Commit 36d68f64 authored by Stephen Boyd's avatar Stephen Boyd Committed by Stephen Boyd

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: default avatarBjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarSricharan R <sricharan@codeaurora.org>
Tested-by: default avatarCraig Tatlor <ctatlor97@gmail.com>
Signed-off-by: default avatarStephen Boyd <sboyd@kernel.org>
parent 5b394b2d
......@@ -7,6 +7,9 @@ config DMABOUNCE
bool
select ZONE_DMA
config KRAIT_L2_ACCESSORS
bool
config SHARP_LOCOMO
bool
......
......@@ -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
......
// 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);
/* 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
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment