From mboxrd@z Thu Jan  1 00:00:00 1970
From: shawn.guo@freescale.com (Shawn Guo)
Date: Wed, 9 Feb 2011 07:38:25 +0800
Subject: [PATCH 1/5] dmaengine: mxs-dma: add dma support for i.MX23/28
In-Reply-To: <19792.552.77000.702221@ipc1.ka-ro>
References: <1296871696-21008-1-git-send-email-shawn.guo@freescale.com>
	<1296871696-21008-2-git-send-email-shawn.guo@freescale.com>
	<19792.552.77000.702221@ipc1.ka-ro>
Message-ID: <20110208233824.GE6963@S2100-06.ap.freescale.net>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Feb 07, 2011 at 03:31:04PM +0100, Lothar Wa?mann 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@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