[PATCH V4 4/9] platform/x86/intel/sdsi: Add attribute to read the current meter state

David E. Box
2024-04-11T02:59:07Z

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>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
V4 - no changes

V3 - no changes

V2 - make control_flags a parameter to be eventually passed to
sdsi_mbox_cmd_read(). This removes the need for a lock which had been
added to protect control_flags when it was a member of the private
struct.

drivers/platform/x86/intel/sdsi.c | 30 ++++++++++++++++++++++++------
1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/x86/intel/sdsi.c b/drivers/platform/x86/intel/sdsi.c
index bb3eaf5eb382..277e4f4b20ac 100644
--- a/drivers/platform/x86/intel/sdsi.c
+++ b/drivers/platform/x86/intel/sdsi.c
@@ -68,6 +68,7 @@
#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)
@@ -95,6 +96,7 @@ enum sdsi_command {
struct sdsi_mbox_info {
u64 *payload;
void *buffer;
+ u64 control_flags;
int size;
};

@@ -250,7 +252,8 @@ 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) |
+ info->control_flags;
writeq(control, priv->control_addr);

return sdsi_mbox_poll(priv, info, data_size);
@@ -424,8 +427,8 @@ static ssize_t provision_cap_write(struct file *filp, struct kobject *kobj,
static BIN_ATTR_WO(provision_cap, SDSI_SIZE_WRITE_MSG);

static ssize_t
-certificate_read(u64 command, struct sdsi_priv *priv, char *buf, loff_t off,
- size_t count)
+certificate_read(u64 command, u64 control_flags, struct sdsi_priv *priv,
+ char *buf, loff_t off, size_t count)
{
struct sdsi_mbox_info info = {};
size_t size;
@@ -441,6 +444,7 @@ certificate_read(u64 command, struct sdsi_priv *priv, char *buf, loff_t off,

info.payload = &command;
info.size = sizeof(command);
+ info.control_flags = control_flags;

ret = mutex_lock_interruptible(&priv->mb_lock);
if (ret)
@@ -472,7 +476,7 @@ state_certificate_read(struct file *filp, struct kobject *kobj,
struct device *dev = kobj_to_dev(kobj);
struct sdsi_priv *priv = dev_get_drvdata(dev);

- return certificate_read(SDSI_CMD_READ_STATE, priv, buf, off, count);
+ return certificate_read(SDSI_CMD_READ_STATE, 0, priv, buf, off, count);
}
static BIN_ATTR_ADMIN_RO(state_certificate, SDSI_SIZE_READ_MSG);

@@ -484,10 +488,23 @@ meter_certificate_read(struct file *filp, struct kobject *kobj,
struct device *dev = kobj_to_dev(kobj);
struct sdsi_priv *priv = dev_get_drvdata(dev);

- return certificate_read(SDSI_CMD_READ_METER, priv, buf, off, count);
+ return certificate_read(SDSI_CMD_READ_METER, 0, priv, buf, off, count);
}
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);
+
+ return certificate_read(SDSI_CMD_READ_METER, CTRL_METER_ENABLE_DRAM,
+ priv, buf, off, count);
+}
+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)
@@ -518,6 +535,7 @@ 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
@@ -537,7 +555,7 @@ 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;

--
2.34.1