[PATCH V11 2/3] powernv: Add support to set power-shifting-ratio

From: Shilpasri G Bhat
Date: Wed Aug 09 2017 - 23:32:05 EST


This patch adds support to set power-shifting-ratio which hints the
firmware how to distribute/throttle power between different entities
in a system (e.g CPU v/s GPU). This ratio is used by OCC for power
capping algorithm.

Signed-off-by: Shilpasri G Bhat <shilpa.bhat@xxxxxxxxxxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-firmware-opal-psr | 18 +++
arch/powerpc/include/asm/opal-api.h | 2 +
arch/powerpc/include/asm/opal.h | 3 +
arch/powerpc/platforms/powernv/Makefile | 2 +-
arch/powerpc/platforms/powernv/opal-psr.c | 175 ++++++++++++++++++++++
arch/powerpc/platforms/powernv/opal-wrappers.S | 2 +
arch/powerpc/platforms/powernv/opal.c | 3 +
7 files changed, 204 insertions(+), 1 deletion(-)
create mode 100644 Documentation/ABI/testing/sysfs-firmware-opal-psr
create mode 100644 arch/powerpc/platforms/powernv/opal-psr.c

diff --git a/Documentation/ABI/testing/sysfs-firmware-opal-psr b/Documentation/ABI/testing/sysfs-firmware-opal-psr
new file mode 100644
index 0000000..cc2ece7
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-firmware-opal-psr
@@ -0,0 +1,18 @@
+What: /sys/firmware/opal/psr
+Date: August 2017
+Contact: Linux for PowerPC mailing list <linuxppc-dev@xxxxxxxxxx>
+Description: Power-Shift-Ratio directory for Powernv P9 servers
+
+ Power-Shift-Ratio allows to provide hints the firmware
+ to shift/throttle power between different entities in
+ the system. Each attribute in this directory indicates
+ a settable PSR.
+
+What: /sys/firmware/opal/psr/cpu_to_gpu_X
+Date: August 2017
+Contact: Linux for PowerPC mailing list <linuxppc-dev@xxxxxxxxxx>
+Description: PSR sysfs attributes for Powernv P9 servers
+
+ Power-Shift-Ratio between CPU and GPU for a given chip
+ with chip-id X. This file gives the ratio (0-100)
+ which is used by OCC for power-capping.
diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index b87305b..0cb7d11 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -196,6 +196,8 @@
#define OPAL_IMC_COUNTERS_STOP 151
#define OPAL_GET_POWERCAP 152
#define OPAL_SET_POWERCAP 153
+#define OPAL_GET_POWER_SHIFT_RATIO 154
+#define OPAL_SET_POWER_SHIFT_RATIO 155
#define OPAL_PCI_SET_P2P 157
#define OPAL_LAST 157

diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 6f09ab7..d87ffcb 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -277,6 +277,8 @@ int64_t opal_imc_counters_init(uint32_t type, uint64_t address,

int opal_get_powercap(u32 handle, int token, u32 *pcap);
int opal_set_powercap(u32 handle, int token, u32 pcap);
+int opal_get_power_shift_ratio(u32 handle, int token, u32 *psr);
+int opal_set_power_shift_ratio(u32 handle, int token, u32 psr);

/* Internal functions */
extern int early_init_dt_scan_opal(unsigned long node, const char *uname,
@@ -356,6 +358,7 @@ static inline int opal_get_async_rc(struct opal_msg msg)
void opal_wake_poller(void);

void opal_powercap_init(void);
+void opal_psr_init(void);

#endif /* __ASSEMBLY__ */

diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index f9ec36d..674ed1e 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -2,7 +2,7 @@ obj-y += setup.o opal-wrappers.o opal.o opal-async.o idle.o
obj-y += opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
obj-y += rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
obj-y += opal-msglog.o opal-hmi.o opal-power.o opal-irqchip.o
-obj-y += opal-kmsg.o opal-powercap.o
+obj-y += opal-kmsg.o opal-powercap.o opal-psr.o

obj-$(CONFIG_SMP) += smp.o subcore.o subcore-asm.o
obj-$(CONFIG_PCI) += pci.o pci-ioda.o npu-dma.o
diff --git a/arch/powerpc/platforms/powernv/opal-psr.c b/arch/powerpc/platforms/powernv/opal-psr.c
new file mode 100644
index 0000000..7313b7f
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-psr.c
@@ -0,0 +1,175 @@
+/*
+ * PowerNV OPAL Power-Shift-Ratio interface
+ *
+ * Copyright 2017 IBM Corp.
+ *
+ * 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 of the License, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) "opal-psr: " fmt
+
+#include <linux/of.h>
+#include <linux/kobject.h>
+#include <linux/slab.h>
+
+#include <asm/opal.h>
+
+DEFINE_MUTEX(psr_mutex);
+
+static struct kobject *psr_kobj;
+
+struct psr_attr {
+ u32 handle;
+ struct kobj_attribute attr;
+} *psr_attrs;
+
+static ssize_t psr_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ struct psr_attr *psr_attr = container_of(attr, struct psr_attr, attr);
+ struct opal_msg msg;
+ int psr, ret, token;
+
+ token = opal_async_get_token_interruptible();
+ if (token < 0) {
+ pr_devel("Failed to get token\n");
+ return token;
+ }
+
+ ret = mutex_lock_interruptible(&psr_mutex);
+ if (ret)
+ goto out_token;
+
+ ret = opal_get_power_shift_ratio(psr_attr->handle, token,
+ (u32 *)__pa(&psr));
+ switch (ret) {
+ case OPAL_ASYNC_COMPLETION:
+ ret = opal_async_wait_response(token, &msg);
+ if (ret) {
+ pr_devel("Failed to wait for the async response\n");
+ ret = -EIO;
+ goto out;
+ }
+ ret = opal_error_code(opal_get_async_rc(msg));
+ if (!ret) {
+ ret = sprintf(buf, "%u\n", be32_to_cpu(psr));
+ if (ret < 0)
+ ret = -EIO;
+ }
+ break;
+ case OPAL_SUCCESS:
+ ret = sprintf(buf, "%u\n", be32_to_cpu(psr));
+ if (ret < 0)
+ ret = -EIO;
+ break;
+ default:
+ ret = opal_error_code(ret);
+ }
+
+out:
+ mutex_unlock(&psr_mutex);
+out_token:
+ opal_async_release_token(token);
+ return ret;
+}
+
+static ssize_t psr_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct psr_attr *psr_attr = container_of(attr, struct psr_attr, attr);
+ struct opal_msg msg;
+ int psr, ret, token;
+
+ ret = kstrtoint(buf, 0, &psr);
+ if (ret)
+ return ret;
+
+ token = opal_async_get_token_interruptible();
+ if (token < 0) {
+ pr_devel("Failed to get token\n");
+ return token;
+ }
+
+ ret = mutex_lock_interruptible(&psr_mutex);
+ if (ret)
+ goto out_token;
+
+ ret = opal_set_power_shift_ratio(psr_attr->handle, token, psr);
+ switch (ret) {
+ case OPAL_ASYNC_COMPLETION:
+ ret = opal_async_wait_response(token, &msg);
+ if (ret) {
+ pr_devel("Failed to wait for the async response\n");
+ ret = -EIO;
+ goto out;
+ }
+ ret = opal_error_code(opal_get_async_rc(msg));
+ if (!ret)
+ ret = count;
+ break;
+ case OPAL_SUCCESS:
+ ret = count;
+ break;
+ default:
+ ret = opal_error_code(ret);
+ }
+
+out:
+ mutex_unlock(&psr_mutex);
+out_token:
+ opal_async_release_token(token);
+ return ret;
+}
+
+void __init opal_psr_init(void)
+{
+ struct device_node *psr, *node;
+ int i = 0;
+
+ psr = of_find_compatible_node(NULL, NULL,
+ "ibm,opal-power-shift-ratio");
+ if (!psr) {
+ pr_devel("Power-shift-ratio node not found\n");
+ return;
+ }
+
+ psr_attrs = kcalloc(of_get_child_count(psr), sizeof(struct psr_attr),
+ GFP_KERNEL);
+ if (!psr_attrs)
+ return;
+
+ psr_kobj = kobject_create_and_add("psr", opal_kobj);
+ if (!psr_kobj) {
+ pr_warn("Failed to create psr kobject\n");
+ goto out;
+ }
+
+ for_each_child_of_node(psr, node) {
+ if (of_property_read_u32(node, "handle",
+ &psr_attrs[i].handle))
+ goto out_kobj;
+
+ sysfs_attr_init(&psr_attrs[i].attr.attr);
+ if (of_property_read_string(node, "label",
+ &psr_attrs[i].attr.attr.name))
+ goto out_kobj;
+ psr_attrs[i].attr.attr.mode = 0664;
+ psr_attrs[i].attr.show = psr_show;
+ psr_attrs[i].attr.store = psr_store;
+ if (sysfs_create_file(psr_kobj, &psr_attrs[i].attr.attr)) {
+ pr_devel("Failed to create psr sysfs file %s\n",
+ psr_attrs[i].attr.attr.name);
+ goto out_kobj;
+ }
+ i++;
+ }
+
+ return;
+out_kobj:
+ kobject_put(psr_kobj);
+out:
+ kfree(psr_attrs);
+}
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index 139286c..09cc6ec 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -316,3 +316,5 @@ OPAL_CALL(opal_imc_counters_stop, OPAL_IMC_COUNTERS_STOP);
OPAL_CALL(opal_pci_set_p2p, OPAL_PCI_SET_P2P);
OPAL_CALL(opal_get_powercap, OPAL_GET_POWERCAP);
OPAL_CALL(opal_set_powercap, OPAL_SET_POWERCAP);
+OPAL_CALL(opal_get_power_shift_ratio, OPAL_GET_POWER_SHIFT_RATIO);
+OPAL_CALL(opal_set_power_shift_ratio, OPAL_SET_POWER_SHIFT_RATIO);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 28323c7..f659edb 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -853,6 +853,9 @@ static int __init opal_init(void)
/* Initialise OPAL powercap interface */
opal_powercap_init();

+ /* Initialise OPAL Power-Shifting-Ratio interface */
+ opal_psr_init();
+
return 0;
}
machine_subsys_initcall(powernv, opal_init);
--
1.8.3.1