Messages in this thread | | | Subject | Re: [PATCH v10 03/12] peci: Add support for PECI bus driver core | From | Jae Hyun Yoo <> | Date | Mon, 14 Jan 2019 14:38:10 -0800 |
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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.yoo@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; >> +} >> + >
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