From 0d72ba930cbc9140a584af7e4e65041b6c7a7d18 Mon Sep 17 00:00:00 2001 From: Olof Johansson Date: Sat, 8 Sep 2007 05:13:19 +1000 Subject: [PATCH] [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: Olof Johansson Signed-off-by: Paul Mackerras --- arch/powerpc/platforms/Kconfig | 10 ++++++++++ arch/powerpc/platforms/pasemi/Kconfig | 1 + arch/powerpc/sysdev/mpic.c | 14 ++++++++++++-- include/asm-powerpc/mpic.h | 4 ++++ 4 files changed, 27 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig index 065f3b19d6..78a7edac57 100644 --- a/arch/powerpc/platforms/Kconfig +++ b/arch/powerpc/platforms/Kconfig @@ -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 diff --git a/arch/powerpc/platforms/pasemi/Kconfig b/arch/powerpc/platforms/pasemi/Kconfig index 95cd90fd81..117d90aa50 100644 --- a/arch/powerpc/platforms/pasemi/Kconfig +++ b/arch/powerpc/platforms/pasemi/Kconfig @@ -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 diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c index 25a81f73ce..8de29f28b4 100644 --- a/arch/powerpc/sysdev/mpic.c +++ b/arch/powerpc/sysdev/mpic.c @@ -228,8 +228,13 @@ 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; - return _mpic_read(mpic->reg_type, &mpic->isus[isu], - reg + (idx * MPIC_INFO(IRQ_STRIDE))); +#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))); } static inline void _mpic_irq_write(struct mpic *mpic, unsigned int src_no, @@ -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)) diff --git a/include/asm-powerpc/mpic.h b/include/asm-powerpc/mpic.h index 0eb3ab9ec2..edb4a7c845 100644 --- a/include/asm-powerpc/mpic.h +++ b/include/asm-powerpc/mpic.h @@ -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; -- 2.39.5