diff options
| author | Stephen Boyd <sboyd@codeaurora.org> | 2018-08-14 17:42:20 +0530 |
|---|---|---|
| committer | Stephen Boyd <sboyd@kernel.org> | 2018-10-17 13:14:33 -0700 |
| commit | 36d68f64c411e09788687d5919886aadeb92adca (patch) | |
| tree | 4f7f19217073c5fa8804358c7bbb8d1407b35c0b | |
| parent | 5b394b2ddf0347bef56e50c69a58773c94343ff3 (diff) | |
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 <mark.rutland@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Tested-by: Craig Tatlor <ctatlor97@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
| -rw-r--r-- | arch/arm/common/Kconfig | 3 | ||||
| -rw-r--r-- | arch/arm/common/Makefile | 1 | ||||
| -rw-r--r-- | arch/arm/common/krait-l2-accessors.c | 48 | ||||
| -rw-r--r-- | arch/arm/include/asm/krait-l2-accessors.h | 9 |
4 files changed, 61 insertions, 0 deletions
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 <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..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 |