Commit c8acd6aa authored Sep 03, 2012 by Zhangfei Gao Committed by Vinod Koul Sep 14, 2012

dmaengine: mmp-pdma support



1. virtual channel vs. physical channel
Virtual channel is managed by dmaengine
Physical channel handling resource, such as irq
Physical channel is alloced dynamically as descending priority,
freed immediately when irq done.
The availble highest priority physically channel will alwayes be alloced

Issue pending list -> alloc highest dma physically channel available -> dma done -> free physically channel

2. list: running list & pending list
submit: desc list -> pending list
issue_pending_list: if (IDLE) pending list -> running list; free pending list (RUN)
irq: free running list (IDLE)
     check pendlist -> pending list -> running list; free pending list (RUN)

3. irq:
Each list generate one irq, calling callback
One list may contain several desc chain, in such case, make sure only the last desc list generate irq.

4. async
Submit will add desc chain to pending list, which can be multi-called
If multi desc chain is submitted, only the last desc would generate irq -> call back
If IDLE, issue_pending_list start pending_list, transforming pendlist to running list
If RUN, irq will start pending list

5. test
5.1 pxa3xx_nand on pxa910
5.2 insmod dmatest.ko (threads_per_chan=y)
By default drivers/dma/dmatest.c test every channel and test memcpy with 1 threads per channel

Signed-off-by: Zhangfei Gao <zhangfei.gao@marvell.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

parent b5f14330

drivers/dma/Kconfig

+7 −0

Original line number	Diff line number	Diff line
		@@ -302,6 +302,13 @@ config DMA_OMAP
		select DMA_ENGINE
		select DMA_VIRTUAL_CHANNELS

		config MMP_PDMA
		bool "MMP PDMA support"
		depends on (ARCH_MMP \|\| ARCH_PXA)
		select DMA_ENGINE
		help
		Support the MMP PDMA engine for PXA and MMP platfrom.

		config DMA_ENGINE
		bool

drivers/dma/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -33,3 +33,4 @@ obj-$(CONFIG_EP93XX_DMA) += ep93xx_dma.o
		obj-$(CONFIG_DMA_SA11X0) += sa11x0-dma.o
		obj-$(CONFIG_MMP_TDMA) += mmp_tdma.o
		obj-$(CONFIG_DMA_OMAP) += omap-dma.o
		obj-$(CONFIG_MMP_PDMA) += mmp_pdma.o

drivers/dma/mmp_pdma.c

0 → 100644

+875 −0

File added.

Preview size limit exceeded, changes collapsed.

include/linux/platform_data/mmp_dma.h

0 → 100644

+19 −0

Original line number	Diff line number	Diff line
		/*
		* MMP Platform DMA Management
		*
		* Copyright (c) 2011 Marvell Semiconductors Inc.
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License version 2 as
		* published by the Free Software Foundation.
		*
		*/

		#ifndef MMP_DMA_H
		#define MMP_DMA_H

		struct mmp_dma_platdata {
		int dma_channels;
		};

		#endif /* MMP_DMA_H */

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