On 3/2/21 4:43 PM, Andre Przywara wrote:
[...]
@@ -488,12 +489,20 @@ int nvme_get_features(struct nvme_dev *dev, unsigned fid,
unsigned nsid,
c.features.prp1 = cpu_to_le64(dma_addr);
c.features.fid = cpu_to_le32(fid);
+ ret = nvme_submit_admin_cmd(dev, &c, result);
+
/*
- * TODO: add cache invalidate operation when the size of
- * the DMA buffer is known
+ * TODO: Add some cache invalidation when a DMA buffer is involved
+ * in the request, here and before the command gets submitted. The
+ * buffer size varies by feature, also some features use a different
+ * field in the command packet to hold the buffer address.
+ * Section 5.21.1 (Set Features command) in the NVMe specification
+ * details the buffer requirements for each feature.
+ *
+ * At the moment there is no user of this function.
If there is no user, remove the function.
*/
- return nvme_submit_admin_cmd(dev, &c, result);
+ return ret;
}
int nvme_set_features(struct nvme_dev *dev, unsigned fid, unsigned dword11,
@@ -508,8 +517,14 @@ int nvme_set_features(struct nvme_dev *dev, unsigned fid,
unsigned dword11,
c.features.dword11 = cpu_to_le32(dword11);
/*
- * TODO: add cache flush operation when the size of
- * the DMA buffer is known
+ * TODO: Add a cache clean (aka flush) operation when a DMA buffer is
The operation is called flush in U-Boot, cache clean is ARM-specific
terminology, avoid it in generic drivers.
+ * involved in the request. The buffer size varies by feature, also
+ * some features use a different field in the command packet to hold
+ * the buffer address. Section 5.21.1 (Set Features command) in the
+ * NVMe specification details the buffer requirements for each
+ * feature.
It would be far more useful to explain the buffer requirements here than
to point to an unknown version of some spec, which could very well be
re-enumerated in the next version.
+ * At the moment the only user of this function is not using
+ * any DMA buffer at all.
*/
return nvme_submit_admin_cmd(dev, &c, result);
[...]
