[PATCH 1/5] dmaengine: mxs-dma: add dma support for i.MX23/28
Shawn Guo
shawn.guo at freescale.com
Tue Feb 8 18:38:25 EST 2011
On Mon, Feb 07, 2011 at 03:31:04PM +0100, Lothar Waßmann wrote:
> Hi,
>
> Shawn Guo writes:
> > This patch adds dma support for Freescale MXS-based SoC i.MX23/28,
> > including apbh-dma and apbx-dma.
> >
> > * apbh-dma and apbx-dma are supported in the driver as two instances,
> > and have to be filtered by dma clients via device id. It becomes
> > the convention that apbh-dma always gets registered prior to
> > apbx-dma.
> >
> > * apbh-dma is different between mx23 and mx28, hardware version
> > register is used to handle the differences.
> >
> > * Every the mxs dma channel is statically assigned to client device
> > by soc design with fixed irq. The irq number is being passed by
> > alloc_chan function with mxs_dma_data, and client driver has to
> > filter the correct channel by its channel id.
> >
> > * mxs-dma supports pio function besides data transfer. The driver
> > uses dma_data_direction DMA_NONE to identify the pio mode, and
> > steals sgl and sg_len to get pio words and numbers from clients.
> >
> > * mxs dmaengine has some very specific features, like sense function
> > and the special NAND support (nand_lock, nand_wait4ready). These
> > are too specific to implemented in generic dmaengine driver.
> >
> > * The parameter "flags" of prep functions is currently being used to
> > pass wait4end flag from clients.
> >
> > * The driver refers to imx-sdma and only a single descriptor is
> > statically assigned to each channel.
> >
> > Signed-off-by: Shawn Guo <shawn.guo at freescale.com>
> > ---
> > arch/arm/mach-mxs/include/mach/dma.h | 16 +
> > drivers/dma/Kconfig | 8 +
> > drivers/dma/Makefile | 1 +
> > drivers/dma/mxs-dma.c | 702 ++++++++++++++++++++++++++++++++++
> > 4 files changed, 727 insertions(+), 0 deletions(-)
> > create mode 100644 arch/arm/mach-mxs/include/mach/dma.h
> > create mode 100644 drivers/dma/mxs-dma.c
> >
> > diff --git a/arch/arm/mach-mxs/include/mach/dma.h b/arch/arm/mach-mxs/include/mach/dma.h
> > new file mode 100644
> > index 0000000..429f431
> > --- /dev/null
> > +++ b/arch/arm/mach-mxs/include/mach/dma.h
> > @@ -0,0 +1,16 @@
> > +/*
> > + * Copyright 2011 Freescale Semiconductor, Inc. All Rights Reserved.
> > + *
> > + * 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 __MACH_MXS_DMA_H__
> > +#define __MACH_MXS_DMA_H__
> > +
> > +struct mxs_dma_data {
> > + int chan_irq;
> > +};
> >
> There is a name clash of this structure with the name of a different
> structure defined in arch/arm/mach-mxs/include/mach/devices-common.h
> (your patch 3/5):
> |diff --git a/arch/arm/mach-mxs/include/mach/devices-common.h b/arch/arm/mach-mxs/include/mach/devices-common.h
> |index e7aefb4..acd74b4 100644
> |--- a/arch/arm/mach-mxs/include/mach/devices-common.h
> |+++ b/arch/arm/mach-mxs/include/mach/devices-common.h
> |@@ -40,6 +40,13 @@ struct mxs_auart_data {
> | struct platform_device *__init mxs_add_auart(
> | const struct mxs_auart_data *data);
> |
> |+/* dma */
> |+struct mxs_dma_data {
> |+ const char *devid;
> |+ resource_size_t iobase;
> |+};
> |+struct platform_device *__init mxs_add_dma(const struct mxs_dma_data *data);
>
Good catch. Thanks.
Regards,
Shawn
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