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Subject[PATCH v4 1/5] firmware: arm_scmi: Add Voltage Domain Support
Date
Add SCMI Voltage Domain protocol support.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3 --> v4
- avoid fixed sized typing in voltage_info
- avoid coccinelle falde complaints about pointer-sized allocations

v2 --> v3
- restrict segmented voltage domain descriptors to one triplet
- removed unneeded inline
- free allocated resources for invalid voltage domain
- added __must_check to info_get voltage operations
- added a few comments
- removed fixed size typing from struct voltage_info

v1 --> v2
- fix voltage levels query loop to reload full cmd description
between iterations as reported by Etienne Carriere
- ensure rx buffer is properly sized calli scmi_reset_rx_to_maxsz
between transfers
---
drivers/firmware/arm_scmi/Makefile | 2 +-
drivers/firmware/arm_scmi/common.h | 1 +
drivers/firmware/arm_scmi/driver.c | 2 +
drivers/firmware/arm_scmi/voltage.c | 397 ++++++++++++++++++++++++++++
include/linux/scmi_protocol.h | 64 +++++
5 files changed, 465 insertions(+), 1 deletion(-)
create mode 100644 drivers/firmware/arm_scmi/voltage.c

diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile
index bc0d54f8e861..6a2ef63306d6 100644
--- a/drivers/firmware/arm_scmi/Makefile
+++ b/drivers/firmware/arm_scmi/Makefile
@@ -4,7 +4,7 @@ scmi-driver-y = driver.o notify.o
scmi-transport-y = shmem.o
scmi-transport-$(CONFIG_MAILBOX) += mailbox.o
scmi-transport-$(CONFIG_HAVE_ARM_SMCCC_DISCOVERY) += smc.o
-scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o system.o
+scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o system.o voltage.o
scmi-module-objs := $(scmi-bus-y) $(scmi-driver-y) $(scmi-protocols-y) \
$(scmi-transport-y)
obj-$(CONFIG_ARM_SCMI_PROTOCOL) += scmi-module.o
diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 65063fa948d4..c0fb45e7c3e8 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -169,6 +169,7 @@ DECLARE_SCMI_REGISTER_UNREGISTER(perf);
DECLARE_SCMI_REGISTER_UNREGISTER(power);
DECLARE_SCMI_REGISTER_UNREGISTER(reset);
DECLARE_SCMI_REGISTER_UNREGISTER(sensors);
+DECLARE_SCMI_REGISTER_UNREGISTER(voltage);
DECLARE_SCMI_REGISTER_UNREGISTER(system);

#define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(id, name) \
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 3dfd8b6a0ebf..ada35e63feae 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -946,6 +946,7 @@ static int __init scmi_driver_init(void)
scmi_power_register();
scmi_reset_register();
scmi_sensors_register();
+ scmi_voltage_register();
scmi_system_register();

return platform_driver_register(&scmi_driver);
@@ -961,6 +962,7 @@ static void __exit scmi_driver_exit(void)
scmi_power_unregister();
scmi_reset_unregister();
scmi_sensors_unregister();
+ scmi_voltage_unregister();
scmi_system_unregister();

platform_driver_unregister(&scmi_driver);
diff --git a/drivers/firmware/arm_scmi/voltage.c b/drivers/firmware/arm_scmi/voltage.c
new file mode 100644
index 000000000000..dde73083262e
--- /dev/null
+++ b/drivers/firmware/arm_scmi/voltage.c
@@ -0,0 +1,397 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * System Control and Management Interface (SCMI) Voltage Protocol
+ *
+ * Copyright (C) 2020 ARM Ltd.
+ */
+
+#include <linux/scmi_protocol.h>
+
+#include "common.h"
+
+#define VOLTAGE_DOMS_NUM_MASK GENMASK(15, 0)
+#define REMAINING_LEVELS_MASK GENMASK(31, 16)
+#define RETURNED_LEVELS_MASK GENMASK(11, 0)
+
+enum scmi_voltage_protocol_cmd {
+ VOLTAGE_DOMAIN_ATTRIBUTES = 0x3,
+ VOLTAGE_DESCRIBE_LEVELS = 0x4,
+ VOLTAGE_CONFIG_SET = 0x5,
+ VOLTAGE_CONFIG_GET = 0x6,
+ VOLTAGE_LEVEL_SET = 0x7,
+ VOLTAGE_LEVEL_GET = 0x8,
+};
+
+struct scmi_msg_resp_protocol_attributes {
+ __le32 attr;
+#define NUM_VOLTAGE_DOMAINS(x) (u16)(FIELD_GET(VOLTAGE_DOMS_NUM_MASK, (x)))
+};
+
+struct scmi_msg_resp_domain_attributes {
+ __le32 attr;
+ u8 name[SCMI_MAX_STR_SIZE];
+};
+
+struct scmi_msg_cmd_describe_levels {
+ __le32 domain_id;
+ __le32 level_index;
+};
+
+struct scmi_msg_resp_describe_levels {
+ __le32 flags;
+#define NUM_REMAINING_LEVELS(f) (u16)(FIELD_GET(REMAINING_LEVELS_MASK, (f)))
+#define NUM_RETURNED_LEVELS(f) (u16)(FIELD_GET(RETURNED_LEVELS_MASK, (f)))
+#define SUPPORTS_SEGMENTED_LEVELS(f) ((f) & BIT(12))
+ __le32 voltage[];
+};
+
+struct scmi_msg_cmd_config_set {
+ __le32 domain_id;
+ __le32 config;
+};
+
+struct scmi_msg_cmd_level_set {
+ __le32 domain_id;
+ __le32 flags;
+ __le32 voltage_level;
+};
+
+struct voltage_info {
+ unsigned int version;
+ unsigned int num_domains;
+ struct scmi_voltage_info **domains;
+};
+
+static int scmi_protocol_attributes_get(const struct scmi_handle *handle,
+ struct voltage_info *vinfo)
+{
+ int ret;
+ struct scmi_xfer *t;
+ struct scmi_msg_resp_protocol_attributes *resp;
+
+ ret = scmi_xfer_get_init(handle, PROTOCOL_ATTRIBUTES,
+ SCMI_PROTOCOL_VOLTAGE, 0, sizeof(*resp), &t);
+ if (ret)
+ return ret;
+
+ resp = t->rx.buf;
+ ret = scmi_do_xfer(handle, t);
+ if (!ret)
+ vinfo->num_domains =
+ NUM_VOLTAGE_DOMAINS(le32_to_cpu(resp->attr));
+
+ scmi_xfer_put(handle, t);
+ return ret;
+}
+
+static inline int scmi_init_voltage_levels(struct device *dev,
+ struct scmi_voltage_info *v,
+ u32 flags, u32 num_returned,
+ u32 num_remaining)
+{
+ bool segmented;
+ u32 num_levels;
+
+ segmented = SUPPORTS_SEGMENTED_LEVELS(flags);
+ num_levels = num_returned + num_remaining;
+ /*
+ * segmented levels entries are represented by a single triplet
+ * returned all in one go.
+ */
+ if (!num_levels ||
+ (segmented && (num_remaining || num_returned != 3))) {
+ dev_err(dev,
+ "Invalid level descriptor(%d/%d/%d) for voltage dom %d\n",
+ num_levels, num_returned, num_remaining, v->id);
+ return -EINVAL;
+ }
+
+ v->levels_uv = devm_kcalloc(dev, num_levels, sizeof(u32), GFP_KERNEL);
+ if (!v->levels_uv)
+ return -ENOMEM;
+
+ v->num_levels = num_levels;
+ v->segmented = segmented;
+
+ return 0;
+}
+
+static int scmi_voltage_descriptors_get(const struct scmi_handle *handle,
+ struct voltage_info *vinfo)
+{
+ int ret, dom;
+ struct scmi_xfer *td, *tl;
+ struct device *dev = handle->dev;
+ struct scmi_msg_resp_domain_attributes *resp_dom;
+ struct scmi_msg_resp_describe_levels *resp_levels;
+
+ ret = scmi_xfer_get_init(handle, VOLTAGE_DOMAIN_ATTRIBUTES,
+ SCMI_PROTOCOL_VOLTAGE, sizeof(__le32),
+ sizeof(*resp_dom), &td);
+ if (ret)
+ return ret;
+ resp_dom = td->rx.buf;
+
+ ret = scmi_xfer_get_init(handle, VOLTAGE_DESCRIBE_LEVELS,
+ SCMI_PROTOCOL_VOLTAGE, sizeof(__le64), 0, &tl);
+ if (ret)
+ goto outd;
+ resp_levels = tl->rx.buf;
+
+ for (dom = 0; dom < vinfo->num_domains; dom++) {
+ u32 desc_index = 0;
+ u16 num_returned = 0, num_remaining = 0;
+ struct scmi_msg_cmd_describe_levels *cmd;
+ struct scmi_voltage_info *v;
+
+ /* Retrieve domain attributes at first ... */
+ put_unaligned_le32(dom, td->tx.buf);
+ ret = scmi_do_xfer(handle, td);
+ /* Skip domain on comms error */
+ if (ret)
+ continue;
+
+ v = devm_kzalloc(dev, sizeof(*v), GFP_KERNEL);
+ if (!v) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ v->id = dom;
+ v->attributes = le32_to_cpu(resp_dom->attr);
+ strlcpy(v->name, resp_dom->name, SCMI_MAX_STR_SIZE);
+
+ cmd = tl->tx.buf;
+ /* ...then retrieve domain levels descriptions */
+ do {
+ u32 flags;
+ int cnt;
+
+ cmd->domain_id = cpu_to_le32(v->id);
+ cmd->level_index = desc_index;
+ ret = scmi_do_xfer(handle, tl);
+ if (ret)
+ break;
+
+ flags = le32_to_cpu(resp_levels->flags);
+ num_returned = NUM_RETURNED_LEVELS(flags);
+ num_remaining = NUM_REMAINING_LEVELS(flags);
+
+ /* Allocate space for num_levels if not already done */
+ if (!v->num_levels) {
+ ret = scmi_init_voltage_levels(dev, v, flags,
+ num_returned,
+ num_remaining);
+ if (ret)
+ break;
+ }
+
+ if (desc_index + num_returned > v->num_levels) {
+ dev_err(handle->dev,
+ "No. of voltage levels can't exceed %d\n",
+ v->num_levels);
+ ret = -EINVAL;
+ break;
+ }
+
+ for (cnt = 0; cnt < num_returned; cnt++) {
+ s32 val;
+
+ val =
+ (s32)le32_to_cpu(resp_levels->voltage[cnt]);
+ v->levels_uv[desc_index + cnt] = val;
+ if (val < 0)
+ v->negative_volts_allowed = true;
+ }
+
+ desc_index += num_returned;
+
+ scmi_reset_rx_to_maxsz(handle, tl);
+ /* check both to avoid infinite loop due to buggy fw */
+ } while (num_returned && num_remaining);
+
+ /*
+ * Bail out only on memory errors, just skip domain and free
+ * on any other error.
+ */
+ if (!ret) {
+ vinfo->domains[dom] = v;
+ } else if (ret != -ENOMEM) {
+ devm_kfree(dev, v->levels_uv);
+ devm_kfree(dev, v);
+ } else {
+ break;
+ }
+
+ scmi_reset_rx_to_maxsz(handle, td);
+ }
+
+ scmi_xfer_put(handle, tl);
+outd:
+ scmi_xfer_put(handle, td);
+
+ return ret;
+}
+
+static int __scmi_voltage_get_u32(const struct scmi_handle *handle,
+ u8 cmd_id, u32 domain_id, u32 *value)
+{
+ int ret;
+ struct scmi_xfer *t;
+ struct voltage_info *vinfo = handle->voltage_priv;
+
+ if (domain_id >= vinfo->num_domains)
+ return -EINVAL;
+
+ ret = scmi_xfer_get_init(handle, cmd_id,
+ SCMI_PROTOCOL_VOLTAGE,
+ sizeof(__le32), 0, &t);
+ if (ret)
+ return ret;
+
+ put_unaligned_le32(domain_id, t->tx.buf);
+ ret = scmi_do_xfer(handle, t);
+ if (!ret)
+ *value = get_unaligned_le32(t->rx.buf);
+
+ scmi_xfer_put(handle, t);
+ return ret;
+}
+
+static int scmi_voltage_config_set(const struct scmi_handle *handle,
+ u32 domain_id, u32 config)
+{
+ int ret;
+ struct scmi_xfer *t;
+ struct voltage_info *vinfo = handle->voltage_priv;
+ struct scmi_msg_cmd_config_set *cmd;
+
+ if (domain_id >= vinfo->num_domains)
+ return -EINVAL;
+
+ ret = scmi_xfer_get_init(handle, VOLTAGE_CONFIG_SET,
+ SCMI_PROTOCOL_VOLTAGE,
+ sizeof(*cmd), 0, &t);
+ if (ret)
+ return ret;
+
+ cmd = t->tx.buf;
+ cmd->domain_id = cpu_to_le32(domain_id);
+ cmd->config = cpu_to_le32(config & GENMASK(3, 0));
+
+ ret = scmi_do_xfer(handle, t);
+
+ scmi_xfer_put(handle, t);
+ return ret;
+}
+
+static int scmi_voltage_config_get(const struct scmi_handle *handle,
+ u32 domain_id, u32 *config)
+{
+ return __scmi_voltage_get_u32(handle, VOLTAGE_CONFIG_GET,
+ domain_id, config);
+}
+
+static int scmi_voltage_level_set(const struct scmi_handle *handle,
+ u32 domain_id, u32 flags, s32 volt_uV)
+{
+ int ret;
+ struct scmi_xfer *t;
+ struct voltage_info *vinfo = handle->voltage_priv;
+ struct scmi_msg_cmd_level_set *cmd;
+
+ if (domain_id >= vinfo->num_domains)
+ return -EINVAL;
+
+ ret = scmi_xfer_get_init(handle, VOLTAGE_LEVEL_SET,
+ SCMI_PROTOCOL_VOLTAGE,
+ sizeof(*cmd), 0, &t);
+ if (ret)
+ return ret;
+
+ cmd = t->tx.buf;
+ cmd->domain_id = cpu_to_le32(domain_id);
+ cmd->flags = cpu_to_le32(flags);
+ cmd->voltage_level = cpu_to_le32(volt_uV);
+
+ ret = scmi_do_xfer(handle, t);
+
+ scmi_xfer_put(handle, t);
+ return ret;
+}
+
+static int scmi_voltage_level_get(const struct scmi_handle *handle,
+ u32 domain_id, s32 *volt_uV)
+{
+ return __scmi_voltage_get_u32(handle, VOLTAGE_LEVEL_GET,
+ domain_id, (u32 *)volt_uV);
+}
+
+static const struct scmi_voltage_info * __must_check
+scmi_voltage_info_get(const struct scmi_handle *handle, u32 domain_id)
+{
+ struct voltage_info *vinfo = handle->voltage_priv;
+
+ if (domain_id >= vinfo->num_domains)
+ return NULL;
+
+ return vinfo->domains[domain_id];
+}
+
+static int scmi_voltage_domains_num_get(const struct scmi_handle *handle)
+{
+ struct voltage_info *vinfo = handle->voltage_priv;
+
+ return vinfo->num_domains;
+}
+
+static struct scmi_voltage_ops voltage_ops = {
+ .num_domains_get = scmi_voltage_domains_num_get,
+ .info_get = scmi_voltage_info_get,
+ .config_set = scmi_voltage_config_set,
+ .config_get = scmi_voltage_config_get,
+ .level_set = scmi_voltage_level_set,
+ .level_get = scmi_voltage_level_get,
+};
+
+static int scmi_voltage_protocol_init(struct scmi_handle *handle)
+{
+ int ret;
+ u32 version;
+ struct voltage_info *vinfo;
+
+ ret = scmi_version_get(handle, SCMI_PROTOCOL_VOLTAGE, &version);
+ if (ret)
+ return ret;
+
+ dev_dbg(handle->dev, "Voltage Version %d.%d\n",
+ PROTOCOL_REV_MAJOR(version), PROTOCOL_REV_MINOR(version));
+
+ vinfo = devm_kzalloc(handle->dev, sizeof(*vinfo), GFP_KERNEL);
+ if (!vinfo)
+ return -ENOMEM;
+ vinfo->version = version;
+
+ ret = scmi_protocol_attributes_get(handle, vinfo);
+ if (ret)
+ return ret;
+
+ if (vinfo->num_domains) {
+ vinfo->domains = devm_kcalloc(handle->dev, vinfo->num_domains,
+ sizeof(void *), GFP_KERNEL);
+ if (!vinfo->domains)
+ return -ENOMEM;
+ ret = scmi_voltage_descriptors_get(handle, vinfo);
+ if (ret)
+ return ret;
+ } else {
+ dev_warn(handle->dev, "No Voltage domains found.\n");
+ }
+
+ handle->voltage_ops = &voltage_ops;
+ handle->voltage_priv = vinfo;
+
+ return 0;
+}
+
+DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(SCMI_PROTOCOL_VOLTAGE, voltage)
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index 9cd312a1ff92..181fdebc2793 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -209,6 +209,64 @@ struct scmi_reset_ops {
int (*deassert)(const struct scmi_handle *handle, u32 domain);
};

+/**
+ * struct scmi_voltage_info - describe one available SCMI Voltage Domain
+ *
+ * @id: the domain ID as advertised by the platform
+ * @segmented: defines the layout of the entries of array @levels_uv.
+ * - when True the entries are to be interpreted as triplets,
+ * each defining a segment representing a range of equally
+ * space voltages: <lowest_volts>, <highest_volt>, <step_uV>
+ * - when False the entries simply represent a single discrete
+ * supported voltage level
+ * @negative_volts_allowed: True if any of the entries of @levels_uv represent
+ * a negative voltage.
+ * @attributes: represents Voltage Domain advertised attributes
+ * @name: name assigned to the Voltage Domain by platform
+ * @num_levels: number of total entries in @levels_uv.
+ * @levels_uv: array of entries describing the available voltage levels for
+ * this domain.
+ */
+struct scmi_voltage_info {
+ unsigned int id;
+ bool segmented;
+#define SCMI_VOLTAGE_SEGMENT_LOW 0
+#define SCMI_VOLTAGE_SEGMENT_HIGH 1
+#define SCMI_VOLTAGE_SEGMENT_STEP 2
+ bool negative_volts_allowed;
+ unsigned int attributes;
+ char name[SCMI_MAX_STR_SIZE];
+ unsigned int num_levels;
+ int *levels_uv;
+};
+
+/**
+ * struct scmi_voltage_ops - represents the various operations provided
+ * by SCMI Voltage Protocol
+ *
+ * @num_domains_get: get the count of voltage domains provided by SCMI
+ * @info_get: get the information of the specified domain
+ * @config_set: set the config for the specified domain
+ * @config_get: get the config of the specified domain
+ * @level_set: set the voltage level for the specified domain
+ * @level_get: get the voltage level of the specified domain
+ */
+struct scmi_voltage_ops {
+ int (*num_domains_get)(const struct scmi_handle *handle);
+ const struct scmi_voltage_info __must_check *(*info_get)
+ (const struct scmi_handle *handle, u32 domain_id);
+ int (*config_set)(const struct scmi_handle *handle, u32 domain_id,
+ u32 config);
+#define SCMI_VOLTAGE_ARCH_STATE_OFF 0x0
+#define SCMI_VOLTAGE_ARCH_STATE_ON 0x7
+ int (*config_get)(const struct scmi_handle *handle, u32 domain_id,
+ u32 *config);
+ int (*level_set)(const struct scmi_handle *handle, u32 domain_id,
+ u32 flags, s32 volt_uV);
+ int (*level_get)(const struct scmi_handle *handle, u32 domain_id,
+ s32 *volt_uV);
+};
+
/**
* struct scmi_notify_ops - represents notifications' operations provided by
* SCMI core
@@ -262,6 +320,7 @@ struct scmi_notify_ops {
* @clk_ops: pointer to set of clock protocol operations
* @sensor_ops: pointer to set of sensor protocol operations
* @reset_ops: pointer to set of reset protocol operations
+ * @voltage_ops: pointer to set of voltage protocol operations
* @notify_ops: pointer to set of notifications related operations
* @perf_priv: pointer to private data structure specific to performance
* protocol(for internal use only)
@@ -273,6 +332,8 @@ struct scmi_notify_ops {
* protocol(for internal use only)
* @reset_priv: pointer to private data structure specific to reset
* protocol(for internal use only)
+ * @voltage_priv: pointer to private data structure specific to voltage
+ * protocol(for internal use only)
* @notify_priv: pointer to private data structure specific to notifications
* (for internal use only)
*/
@@ -284,6 +345,7 @@ struct scmi_handle {
const struct scmi_power_ops *power_ops;
const struct scmi_sensor_ops *sensor_ops;
const struct scmi_reset_ops *reset_ops;
+ const struct scmi_voltage_ops *voltage_ops;
const struct scmi_notify_ops *notify_ops;
/* for protocol internal use */
void *perf_priv;
@@ -291,6 +353,7 @@ struct scmi_handle {
void *power_priv;
void *sensor_priv;
void *reset_priv;
+ void *voltage_priv;
void *notify_priv;
void *system_priv;
};
@@ -303,6 +366,7 @@ enum scmi_std_protocol {
SCMI_PROTOCOL_CLOCK = 0x14,
SCMI_PROTOCOL_SENSOR = 0x15,
SCMI_PROTOCOL_RESET = 0x16,
+ SCMI_PROTOCOL_VOLTAGE = 0x17,
};

enum scmi_system_events {
--
2.17.1
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