Messages in this thread | | | Subject | Re: [PATCH v3 1/2] scsi: ufs: Probe for temperature notification support | From | Guenter Roeck <> | Date | Mon, 13 Sep 2021 00:41:02 -0700 |
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On 9/13/21 12:06 AM, Avri Altman wrote: >>> +config SCSI_UFS_HWMON >>> + bool "UFS Temperature Notification" >>> + depends on SCSI_UFSHCD && HWMON >>> + help >>> + This provides support for UFS hardware monitoring. If enabled, >>> + a hardware monitoring device will be created for the UFS device. >>> + >>> + If unsure, say N. >>> + >> >> git complains about blank line at EOF. > Done. > >> >>> diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile >>> index c407da9b5171..966048875b50 100644 >>> --- a/drivers/scsi/ufs/Makefile >>> +++ b/drivers/scsi/ufs/Makefile >>> @@ -10,6 +10,7 @@ ufshcd-core-$(CONFIG_SCSI_UFS_BSG) += ufs_bsg.o >>> ufshcd-core-$(CONFIG_SCSI_UFS_CRYPTO) += ufshcd-crypto.o >>> ufshcd-core-$(CONFIG_SCSI_UFS_HPB) += ufshpb.o >>> ufshcd-core-$(CONFIG_SCSI_UFS_FAULT_INJECTION) += >>> ufs-fault-injection.o >>> +ufshcd-core-$(CONFIG_SCSI_UFS_HWMON) += ufs-hwmon.o >>> >>> obj-$(CONFIG_SCSI_UFS_DWC_TC_PCI) += tc-dwc-g210-pci.o ufshcd-dwc.o >> tc-dwc-g210.o >>> obj-$(CONFIG_SCSI_UFS_DWC_TC_PLATFORM) += tc-dwc-g210-pltfrm.o >>> ufshcd-dwc.o tc-dwc-g210.o diff --git a/drivers/scsi/ufs/ufs-hwmon.c >>> b/drivers/scsi/ufs/ufs-hwmon.c new file mode 100644 index >>> 000000000000..a50e83f645f4 >>> --- /dev/null >>> +++ b/drivers/scsi/ufs/ufs-hwmon.c >>> @@ -0,0 +1,179 @@ >>> +// SPDX-License-Identifier: GPL-2.0 >>> +/* >>> + * UFS hardware monitoring support >>> + * Copyright (c) 2021, Western Digital Corporation */ >>> + >>> +#include <linux/hwmon.h> >>> + >>> +#include "ufshcd.h" >>> + >>> +struct ufs_hwmon_data { >>> + struct ufs_hba *hba; >>> + u8 mask; >>> +}; >>> + >>> +static bool ufs_temp_enabled(struct ufs_hba *hba, u8 mask) { >>> + u32 ee_mask; >>> + >>> + if (ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR, >>> + QUERY_ATTR_IDN_EE_CONTROL, 0, 0, &ee_mask)) >>> + return false; >>> + >>> + return (mask & ee_mask & MASK_EE_TOO_HIGH_TEMP) || >>> + (mask & ee_mask & MASK_EE_TOO_LOW_TEMP); } >>> + >>> +static bool ufs_temp_valid(struct ufs_hba *hba, u8 mask, >>> + enum attr_idn idn, u32 value) { >>> + return (idn == QUERY_ATTR_IDN_CASE_ROUGH_TEMP && value >= 1 >> && >>> + value <= 250 && ufs_temp_enabled(hba, mask)) || >>> + (idn == QUERY_ATTR_IDN_HIGH_TEMP_BOUND && value >= 100 && >>> + value <= 250) || >>> + (idn == QUERY_ATTR_IDN_LOW_TEMP_BOUND && value >= 1 && >>> + value <= 80); >>> +} >>> + >> The value ranges checed above suggest that the temperature is reported in >> degrees C (or maybe degrees C with an offset). > Yes. No offset. > >> The hwmon API expects >> temperatures to be reported in milli-degrees C, and I don't see a conversion in >> the actual read functions. What does the "sensors" command report ? > I missed that (Although it is well documented) - sorry about that. > I wasn't aware of the sensors command. I don't have it in my arm64 android platform image (galaxy s21). > Will try to get it. > I was reading the temperature using hwmon sysfs entries, which indicate the correct temperature. > e.g > t2s:/ # ls -la /sys/class/hwmon/ > total 0 > drwxr-xr-x 2 root root 0 2020-12-20 10:16 . > drwxr-xr-x 104 root root 0 2020-12-19 19:05 .. > lrwxrwxrwx 1 root root 0 2020-12-20 10:16 hwmon0 -> ../../devices/platform/13100000.ufs/hwmon/hwmon0 > ..... > > t2s:/ # cat /sys/class/hwmon/hwmon0/temp1_input > 25 > > Will fix it. Thanks. > >> >>> +static int ufs_get_temp(struct ufs_hba *hba, u8 mask, enum attr_idn >>> +idn) { >>> + u32 value; >>> + >>> + if (ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR, idn, 0, 0, >>> + &value)) >> >> checkpatch states that alignment is off, and I am quite sure this fits into one >> line anyway (with the 100-column limit). There are more instances with bad >> alignment according to checkpatch. > I wasn't aware that the Linux Kernel deprecates the 80 Character Line Coding Style. > Will try to make it full 100-characters lines. > I didn't get any alignment complaints from checkpatch. > >> >> Also, ufshcd_query_attr() returns a valid Linux error code. That should be >> returned to the caller and not be replaced. More on that below. >> >>> + return 0; >>> + >>> + if (ufs_temp_valid(hba, mask, idn, value)) >>> + return value - 80; >>> + >> >> This again suggests that the temperature is not milli-degrees C. >> >> Is there reason to believe that this validation is necessary ? >> Note that this reports an "error" if the returned temperature value happens to >> have a value of 80. Again, more on that below. > Data->mask holds the temperature related bits in the ufs features register: TOO_LOW_TEMPERATURE and TOO_HIGH_TEMPERATURE. > This is set for the device by the flash vendor and can't be changed by the OEMs. > If the device doesn't support any of that, then hwmon_probe is not even called, see ufshcd_temp_notif_probe. > So data->mask is not 0, and never changes. > > When the device returns a 0 temperature value, it means that it is not valid. > The spec say about the Device’s rough package case surface temperature: > " > This value shall be valid when (TOO_HIGH_TEMPERATURE is supported and TOO_HIGH_TEMP_EN is enabled) or > ( TOO_LOW_TEMPERATURE is supported and TOO_LOW_TEMP_EN is enabled ). > 0 : Unknown Temperature , 1~250 : ( this value – 80 ) degrees in Celsius. ( i.e., -79 ºC ~ 170 ºC ) > Others: Reserved > " > data->mask is not 0, but the temperature exception bits: TOO_HIGH_TEMP_EN and TOO_LOW_TEMP_EN are of type read/volatile, > Meaning it can be written many times, e.g. by debugfs or ufs-utils. > > To sum up: > - yes, checking the temperature against the spec boundaries is useless. > The device will return 0 if it is not valid. > ufs_temp_valid() can be removed, and just need to check that the temperature is not 0. > > - The return value of querry_attr is of less interest. > if it failed or temp == 0, then the temperature is invalid and the proper return value should be -EINVAL. > >> >>> + return 0; >>> +} >>> + >>> +static int ufs_hwmon_read(struct device *dev, enum hwmon_sensor_types >> type, >>> + u32 attr, int channel, long *val) { >>> + struct ufs_hwmon_data *data = dev_get_drvdata(dev); >>> + struct ufs_hba *hba = data->hba; >>> + u8 mask = data->mask; >>> + int err = 0; >>> + bool get_temp = true; >>> + >>> + if (type != hwmon_temp) >>> + return 0; >>> + >>> + down(&hba->host_sem); >>> + >>> + if (!ufshcd_is_user_access_allowed(hba)) { >>> + up(&hba->host_sem); >>> + return -EBUSY; >>> + } >>> + >>> + ufshcd_rpm_get_sync(hba); >>> + >>> + switch (attr) { >>> + case hwmon_temp_enable: >>> + *val = ufs_temp_enabled(hba, mask); >>> + get_temp = false; >>> + >> >> This seems to be read-only, and the mask only affects the limit registers as far >> as I con see. If so, this is wrong: The mask should be used to enable or hide the >> limit attributes as needed. If the mask is 0, and if this means that the current >> temperature is not reported either, the driver should not instantiate at all. >> >> The "enable" attribute only makes sense if it can be used to actually enable or >> disable a specific sensor, and is not tied to limit attributes but to the actual >> sensor values. > See explanation above. > Will make it writable as well. >
That only makes sense if the information is passed to the chip. What is going to happen if the user writes 0 into the attribute ?
Guenter
>> >>> + break; >>> + case hwmon_temp_max_alarm: >>> + *val = ufs_get_temp(hba, mask, >>> + QUERY_ATTR_IDN_HIGH_TEMP_BOUND); >>> + >>> + break; >>> + case hwmon_temp_min_alarm: >>> + *val = ufs_get_temp(hba, mask, >>> + QUERY_ATTR_IDN_LOW_TEMP_BOUND); >>> + >>> + break; >>> + case hwmon_temp_input: >>> + *val = ufs_get_temp(hba, mask, >>> + QUERY_ATTR_IDN_CASE_ROUGH_TEMP); >>> + >> If an enable attribute exists and is 0 (disabled), this should return -ENODATA. >> In this case, that would imply that the driver should not be instantiated in the >> first place since it has nothing to report. > See explanation above. > Will fix it so the error value will make more sense. > >> >>> + break; >>> + default: >>> + err = -EOPNOTSUPP; >>> + >>> + break; >>> + } >>> + >>> + ufshcd_rpm_put_sync(hba); >>> + >>> + up(&hba->host_sem); >>> + >>> + if (get_temp && !err && *val == 0) >>> + err = -EINVAL; >>> + >> That is an odd way of detection errors. If it was in the hwmon subsystem, I'd ask >> for the error handling to be moved into the case statements. On top of that, >> interpreting a return value of "0" as error seems wrong. >> ufs_get_temp() returns 0 if the measured temperature or the reported limit >> happens to have a value of 80, and that is perfectly valid. If ufs_get_temp() >> reports an error, it should report that as error. >> >> Also, EINVAL is "invalid argument", which I am quite sure does not apply here. > Ditto. > EINVAL implies that the temperature is invalid. > >>> >>> +static void ufshcd_temp_notif_probe(struct ufs_hba *hba, u8 >>> +*desc_buf) { >>> + struct ufs_dev_info *dev_info = &hba->dev_info; >>> + u32 ext_ufs_feature; >>> + u8 mask = 0; >>> + >>> + if (!(hba->caps & UFSHCD_CAP_TEMP_NOTIF) || >>> + dev_info->wspecversion < 0x300) >> >> I am quite sure this fits a single line. > Done. >
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