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firmware: arm_scmi: Add discovery of SCMI v2.0 performance fastchannels
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SCMI v2.0 adds support for "FastChannel", a lightweight unidirectional
channel that is dedicated to a single SCMI message type for controlling
a specific platform resource. They do not use a message header as they
are specialized for a single message.

Only PERFORMANCE_LIMITS_{SET,GET} and PERFORMANCE_LEVEL_{SET,GET}
commands are supported over fastchannels. As they are optional, they
need to be discovered by PERFORMANCE_DESCRIBE_FASTCHANNEL command.
Further {LIMIT,LEVEL}_SET commands can have optional doorbell support.

Add support for discovery of these fastchannels.

Cc: Ionela Voinescu <Ionela.Voinescu@arm.com>
Cc: Chris Redpath <Chris.Redpath@arm.com>
Cc: Quentin Perret <Quentin.Perret@arm.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
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Sudeep Holla committed Aug 12, 2019
1 parent aa90ac4 commit ac8aaf3
Showing 1 changed file with 149 additions and 4 deletions.
153 changes: 149 additions & 4 deletions drivers/firmware/arm_scmi/perf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,9 @@
* Copyright (C) 2018 ARM Ltd.
*/

#include <linux/bits.h>
#include <linux/of.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/sort.h>
Expand All @@ -21,6 +23,7 @@ enum scmi_performance_protocol_cmd {
PERF_LEVEL_GET = 0x8,
PERF_NOTIFY_LIMITS = 0x9,
PERF_NOTIFY_LEVEL = 0xa,
PERF_DESCRIBE_FASTCHANNEL = 0xb,
};

struct scmi_opp {
Expand All @@ -44,6 +47,7 @@ struct scmi_msg_resp_perf_domain_attributes {
#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))
#define SUPPORTS_PERF_FASTCHANNELS(x) ((x) & BIT(27))
__le32 rate_limit_us;
__le32 sustained_freq_khz;
__le32 sustained_perf_level;
Expand Down Expand Up @@ -87,17 +91,56 @@ struct scmi_msg_resp_perf_describe_levels {
} opp[0];
};

struct scmi_perf_get_fc_info {
__le32 domain;
__le32 message_id;
};

struct scmi_msg_resp_perf_desc_fc {
__le32 attr;
#define SUPPORTS_DOORBELL(x) ((x) & BIT(0))
#define DOORBELL_REG_WIDTH(x) FIELD_GET(GENMASK(2, 1), (x))
__le32 rate_limit;
__le32 chan_addr_low;
__le32 chan_addr_high;
__le32 chan_size;
__le32 db_addr_low;
__le32 db_addr_high;
__le32 db_set_lmask;
__le32 db_set_hmask;
__le32 db_preserve_lmask;
__le32 db_preserve_hmask;
};

struct scmi_fc_db_info {
int width;
u64 set;
u64 mask;
void __iomem *addr;
};

struct scmi_fc_info {
void __iomem *level_set_addr;
void __iomem *limit_set_addr;
void __iomem *level_get_addr;
void __iomem *limit_get_addr;
struct scmi_fc_db_info *level_set_db;
struct scmi_fc_db_info *limit_set_db;
};

struct perf_dom_info {
bool set_limits;
bool set_perf;
bool perf_limit_notify;
bool perf_level_notify;
bool perf_fastchannels;
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_fc_info *fc_info;
};

struct scmi_perf_info {
Expand Down Expand Up @@ -162,6 +205,7 @@ scmi_perf_domain_attributes_get(const struct scmi_handle *handle, u32 domain,
dom_info->set_perf = SUPPORTS_SET_PERF_LVL(flags);
dom_info->perf_limit_notify = SUPPORTS_PERF_LIMIT_NOTIFY(flags);
dom_info->perf_level_notify = SUPPORTS_PERF_LEVEL_NOTIFY(flags);
dom_info->perf_fastchannels = SUPPORTS_PERF_FASTCHANNELS(flags);
dom_info->sustained_freq_khz =
le32_to_cpu(attr->sustained_freq_khz);
dom_info->sustained_perf_level =
Expand Down Expand Up @@ -250,7 +294,7 @@ scmi_perf_describe_levels_get(const struct scmi_handle *handle, u32 domain,
}

static int scmi_perf_limits_set(const struct scmi_handle *handle, u32 domain,
u32 max_perf, u32 min_perf)
u32 max_perf, u32 min_perf)
{
int ret;
struct scmi_xfer *t;
Expand All @@ -273,7 +317,7 @@ static int scmi_perf_limits_set(const struct scmi_handle *handle, u32 domain,
}

static int scmi_perf_limits_get(const struct scmi_handle *handle, u32 domain,
u32 *max_perf, u32 *min_perf)
u32 *max_perf, u32 *min_perf)
{
int ret;
struct scmi_xfer *t;
Expand All @@ -299,7 +343,7 @@ static int scmi_perf_limits_get(const struct scmi_handle *handle, u32 domain,
}

static int scmi_perf_level_set(const struct scmi_handle *handle, u32 domain,
u32 level, bool poll)
u32 level, bool poll)
{
int ret;
struct scmi_xfer *t;
Expand All @@ -322,7 +366,7 @@ static int scmi_perf_level_set(const struct scmi_handle *handle, u32 domain,
}

static int scmi_perf_level_get(const struct scmi_handle *handle, u32 domain,
u32 *level, bool poll)
u32 *level, bool poll)
{
int ret;
struct scmi_xfer *t;
Expand All @@ -343,6 +387,104 @@ static int scmi_perf_level_get(const struct scmi_handle *handle, u32 domain,
return ret;
}

static bool scmi_perf_fc_size_is_valid(u32 msg, u32 size)
{
if ((msg == PERF_LEVEL_GET || msg == PERF_LEVEL_SET) && size == 4)
return true;
if ((msg == PERF_LIMITS_GET || msg == PERF_LIMITS_SET) && size == 8)
return true;
return false;
}

static void
scmi_perf_domain_desc_fc(const struct scmi_handle *handle, u32 domain,
u32 message_id, void __iomem **p_addr,
struct scmi_fc_db_info **p_db)
{
int ret;
u32 flags;
u64 phys_addr;
u8 size;
void __iomem *addr;
struct scmi_xfer *t;
struct scmi_fc_db_info *db;
struct scmi_perf_get_fc_info *info;
struct scmi_msg_resp_perf_desc_fc *resp;

if (!p_addr)
return;

ret = scmi_xfer_get_init(handle, PERF_DESCRIBE_FASTCHANNEL,
SCMI_PROTOCOL_PERF,
sizeof(*info), sizeof(*resp), &t);
if (ret)
return;

info = t->tx.buf;
info->domain = cpu_to_le32(domain);
info->message_id = cpu_to_le32(message_id);

ret = scmi_do_xfer(handle, t);
if (ret)
goto err_xfer;

resp = t->rx.buf;
flags = le32_to_cpu(resp->attr);
size = le32_to_cpu(resp->chan_size);
if (!scmi_perf_fc_size_is_valid(message_id, size))
goto err_xfer;

phys_addr = le32_to_cpu(resp->chan_addr_low);
phys_addr |= (u64)le32_to_cpu(resp->chan_addr_high) << 32;
addr = devm_ioremap(handle->dev, phys_addr, size);
if (!addr)
goto err_xfer;
*p_addr = addr;

if (p_db && SUPPORTS_DOORBELL(flags)) {
db = devm_kzalloc(handle->dev, sizeof(*db), GFP_KERNEL);
if (!db)
goto err_xfer;

size = 1 << DOORBELL_REG_WIDTH(flags);
phys_addr = le32_to_cpu(resp->db_addr_low);
phys_addr |= (u64)le32_to_cpu(resp->db_addr_high) << 32;
addr = devm_ioremap(handle->dev, phys_addr, size);
if (!addr)
goto err_xfer;

db->addr = addr;
db->width = size;
db->set = le32_to_cpu(resp->db_set_lmask);
db->set |= (u64)le32_to_cpu(resp->db_set_hmask) << 32;
db->mask = le32_to_cpu(resp->db_preserve_lmask);
db->mask |= (u64)le32_to_cpu(resp->db_preserve_hmask) << 32;
*p_db = db;
}
err_xfer:
scmi_xfer_put(handle, t);
}

static void scmi_perf_domain_init_fc(const struct scmi_handle *handle,
u32 domain, struct scmi_fc_info **p_fc)
{
struct scmi_fc_info *fc;

fc = devm_kzalloc(handle->dev, sizeof(*fc), GFP_KERNEL);
if (!fc)
return;

scmi_perf_domain_desc_fc(handle, domain, PERF_LEVEL_SET,
&fc->level_set_addr, &fc->level_set_db);
scmi_perf_domain_desc_fc(handle, domain, PERF_LEVEL_GET,
&fc->level_get_addr, NULL);
scmi_perf_domain_desc_fc(handle, domain, PERF_LIMITS_SET,
&fc->limit_set_addr, &fc->limit_set_db);
scmi_perf_domain_desc_fc(handle, domain, PERF_LIMITS_GET,
&fc->limit_get_addr, NULL);
*p_fc = fc;
}

/* Device specific ops */
static int scmi_dev_domain_id(struct device *dev)
{
Expand Down Expand Up @@ -494,6 +636,9 @@ static int scmi_perf_protocol_init(struct scmi_handle *handle)

scmi_perf_domain_attributes_get(handle, domain, dom);
scmi_perf_describe_levels_get(handle, domain, dom);

if (dom->perf_fastchannels)
scmi_perf_domain_init_fc(handle, domain, &dom->fc_info);
}

handle->perf_ops = &perf_ops;
Expand Down

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