nfit: export subsystem ids as attributes

Similar to pci-sysfs export the subsystem information available in the
NFIT.  ACPI 6.1 clarifies that this data is copied as an array of bytes
from the DIMM SPD data.

Reported-by: Ryon Jensen <ryon.jensen@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 32 insertions, 1 deletions

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index 5a7199db2e06..0a1ba3d2e39a 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -847,6 +847,34 @@ static ssize_t format_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(format);
 
+static ssize_t subsystem_vendor_show(struct device *dev,
+                struct device_attribute *attr, char *buf)
+{
+        struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
+
+        return sprintf(buf, "0x%04x\n", be16_to_cpu(dcr->subsystem_vendor_id));
+}
+static DEVICE_ATTR_RO(subsystem_vendor);
+
+static ssize_t subsystem_rev_id_show(struct device *dev,
+                struct device_attribute *attr, char *buf)
+{
+        struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
+
+        return sprintf(buf, "0x%04x\n",
+                        be16_to_cpu(dcr->subsystem_revision_id));
+}
+static DEVICE_ATTR_RO(subsystem_rev_id);
+
+static ssize_t subsystem_device_show(struct device *dev,
+                struct device_attribute *attr, char *buf)
+{
+        struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
+
+        return sprintf(buf, "0x%04x\n", be16_to_cpu(dcr->subsystem_device_id));
+}
+static DEVICE_ATTR_RO(subsystem_device);
+
 static ssize_t serial_show(struct device *dev,
                 struct device_attribute *attr, char *buf)
 {
@@ -893,9 +921,12 @@ static struct attribute *acpi_nfit_dimm_attributes[] = {
         &dev_attr_phys_id.attr,
         &dev_attr_vendor.attr,
         &dev_attr_device.attr,
+        &dev_attr_rev_id.attr,
+        &dev_attr_subsystem_vendor.attr,
+        &dev_attr_subsystem_device.attr,
+        &dev_attr_subsystem_rev_id.attr,
         &dev_attr_format.attr,
         &dev_attr_serial.attr,
-        &dev_attr_rev_id.attr,
         &dev_attr_flags.attr,
         &dev_attr_id.attr,
         NULL,