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SubjectRe: [PATCH v2 05/18] firmware: arm_scmi: add initial support for performance protocol
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On 05/09/17 16:04, Julien Thierry wrote:
> Hi Sudeep,
>
> On 04/08/17 15:31, Sudeep Holla wrote:
>> The performance protocol is intended for the performance management of
>> group(s) of device(s) that run in the same performance domain. It
>> includes even the CPUs. A performance domain is defined by a set of
>> devices that always have to run at the same performance level.
>> For example, a set of CPUs that share a voltage domain, and have a
>> common frequency control, is said to be in the same performance domain.
>>
>> The commands in this protocol provide functionality to describe the
>> protocol version, describe various attribute flags, set and get the
>> performance level of a domain. It also supports discovery of the list
>> of performance levels supported by a performance domain, and the
>> properties of each performance level.
>>
>> This patch adds basic support for the performance protocol.
>>
>> Cc: Arnd Bergmann <arnd@arndb.de>
>> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
>> ---
>> drivers/firmware/arm_scmi/Makefile | 2 +-
>> drivers/firmware/arm_scmi/common.h | 1 +
>> drivers/firmware/arm_scmi/perf.c | 511
>> +++++++++++++++++++++++++++++++++++++
>> include/linux/scmi_protocol.h | 31 +++
>> 4 files changed, 544 insertions(+), 1 deletion(-)
>> create mode 100644 drivers/firmware/arm_scmi/perf.c
>>
>> diff --git a/drivers/firmware/arm_scmi/Makefile
>> b/drivers/firmware/arm_scmi/Makefile
>> index 21d01d1d6b9c..159de726ee45 100644
>> --- a/drivers/firmware/arm_scmi/Makefile
>> +++ b/drivers/firmware/arm_scmi/Makefile
>> @@ -1,2 +1,2 @@
>> obj-$(CONFIG_ARM_SCMI_PROTOCOL) = arm_scmi.o
>> -arm_scmi-y = base.o driver.o
>> +arm_scmi-y = base.o driver.o perf.o
>> diff --git a/drivers/firmware/arm_scmi/common.h
>> b/drivers/firmware/arm_scmi/common.h
>> index e3fe5d9acc82..7473dfcad4ee 100644
>> --- a/drivers/firmware/arm_scmi/common.h
>> +++ b/drivers/firmware/arm_scmi/common.h
>> @@ -30,6 +30,7 @@
>> #define PROTOCOL_REV_MAJOR(x) ((x) >> PROTOCOL_REV_MINOR_BITS)
>> #define PROTOCOL_REV_MINOR(x) ((x) & PROTOCOL_REV_MINOR_MASK)
>> #define MAX_PROTOCOLS_IMP 16
>> +#define MAX_OPPS 16
>> enum scmi_std_protocol {
>> SCMI_PROTOCOL_BASE = 0x10,
>> diff --git a/drivers/firmware/arm_scmi/perf.c
>> b/drivers/firmware/arm_scmi/perf.c
>> new file mode 100644
>> index 000000000000..13d84d829201
>> --- /dev/null
>> +++ b/drivers/firmware/arm_scmi/perf.c
>> @@ -0,0 +1,511 @@
>> +/*
>> + * System Control and Management Interface (SCMI) Performance Protocol
>> + *
>> + * Copyright (C) 2017 ARM Ltd.
>> + *
>> + * This program is free software; you can redistribute it and/or
>> modify it
>> + * under the terms and conditions of the GNU General Public License,
>> + * version 2, as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope 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, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm_opp.h>
>> +#include <linux/sort.h>
>> +
>> +#include "common.h"
>> +
>> +enum scmi_performance_protocol_cmd {
>> + PERF_DOMAIN_ATTRIBUTES = 0x3,
>> + PERF_DESCRIBE_LEVELS = 0x4,
>> + PERF_LIMITS_SET = 0x5,
>> + PERF_LIMITS_GET = 0x6,
>> + PERF_LEVEL_SET = 0x7,
>> + PERF_LEVEL_GET = 0x8,
>> + PERF_NOTIFY_LIMITS = 0x9,
>> + PERF_NOTIFY_LEVEL = 0xa,
>> +};
>> +
>> +struct scmi_opp {
>> + u32 perf;
>> + u32 power;
>> + u32 trans_latency_us;
>> +};
>> +
>> +struct scmi_msg_resp_perf_attributes {
>> + __le16 num_domains;
>> + __le16 flags;
>> +#define POWER_SCALE_IN_MILLIWATT(x) ((x) & BIT(0))
>> + __le32 stats_addr_low;
>> + __le32 stats_addr_high;
>> + __le32 stats_size;
>> +};
>> +
>> +struct scmi_msg_resp_perf_domain_attributes {
>> + __le32 flags;
>> +#define SUPPORTS_SET_LIMITS(x) ((x) & BIT(31))
>> +#define SUPPORTS_SET_PERF_LVL(x) ((x) & BIT(30))
>> +#define SUPPORTS_PERF_LIMIT_NOTIFY(x) ((x) & BIT(29))
>> +#define SUPPORTS_PERF_LEVEL_NOTIFY(x) ((x) & BIT(28))
>> + __le32 rate_limit_us;
>> + __le32 sustained_freq_khz;
>> + __le32 sustained_perf_level;
>> + u8 name[SCMI_MAX_STR_SIZE];
>> +};
>> +
>> +struct scmi_msg_perf_describe_levels {
>> + __le32 domain;
>> + __le32 level_index;
>> +};
>> +
>> +struct scmi_perf_set_limits {
>> + __le32 domain;
>> + __le32 max_level;
>> + __le32 min_level;
>> +};
>> +
>> +struct scmi_perf_get_limits {
>> + __le32 max_level;
>> + __le32 min_level;
>> +};
>> +
>> +struct scmi_perf_set_level {
>> + __le32 domain;
>> + __le32 level;
>> +};
>> +
>> +struct scmi_perf_notify_level_or_limits {
>> + __le32 domain;
>> + __le32 notify_enable;
>> +};
>> +
>> +struct scmi_msg_resp_perf_describe_levels {
>> + __le16 num_returned;
>> + __le16 num_remaining;
>> + struct {
>> + __le32 perf_val;
>> + __le32 power;
>> + __le16 transition_latency_us;
>> + __le16 reserved;
>> + } opp[0];
>> +};
>> +
>> +struct perf_dom_info {
>> + bool set_limits;
>> + bool set_perf;
>> + bool perf_limit_notify;
>> + bool perf_level_notify;
>> + u32 opp_count;
>> + u32 sustained_freq_khz;
>> + u32 sustained_perf_level;
>> + u32 mult_factor;
>> + char name[SCMI_MAX_STR_SIZE];
>> + struct scmi_opp opp[MAX_OPPS];
>> +};
>> +
>> +struct scmi_perf_info {
>> + int num_domains;
>> + bool power_scale_mw;
>> + u64 stats_addr;
>> + u32 stats_size;
>> + struct perf_dom_info *dom_info;
>> +};
>> +
>> +static struct scmi_perf_info perf_info;
>> +
>> +static int scmi_perf_attributes_get(const struct scmi_handle *handle,
>> + struct scmi_perf_info *perf_info)
>> +{
>> + int ret;
>> + struct scmi_xfer *t;
>> + struct scmi_msg_resp_perf_attributes *attr;
>> +
>> + ret = scmi_one_xfer_init(handle, PROTOCOL_ATTRIBUTES,
>> + SCMI_PROTOCOL_PERF, 0, sizeof(*attr), &t);
>> + if (ret)
>> + return ret;
>> +
>> + attr = t->rx.buf;
>> +
>> + ret = scmi_do_xfer(handle, t);
>> + if (!ret) {
>> + u16 flags = le16_to_cpu(attr->flags);
>> +
>> + perf_info->num_domains = le16_to_cpu(attr->num_domains);
>> + perf_info->power_scale_mw = POWER_SCALE_IN_MILLIWATT(flags);
>> + perf_info->stats_addr = le32_to_cpu(attr->stats_addr_low) |
>> + (u64)le32_to_cpu(attr->stats_addr_high) << 32;
>
> This seems odd, shouldn't it be the following?
> le64_to_cpu(attr->stats_addr_low | (__le64)attr->stats_addr_high << 32)
>

After further reflexion, I think you are right. If I understood the
specification, the address seems to be split into upper and lower 32bits
and each one is stored as a uint32, which fits what you are doing to
obtain the address.

You can ignore my previous comment.

--
Julien Thierry

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