FAULT_COMPLETING) UNTIL(thrd, PL330_STATE_FAULTING | PL330_STATE_KILLING); @@ -1018,10 +1019,13 @@ static void _stop(struct pl330_thread *thrd)
_emit_KILL(0, insn);
- /* Stop generating interrupts for SEV */ - writel(readl(regs + INTEN) & ~(1 << thrd->ev), regs + INTEN); - _execute_DBGINSN(thrd, insn, is_manager(thrd)); + + /* clear the event */ + if (inten & (1 << thrd->ev)) + writel(1 << thrd->ev, regs + INTCLR); + /* Stop generating interrupts for SEV */ + writel(inten & ~(1 << thrd->ev), regs + INTEN); }
/* Start doing req 'idx' of thread 'thrd' */