Hello Joel,
On 1/14/2019 3:13 AM, Joel Stanley wrote:
Hello Jae,
On Tue, 8 Jan 2019 at 08:11, Jae Hyun Yoo <jae.hyun....@linux.intel.com> wrote:
This commit adds driver implementation for PECI bus core into linux
driver framework.
I would like to help you get this merged next release cycle, as we are
now carrying it in OpenBMC. I suggest we ask Greg to queue it up if
there are no objections after you've addressed my questions.
Thanks a lot for your help on reviewing this patch series. I'll submit
v11 to address your comments. We could ask Greg to queue it then.
+static u8 peci_aw_fcs(u8 *data, int len)
I was wondering what aw_fcs meant. I notice that later on you describe
it as an Assure Write Frame Check Sequence byte. You could add a
comment next to this function :)
Agreed. I'll add a comment like you suggested.
Instead of casing to u8 every time you call this, you could have this
take a struct peci_xfer_msg * and cast when calling crc8.
Yes, that would be neater. Will fix it.
+{
+ return crc8(peci_crc8_table, data, (size_t)len, 0);
+}
+
+static int __peci_xfer(struct peci_adapter *adapter, struct peci_xfer_msg *msg,
+ bool do_retry, bool has_aw_fcs)
+{
+ ktime_t start, end;
+ s64 elapsed_ms;
+ int rc = 0;
+
+ /**
These are for kerneldoc, and the comments aren't kerneldoc. Replace
them with /* instead.
Okay, I'll check all comments again in this series.
+ * For some commands, the PECI originator may need to retry a command if
+ * the processor PECI client responds with a 0x8x completion code. In
+ * each instance, the processor PECI client may have started the
+ * operation but not completed it yet. When the 'retry' bit is set, the
+ * PECI client will ignore a new request if it exactly matches a
+ * previous valid request.
+ */
+
+ if (do_retry)
+ start = ktime_get();
+
+ do {
+ rc = adapter->xfer(adapter, msg);
+
+ if (!do_retry || rc)
+ break;
+
+ if (msg->rx_buf[0] == DEV_PECI_CC_SUCCESS)
+ break;
+
+ /* Retry is needed when completion code is 0x8x */
+ if ((msg->rx_buf[0] & DEV_PECI_CC_RETRY_CHECK_MASK) !=
+ DEV_PECI_CC_NEED_RETRY) {
+ rc = -EIO;
+ break;
+ }
+
+ /* Set the retry bit to indicate a retry attempt */
+ msg->tx_buf[1] |= DEV_PECI_RETRY_BIT;
+
+ /* Recalculate the AW FCS if it has one */
+ if (has_aw_fcs)
+ msg->tx_buf[msg->tx_len - 1] = 0x80 ^
Can we guarantee that msg->tx_len will be set to non-zero whenever has_aw_fcs?
I suggest checking before doing the assignment in case a new caller is
added and they make a mistake.
The msg->tx_len is already checked by callers - peci_ioctl_wr_pkg_cfg()
and peci_ioctl_wr_pci_cfg_local() - so it's not needed to be checked
again at here.
+static int peci_ioctl_get_dib(struct peci_adapter *adapter, void *vmsg)
+{
+ struct peci_get_dib_msg *umsg = vmsg;
+ struct peci_xfer_msg msg;
+ int rc;
+
+ msg.addr = umsg->addr;
+ msg.tx_len = GET_DIB_WR_LEN;
+ msg.rx_len = GET_DIB_RD_LEN;
+ msg.tx_buf[0] = GET_DIB_PECI_CMD;
+
+ rc = peci_xfer(adapter, &msg);
Most of tx_buf is going to be uninitialised. I assume a well behaving
adapter->xfer will check this and only send the correct number of
bytes, but it might pay to zero out struct peci_xfer_msg in all of
these functions?
The tx_buf will be initialized only amounts it needs to be in each
command. The adapter->xfer is handling exactly up to msg->tx_len so
it would be better keep the current code without using zeroing out the
struct.
+ if (rc)
+ return rc;
+
+ umsg->dib = le64_to_cpup((__le64 *)msg.rx_buf);
+
+ return 0;
+}
+
+#if IS_ENABLED(CONFIG_OF)
+static struct peci_client *peci_of_register_device(struct peci_adapter
*adapter,
+ struct device_node *node)
+{
+ struct peci_board_info info = {};
+ struct peci_client *result;
+ const __be32 *addr_be;
+ int len;
+
+ dev_dbg(&adapter->dev, "register %pOF\n", node);
+
+ if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
I don't understand why you're doing this. Won't this always be peci,
as your binding requires?
Since it supports only 'intel,peci-client' for now, it's not needed
actually. I'll drop it at this time. It would be added later if needed.
+ dev_err(&adapter->dev, "modalias failure on %pOF\n", node);
+ return ERR_PTR(-EINVAL);
+ }
+
+ addr_be = of_get_property(node, "reg", &len);
+ if (!addr_be || len < sizeof(*addr_be)) {
The second check looks suspicious.
You could fix it to check the expected length (4), or use of_property_read_u32.
Right, I'll fix it using of_property_read_u32.
+ dev_err(&adapter->dev, "invalid reg on %pOF\n", node);
+ return ERR_PTR(-EINVAL);
+ }
+
+ info.addr = be32_to_cpup(addr_be);
+ info.of_node = of_node_get(node);
+
+ result = peci_new_device(adapter, &info);
+ if (!result)
Should you do an of_node_put here?
Oh, this code is definitely incorrect. I should to put the of_node
reference at here if peci_new_device() fails and should keep the
reference until peci_unregister_device() is called. Will fix it.
Thank you for your pointing it out!
+ result = ERR_PTR(-EINVAL);
+
+ of_node_put(node);
Why do you release the reference here?
This is incorrect too. Will move the of_node_get/put code into
peci_new_device() and peci_unregister_device() to avoid confusion.
Thanks again for your pointing it out. :)
+ return result;
+}
+
