[PATCH 6/8] platform/x86/intel/sdsi: Add attribute to read the current meter state

David E. Box
2024-02-01T01:07:51Z

The meter_certificate file provides access to metering information that may
be attested but is only updated every 8 hours. Add new attribute,
meter_current, to allow reading an untested snapshot of the current values.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
---
drivers/platform/x86/intel/sdsi.c | 42 ++++++++++++++++++++++++++++---
drivers/platform/x86/intel/sdsi.h | 2 ++
2 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/intel/sdsi.c b/drivers/platform/x86/intel/sdsi.c
index 287780fe65bb..171899b4a671 100644
--- a/drivers/platform/x86/intel/sdsi.c
+++ b/drivers/platform/x86/intel/sdsi.c
@@ -62,6 +62,7 @@
#define CTRL_COMPLETE BIT(6)
#define CTRL_READY BIT(7)
#define CTRL_INBAND_LOCK BIT(32)
+#define CTRL_METER_ENABLE_DRAM BIT(33)
#define CTRL_STATUS GENMASK(15, 8)
#define CTRL_PACKET_SIZE GENMASK(31, 16)
#define CTRL_MSG_SIZE GENMASK(63, 48)
@@ -235,8 +236,10 @@ static int sdsi_mbox_cmd_read(struct sdsi_priv *priv, struct sdsi_mbox_info *inf
control = FIELD_PREP(CTRL_EOM, 1) |
FIELD_PREP(CTRL_SOM, 1) |
FIELD_PREP(CTRL_RUN_BUSY, 1) |
- FIELD_PREP(CTRL_PACKET_SIZE, info->size);
+ FIELD_PREP(CTRL_PACKET_SIZE, info->size) |
+ priv->control_flags;
writeq(control, priv->control_addr);
+ priv->control_flags = 0;

return sdsi_mbox_poll(priv, info, data_size);
}
@@ -468,11 +471,42 @@ meter_certificate_read(struct file *filp, struct kobject *kobj,
{
struct device *dev = kobj_to_dev(kobj);
struct sdsi_priv *priv = dev_get_drvdata(dev);
+ int ret;

- return certificate_read(SDSI_CMD_READ_METER, priv, buf, off, count);
+ ret = mutex_lock_interruptible(&priv->meter_lock);
+ if (ret)
+ return ret;
+
+ ret = certificate_read(SDSI_CMD_READ_METER, priv, buf, off, count);
+
+ mutex_unlock(&priv->meter_lock);
+
+ return ret;
}
static BIN_ATTR_ADMIN_RO(meter_certificate, SDSI_SIZE_READ_MSG);

+static ssize_t
+meter_current_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr, char *buf, loff_t off,
+ size_t count)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct sdsi_priv *priv = dev_get_drvdata(dev);
+ int ret;
+
+ ret = mutex_lock_interruptible(&priv->meter_lock);
+ if (ret)
+ return ret;
+
+ priv->control_flags = CTRL_METER_ENABLE_DRAM;
+ ret = certificate_read(SDSI_CMD_READ_METER, priv, buf, off, count);
+
+ mutex_unlock(&priv->meter_lock);
+
+ return ret;
+}
+static BIN_ATTR_ADMIN_RO(meter_current, SDSI_SIZE_READ_MSG);
+
static ssize_t registers_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr, char *buf, loff_t off,
size_t count)
@@ -503,6 +537,7 @@ static struct bin_attribute *sdsi_bin_attrs[] = {
&bin_attr_registers,
&bin_attr_state_certificate,
&bin_attr_meter_certificate,
+ &bin_attr_meter_current,
&bin_attr_provision_akc,
&bin_attr_provision_cap,
NULL
@@ -522,7 +557,7 @@ sdsi_battr_is_visible(struct kobject *kobj, struct bin_attribute *attr, int n)
if (!(priv->features & SDSI_FEATURE_SDSI))
return 0;

- if (attr == &bin_attr_meter_certificate)
+ if (attr == &bin_attr_meter_certificate || attr == &bin_attr_meter_current)
return (priv->features & SDSI_FEATURE_METERING) ?
attr->attr.mode : 0;

@@ -725,6 +760,7 @@ static int sdsi_probe(struct auxiliary_device *auxdev, const struct auxiliary_de
priv->dev = &auxdev->dev;
priv->id = auxdev->id;
mutex_init(&priv->mb_lock);
+ mutex_init(&priv->meter_lock);
auxiliary_set_drvdata(auxdev, priv);

/* Get the SDSi discovery table */
diff --git a/drivers/platform/x86/intel/sdsi.h b/drivers/platform/x86/intel/sdsi.h
index 256618eb3136..e20cf279212e 100644
--- a/drivers/platform/x86/intel/sdsi.h
+++ b/drivers/platform/x86/intel/sdsi.h
@@ -18,12 +18,14 @@ struct device;

struct sdsi_priv {
struct mutex mb_lock; /* Mailbox access lock */
+ struct mutex meter_lock;
struct device *dev;
struct intel_vsec_device *ivdev;
struct list_head node;
void __iomem *control_addr;
void __iomem *mbox_addr;
void __iomem *regs_addr;
+ u64 control_flags;
int control_size;
int maibox_size;
int registers_size;
--
2.34.1