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m68k: coldfire: create IO access functions for internal registers

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The internal peripheral registers contained in all varieties of ColdFire
SoCs require simple big endian access ranging in sizes from 8, 16 and 32
bit. Currently there is a mixture of IO access methods used across the
various CPU support code, some using readx/writex and some using the
simpler __raw_readx/__raw_writew.

The readx/writex use cases are particularly kludgy in that they contain
code to differentiate internal register access and other general attached
peripheral register access - say on a PCI bus. In effect this means that
the readx/writex family for ColdFire is non-standard. This ultimately
ends up causing problems with definitions of other IO access support
functions like ioreadx/ioreadxbe/iowritex/iowritexbe which in the
generic case are defined in terms of readx/writex.

Create a set of internal only register access methods to ultimately
replace all internal register access code. The new access functions
mirror the existing readx/writex family but using the preferred 8/16/32
suffixes.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
This commit is contained in:
Greg Ungerer 2026-04-17 23:35:52 +10:00 committed by Greg Ungerer
parent cd30961957
commit 13cb6440d8
1 changed files with 16 additions and 0 deletions
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16
arch/m68k/include/asm/io_no.h
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@ -107,6 +107,22 @@ static inline void writel(u32 value, volatile void __iomem *addr)
#endif /* IOMEMBASE */
#if defined(CONFIG_COLDFIRE)
/*
* The ColdFire internal peripheral registers are big-endian, so you
* cannot use the conventional little-endian readb/readw/readl and
* writeb/writew/writel access functions. Define a family of access
* functions to give correct endian access that can be used by all
* architecture code.
*/
#define mcf_read8 __raw_readb
#define mcf_read16 __raw_readw
#define mcf_read32 __raw_readl
#define mcf_write8 __raw_writeb
#define mcf_write16 __raw_writew
#define mcf_write32 __raw_writel
#endif /* CONFIG_COLDFIRE */
#if defined(CONFIG_PCI)
/*
* Support for PCI bus access uses the asm-generic access functions.