Hi Andrew,
Thanks for sharing your time to review it. Please check my answers inline.
On 2/21/2018 9:04 AM, Andrew Lunn wrote:
+static int peci_locked_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;
+
+ if (!adapter->xfer) {
+ dev_dbg(&adapter->dev, "PECI level transfers not supported\n");
+ return -ENODEV;
+ }
+
+ if (in_atomic() || irqs_disabled()) {
Hi Jae
Is there a real need to do transfers in atomic context, or with
interrupts disabled?
Actually, no. Generally, this function will be called in sleep-able
context so this code is for an exceptional case handling.
I'll rewrite this code like below:
if (in_atomic() || irqs_disabled()) {
dev_dbg(&adapter->dev,
"xfer in non-sleepable context is not supported\n");
return -EWOULDBLOCK;
}
And then, will add a sleep call into the below loop.
I know that in_atomic() call is not recommended in driver code but some
driver codes still use it since there is no alternative way at this
time, AFAIK. Please tell me if there is a better solution.
+ rt_mutex_trylock(&adapter->bus_lock);
+ if (!rc)
+ return -EAGAIN; /* PECI activity is ongoing */
+ } else {
+ rt_mutex_lock(&adapter->bus_lock);
+ }
+
+ if (do_retry)
+ start = ktime_get();
+
+ do {
+ rc = adapter->xfer(adapter, msg);
+
+ if (!do_retry)
+ break;
+
+ /* Per the PECI spec, need to retry commands that return 0x8x */
+ if (!(!rc && ((msg->rx_buf[0] & DEV_PECI_CC_RETRY_ERR_MASK) ==
+ DEV_PECI_CC_TIMEOUT)))
+ 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 ^
+ peci_aw_fcs((u8 *)msg,
+ 2 + msg->tx_len);
+
+ /* Retry for at least 250ms before returning an error */
+ end = ktime_get();
+ elapsed_ms = ktime_to_ms(ktime_sub(end, start));
+ if (elapsed_ms >= DEV_PECI_RETRY_TIME_MS) {
+ dev_dbg(&adapter->dev, "Timeout retrying xfer!\n");
+ break;
+ }
+ } while (true);
So you busy loop to 1/4 second? How about putting a sleep in here so
other things can be done between each retry.
And should it not return -ETIMEDOUT after that 1/4 second?
Yes, you are right. I'll rewrite this code like below after adding the
above change:
/**
* Retry for at least 250ms before returning an error.
* Retry interval guideline:
* No minimum < Retry Interval < No maximum
* (recommend 10ms)
*/
end = ktime_get();
elapsed_ms = ktime_to_ms(ktime_sub(end, start));
if (elapsed_ms >= DEV_PECI_RETRY_TIME_MS) {
dev_dbg(&adapter->dev, "Timeout retrying xfer!\n");
rc = -ETIMEDOUT;
break;
}
usleep_range(DEV_PECI_RETRY_INTERVAL_MS * 1000,
(DEV_PECI_RETRY_INTERVAL_MS * 1000) + 1000);
+static int peci_scan_cmd_mask(struct peci_adapter *adapter)
+{
+ struct peci_xfer_msg msg;
+ u32 dib;
+ int rc = 0;
+
+ /* Update command mask just once */
+ if (adapter->cmd_mask & BIT(PECI_CMD_PING))
+ return 0;
+
+ msg.addr = PECI_BASE_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);
+ if (rc < 0) {
+ dev_dbg(&adapter->dev, "PECI xfer error, rc : %d\n", rc);
+ return rc;
+ }
+
+ dib = msg.rx_buf[0] | (msg.rx_buf[1] << 8) |
+ (msg.rx_buf[2] << 16) | (msg.rx_buf[3] << 24);
+
+ /* Check special case for Get DIB command */
+ if (dib == 0x00) {
+ dev_dbg(&adapter->dev, "DIB read as 0x00\n");
+ return -1;
+ }
+
+ if (!rc) {
+ /**
+ * setting up the supporting commands based on minor rev#
+ * see PECI Spec Table 3-1
+ */
+ dib = (dib >> 8) & 0xF;
+
+ if (dib >= 0x1) {
+ adapter->cmd_mask |= BIT(PECI_CMD_RD_PKG_CFG);
+ adapter->cmd_mask |= BIT(PECI_CMD_WR_PKG_CFG);
+ }
+
+ if (dib >= 0x2)
+ adapter->cmd_mask |= BIT(PECI_CMD_RD_IA_MSR);
+
+ if (dib >= 0x3) {
+ adapter->cmd_mask |= BIT(PECI_CMD_RD_PCI_CFG_LOCAL);
+ adapter->cmd_mask |= BIT(PECI_CMD_WR_PCI_CFG_LOCAL);
+ }
+
+ if (dib >= 0x4)
+ adapter->cmd_mask |= BIT(PECI_CMD_RD_PCI_CFG);
+
+ if (dib >= 0x5)
+ adapter->cmd_mask |= BIT(PECI_CMD_WR_PCI_CFG);
+
+ if (dib >= 0x6)
+ adapter->cmd_mask |= BIT(PECI_CMD_WR_IA_MSR);
Lots of magic numbers here. Can they be replaced with #defines. Also,
it looks like a switch statement could be used, with fall through.
I agree. Will rewrite it.
+
+ adapter->cmd_mask |= BIT(PECI_CMD_GET_TEMP);
+ adapter->cmd_mask |= BIT(PECI_CMD_GET_DIB);
+ adapter->cmd_mask |= BIT(PECI_CMD_PING);
+ } else {
+ dev_dbg(&adapter->dev, "Error reading DIB, rc : %d\n", rc);
+ }
+
+ return rc;
+}
+
+static int peci_ioctl_get_temp(struct peci_adapter *adapter, void *vmsg)
+{
+ struct peci_get_temp_msg *umsg = vmsg;
+ struct peci_xfer_msg msg;
+ int rc;
+
Is this getting the temperature?
Yes, this is getting the 'die' temperature of a processor package.
+ rc = peci_cmd_support(adapter, PECI_CMD_GET_TEMP);
+ if (rc < 0)
+ return rc;
+
+ msg.addr = umsg->addr;
+ msg.tx_len = GET_TEMP_WR_LEN;
+ msg.rx_len = GET_TEMP_RD_LEN;
+ msg.tx_buf[0] = GET_TEMP_PECI_CMD;
+
+ rc = peci_xfer(adapter, &msg);
+ if (rc < 0)
+ return rc;
+
+ umsg->temp_raw = msg.rx_buf[0] | (msg.rx_buf[1] << 8);
+
+ return 0;
+}
+static long peci_ioctl(struct file *file, unsigned int iocmd, unsigned long
arg)
+{
+ struct peci_adapter *adapter = file->private_data;
+ void __user *argp = (void __user *)arg;
+ unsigned int msg_len;
+ enum peci_cmd cmd;
+ u8 *msg;
+ int rc = 0;
+
+ dev_dbg(&adapter->dev, "ioctl, cmd=0x%x, arg=0x%lx\n", iocmd, arg);
+
+ switch (iocmd) {
+ case PECI_IOC_PING:
+ case PECI_IOC_GET_DIB:
+ case PECI_IOC_GET_TEMP:
+ case PECI_IOC_RD_PKG_CFG:
+ case PECI_IOC_WR_PKG_CFG:
+ case PECI_IOC_RD_IA_MSR:
+ case PECI_IOC_RD_PCI_CFG:
+ case PECI_IOC_RD_PCI_CFG_LOCAL:
+ case PECI_IOC_WR_PCI_CFG_LOCAL:
+ cmd = _IOC_TYPE(iocmd) - PECI_IOC_BASE;
+ msg_len = _IOC_SIZE(iocmd);
+ break;
Adding new ioctl calls is pretty frowned up. Can you export this info
via /sysfs?
Most of these are not simple IOs so ioctl is better suited, I think.
Also, should there be some permission checks here? Or is any user
allowed to call these ioctls?
I agree. I will add some permission checks here.
Andrew
Thanks a lot,
Jae
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