Commit 0d72ba93 authored by Olof Johansson's avatar Olof Johansson Committed by Paul Mackerras
Browse files

[POWERPC] Add workaround for MPICs with broken register reads 



Some versions of PWRficient 1682M have an interrupt controller in which
the first register in each pair for interrupt sources doesn't always
read with the right polarity/sense values.

To work around this, keep a software copy of the register instead.  Since
it's not modified from the mpic itself, it's a feasible solution.  Still,
keep it under a config option to avoid wasting memory on other platforms.

Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 2099172d

arch/powerpc/platforms/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -137,6 +137,16 @@ config MPIC_U3_HT_IRQS 
	depends on PPC_MAPLE

	default y



config MPIC_BROKEN_REGREAD

	bool

	depends on MPIC

	help

	  This option enables a MPIC driver workaround for some chips

	  that have a bug that causes some interrupt source information

	  to not read back properly. It is safe to use on other chips as

	  well, but enabling it uses about 8KB of memory to keep copies

	  of the register contents in software.



config IBMVIO

	depends on PPC_PSERIES || PPC_ISERIES

	bool

arch/powerpc/platforms/pasemi/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ config PPC_PASEMI 
	select MPIC

	select PPC_UDBG_16550

	select PPC_NATIVE

	select MPIC_BROKEN_REGREAD

	help

	  This option enables support for PA Semi's PWRficient line

	  of SoC processors, including PA6T-1682M

arch/powerpc/sysdev/mpic.c

+12 −2
Original line number Diff line number Diff line
@@ -228,6 +228,11 @@ static inline u32 _mpic_irq_read(struct mpic *mpic, unsigned int src_no, unsigne 
	unsigned int	isu = src_no >> mpic->isu_shift;

	unsigned int	idx = src_no & mpic->isu_mask;



#ifdef CONFIG_MPIC_BROKEN_REGREAD

	if (reg == 0)

		return mpic->isu_reg0_shadow[idx];

	else

#endif

		return _mpic_read(mpic->reg_type, &mpic->isus[isu],

				  reg + (idx * MPIC_INFO(IRQ_STRIDE)));

}
@@ -240,6 +245,11 @@ static inline void _mpic_irq_write(struct mpic *mpic, unsigned int src_no, 


	_mpic_write(mpic->reg_type, &mpic->isus[isu],

		    reg + (idx * MPIC_INFO(IRQ_STRIDE)), value);



#ifdef CONFIG_MPIC_BROKEN_REGREAD

	if (reg == 0)

		mpic->isu_reg0_shadow[idx] = value;

#endif

}



#define mpic_read(b,r)		_mpic_read(mpic->reg_type,&(b),(r))

include/asm-powerpc/mpic.h

+4 −0
Original line number Diff line number Diff line
@@ -306,6 +306,10 @@ struct mpic 
	unsigned long		*hwirq_bitmap;

#endif



#ifdef CONFIG_MPIC_BROKEN_REGREAD

	u32			isu_reg0_shadow[MPIC_MAX_IRQ_SOURCES];

#endif



	/* link */

	struct mpic		*next;

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