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 <mark.rutland@xxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxxx> Cc: Courtney Cavin <courtney.cavin@xxxxxxxxxxxxxx> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> --- arch/arm/common/Kconfig | 3 ++ arch/arm/common/Makefile | 1 + arch/arm/common/krait-l2-accessors.c | 58 +++++++++++++++++++++++++++++++ arch/arm/include/asm/krait-l2-accessors.h | 20 +++++++++++ 4 files changed, 82 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 c3a4e9ceba34..9da52dc6260b 100644 --- a/arch/arm/common/Kconfig +++ b/arch/arm/common/Kconfig @@ -9,6 +9,9 @@ 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 70b1eff477b3..6b2cddf6e8d0 100644 --- a/arch/arm/common/Makefile +++ b/arch/arm/common/Makefile @@ -7,6 +7,7 @@ obj-y += firmware.o obj-$(CONFIG_ICST) += icst.o obj-$(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..5d514bbc88a6 --- /dev/null +++ b/arch/arm/common/krait-l2-accessors.c @@ -0,0 +1,58 @@ +/* + * Copyright (c) 2011-2013, The Linux Foundation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/spinlock.h> +#include <linux/export.h> + +#include <asm/barrier.h> +#include <asm/krait-l2-accessors.h> + +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..48fe5527bc01 --- /dev/null +++ b/arch/arm/include/asm/krait-l2-accessors.h @@ -0,0 +1,20 @@ +/* + * Copyright (c) 2011-2013, The Linux Foundation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#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 -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html