[RFC,13/15] cxl/core/port: Add attrs for root ways & granularity

Commit Message

Ben Widawsky April 13, 2022, 6:37 p.m. UTC

Region programming requires knowledge of root decoder attributes. For
example, if the root decoder supports only 256b granularity then a
region with > 256b granularity cannot work. Add sysfs attributes in
order to provide this information to userspace. The CXL driver controls
programming of switch and endpoint decoders, but the attributes are also
exported for informational purposes.

Signed-off-by: Ben Widawsky <[e-mail]>
---
 drivers/cxl/core/port.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

Patch

diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 5ef8a6e1ea23..19cf1fd16118 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -318,10 +318,31 @@  static ssize_t target_list_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(target_list);
 
+static ssize_t interleave_granularity_show(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct cxl_decoder *cxld = to_cxl_decoder(dev);
+
+	return sysfs_emit(buf, "%d\n", cxld->interleave_granularity);
+}
+static DEVICE_ATTR_RO(interleave_granularity);
+
+static ssize_t interleave_ways_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct cxl_decoder *cxld = to_cxl_decoder(dev);
+
+	return sysfs_emit(buf, "%d\n", cxld->interleave_ways);
+}
+static DEVICE_ATTR_RO(interleave_ways);
+
 static struct attribute *cxl_decoder_base_attrs[] = {
 	&dev_attr_start.attr,
 	&dev_attr_size.attr,
 	&dev_attr_locked.attr,
+	&dev_attr_interleave_granularity.attr,
+	&dev_attr_interleave_ways.attr,
 	NULL,
 };