[PATCH 4/4] platform/x86/amd/hsmp: Add pwr_current_active_freq_limit_source_raw

[Erwan Velu <erwanaliasr1@gmail.com>]

From: Erwan Velu <e.velu@criteo.com>

pwr_current_active_freq_limit_source reports the active frequency limit
sources as a list of names, one per line, which metrics exporters have
to parse and map back to a value.

Add pwr_current_active_freq_limit_source_raw, reporting the same source
bitmask as a single hexadecimal value. Exporters only need a plain
integer conversion, and its interpretation can be centralized in the
monitoring stack, e.g. with Grafana value mappings, instead of being
decoded on each server.

The bit assignment is defined by the HSMP specification and is stable:
new limit sources are only appended, existing bits never change meaning.
A given value therefore has a single interpretation, whatever the
platform or kernel version it comes from.

Assisted-by: claude-opus-5-5
Signed-off-by: Erwan Velu <e.velu@criteo.com>
---
 Documentation/arch/x86/amd_hsmp.rst   |  4 ++++
 drivers/platform/x86/amd/hsmp/sysfs.c | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/Documentation/arch/x86/amd_hsmp.rst b/Documentation/arch/x86/amd_hsmp.rst
index 954e938eea3d..66dbf506db05 100644
--- a/Documentation/arch/x86/amd_hsmp.rst
+++ b/Documentation/arch/x86/amd_hsmp.rst
@@ -109,6 +109,10 @@ Following sysfs files are available at /sys/devices/amd_hsmp/socket%d/.
   in MHz.
 * pwr_current_active_freq_limit_source: Source of current active frequency
   limit.
+* pwr_current_active_freq_limit_source_raw: Source of current active
+  frequency limit, as a hexadecimal bitmask. Bits 0 to 7 are, in order:
+  cHTC-Active, PROCHOT, TDC limit, PPT Limit, OPN Max, Reliability Limit,
+  APML Agent, HSMP Agent.
 
 ACPI device object format
 =========================
diff --git a/drivers/platform/x86/amd/hsmp/sysfs.c b/drivers/platform/x86/amd/hsmp/sysfs.c
index e9e91b640b2a..fa1cf8dc3b6f 100644
--- a/drivers/platform/x86/amd/hsmp/sysfs.c
+++ b/drivers/platform/x86/amd/hsmp/sysfs.c
@@ -274,6 +274,21 @@ static ssize_t hsmp_freq_limit_source_show(struct device *dev, struct device_att
 	return len;
 }
 
+static ssize_t hsmp_freq_limit_source_raw_show(struct device *dev,
+					       struct device_attribute *attr, char *buf)
+{
+	struct hsmp_sys_attr *hattr = to_hsmp_sys_attr(attr);
+	struct hsmp_socket *sock = dev_get_drvdata(dev);
+	u32 data;
+	int ret;
+
+	ret = hsmp_msg_get_nargs(sock->sock_ind, hattr->msg_id, &data, 1);
+	if (ret)
+		return ret;
+
+	return sysfs_emit(buf, "0x%04lx\n", FIELD_GET(FREQ_SRC_IND_MASK, data));
+}
+
 static const struct bin_attribute  hsmp_metric_tbl_attr = {
 	.attr = { .name = HSMP_METRICS_TABLE_NAME, .mode = 0444},
 	.read = hsmp_metric_tbl_acpi_read,
@@ -307,6 +322,8 @@ HSMP_DEV_ATTR(pwr_current_active_freq_limit, HSMP_GET_SOCKET_FREQ_LIMIT,
 	      hsmp_freq_limit_show, 0444);
 HSMP_DEV_ATTR(pwr_current_active_freq_limit_source, HSMP_GET_SOCKET_FREQ_LIMIT,
 	      hsmp_freq_limit_source_show, 0444);
+HSMP_DEV_ATTR(pwr_current_active_freq_limit_source_raw, HSMP_GET_SOCKET_FREQ_LIMIT,
+	      hsmp_freq_limit_source_raw_show, 0444);
 
 static struct attribute *hsmp_dev_attr_list[] = {
 	&hattr_c0_residency_input.dattr.attr,
@@ -323,6 +340,7 @@ static struct attribute *hsmp_dev_attr_list[] = {
 	&hattr_clk_fmin.dattr.attr,
 	&hattr_pwr_current_active_freq_limit.dattr.attr,
 	&hattr_pwr_current_active_freq_limit_source.dattr.attr,
+	&hattr_pwr_current_active_freq_limit_source_raw.dattr.attr,
 	NULL
 };
 
-- 
2.53.0