[PATCH v2 0/5] ARM: vexpress: TC2 MCPM/SPC again, the complete series

[PATCH v2 0/5] ARM: vexpress: TC2 MCPM/SPC again, the complete series

[Pawel Moll]

Hi Olof,

A couple of iterations later and it seems we have solution.
SCC bindings are back and SPC driver is simply getting
the base address from the TC2 PM code during the initialization.

That way we've got clean situation now, and can make proper
MFD driver for SCC in future. As I said - all your changes are folded
into the original patches.

Lorenzo tested the series and it still works, so this time (hopefully)
we're ready for 3.12...

The following changes since commit 3b2f64d00c46e1e4e9bd0bb9bb12619adac27a4b:

  Linux 3.11-rc2 (2013-07-21 12:05:29 -0700)

are available in the git repository at:

  git://git.linaro.org/people/pawelmoll/linux.git tags/tc2-pm

for you to fetch changes up to e607b0f985f5277324e3fdce5bb462ef4eac4bc9:

  ARM: vexpress/TC2: implement PM suspend method (2013-08-07 14:55:54 +0100)

----------------------------------------------------------------
>From Nicolas Pitre:
- Fixes to the existing Vexpress DCSCB backend.

- Lorenzo's minimal SPC driver required by the TC2 MCPM backend.

- The MCPM backend enabling SMP secondary boot and CPU hotplug
  on the VExpress TC2 big.LITTLE platform.

- MCPM suspend method to the TC2 backend allowing basic CPU
  idle/suspend.  The cpuidle driver that hooks into this will be
  submitted separately.

----------------------------------------------------------------
Lorenzo Pieralisi (1):
  ARM: vexpress/TC2: add Serial Power Controller (SPC) support

Nicolas Pitre (3):
  ARM: vexpress/dcscb: fix cache disabling sequences
  ARM: vexpress/TC2: basic PM support
  ARM: vexpress/TC2: implement PM suspend method

Pawel Moll (1):
  ARM: vexpress: Add SCC to V2P-CA15_A7's device tree

 .../devicetree/bindings/arm/vexpress-scc.txt       |  33 ++
 arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts         |   6 +
 arch/arm/mach-vexpress/Kconfig                     |   8 +
 arch/arm/mach-vexpress/Makefile                    |   1 +
 arch/arm/mach-vexpress/dcscb.c                     |  58 ++--
 arch/arm/mach-vexpress/spc.c                       | 180 +++++++++++
 arch/arm/mach-vexpress/spc.h                       |  24 ++
 arch/arm/mach-vexpress/tc2_pm.c                    | 344 +++++++++++++++++++++
 8 files changed, 633 insertions(+), 21 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/arm/vexpress-scc.txt
 create mode 100644 arch/arm/mach-vexpress/spc.c
 create mode 100644 arch/arm/mach-vexpress/spc.h
 create mode 100644 arch/arm/mach-vexpress/tc2_pm.c

-- 
1.8.1.2

[PATCH v2 1/5] ARM: vexpress/dcscb: fix cache disabling sequences

[Pawel Moll]

From: Nicolas Pitre <nicolas.pitre@linaro.org>

Unlike real A15/A7's, the RTSM simulation doesn't appear to hit the
cache when the CTRL.C bit is cleared.  Let's ensure there is no memory
access within the disable and flush cache sequence, including to the
stack.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
---
 arch/arm/mach-vexpress/dcscb.c | 58 +++++++++++++++++++++++++++---------------
 1 file changed, 37 insertions(+), 21 deletions(-)

diff --git a/arch/arm/mach-vexpress/dcscb.c b/arch/arm/mach-vexpress/dcscb.c
index 16d57a8..85fffa7 100644
--- a/arch/arm/mach-vexpress/dcscb.c
+++ b/arch/arm/mach-vexpress/dcscb.c
@@ -136,14 +136,29 @@ static void dcscb_power_down(void)
 		/*
 		 * Flush all cache levels for this cluster.
 		 *
-		 * A15/A7 can hit in the cache with SCTLR.C=0, so we don't need
-		 * a preliminary flush here for those CPUs.  At least, that's
-		 * the theory -- without the extra flush, Linux explodes on
-		 * RTSM (to be investigated).
+		 * To do so we do:
+		 * - Clear the SCTLR.C bit to prevent further cache allocations
+		 * - Flush the whole cache
+		 * - Clear the ACTLR "SMP" bit to disable local coherency
+		 *
+		 * Let's do it in the safest possible way i.e. with
+		 * no memory access within the following sequence
+		 * including to the stack.
 		 */
-		flush_cache_all();
-		set_cr(get_cr() & ~CR_C);
-		flush_cache_all();
+		asm volatile(
+		"mrc	p15, 0, r0, c1, c0, 0	@ get CR \n\t"
+		"bic	r0, r0, #"__stringify(CR_C)" \n\t"
+		"mcr	p15, 0, r0, c1, c0, 0	@ set CR \n\t"
+		"isb	\n\t"
+		"bl	v7_flush_dcache_all \n\t"
+		"clrex	\n\t"
+		"mrc	p15, 0, r0, c1, c0, 1	@ get AUXCR \n\t"
+		"bic	r0, r0, #(1 << 6)	@ disable local coherency \n\t"
+		"mcr	p15, 0, r0, c1, c0, 1	@ set AUXCR \n\t"
+		"isb	\n\t"
+		"dsb	"
+		: : : "r0","r1","r2","r3","r4","r5","r6","r7",
+		      "r9","r10","r11","lr","memory");
 
 		/*
 		 * This is a harmless no-op.  On platforms with a real
@@ -152,9 +167,6 @@ static void dcscb_power_down(void)
 		 */
 		outer_flush_all();
 
-		/* Disable local coherency by clearing the ACTLR "SMP" bit: */
-		set_auxcr(get_auxcr() & ~(1 << 6));
-
 		/*
 		 * Disable cluster-level coherency by masking
 		 * incoming snoops and DVM messages:
@@ -167,18 +179,22 @@ static void dcscb_power_down(void)
 
 		/*
 		 * Flush the local CPU cache.
-		 *
-		 * A15/A7 can hit in the cache with SCTLR.C=0, so we don't need
-		 * a preliminary flush here for those CPUs.  At least, that's
-		 * the theory -- without the extra flush, Linux explodes on
-		 * RTSM (to be investigated).
+		 * Let's do it in the safest possible way as above.
 		 */
-		flush_cache_louis();
-		set_cr(get_cr() & ~CR_C);
-		flush_cache_louis();
-
-		/* Disable local coherency by clearing the ACTLR "SMP" bit: */
-		set_auxcr(get_auxcr() & ~(1 << 6));
+		asm volatile(
+		"mrc	p15, 0, r0, c1, c0, 0	@ get CR \n\t"
+		"bic	r0, r0, #"__stringify(CR_C)" \n\t"
+		"mcr	p15, 0, r0, c1, c0, 0	@ set CR \n\t"
+		"isb	\n\t"
+		"bl	v7_flush_dcache_louis \n\t"
+		"clrex	\n\t"
+		"mrc	p15, 0, r0, c1, c0, 1	@ get AUXCR \n\t"
+		"bic	r0, r0, #(1 << 6)	@ disable local coherency \n\t"
+		"mcr	p15, 0, r0, c1, c0, 1	@ set AUXCR \n\t"
+		"isb	\n\t"
+		"dsb	"
+		: : : "r0","r1","r2","r3","r4","r5","r6","r7",
+		      "r9","r10","r11","lr","memory");
 	}
 
 	__mcpm_cpu_down(cpu, cluster);
-- 
1.8.1.2

[PATCH v2 2/5] ARM: vexpress/TC2: add Serial Power Controller (SPC) support

[Pawel Moll]

From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

The TC2 versatile express core tile integrates a logic block that provides
the interface between the dual cluster test-chip and the M3 microcontroller
that carries out power management. The logic block, called Serial Power
Controller (SPC), contains several memory mapped registers to control among
other things low-power states, wake-up irqs and per-CPU jump addresses
registers.

This patch provides a driver that enables run-time control of features
implemented by the SPC power management control logic with an API to
be used by different subsystem drivers on top.

The SPC control logic is required to be programmed very early in the boot
process to reset secondary CPUs on the TC2 testchip, set-up jump addresses
and wake-up IRQs for power management. Hence, waiting for core changes to
be made in the device core code to enable early registration of platform
devices, the driver puts in place an early init scheme that allows kernel
drivers to initialize the SPC driver directly from the components requiring
it, if their initialization routine is called before this driver init
function during the boot process.

Device tree bindings documentation for the SPC component is also provided.

Cc: Olof Johansson <olof@lixom.net>
Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
Acked-by: Pawel Moll <pawel.moll@arm.com>
[ np: moved from drivers/mfd/ to drivers/platform/vexpress/ ]
Signed-off-by: Nicolas Pitre <nico@linaro.org>
[ PM: moved again to arch/arm/mach-vexpress, requested by Olof ]
[ PM: removed useless printk, from Olof ]
[ PM: made the driver SPC-only ]
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
---
 arch/arm/mach-vexpress/spc.c | 180 +++++++++++++++++++++++++++++++++++++++++++
 arch/arm/mach-vexpress/spc.h |  24 ++++++
 2 files changed, 204 insertions(+)
 create mode 100644 arch/arm/mach-vexpress/spc.c
 create mode 100644 arch/arm/mach-vexpress/spc.h

diff --git a/arch/arm/mach-vexpress/spc.c b/arch/arm/mach-vexpress/spc.c
new file mode 100644
index 0000000..eefb029
--- /dev/null
+++ b/arch/arm/mach-vexpress/spc.c
@@ -0,0 +1,180 @@
+/*
+ * Versatile Express Serial Power Controller (SPC) support
+ *
+ * Copyright (C) 2013 ARM Ltd.
+ *
+ * Authors: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
+ *          Achin Gupta           <achin.gupta@arm.com>
+ *          Lorenzo Pieralisi     <lorenzo.pieralisi@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+
+#include <asm/cacheflush.h>
+
+#define SPCLOG "vexpress-spc: "
+
+/* SPC wake-up IRQs status and mask */
+#define WAKE_INT_MASK		0x24
+#define WAKE_INT_RAW		0x28
+#define WAKE_INT_STAT		0x2c
+/* SPC power down registers */
+#define A15_PWRDN_EN		0x30
+#define A7_PWRDN_EN		0x34
+/* SPC per-CPU mailboxes */
+#define A15_BX_ADDR0		0x68
+#define A7_BX_ADDR0		0x78
+
+/* wake-up interrupt masks */
+#define GBL_WAKEUP_INT_MSK	(0x3 << 10)
+
+/* TC2 static dual-cluster configuration */
+#define MAX_CLUSTERS		2
+
+struct ve_spc_drvdata {
+	void __iomem *baseaddr;
+	/*
+	 * A15s cluster identifier
+	 * It corresponds to A15 processors MPIDR[15:8] bitfield
+	 */
+	u32 a15_clusid;
+};
+
+static struct ve_spc_drvdata *info;
+
+static inline bool cluster_is_a15(u32 cluster)
+{
+	return cluster == info->a15_clusid;
+}
+
+/**
+ * ve_spc_global_wakeup_irq()
+ *
+ * Function to set/clear global wakeup IRQs. Not protected by locking since
+ * it might be used in code paths where normal cacheable locks are not
+ * working. Locking must be provided by the caller to ensure atomicity.
+ *
+ * @set: if true, global wake-up IRQs are set, if false they are cleared
+ */
+void ve_spc_global_wakeup_irq(bool set)
+{
+	u32 reg;
+
+	reg = readl_relaxed(info->baseaddr + WAKE_INT_MASK);
+
+	if (set)
+		reg |= GBL_WAKEUP_INT_MSK;
+	else
+		reg &= ~GBL_WAKEUP_INT_MSK;
+
+	writel_relaxed(reg, info->baseaddr + WAKE_INT_MASK);
+}
+
+/**
+ * ve_spc_cpu_wakeup_irq()
+ *
+ * Function to set/clear per-CPU wake-up IRQs. Not protected by locking since
+ * it might be used in code paths where normal cacheable locks are not
+ * working. Locking must be provided by the caller to ensure atomicity.
+ *
+ * @cluster: mpidr[15:8] bitfield describing cluster affinity level
+ * @cpu: mpidr[7:0] bitfield describing cpu affinity level
+ * @set: if true, wake-up IRQs are set, if false they are cleared
+ */
+void ve_spc_cpu_wakeup_irq(u32 cluster, u32 cpu, bool set)
+{
+	u32 mask, reg;
+
+	if (cluster >= MAX_CLUSTERS)
+		return;
+
+	mask = 1 << cpu;
+
+	if (!cluster_is_a15(cluster))
+		mask <<= 4;
+
+	reg = readl_relaxed(info->baseaddr + WAKE_INT_MASK);
+
+	if (set)
+		reg |= mask;
+	else
+		reg &= ~mask;
+
+	writel_relaxed(reg, info->baseaddr + WAKE_INT_MASK);
+}
+
+/**
+ * ve_spc_set_resume_addr() - set the jump address used for warm boot
+ *
+ * @cluster: mpidr[15:8] bitfield describing cluster affinity level
+ * @cpu: mpidr[7:0] bitfield describing cpu affinity level
+ * @addr: physical resume address
+ */
+void ve_spc_set_resume_addr(u32 cluster, u32 cpu, u32 addr)
+{
+	void __iomem *baseaddr;
+
+	if (cluster >= MAX_CLUSTERS)
+		return;
+
+	if (cluster_is_a15(cluster))
+		baseaddr = info->baseaddr + A15_BX_ADDR0 + (cpu << 2);
+	else
+		baseaddr = info->baseaddr + A7_BX_ADDR0 + (cpu << 2);
+
+	writel_relaxed(addr, baseaddr);
+}
+
+/**
+ * ve_spc_powerdown()
+ *
+ * Function to enable/disable cluster powerdown. Not protected by locking
+ * since it might be used in code paths where normal cacheable locks are not
+ * working. Locking must be provided by the caller to ensure atomicity.
+ *
+ * @cluster: mpidr[15:8] bitfield describing cluster affinity level
+ * @enable: if true enables powerdown, if false disables it
+ */
+void ve_spc_powerdown(u32 cluster, bool enable)
+{
+	u32 pwdrn_reg;
+
+	if (cluster >= MAX_CLUSTERS)
+		return;
+
+	pwdrn_reg = cluster_is_a15(cluster) ? A15_PWRDN_EN : A7_PWRDN_EN;
+	writel_relaxed(enable, info->baseaddr + pwdrn_reg);
+}
+
+int __init ve_spc_init(void __iomem *baseaddr, u32 a15_clusid)
+{
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		pr_err(SPCLOG "unable to allocate mem\n");
+		return -ENOMEM;
+	}
+
+	info->baseaddr = baseaddr;
+	info->a15_clusid = a15_clusid;
+
+	/*
+	 * Multi-cluster systems may need this data when non-coherent, during
+	 * cluster power-up/power-down. Make sure driver info reaches main
+	 * memory.
+	 */
+	sync_cache_w(info);
+	sync_cache_w(&info);
+
+	return 0;
+}
diff --git a/arch/arm/mach-vexpress/spc.h b/arch/arm/mach-vexpress/spc.h
new file mode 100644
index 0000000..5f7e4a4
--- /dev/null
+++ b/arch/arm/mach-vexpress/spc.h
@@ -0,0 +1,24 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License 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.
+ *
+ * Copyright (C) 2012 ARM Limited
+ */
+
+
+#ifndef __SPC_H_
+#define __SPC_H_
+
+int __init ve_spc_init(void __iomem *base, u32 a15_clusid);
+void ve_spc_global_wakeup_irq(bool set);
+void ve_spc_cpu_wakeup_irq(u32 cluster, u32 cpu, bool set);
+void ve_spc_set_resume_addr(u32 cluster, u32 cpu, u32 addr);
+void ve_spc_powerdown(u32 cluster, bool enable);
+
+#endif
-- 
1.8.1.2

[PATCH v2 3/5] ARM: vexpress: Add SCC to V2P-CA15_A7's device tree

[Pawel Moll]

SCC (Serial Configuration Controller) is used to set initial
conditions for the test chip (TC2). Its registers are also mapped
in normal address space and used to obtain runtime information
and for power management.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
---
 .../devicetree/bindings/arm/vexpress-scc.txt       | 33 ++++++++++++++++++++++
 arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts         |  6 ++++
 2 files changed, 39 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/vexpress-scc.txt

diff --git a/Documentation/devicetree/bindings/arm/vexpress-scc.txt b/Documentation/devicetree/bindings/arm/vexpress-scc.txt
new file mode 100644
index 0000000..ae5043e4
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/vexpress-scc.txt
@@ -0,0 +1,33 @@
+ARM Versatile Express Serial Configuration Controller
+-----------------------------------------------------
+
+Test chips for ARM Versatile Express platform implement SCC (Serial
+Configuration Controller) interface, used to set initial conditions
+for the test chip.
+
+In some cases its registers are also mapped in normal address space
+and can be used to obtain runtime information about the chip internals
+(like silicon temperature sensors) and as interface to other subsystems
+like platform configuration control and power management.
+
+Required properties:
+
+- compatible value: "arm,vexpress-scc,<model>", "arm,vexpress-scc";
+		    where <model> is the full tile model name (as used
+		    in the tile's Technical Reference Manual),
+		    eg. for Coretile Express A15x2 A7x3 (V2P-CA15_A7):
+	compatible = "arm,vexpress-scc,v2p-ca15_a7", "arm,vexpress-scc";
+
+Optional properties:
+
+- reg: when the SCC is memory mapped, physical address and size of the
+       registers window
+- interrupts: when the SCC can generate a system-level interrupt
+
+Example:
+
+	scc at 7fff0000 {
+		compatible = "arm,vexpress-scc,v2p-ca15_a7", "arm,vexpress-scc";
+		reg = <0 0x7fff0000 0 0x1000>;
+		interrupts = <0 95 4>;
+	};
diff --git a/arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts b/arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts
index d2803be..759b0cd 100644
--- a/arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts
+++ b/arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts
@@ -125,6 +125,12 @@
 		clock-names = "apb_pclk";
 	};
 
+        scc at 7fff0000 {
+		compatible = "arm,vexpress-scc,v2p-ca15_a7", "arm,vexpress-scc";
+		reg = <0 0x7fff0000 0 0x1000>;
+		interrupts = <0 95 4>;
+        };
+
 	timer {
 		compatible = "arm,armv7-timer";
 		interrupts = <1 13 0xf08>,
-- 
1.8.1.2

[PATCH v2 4/5] ARM: vexpress/TC2: basic PM support

[Pawel Moll]

From: Nicolas Pitre <nico@linaro.org>

This is the MCPM backend for the Virtual Express A15x2 A7x3 CoreTile
aka TC2.  This provides cluster management for SMP secondary boot and
CPU hotplug.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Pawel Moll <pawel.moll@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
[PM: made it drive SCC registers directly and provide base for SPC]
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
---
 arch/arm/mach-vexpress/Kconfig  |   8 +
 arch/arm/mach-vexpress/Makefile |   1 +
 arch/arm/mach-vexpress/tc2_pm.c | 327 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 336 insertions(+)
 create mode 100644 arch/arm/mach-vexpress/tc2_pm.c

diff --git a/arch/arm/mach-vexpress/Kconfig b/arch/arm/mach-vexpress/Kconfig
index b8bbabe..c700e62 100644
--- a/arch/arm/mach-vexpress/Kconfig
+++ b/arch/arm/mach-vexpress/Kconfig
@@ -66,4 +66,12 @@ config ARCH_VEXPRESS_DCSCB
 	  This is needed to provide CPU and cluster power management
 	  on RTSM implementing big.LITTLE.
 
+config ARCH_VEXPRESS_TC2_PM
+	bool "Versatile Express TC2 power management"
+	depends on MCPM
+	select ARM_CCI
+	help
+	  Support for CPU and cluster power management on Versatile Express
+	  with a TC2 (A15x2 A7x3) big.LITTLE core tile.
+
 endmenu
diff --git a/arch/arm/mach-vexpress/Makefile b/arch/arm/mach-vexpress/Makefile
index 48ba89a..36ea824 100644
--- a/arch/arm/mach-vexpress/Makefile
+++ b/arch/arm/mach-vexpress/Makefile
@@ -7,5 +7,6 @@ ccflags-$(CONFIG_ARCH_MULTIPLATFORM) := -I$(srctree)/$(src)/include \
 obj-y					:= v2m.o
 obj-$(CONFIG_ARCH_VEXPRESS_CA9X4)	+= ct-ca9x4.o
 obj-$(CONFIG_ARCH_VEXPRESS_DCSCB)	+= dcscb.o	dcscb_setup.o
+obj-$(CONFIG_ARCH_VEXPRESS_TC2_PM)	+= tc2_pm.o spc.o
 obj-$(CONFIG_SMP)			+= platsmp.o
 obj-$(CONFIG_HOTPLUG_CPU)		+= hotplug.o
diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c
new file mode 100644
index 0000000..cdc6068
--- /dev/null
+++ b/arch/arm/mach-vexpress/tc2_pm.c
@@ -0,0 +1,327 @@
+/*
+ * arch/arm/mach-vexpress/tc2_pm.c - TC2 power management support
+ *
+ * Created by:	Nicolas Pitre, October 2012
+ * Copyright:	(C) 2012-2013  Linaro Limited
+ *
+ * Some portions of this file were originally written by Achin Gupta
+ * Copyright:   (C) 2012  ARM Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/of_address.h>
+#include <linux/spinlock.h>
+#include <linux/errno.h>
+
+#include <asm/mcpm.h>
+#include <asm/proc-fns.h>
+#include <asm/cacheflush.h>
+#include <asm/cputype.h>
+#include <asm/cp15.h>
+
+#include <linux/arm-cci.h>
+
+#include "spc.h"
+
+/* SCC conf registers */
+#define A15_CONF		0x400
+#define A7_CONF			0x500
+#define SYS_INFO		0x700
+#define SPC_BASE		0xb00
+
+/*
+ * We can't use regular spinlocks. In the switcher case, it is possible
+ * for an outbound CPU to call power_down() after its inbound counterpart
+ * is already live using the same logical CPU number which trips lockdep
+ * debugging.
+ */
+static arch_spinlock_t tc2_pm_lock = __ARCH_SPIN_LOCK_UNLOCKED;
+
+#define TC2_CLUSTERS			2
+#define TC2_MAX_CPUS_PER_CLUSTER	3
+
+static unsigned int tc2_nr_cpus[TC2_CLUSTERS];
+
+/* Keep per-cpu usage count to cope with unordered up/down requests */
+static int tc2_pm_use_count[TC2_MAX_CPUS_PER_CLUSTER][TC2_CLUSTERS];
+
+#define tc2_cluster_unused(cluster) \
+	(!tc2_pm_use_count[0][cluster] && \
+	 !tc2_pm_use_count[1][cluster] && \
+	 !tc2_pm_use_count[2][cluster])
+
+static int tc2_pm_power_up(unsigned int cpu, unsigned int cluster)
+{
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+	if (cluster >= TC2_CLUSTERS || cpu >= tc2_nr_cpus[cluster])
+		return -EINVAL;
+
+	/*
+	 * Since this is called with IRQs enabled, and no arch_spin_lock_irq
+	 * variant exists, we need to disable IRQs manually here.
+	 */
+	local_irq_disable();
+	arch_spin_lock(&tc2_pm_lock);
+
+	if (tc2_cluster_unused(cluster))
+		ve_spc_powerdown(cluster, false);
+
+	tc2_pm_use_count[cpu][cluster]++;
+	if (tc2_pm_use_count[cpu][cluster] == 1) {
+		ve_spc_set_resume_addr(cluster, cpu,
+				       virt_to_phys(mcpm_entry_point));
+		ve_spc_cpu_wakeup_irq(cluster, cpu, true);
+	} else if (tc2_pm_use_count[cpu][cluster] != 2) {
+		/*
+		 * The only possible values are:
+		 * 0 = CPU down
+		 * 1 = CPU (still) up
+		 * 2 = CPU requested to be up before it had a chance
+		 *     to actually make itself down.
+		 * Any other value is a bug.
+		 */
+		BUG();
+	}
+
+	arch_spin_unlock(&tc2_pm_lock);
+	local_irq_enable();
+
+	return 0;
+}
+
+static void tc2_pm_power_down(void)
+{
+	unsigned int mpidr, cpu, cluster;
+	bool last_man = false, skip_wfi = false;
+
+	mpidr = read_cpuid_mpidr();
+	cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+	cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+	BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER);
+
+	__mcpm_cpu_going_down(cpu, cluster);
+
+	arch_spin_lock(&tc2_pm_lock);
+	BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
+	tc2_pm_use_count[cpu][cluster]--;
+	if (tc2_pm_use_count[cpu][cluster] == 0) {
+		ve_spc_cpu_wakeup_irq(cluster, cpu, true);
+		if (tc2_cluster_unused(cluster)) {
+			ve_spc_powerdown(cluster, true);
+			ve_spc_global_wakeup_irq(true);
+			last_man = true;
+		}
+	} else if (tc2_pm_use_count[cpu][cluster] == 1) {
+		/*
+		 * A power_up request went ahead of us.
+		 * Even if we do not want to shut this CPU down,
+		 * the caller expects a certain state as if the WFI
+		 * was aborted.  So let's continue with cache cleaning.
+		 */
+		skip_wfi = true;
+	} else
+		BUG();
+
+	if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) {
+		arch_spin_unlock(&tc2_pm_lock);
+
+		if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A15) {
+			/*
+			 * On the Cortex-A15 we need to disable
+			 * L2 prefetching before flushing the cache.
+			 */
+			asm volatile(
+			"mcr	p15, 1, %0, c15, c0, 3 \n\t"
+			"isb	\n\t"
+			"dsb	"
+			: : "r" (0x400) );
+		}
+
+		/*
+		 * We need to disable and flush the whole (L1 and L2) cache.
+		 * Let's do it in the safest possible way i.e. with
+		 * no memory access within the following sequence
+		 * including the stack.
+		 */
+		asm volatile(
+		"mrc	p15, 0, r0, c1, c0, 0	@ get CR \n\t"
+		"bic	r0, r0, #"__stringify(CR_C)" \n\t"
+		"mcr	p15, 0, r0, c1, c0, 0	@ set CR \n\t"
+		"isb	\n\t"
+		"bl	v7_flush_dcache_all \n\t"
+		"clrex	\n\t"
+		"mrc	p15, 0, r0, c1, c0, 1	@ get AUXCR \n\t"
+		"bic	r0, r0, #(1 << 6)	@ disable local coherency \n\t"
+		"mcr	p15, 0, r0, c1, c0, 1	@ set AUXCR \n\t"
+		"isb	\n\t"
+		"dsb	"
+		: : : "r0","r1","r2","r3","r4","r5","r6","r7",
+		      "r9","r10","r11","lr","memory");
+
+		cci_disable_port_by_cpu(mpidr);
+
+		__mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN);
+	} else {
+		/*
+		 * If last man then undo any setup done previously.
+		 */
+		if (last_man) {
+			ve_spc_powerdown(cluster, false);
+			ve_spc_global_wakeup_irq(false);
+		}
+
+		arch_spin_unlock(&tc2_pm_lock);
+
+		/*
+		 * We need to disable and flush only the L1 cache.
+		 * Let's do it in the safest possible way as above.
+		 */
+		asm volatile(
+		"mrc	p15, 0, r0, c1, c0, 0	@ get CR \n\t"
+		"bic	r0, r0, #"__stringify(CR_C)" \n\t"
+		"mcr	p15, 0, r0, c1, c0, 0	@ set CR \n\t"
+		"isb	\n\t"
+		"bl	v7_flush_dcache_louis \n\t"
+		"clrex	\n\t"
+		"mrc	p15, 0, r0, c1, c0, 1	@ get AUXCR \n\t"
+		"bic	r0, r0, #(1 << 6)	@ disable local coherency \n\t"
+		"mcr	p15, 0, r0, c1, c0, 1	@ set AUXCR \n\t"
+		"isb	\n\t"
+		"dsb	"
+		: : : "r0","r1","r2","r3","r4","r5","r6","r7",
+		      "r9","r10","r11","lr","memory");
+	}
+
+	__mcpm_cpu_down(cpu, cluster);
+
+	/* Now we are prepared for power-down, do it: */
+	if (!skip_wfi)
+		wfi();
+
+	/* Not dead@this point?  Let our caller cope. */
+}
+
+static void tc2_pm_powered_up(void)
+{
+	unsigned int mpidr, cpu, cluster;
+	unsigned long flags;
+
+	mpidr = read_cpuid_mpidr();
+	cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+	cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+	BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER);
+
+	local_irq_save(flags);
+	arch_spin_lock(&tc2_pm_lock);
+
+	if (tc2_cluster_unused(cluster)) {
+		ve_spc_powerdown(cluster, false);
+		ve_spc_global_wakeup_irq(false);
+	}
+
+	if (!tc2_pm_use_count[cpu][cluster])
+		tc2_pm_use_count[cpu][cluster] = 1;
+
+	ve_spc_cpu_wakeup_irq(cluster, cpu, false);
+	ve_spc_set_resume_addr(cluster, cpu, 0);
+
+	arch_spin_unlock(&tc2_pm_lock);
+	local_irq_restore(flags);
+}
+
+static const struct mcpm_platform_ops tc2_pm_power_ops = {
+	.power_up	= tc2_pm_power_up,
+	.power_down	= tc2_pm_power_down,
+	.powered_up	= tc2_pm_powered_up,
+};
+
+static bool __init tc2_pm_usage_count_init(void)
+{
+	unsigned int mpidr, cpu, cluster;
+
+	mpidr = read_cpuid_mpidr();
+	cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+	cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+	if (cluster >= TC2_CLUSTERS || cpu >= tc2_nr_cpus[cluster]) {
+		pr_err("%s: boot CPU is out of bound!\n", __func__);
+		return false;
+	}
+	tc2_pm_use_count[cpu][cluster] = 1;
+	return true;
+}
+
+/*
+ * Enable cluster-level coherency, in preparation for turning on the MMU.
+ */
+static void __naked tc2_pm_power_up_setup(unsigned int affinity_level)
+{
+	asm volatile (" \n"
+"	cmp	r0, #1 \n"
+"	bxne	lr \n"
+"	b	cci_enable_port_for_self ");
+}
+
+static int __init tc2_pm_init(void)
+{
+	int ret;
+	void __iomem *scc;
+	u32 a15_cluster_id, a7_cluster_id, sys_info;
+	struct device_node *np;
+
+	/*
+	 * The power management-related features are hidden behind
+	 * SCC registers. We need to extract runtime information like
+	 * cluster ids and number of CPUs really available in clusters.
+	 */
+	np = of_find_compatible_node(NULL, NULL,
+			"arm,vexpress-scc,v2p-ca15_a7");
+	scc = of_iomap(np, 0);
+	if (!scc)
+		return -ENODEV;
+
+	a15_cluster_id = readl_relaxed(scc + A15_CONF) & 0xf;
+	a7_cluster_id = readl_relaxed(scc + A7_CONF) & 0xf;
+	if (a15_cluster_id >= TC2_CLUSTERS || a7_cluster_id >= TC2_CLUSTERS)
+		return -EINVAL;
+
+	sys_info = readl_relaxed(scc + SYS_INFO);
+	tc2_nr_cpus[a15_cluster_id] = (sys_info >> 16) & 0xf;
+	tc2_nr_cpus[a7_cluster_id] = (sys_info >> 20) & 0xf;
+
+	/*
+	 * A subset of the SCC registers is also used to communicate
+	 * with the SPC (power controller). We need to be able to
+	 * drive it very early in the boot process to power up
+	 * processors, so we initialize the SPC driver here.
+	 */
+	ret = ve_spc_init(scc + SPC_BASE, a15_cluster_id);
+	if (ret)
+		return ret;
+
+	if (!cci_probed())
+		return -ENODEV;
+
+	if (!tc2_pm_usage_count_init())
+		return -EINVAL;
+
+	ret = mcpm_platform_register(&tc2_pm_power_ops);
+	if (!ret) {
+		mcpm_sync_init(tc2_pm_power_up_setup);
+		pr_info("TC2 power management initialized\n");
+	}
+	return ret;
+}
+
+early_initcall(tc2_pm_init);
-- 
1.8.1.2

[PATCH v2 5/5] ARM: vexpress/TC2: implement PM suspend method

[Pawel Moll]

From: Nicolas Pitre <nico@linaro.org>

Similar to power_down(), except that for a suspend, the firmware
mailbox address has to be set prior entering low power mode.

The residency argument is not used yet, so the last man always shuts
down the cluster for now.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Pawel Moll <pawel.moll@arm.com>
---
 arch/arm/mach-vexpress/tc2_pm.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c
index cdc6068..ddd97dd 100644
--- a/arch/arm/mach-vexpress/tc2_pm.c
+++ b/arch/arm/mach-vexpress/tc2_pm.c
@@ -95,7 +95,7 @@ static int tc2_pm_power_up(unsigned int cpu, unsigned int cluster)
 	return 0;
 }
 
-static void tc2_pm_power_down(void)
+static void tc2_pm_down(u64 residency)
 {
 	unsigned int mpidr, cpu, cluster;
 	bool last_man = false, skip_wfi = false;
@@ -209,6 +209,22 @@ static void tc2_pm_power_down(void)
 	/* Not dead at this point?  Let our caller cope. */
 }
 
+static void tc2_pm_power_down(void)
+{
+	tc2_pm_down(0);
+}
+
+static void tc2_pm_suspend(u64 residency)
+{
+	unsigned int mpidr, cpu, cluster;
+
+	mpidr = read_cpuid_mpidr();
+	cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+	cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+	ve_spc_set_resume_addr(cluster, cpu, virt_to_phys(mcpm_entry_point));
+	tc2_pm_down(residency);
+}
+
 static void tc2_pm_powered_up(void)
 {
 	unsigned int mpidr, cpu, cluster;
@@ -242,6 +258,7 @@ static void tc2_pm_powered_up(void)
 static const struct mcpm_platform_ops tc2_pm_power_ops = {
 	.power_up	= tc2_pm_power_up,
 	.power_down	= tc2_pm_power_down,
+	.suspend	= tc2_pm_suspend,
 	.powered_up	= tc2_pm_powered_up,
 };
 
-- 
1.8.1.2

[PATCH v2 0/5] ARM: vexpress: TC2 MCPM/SPC again, the complete series

[Olof Johansson]

On Wed, Aug 07, 2013 at 04:09:43PM +0100, Pawel Moll wrote:
> Hi Olof,
> 
> A couple of iterations later and it seems we have solution.
> SCC bindings are back and SPC driver is simply getting
> the base address from the TC2 PM code during the initialization.
> 
> That way we've got clean situation now, and can make proper
> MFD driver for SCC in future. As I said - all your changes are folded
> into the original patches.
> 
> Lorenzo tested the series and it still works, so this time (hopefully)
> we're ready for 3.12...
> 
> The following changes since commit 3b2f64d00c46e1e4e9bd0bb9bb12619adac27a4b:
> 
>   Linux 3.11-rc2 (2013-07-21 12:05:29 -0700)
> 
> are available in the git repository at:
> 
>   git://git.linaro.org/people/pawelmoll/linux.git tags/tc2-pm

Thanks, pulled.


-Olof