From: Scott Moser <smoser@redhat.com>
Date: Thu, 6 Dec 2007 09:14:09 -0500
Subject: [ppc64] spu: add temperature and throttling support
Message-id: Pine.LNX.4.64.0712060911240.19799@squad5-lp1.lab.boston.redhat.com
O-Subject: [PATCH RHEL5u2] bz279171 Cell/B.E. Power and Thermal Management [4/4] [revised]
Bugzilla: 279171

Reposting patch with signed-ness fix suggested by David.

commit b3d7dc1967d1303d4897ff9537d29f6e077de147
Subject: add temperature and throttling support to SPU and CPU

From: Christian Krafft <krafft@linux.ibm.com>
This patch backports the cbe_thermal driver to rhel-5-2 kernel.

It adds a module that registers sysfs attributes to CPU and SPU
containing the temperature and throttling values of the CBE.

They can be found under
/sys/devices/system/spu/cpuX/thermal/*
/sys/devices/system/spu/spuX/thermal/*

The temperature is read from the on-chip temperature sensors.

Signed-off-by: Christian Krafft <krafft@de.ibm.com>

--
 arch/powerpc/configs/cell_defconfig       |    1
 arch/powerpc/platforms/cell/Kconfig       |    5
 arch/powerpc/platforms/cell/Makefile      |    2
 arch/powerpc/platforms/cell/cbe_thermal.c |  384 ++++++++++++++++++++++++
 4 files changed, 392 insertions(+)

Acked-by: David Howells <dhowells@redhat.com>

diff --git a/arch/powerpc/configs/cell_defconfig b/arch/powerpc/configs/cell_defconfig
index 327c2d2..716a840 100644
--- a/arch/powerpc/configs/cell_defconfig
+++ b/arch/powerpc/configs/cell_defconfig
@@ -156,6 +156,7 @@ CONFIG_SPU_FS=m
 CONFIG_SPU_BASE=y
 CONFIG_SPUFS_MMAP=y
 CONFIG_CBE_RAS=y
+CONFIG_CBE_THERM=m
 CONFIG_CBE_CPUFREQ=m
 CONFIG_CBE_CPUFREQ_PMI=m
 
diff --git a/arch/powerpc/platforms/cell/Kconfig b/arch/powerpc/platforms/cell/Kconfig
index e5d2e8c..5e20939 100644
--- a/arch/powerpc/platforms/cell/Kconfig
+++ b/arch/powerpc/platforms/cell/Kconfig
@@ -25,6 +25,11 @@ config CBE_RAS
 	bool "RAS features for bare metal Cell BE"
 	default y
 
+config CBE_THERM
+	tristate "CBE thermal support"
+	default m
+	depends on CBE_RAS
+
 config CBE_CPUFREQ
         tristate "CBE frequency scaling"
         depends on CBE_RAS && CPU_FREQ
diff --git a/arch/powerpc/platforms/cell/Makefile b/arch/powerpc/platforms/cell/Makefile
index 9f671e4..0649f46 100644
--- a/arch/powerpc/platforms/cell/Makefile
+++ b/arch/powerpc/platforms/cell/Makefile
@@ -3,6 +3,8 @@ obj-$(CONFIG_PPC_CELL_NATIVE)		+= interrupt.o iommu.o setup.o \
 					   io-workarounds.o
 obj-$(CONFIG_CBE_RAS)			+= ras.o
 
+obj-$(CONFIG_CBE_THERM)			+= cbe_thermal.o
+
 obj-$(CONFIG_CBE_CPUFREQ_PMI)           += cbe_cpufreq_pmi.o
 obj-$(CONFIG_CBE_CPUFREQ)               += cbe-cpufreq.o
 cbe-cpufreq-y                           += cbe_cpufreq_pervasive.o cbe_cpufreq.o
diff --git a/arch/powerpc/platforms/cell/cbe_thermal.c b/arch/powerpc/platforms/cell/cbe_thermal.c
new file mode 100644
index 0000000..9a27b19
--- /dev/null
+++ b/arch/powerpc/platforms/cell/cbe_thermal.c
@@ -0,0 +1,384 @@
+/*
+ * thermal support for the cell processor
+ *
+ * This module adds some sysfs attributes to cpu and spu nodes.
+ * Base for measurements are the digital thermal sensors (DTS)
+ * located on the chip.
+ * The accuracy is 2 degrees, starting from 65 up to 125 degrees celsius
+ * The attributes can be found under
+ * /sys/devices/system/cpu/cpuX/thermal
+ * /sys/devices/system/spu/spuX/thermal
+ *
+ * The following attributes are added for each node:
+ * temperature:
+ *	contains the current temperature measured by the DTS
+ * throttle_begin:
+ *	throttling begins when temperature is greater or equal to
+ *	throttle_begin. Setting this value to 125 prevents throttling.
+ * throttle_end:
+ *	throttling is being ceased, if the temperature is lower than
+ *	throttle_end. Due to a delay between applying throttling and
+ *	a reduced temperature this value should be less than throttle_begin.
+ *	A value equal to throttle_begin provides only a very little hysteresis.
+ * throttle_full_stop:
+ *	If the temperatrue is greater or equal to throttle_full_stop,
+ *	full throttling is applied to the cpu or spu. This value should be
+ *	greater than throttle_begin and throttle_end. Setting this value to
+ *	65 prevents the unit from running code at all.
+ *
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
+ *
+ * Author: Christian Krafft <krafft@de.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/sysdev.h>
+#include <linux/kernel.h>
+#include <linux/cpu.h>
+#include <asm/spu.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+
+#include "cbe_regs.h"
+#include "spu_priv1_mmio.h"
+
+#define TEMP_MIN 65
+#define TEMP_MAX 125
+
+#define SYSDEV_PREFIX_ATTR(_prefix,_name,_mode)			\
+struct sysdev_attribute attr_ ## _prefix ## _ ## _name = {	\
+	.attr = { .name = __stringify(_name), .mode = _mode },	\
+	.show	= _prefix ## _show_ ## _name,			\
+	.store	= _prefix ## _store_ ## _name,			\
+};
+
+static inline u8 reg_to_temp(u8 reg_value)
+{
+	return ((reg_value & 0x3f) << 1) + TEMP_MIN;
+}
+
+static inline u8 temp_to_reg(u8 temp)
+{
+	return ((temp - TEMP_MIN) >> 1) & 0x3f;
+}
+
+static struct cbe_pmd_regs __iomem *get_pmd_regs(struct sys_device *sysdev)
+{
+	struct spu *spu;
+
+	spu = container_of(sysdev, struct spu, sysdev);
+
+	return cbe_get_pmd_regs(spu_devnode(spu));
+}
+
+/* returns the value for a given spu in a given register */
+static u8 spu_read_register_value(struct sys_device *sysdev, union spe_reg __iomem *reg)
+{
+	union spe_reg value;
+	struct spu *spu;
+
+	spu = container_of(sysdev, struct spu, sysdev);
+	value.val = in_be64(&reg->val);
+
+	return value.spe[spu->spe_id];
+}
+
+static ssize_t spu_show_temp(struct sys_device *sysdev, char *buf)
+{
+	u8 value;
+	struct cbe_pmd_regs __iomem *pmd_regs;
+
+	pmd_regs = get_pmd_regs(sysdev);
+
+	value = spu_read_register_value(sysdev, &pmd_regs->ts_ctsr1);
+
+	return sprintf(buf, "%d\n", reg_to_temp(value));
+}
+
+static ssize_t show_throttle(struct cbe_pmd_regs __iomem *pmd_regs, char *buf, int pos)
+{
+	u64 value;
+
+	value = in_be64(&pmd_regs->tm_tpr.val);
+	/* access the corresponding byte */
+	value >>= pos;
+	value &= 0x3F;
+
+	return sprintf(buf, "%d\n", reg_to_temp(value));
+}
+
+static ssize_t store_throttle(struct cbe_pmd_regs __iomem *pmd_regs, const char *buf, size_t size, int pos)
+{
+	u64 reg_value;
+	int temp;
+	u64 new_value;
+	int ret;
+
+	ret = sscanf(buf, "%d", &temp);
+
+	if (ret != 1 || temp < TEMP_MIN || temp > TEMP_MAX)
+		return -EINVAL;
+
+	new_value = temp_to_reg(temp);
+
+	reg_value = in_be64(&pmd_regs->tm_tpr.val);
+
+	/* zero out bits for new value */
+	reg_value &= ~(0xffull << pos);
+	/* set bits to new value */
+	reg_value |= new_value << pos;
+
+	out_be64(&pmd_regs->tm_tpr.val, reg_value);
+	return size;
+}
+
+static ssize_t spu_show_throttle_end(struct sys_device *sysdev, char *buf)
+{
+	return show_throttle(get_pmd_regs(sysdev), buf, 0);
+}
+
+static ssize_t spu_show_throttle_begin(struct sys_device *sysdev, char *buf)
+{
+	return show_throttle(get_pmd_regs(sysdev), buf, 8);
+}
+
+static ssize_t spu_show_throttle_full_stop(struct sys_device *sysdev, char *buf)
+{
+	return show_throttle(get_pmd_regs(sysdev), buf, 16);
+}
+
+static ssize_t spu_store_throttle_end(struct sys_device *sysdev, const char *buf, size_t size)
+{
+	return store_throttle(get_pmd_regs(sysdev), buf, size, 0);
+}
+
+static ssize_t spu_store_throttle_begin(struct sys_device *sysdev, const char *buf, size_t size)
+{
+	return store_throttle(get_pmd_regs(sysdev), buf, size, 8);
+}
+
+static ssize_t spu_store_throttle_full_stop(struct sys_device *sysdev, const char *buf, size_t size)
+{
+	return store_throttle(get_pmd_regs(sysdev), buf, size, 16);
+}
+
+static ssize_t ppe_show_temp(struct sys_device *sysdev, char *buf, int pos)
+{
+	struct cbe_pmd_regs __iomem *pmd_regs;
+	u64 value;
+
+	pmd_regs = cbe_get_cpu_pmd_regs(sysdev->id);
+	value = in_be64(&pmd_regs->ts_ctsr2);
+
+	value = (value >> pos) & 0x3f;
+
+	return sprintf(buf, "%d\n", reg_to_temp(value));
+}
+
+
+/* shows the temperature of the DTS on the PPE,
+ * located near the linear thermal sensor */
+static ssize_t ppe_show_temp0(struct sys_device *sysdev, char *buf)
+{
+	return ppe_show_temp(sysdev, buf, 32);
+}
+
+/* shows the temperature of the second DTS on the PPE */
+static ssize_t ppe_show_temp1(struct sys_device *sysdev, char *buf)
+{
+	return ppe_show_temp(sysdev, buf, 0);
+}
+
+static ssize_t ppe_show_throttle_end(struct sys_device *sysdev, char *buf)
+{
+	return show_throttle(cbe_get_cpu_pmd_regs(sysdev->id), buf, 32);
+}
+
+static ssize_t ppe_show_throttle_begin(struct sys_device *sysdev, char *buf)
+{
+	return show_throttle(cbe_get_cpu_pmd_regs(sysdev->id), buf, 40);
+}
+
+static ssize_t ppe_show_throttle_full_stop(struct sys_device *sysdev, char *buf)
+{
+	return show_throttle(cbe_get_cpu_pmd_regs(sysdev->id), buf, 48);
+}
+
+static ssize_t ppe_store_throttle_end(struct sys_device *sysdev, const char *buf, size_t size)
+{
+	return store_throttle(cbe_get_cpu_pmd_regs(sysdev->id), buf, size, 32);
+}
+
+static ssize_t ppe_store_throttle_begin(struct sys_device *sysdev, const char *buf, size_t size)
+{
+	return store_throttle(cbe_get_cpu_pmd_regs(sysdev->id), buf, size, 40);
+}
+
+static ssize_t ppe_store_throttle_full_stop(struct sys_device *sysdev, const char *buf, size_t size)
+{
+	return store_throttle(cbe_get_cpu_pmd_regs(sysdev->id), buf, size, 48);
+}
+
+
+static struct sysdev_attribute attr_spu_temperature = {
+	.attr = {.name = "temperature", .mode = 0400 },
+	.show = spu_show_temp,
+};
+
+static SYSDEV_PREFIX_ATTR(spu, throttle_end, 0600);
+static SYSDEV_PREFIX_ATTR(spu, throttle_begin, 0600);
+static SYSDEV_PREFIX_ATTR(spu, throttle_full_stop, 0600);
+
+
+static struct attribute *spu_attributes[] = {
+	&attr_spu_temperature.attr,
+	&attr_spu_throttle_end.attr,
+	&attr_spu_throttle_begin.attr,
+	&attr_spu_throttle_full_stop.attr,
+	NULL,
+};
+
+static struct attribute_group spu_attribute_group = {
+	.name	= "thermal",
+	.attrs	= spu_attributes,
+};
+
+static struct sysdev_attribute attr_ppe_temperature0 = {
+	.attr = {.name = "temperature0", .mode = 0400 },
+	.show = ppe_show_temp0,
+};
+
+static struct sysdev_attribute attr_ppe_temperature1 = {
+	.attr = {.name = "temperature1", .mode = 0400 },
+	.show = ppe_show_temp1,
+};
+
+static SYSDEV_PREFIX_ATTR(ppe, throttle_end, 0600);
+static SYSDEV_PREFIX_ATTR(ppe, throttle_begin, 0600);
+static SYSDEV_PREFIX_ATTR(ppe, throttle_full_stop, 0600);
+
+static struct attribute *ppe_attributes[] = {
+	&attr_ppe_temperature0.attr,
+	&attr_ppe_temperature1.attr,
+	&attr_ppe_throttle_end.attr,
+	&attr_ppe_throttle_begin.attr,
+	&attr_ppe_throttle_full_stop.attr,
+	NULL,
+};
+
+static struct attribute_group ppe_attribute_group = {
+	.name	= "thermal",
+	.attrs	= ppe_attributes,
+};
+
+/*
+ * initialize throttling with default values
+ */
+static int __init init_default_values(void)
+{
+	int cpu;
+	struct cbe_pmd_regs __iomem *pmd_regs;
+	struct sys_device *sysdev;
+	union ppe_spe_reg tpr;
+	union spe_reg str1;
+	u64 str2;
+	union spe_reg cr1;
+	u64 cr2;
+
+	/* TPR defaults */
+	/* ppe
+	 *	1F - no full stop
+	 *	08 - dynamic throttling starts if over 80 degrees
+	 *	03 - dynamic throttling ceases if below 70 degrees */
+	tpr.ppe = 0x1F0803;
+	/* spe
+	 *	10 - full stopped when over 96 degrees
+	 *	08 - dynamic throttling starts if over 80 degrees
+	 *	03 - dynamic throttling ceases if below 70 degrees
+	 */
+	tpr.spe = 0x100803;
+
+	/* STR defaults */
+	/* str1
+	 *	10 - stop 16 of 32 cycles
+	 */
+	str1.val = 0x1010101010101010ull;
+	/* str2
+	 *	10 - stop 16 of 32 cycles
+	 */
+	str2 = 0x10;
+
+	/* CR defaults */
+	/* cr1
+	 *	4 - normal operation
+	 */
+	cr1.val = 0x0404040404040404ull;
+	/* cr2
+	 *	4 - normal operation
+	 */
+	cr2 = 0x04;
+
+	for_each_possible_cpu (cpu) {
+		pr_debug("processing cpu %d\n", cpu);
+		sysdev = get_cpu_sysdev(cpu);
+
+		if (!sysdev) {
+			pr_info("invalid sysdev pointer for cbe_thermal\n");
+			return -EINVAL;
+		}
+
+		pmd_regs = cbe_get_cpu_pmd_regs(sysdev->id);
+
+		if (!pmd_regs) {
+			pr_info("invalid CBE regs pointer for cbe_thermal\n");
+			return -EINVAL;
+		}
+
+		out_be64(&pmd_regs->tm_str2, str2);
+		out_be64(&pmd_regs->tm_str1.val, str1.val);
+		out_be64(&pmd_regs->tm_tpr.val, tpr.val);
+		out_be64(&pmd_regs->tm_cr1.val, cr1.val);
+		out_be64(&pmd_regs->tm_cr2, cr2);
+	}
+
+	return 0;
+}
+
+
+static int __init thermal_init(void)
+{
+	int rc = init_default_values();
+
+	if (rc == 0) {
+		spu_add_sysdev_attr_group(&spu_attribute_group);
+		cpu_add_sysdev_attr_group(&ppe_attribute_group);
+	}
+
+	return rc;
+}
+module_init(thermal_init);
+
+static void __exit thermal_exit(void)
+{
+	spu_remove_sysdev_attr_group(&spu_attribute_group);
+	cpu_remove_sysdev_attr_group(&ppe_attribute_group);
+}
+module_exit(thermal_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
+