From 36d68f64c411e09788687d5919886aadeb92adca Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Tue, 14 Aug 2018 17:42:20 +0530 Subject: ARM: Add Krait L2 register accessor functions Krait CPUs have a handful of L2 cache controller registers that live behind a cp15 based indirection register. First you program the indirection register (l2cpselr) to point the L2 'window' register (l2cpdr) at what you want to read/write. Then you read/write the 'window' register to do what you want. The l2cpselr register is not banked per-cpu so we must lock around accesses to it to prevent other CPUs from re-pointing l2cpdr underneath us. Cc: Mark Rutland Cc: Russell King Acked-by: Bjorn Andersson Signed-off-by: Stephen Boyd Signed-off-by: Sricharan R Tested-by: Craig Tatlor Signed-off-by: Stephen Boyd --- arch/arm/common/Kconfig | 3 ++ arch/arm/common/Makefile | 1 + arch/arm/common/krait-l2-accessors.c | 48 +++++++++++++++++++++++++++++++ arch/arm/include/asm/krait-l2-accessors.h | 9 ++++++ 4 files changed, 61 insertions(+) create mode 100644 arch/arm/common/krait-l2-accessors.c create mode 100644 arch/arm/include/asm/krait-l2-accessors.h diff --git a/arch/arm/common/Kconfig b/arch/arm/common/Kconfig index e5ad0708849a..c8e198631d41 100644 --- a/arch/arm/common/Kconfig +++ b/arch/arm/common/Kconfig @@ -7,6 +7,9 @@ config DMABOUNCE bool select ZONE_DMA +config KRAIT_L2_ACCESSORS + bool + config SHARP_LOCOMO bool diff --git a/arch/arm/common/Makefile b/arch/arm/common/Makefile index 3157be413297..219a260bbe5f 100644 --- a/arch/arm/common/Makefile +++ b/arch/arm/common/Makefile @@ -7,6 +7,7 @@ obj-y += firmware.o obj-$(CONFIG_SA1111) += sa1111.o obj-$(CONFIG_DMABOUNCE) += dmabounce.o +obj-$(CONFIG_KRAIT_L2_ACCESSORS) += krait-l2-accessors.o obj-$(CONFIG_SHARP_LOCOMO) += locomo.o obj-$(CONFIG_SHARP_PARAM) += sharpsl_param.o obj-$(CONFIG_SHARP_SCOOP) += scoop.o diff --git a/arch/arm/common/krait-l2-accessors.c b/arch/arm/common/krait-l2-accessors.c new file mode 100644 index 000000000000..9a97ddadecd6 --- /dev/null +++ b/arch/arm/common/krait-l2-accessors.c @@ -0,0 +1,48 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018, The Linux Foundation. All rights reserved. + +#include +#include + +#include +#include + +static DEFINE_RAW_SPINLOCK(krait_l2_lock); + +void krait_set_l2_indirect_reg(u32 addr, u32 val) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&krait_l2_lock, flags); + /* + * Select the L2 window by poking l2cpselr, then write to the window + * via l2cpdr. + */ + asm volatile ("mcr p15, 3, %0, c15, c0, 6 @ l2cpselr" : : "r" (addr)); + isb(); + asm volatile ("mcr p15, 3, %0, c15, c0, 7 @ l2cpdr" : : "r" (val)); + isb(); + + raw_spin_unlock_irqrestore(&krait_l2_lock, flags); +} +EXPORT_SYMBOL(krait_set_l2_indirect_reg); + +u32 krait_get_l2_indirect_reg(u32 addr) +{ + u32 val; + unsigned long flags; + + raw_spin_lock_irqsave(&krait_l2_lock, flags); + /* + * Select the L2 window by poking l2cpselr, then read from the window + * via l2cpdr. + */ + asm volatile ("mcr p15, 3, %0, c15, c0, 6 @ l2cpselr" : : "r" (addr)); + isb(); + asm volatile ("mrc p15, 3, %0, c15, c0, 7 @ l2cpdr" : "=r" (val)); + + raw_spin_unlock_irqrestore(&krait_l2_lock, flags); + + return val; +} +EXPORT_SYMBOL(krait_get_l2_indirect_reg); diff --git a/arch/arm/include/asm/krait-l2-accessors.h b/arch/arm/include/asm/krait-l2-accessors.h new file mode 100644 index 000000000000..a5f2cdd6445f --- /dev/null +++ b/arch/arm/include/asm/krait-l2-accessors.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __ASMARM_KRAIT_L2_ACCESSORS_H +#define __ASMARM_KRAIT_L2_ACCESSORS_H + +extern void krait_set_l2_indirect_reg(u32 addr, u32 val); +extern u32 krait_get_l2_indirect_reg(u32 addr); + +#endif -- cgit