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drivers/dma/dw_dmac: make driver's endianness configurable

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The dw_dmac driver was originally developed for avr32 to be used with the
Synopsys DesignWare AHB DMA controller.  Starting from 2.6.38, access to
the device's i/o memory was done with the little-endian readl/writel
functions(1)

This broke the driver for the avr32 platform, because it needs big
(native) endian accessors.  This patch makes the endianness configurable
using 'DW_DMAC_BIG_ENDIAN_IO', which will default be true for AVR32

I submitted this patch before(2) but then waited for Andy to finish other
changes to the same module(3).

(1) https://patchwork.kernel.org/patch/608211
(2) https://lkml.org/lkml/2012/8/26/148
(3) https://lkml.org/lkml/2012/9/21/173

Signed-off-by: Hein Tibosch <hein_tibosch@yahoo.es>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: Havard Skinnemoen <havard@skinnemoen.net>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Hein Tibosch 2012-10-25 13:38:05 -07:00 committed by Linus Torvalds
parent 35cfa2b0b4
commit d5ea7b5ec1
2 changed files with 24 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
drivers/dma/Kconfig
View File

@ -90,6 +90,17 @@ config DW_DMAC
Support the Synopsys DesignWare AHB DMA controller. This
can be integrated in chips such as the Atmel AT32ap7000.
config DW_DMAC_BIG_ENDIAN_IO
bool "Use big endian I/O register access"
default y if AVR32
depends on DW_DMAC
help
Say yes here to use big endian I/O access when reading and writing
to the DMA controller registers. This is needed on some platforms,
like the Atmel AVR32 architecture.
If unsure, use the default setting.
config AT_HDMAC
tristate "Atmel AHB DMA support"
depends on ARCH_AT91

18
drivers/dma/dw_dmac_regs.h
View File

@ -98,9 +98,17 @@ struct dw_dma_regs {
u32 DW_PARAMS;
};
#ifdef CONFIG_DW_DMAC_BIG_ENDIAN_IO
#define dma_readl_native ioread32be
#define dma_writel_native iowrite32be
#else
#define dma_readl_native readl
#define dma_writel_native writel
#endif
/* To access the registers in early stage of probe */
#define dma_read_byaddr(addr, name) \
readl((addr) + offsetof(struct dw_dma_regs, name))
dma_readl_native((addr) + offsetof(struct dw_dma_regs, name))
/* Bitfields in DW_PARAMS */
#define DW_PARAMS_NR_CHAN 8 /* number of channels */
@ -216,9 +224,9 @@ __dwc_regs(struct dw_dma_chan *dwc)
}
#define channel_readl(dwc, name) \
readl(&(__dwc_regs(dwc)->name))
dma_readl_native(&(__dwc_regs(dwc)->name))
#define channel_writel(dwc, name, val) \
writel((val), &(__dwc_regs(dwc)->name))
dma_writel_native((val), &(__dwc_regs(dwc)->name))
static inline struct dw_dma_chan *to_dw_dma_chan(struct dma_chan *chan)
{
@ -246,9 +254,9 @@ static inline struct dw_dma_regs __iomem *__dw_regs(struct dw_dma *dw)
}
#define dma_readl(dw, name) \
readl(&(__dw_regs(dw)->name))
dma_readl_native(&(__dw_regs(dw)->name))
#define dma_writel(dw, name, val) \
writel((val), &(__dw_regs(dw)->name))
dma_writel_native((val), &(__dw_regs(dw)->name))
#define channel_set_bit(dw, reg, mask) \
dma_writel(dw, reg, ((mask) << 8) | (mask))