On Wed, Jun 7, 2017 at 6:10 PM, Sudeep Holla [off-list ref] wrote:

+struct scmi_msg_resp_power_attributes {
+       __le16 num_domains;
+       __le16 reserved;
+       __le32 stats_addr_low;
+       __le32 stats_addr_high;
+       __le32 stats_size;
+} __packed;
+
+struct scmi_msg_resp_power_domain_attributes {
+       __le32 flags;
+#define SUPPORTS_STATE_SET_NOTIFY(x)   ((x) & BIT(31))
+#define SUPPORTS_STATE_SET_ASYNC(x)    ((x) & BIT(30))
+#define SUPPORTS_STATE_SET_SYNC(x)     ((x) & BIT(29))
+           u8 name[SCMI_MAX_STR_SIZE];
+} __packed;

I think it would be better to leave out the __packed here, which
can lead to rather inefficient code. It's only really a problem when
building with -mstrict-align, but it's better to write code in a way that
doesn't rely on that.

+static int
+scmi_power_domain_attributes_get(struct scmi_handle *handle, u32 domain,
+                                struct power_dom_info *dom_info)
+{
+       int ret;
+       struct scmi_xfer *t;
+       struct scmi_msg_resp_power_domain_attributes *attr;
+
+       ret = scmi_one_xfer_init(handle, POWER_DOMAIN_ATTRIBUTES,
+                                SCMI_PROTOCOL_POWER, sizeof(domain),
+                                sizeof(*attr), &t);
+       if (ret)
+               return ret;
+
+       *(__le32 *)t->tx.buf = cpu_to_le32(domain);
+       attr = (struct scmi_msg_resp_power_domain_attributes *)t->rx.buf;

It seems you require a similar pattern in each caller of scmi_one_xfer_init(),
but it seems a little clumsy to always require those casts, so maybe there
is a nicer way to do this. How about making scmi_one_xfer_init() act
as an allocation function and having it return the buffer or a PTR_ERR?

It also seems odd to have it named 'init' but actually allocate the scmi_xfer
structure rather than filling a local variable that gets passed by reference.

       Arnd
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