From 69255e746890274e887ba36a403019380cde0b48 Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Mon, 20 Dec 2021 19:56:41 +0000 Subject: firmware: arm_scmi: Add support for atomic transports An SCMI transport can be configured as .atomic_enabled in order to signal to the SCMI core that all its TX path is executed in atomic context and that, when requested, polling mode should be used while waiting for command responses. When a specific platform configuration had properly configured such a transport as .atomic_enabled, the SCMI core will also take care not to sleep in the corresponding RX path while waiting for a response if that specific command transaction was requested as atomic using polling mode. Asynchronous commands should not be used in an atomic context and so a warning is emitted if polling was requested for an asynchronous command. Add also a method to check, from the SCMI drivers, if the underlying SCMI transport is currently configured to support atomic transactions: this will be used by upper layers to determine if atomic requests can be supported at all on this SCMI instance. Link: https://lore.kernel.org/r/20211220195646.44498-7-cristian.marussi@arm.com Signed-off-by: Cristian Marussi Signed-off-by: Sudeep Holla --- include/linux/scmi_protocol.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include/linux/scmi_protocol.h') diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h index 80e781c51ddc..9f895cb81818 100644 --- a/include/linux/scmi_protocol.h +++ b/include/linux/scmi_protocol.h @@ -612,6 +612,13 @@ struct scmi_notify_ops { * @devm_protocol_get: devres managed method to acquire a protocol and get specific * operations and a dedicated protocol handler * @devm_protocol_put: devres managed method to release a protocol + * @is_transport_atomic: method to check if the underlying transport for this + * instance handle is configured to support atomic + * transactions for commands. + * Some users of the SCMI stack in the upper layers could + * be interested to know if they can assume SCMI + * command transactions associated to this handle will + * never sleep and act accordingly. * @notify_ops: pointer to set of notifications related operations */ struct scmi_handle { @@ -622,6 +629,7 @@ struct scmi_handle { (*devm_protocol_get)(struct scmi_device *sdev, u8 proto, struct scmi_protocol_handle **ph); void (*devm_protocol_put)(struct scmi_device *sdev, u8 proto); + bool (*is_transport_atomic)(const struct scmi_handle *handle); const struct scmi_notify_ops *notify_ops; }; -- cgit v1.2.3-59-g8ed1b From 05976c5f3bff8f8b5230da4b39f7cd6dfba9943e Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Thu, 17 Feb 2022 13:12:31 +0000 Subject: firmware: arm_scmi: Support optional system wide atomic-threshold-us An SCMI agent can be configured system-wide with a well-defined atomic threshold: only SCMI synchronous command whose latency has been advertised by the SCMI platform to be lower or equal to this configured threshold will be considered for atomic operations, when requested and if supported by the underlying transport at all. Link: https://lore.kernel.org/r/20220217131234.50328-6-cristian.marussi@arm.com Signed-off-by: Cristian Marussi Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/driver.c | 27 ++++++++++++++++++++++++--- include/linux/scmi_protocol.h | 5 ++++- 2 files changed, 28 insertions(+), 4 deletions(-) (limited to 'include/linux/scmi_protocol.h') diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index 4fd5a35ffa2f..7436c475e708 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -131,6 +131,12 @@ struct scmi_protocol_instance { * MAX_PROTOCOLS_IMP elements allocated by the base protocol * @active_protocols: IDR storing device_nodes for protocols actually defined * in the DT and confirmed as implemented by fw. + * @atomic_threshold: Optional system wide DT-configured threshold, expressed + * in microseconds, for atomic operations. + * Only SCMI synchronous commands reported by the platform + * to have an execution latency lesser-equal to the threshold + * should be considered for atomic mode operation: such + * decision is finally left up to the SCMI drivers. * @notify_priv: Pointer to private data structure specific to notifications. * @node: List head * @users: Number of users of this instance @@ -149,6 +155,7 @@ struct scmi_info { struct mutex protocols_mtx; u8 *protocols_imp; struct idr active_protocols; + unsigned int atomic_threshold; void *notify_priv; struct list_head node; int users; @@ -1406,15 +1413,22 @@ static void scmi_devm_protocol_put(struct scmi_device *sdev, u8 protocol_id) * SCMI instance is configured as atomic. * * @handle: A reference to the SCMI platform instance. + * @atomic_threshold: An optional return value for the system wide currently + * configured threshold for atomic operations. * * Return: True if transport is configured as atomic */ -static bool scmi_is_transport_atomic(const struct scmi_handle *handle) +static bool scmi_is_transport_atomic(const struct scmi_handle *handle, + unsigned int *atomic_threshold) { + bool ret; struct scmi_info *info = handle_to_scmi_info(handle); - return info->desc->atomic_enabled && - is_transport_polling_capable(info); + ret = info->desc->atomic_enabled && is_transport_polling_capable(info); + if (ret && atomic_threshold) + *atomic_threshold = info->atomic_threshold; + + return ret; } static inline @@ -1954,6 +1968,13 @@ static int scmi_probe(struct platform_device *pdev) handle->version = &info->version; handle->devm_protocol_get = scmi_devm_protocol_get; handle->devm_protocol_put = scmi_devm_protocol_put; + + /* System wide atomic threshold for atomic ops .. if any */ + if (!of_property_read_u32(np, "atomic-threshold-us", + &info->atomic_threshold)) + dev_info(dev, + "SCMI System wide atomic threshold set to %d us\n", + info->atomic_threshold); handle->is_transport_atomic = scmi_is_transport_atomic; if (desc->ops->link_supplier) { diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h index 9f895cb81818..fdf6bd83cc59 100644 --- a/include/linux/scmi_protocol.h +++ b/include/linux/scmi_protocol.h @@ -619,6 +619,8 @@ struct scmi_notify_ops { * be interested to know if they can assume SCMI * command transactions associated to this handle will * never sleep and act accordingly. + * An optional atomic threshold value could be returned + * where configured. * @notify_ops: pointer to set of notifications related operations */ struct scmi_handle { @@ -629,7 +631,8 @@ struct scmi_handle { (*devm_protocol_get)(struct scmi_device *sdev, u8 proto, struct scmi_protocol_handle **ph); void (*devm_protocol_put)(struct scmi_device *sdev, u8 proto); - bool (*is_transport_atomic)(const struct scmi_handle *handle); + bool (*is_transport_atomic)(const struct scmi_handle *handle, + unsigned int *atomic_threshold); const struct scmi_notify_ops *notify_ops; }; -- cgit v1.2.3-59-g8ed1b From b7bd36f2e9430a58aefdc326f8e6653e9b000243 Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Thu, 17 Feb 2022 13:12:32 +0000 Subject: firmware: arm_scmi: Add atomic support to clock protocol Introduce new _atomic variant for SCMI clock protocol operations related to enable disable operations: when an atomic operation is required the xfer poll_completion flag is set for that transaction. Link: https://lore.kernel.org/r/20220217131234.50328-7-cristian.marussi@arm.com Signed-off-by: Cristian Marussi Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/clock.c | 22 +++++++++++++++++++--- include/linux/scmi_protocol.h | 3 +++ 2 files changed, 22 insertions(+), 3 deletions(-) (limited to 'include/linux/scmi_protocol.h') diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c index 35b56c8ba0c0..72f930c0e3e2 100644 --- a/drivers/firmware/arm_scmi/clock.c +++ b/drivers/firmware/arm_scmi/clock.c @@ -273,7 +273,7 @@ static int scmi_clock_rate_set(const struct scmi_protocol_handle *ph, static int scmi_clock_config_set(const struct scmi_protocol_handle *ph, u32 clk_id, - u32 config) + u32 config, bool atomic) { int ret; struct scmi_xfer *t; @@ -284,6 +284,8 @@ scmi_clock_config_set(const struct scmi_protocol_handle *ph, u32 clk_id, if (ret) return ret; + t->hdr.poll_completion = atomic; + cfg = t->tx.buf; cfg->id = cpu_to_le32(clk_id); cfg->attributes = cpu_to_le32(config); @@ -296,12 +298,24 @@ scmi_clock_config_set(const struct scmi_protocol_handle *ph, u32 clk_id, static int scmi_clock_enable(const struct scmi_protocol_handle *ph, u32 clk_id) { - return scmi_clock_config_set(ph, clk_id, CLOCK_ENABLE); + return scmi_clock_config_set(ph, clk_id, CLOCK_ENABLE, false); } static int scmi_clock_disable(const struct scmi_protocol_handle *ph, u32 clk_id) { - return scmi_clock_config_set(ph, clk_id, 0); + return scmi_clock_config_set(ph, clk_id, 0, false); +} + +static int scmi_clock_enable_atomic(const struct scmi_protocol_handle *ph, + u32 clk_id) +{ + return scmi_clock_config_set(ph, clk_id, CLOCK_ENABLE, true); +} + +static int scmi_clock_disable_atomic(const struct scmi_protocol_handle *ph, + u32 clk_id) +{ + return scmi_clock_config_set(ph, clk_id, 0, true); } static int scmi_clock_count_get(const struct scmi_protocol_handle *ph) @@ -330,6 +344,8 @@ static const struct scmi_clk_proto_ops clk_proto_ops = { .rate_set = scmi_clock_rate_set, .enable = scmi_clock_enable, .disable = scmi_clock_disable, + .enable_atomic = scmi_clock_enable_atomic, + .disable_atomic = scmi_clock_disable_atomic, }; static int scmi_clock_protocol_init(const struct scmi_protocol_handle *ph) diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h index fdf6bd83cc59..306e576835f8 100644 --- a/include/linux/scmi_protocol.h +++ b/include/linux/scmi_protocol.h @@ -82,6 +82,9 @@ struct scmi_clk_proto_ops { u64 rate); int (*enable)(const struct scmi_protocol_handle *ph, u32 clk_id); int (*disable)(const struct scmi_protocol_handle *ph, u32 clk_id); + int (*enable_atomic)(const struct scmi_protocol_handle *ph, u32 clk_id); + int (*disable_atomic)(const struct scmi_protocol_handle *ph, + u32 clk_id); }; /** -- cgit v1.2.3-59-g8ed1b From 18f295b758b227857133f680a397a42e83c62f3f Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Thu, 17 Feb 2022 13:12:33 +0000 Subject: firmware: arm_scmi: Add support for clock_enable_latency An SCMI platform can optionally advertise an enable latency typically associated with a specific clock resource: add support for parsing such optional message field and export such information in the usual publicly accessible clock descriptor. Link: https://lore.kernel.org/r/20220217131234.50328-8-cristian.marussi@arm.com Signed-off-by: Cristian Marussi Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/clock.c | 12 +++++++++--- include/linux/scmi_protocol.h | 1 + 2 files changed, 10 insertions(+), 3 deletions(-) (limited to 'include/linux/scmi_protocol.h') diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c index 72f930c0e3e2..cf6fed6dec77 100644 --- a/drivers/firmware/arm_scmi/clock.c +++ b/drivers/firmware/arm_scmi/clock.c @@ -27,7 +27,8 @@ struct scmi_msg_resp_clock_protocol_attributes { struct scmi_msg_resp_clock_attributes { __le32 attributes; #define CLOCK_ENABLE BIT(0) - u8 name[SCMI_MAX_STR_SIZE]; + u8 name[SCMI_MAX_STR_SIZE]; + __le32 clock_enable_latency; }; struct scmi_clock_set_config { @@ -116,10 +117,15 @@ static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph, attr = t->rx.buf; ret = ph->xops->do_xfer(ph, t); - if (!ret) + if (!ret) { strlcpy(clk->name, attr->name, SCMI_MAX_STR_SIZE); - else + /* Is optional field clock_enable_latency provided ? */ + if (t->rx.len == sizeof(*attr)) + clk->enable_latency = + le32_to_cpu(attr->clock_enable_latency); + } else { clk->name[0] = '\0'; + } ph->xops->xfer_put(ph, t); return ret; diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h index 306e576835f8..b87551f41f9f 100644 --- a/include/linux/scmi_protocol.h +++ b/include/linux/scmi_protocol.h @@ -42,6 +42,7 @@ struct scmi_revision_info { struct scmi_clock_info { char name[SCMI_MAX_STR_SIZE]; + unsigned int enable_latency; bool rate_discrete; union { struct { -- cgit v1.2.3-59-g8ed1b