[PATCH v2 8/9] [RFC] firmware: arm_scmi: Add support for clock_enable_latency

Cristian Marussi
2022-02-01T17:16:51Z

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.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
RFC tag is due to the fact that this SCMI spec Clock protocol field
addition is still to be published.

v1 --> v2
- moved enable_latency flag definition from the previous commit
---
drivers/firmware/arm_scmi/clock.c | 12 +++++++++---
include/linux/scmi_protocol.h | 1 +
2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c
index 72f930c0e3e2..552610bfb91e 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
+ /* TODO Use CLOCK Proto Versioning once SCMI spec is updated */
+ if (t->rx.len > sizeof(attr->attributes) + SCMI_MAX_STR_SIZE)
+ 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 {
--
2.17.1