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Message-Id: <1383164736-1849-4-git-send-email-sboyd@codeaurora.org>
Date: Wed, 30 Oct 2013 13:25:33 -0700
From: Stephen Boyd <sboyd@...eaurora.org>
To: linux-edac@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
Mark Rutland <mark.rutland@....com>,
Russell King <linux@....linux.org.uk>
Subject: [PATCH v2 3/6] ARM: Add Krait L2 accessor functions
Qualcomm's 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@....com>
Cc: Russell King <linux@....linux.org.uk>
Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
---
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 c3a4e9c..9da52dc 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 8c60f47..606131a 100644
--- a/arch/arm/common/Makefile
+++ b/arch/arm/common/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_ICST) += icst.o
obj-$(CONFIG_SA1111) += sa1111.o
obj-$(CONFIG_PCI_HOST_VIA82C505) += via82c505.o
obj-$(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 0000000..f17c361
--- /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 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(set_l2_indirect_reg);
+
+u32 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(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 0000000..d5305c4
--- /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 set_l2_indirect_reg(u32 addr, u32 val);
+extern u32 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
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