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[ Upstream commit 2da254cc79 ]
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>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.