Hi Sui I am not sure that there is a standard that returning -ENXIO means always NACK, and I am not sure that there are no other cases where we return -ENXIO which is not NACK, unless you are asking for local modification that will not be upstreamed. Also you can know the per-address counters via the 'adap' stract you use for transfer. Thanks, Avi On Tue, Apr 12, 2022 at 9:57 AM Sui Chen <suichen@xxxxxxxxxx> wrote: > > Hello Avi, > > I recently installed a patched kernel on a real machine and am trying > to validate the counters a bit; I would like to find out how the > counters in the i2c core relate to the counters in the npcm7xx driver, > and also explore the possibility of per-address counters, then update > to this list and the linux-kernel list when the results are clear. > > And also I need to find a better place to create the sysfs folders > than from within i2c_transfer and i2c_recover_bus. > > Thanks, > Sui > > > On Sun, Apr 3, 2022 at 5:12 AM Avi Fishman <avifishman70@xxxxxxxxx> wrote: > > > > Hi Sui, > > > > Do you intend later to push it also to kernel.org? > > > > Avi > > > > On Fri, Apr 1, 2022 at 3:28 AM Sui Chen <suichen@xxxxxxxxxx> wrote: > > > > > > This change renames the I2C debug counters as suggested, and moves their > > > processing into the i2c core: > > > - bus_errors > > > - transfers > > > - nacks > > > - recovery_successes > > > - recovery_failures > > > - timeouts > > > > > > The function i2c_adapter_create_stats_folder creates a stats directory > > > in the device's sysfs directory to hold the above debug counters. > > > > > > Did some brief tests with a few test programs that saves/replays I2C > > > trace by reading hwmon sensors. The test program and hardware run in > > > QEMU. The test programs are located at > > > https://gerrit.openbmc-project.xyz/c/openbmc/openbmc-tools/+/52527 > > > > > > (A normal read) > > > > > > root@gsj:/tmp# cat /sys/class/i2c-adapter/i2c-1/stats/transfers > > > 264 > > > root@gsj:/tmp# ./i2c_bmk_bmc 0 > > > idx=0 > > > Processing 1 inputs > > > /sys/class/hwmon/hwmon0/temp1_input > > > (../../devices/platform/ahb/ahb:apb/f0081000.i2c/i2c-1/1-005c/hwmon/hwmon0): > > > 0 > > > [FindTraceEntries] t0=391.000000 t1=393.000000 > > > Found 4 interesting I2C trace entries: > > > i2c_write: i2c-1 #0 a=05c f=0000 l=1 [00] > > > i2c_read: i2c-1 #1 a=05c f=0001 l=2 > > > i2c_reply: i2c-1 #1 a=05c f=0001 l=2 [00-00] > > > i2c_result: i2c-1 n=2 ret=2 > > > root@gsj:/tmp# cat /sys/class/i2c-adapter/i2c-1/stats/transfers > > > 265 > > > > > > (Read from an inexistent address, NACK) > > > > > > root@gsj:/tmp# cat /sys/class/i2c-adapter/i2c-1/stats/nacks > > > 6 > > > root@gsj:/tmp# cat /sys/class/i2c-adapter/i2c-1/stats/transfers > > > 265 > > > > > > root@gsj:/tmp# cat i2c_trace.txt > > > i2c_write: i2c-1 #0 a=0ff f=0000 l=1 [00] > > > i2c_read: i2c-1 #1 a=0ff f=0001 l=2 > > > root@gsj:/tmp# ./i2c_replay_bmc i2c_trace.txt > > > (program runs and completes) > > > > > > root@gsj:/tmp# cat /sys/class/i2c-adapter/i2c-1/stats/nacks > > > 12 > > > root@gsj:/tmp# cat /sys/class/i2c-adapter/i2c-1/stats/transfers > > > 265 > > > > > > The program makes 2 attempts, performing 3 I2C operations at each > > > attempt, which translates to the 6 nack events. > > > > > > Signed-off-by: Sui Chen <suichen@xxxxxxxxxx> > > > --- > > > drivers/i2c/i2c-core-base.c | 32 ++++++++++++- > > > drivers/i2c/i2c-dev.c | 94 +++++++++++++++++++++++++++++++++++++ > > > include/linux/i2c.h | 26 ++++++++++ > > > 3 files changed, 151 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c > > > index 84f12bf90644..53688b1d855a 100644 > > > --- a/drivers/i2c/i2c-core-base.c > > > +++ b/drivers/i2c/i2c-core-base.c > > > @@ -270,11 +270,22 @@ EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery); > > > > > > int i2c_recover_bus(struct i2c_adapter *adap) > > > { > > > + > > > + if (adap->stats == NULL) > > > + i2c_adapter_create_stats_directory(adap); > > > + > > > if (!adap->bus_recovery_info) > > > return -EBUSY; > > > > > > dev_dbg(&adap->dev, "Trying i2c bus recovery\n"); > > > - return adap->bus_recovery_info->recover_bus(adap); > > > + int ret = adap->bus_recovery_info->recover_bus(adap); > > > + > > > + if (ret == 0) > > > + ++(adap->stats->recovery_successes); > > > + else > > > + ++(adap->stats->recovery_failures); > > > + > > > + return ret; > > > } > > > EXPORT_SYMBOL_GPL(i2c_recover_bus); > > > > > > @@ -2223,6 +2234,23 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) > > > trace_i2c_result(adap, num, ret); > > > } > > > > > > + if (adap->stats == NULL) { > > > + i2c_adapter_create_stats_directory(adap); > > > + } > > > + > > > + if (ret < 0) { > > > + if (ret == -ENXIO) > > > + ++(adap->stats->nacks); > > > + else if (ret == -ETIMEDOUT) > > > + ++(adap->stats->timeouts); > > > + else > > > + ++(adap->stats->bus_errors); > > > + } > > > + > > > + if (ret == num) { > > > + ++(adap->stats->transfers); > > > + } > > > + > > > return ret; > > > } > > > EXPORT_SYMBOL(__i2c_transfer); > > > @@ -2485,6 +2513,7 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) > > > } > > > > > > kfree(temp_client); > > > + i2c_adapter_create_stats_directory(adapter); > > > return err; > > > } > > > > > > @@ -2617,6 +2646,7 @@ void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred) > > > > > > kfree(buf); > > > } > > > + > > > EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf); > > > > > > MODULE_AUTHOR("Simon G. Vogl <simon@xxxxxxxxxxxxxxxxx>"); > > > diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c > > > index 77f576e51652..253622706b63 100644 > > > --- a/drivers/i2c/i2c-dev.c > > > +++ b/drivers/i2c/i2c-dev.c > > > @@ -767,6 +767,100 @@ static void __exit i2c_dev_exit(void) > > > unregister_chrdev_region(MKDEV(I2C_MAJOR, 0), I2C_MINORS); > > > } > > > > > > +static struct i2c_adapter *kobj_to_adapter(struct device *pdev) > > > +{ > > > + struct kobject *dev_kobj; > > > + struct device *dev; > > > + > > > + dev_kobj = ((struct kobject *)pdev)->parent; > > > + dev = container_of(dev_kobj, struct device, kobj); > > > + return to_i2c_adapter(dev); > > > +} > > > + > > > +ssize_t bus_errors_show(struct device *pdev, > > > + struct device_attribute *attr, char *buf) > > > +{ > > > + return sysfs_emit(buf, "%llu\n", kobj_to_adapter(pdev)->stats->bus_errors); > > > +} > > > +DEVICE_ATTR_RO(bus_errors); > > > + > > > +ssize_t transfers_show(struct device *pdev, > > > + struct device_attribute *attr, char *buf) > > > +{ > > > + return sysfs_emit(buf, "%llu\n", kobj_to_adapter(pdev)->stats->transfers); > > > +} > > > +DEVICE_ATTR_RO(transfers); > > > + > > > +ssize_t nacks_show(struct device *pdev, > > > + struct device_attribute *attr, char *buf) > > > +{ > > > + return sysfs_emit(buf, "%llu\n", kobj_to_adapter(pdev)->stats->nacks); > > > +} > > > +DEVICE_ATTR_RO(nacks); > > > + > > > +ssize_t recovery_successes_show(struct device *pdev, > > > + struct device_attribute *attr, char *buf) > > > +{ > > > + return sysfs_emit(buf, "%llu\n", kobj_to_adapter(pdev)->stats->recovery_successes); > > > +} > > > +DEVICE_ATTR_RO(recovery_successes); > > > + > > > +ssize_t recovery_failures_show(struct device *pdev, > > > + struct device_attribute *attr, char *buf) > > > +{ > > > + return sysfs_emit(buf, "%llu\n", kobj_to_adapter(pdev)->stats->recovery_failures); > > > +} > > > +DEVICE_ATTR_RO(recovery_failures); > > > + > > > +ssize_t timeouts_show(struct device *pdev, > > > + struct device_attribute *attr, char *buf) > > > +{ > > > + return sysfs_emit(buf, "%llu\n", kobj_to_adapter(pdev)->stats->timeouts); > > > +} > > > +DEVICE_ATTR_RO(timeouts); > > > + > > > +/** > > > + * i2c_adapter_create_stats_directory - creates folder for I2C statistics. > > > + * @adapter: the i2c_adapter to create the stats directory for. > > > + * > > > + * Return: 0 if successful, 1 if failed. > > > + */ > > > +int i2c_adapter_create_stats_directory(struct i2c_adapter *adapter) > > > +{ > > > + struct i2c_adapter_stats *stats; > > > + int ret = 1; > > > + > > > + stats = kzalloc(sizeof(*stats), GFP_KERNEL); > > > + if (!stats) { > > > + adapter->stats = NULL; > > > + return ret; > > > + } > > > + adapter->stats = stats; > > > + adapter->stats->kobj = kobject_create_and_add("stats", &adapter->dev.kobj); > > > + > > > + ret = sysfs_create_file(adapter->stats->kobj, &dev_attr_transfers.attr); > > > + if (ret) > > > + dev_warn(&adapter->dev, "Failed to create sysfs file for tx_complete_cnt\n"); > > > + > > > + ret = sysfs_create_file(adapter->stats->kobj, &dev_attr_bus_errors.attr); > > > + if (ret) > > > + dev_warn(&adapter->dev, "Failed to create sysfs file for bus_errors\n"); > > > + > > > + ret = sysfs_create_file(adapter->stats->kobj, &dev_attr_nacks.attr); > > > + if (ret) > > > + dev_warn(&adapter->dev, "Failed to create sysfs file for nacks\n"); > > > + > > > + ret = sysfs_create_file(adapter->stats->kobj, &dev_attr_recovery_successes.attr); > > > + if (ret) > > > + dev_warn(&adapter->dev, "Failed to create sysfs file for recovery_successes\n"); > > > + > > > + ret = sysfs_create_file(adapter->stats->kobj, &dev_attr_recovery_failures.attr); > > > + if (ret) > > > + dev_warn(&adapter->dev, "Failed to create sysfs file for recovery_failures\n"); > > > + > > > + return ret; > > > +} > > > + > > > MODULE_AUTHOR("Frodo Looijaard <frodol@xxxxxx>"); > > > MODULE_AUTHOR("Simon G. Vogl <simon@xxxxxxxxxxxxxxxxx>"); > > > MODULE_DESCRIPTION("I2C /dev entries driver"); > > > diff --git a/include/linux/i2c.h b/include/linux/i2c.h > > > index 3eb60a2e9e61..c8608378da2a 100644 > > > --- a/include/linux/i2c.h > > > +++ b/include/linux/i2c.h > > > @@ -21,6 +21,7 @@ > > > #include <linux/of.h> /* for struct device_node */ > > > #include <linux/swab.h> /* for swab16 */ > > > #include <uapi/linux/i2c.h> > > > +#include <linux/slab.h> /* for kzalloc */ > > > > > > extern struct bus_type i2c_bus_type; > > > extern struct device_type i2c_adapter_type; > > > @@ -684,6 +685,25 @@ struct i2c_adapter_quirks { > > > u16 max_comb_2nd_msg_len; > > > }; > > > > > > +/** > > > + * I2C statistics > > > + * The list of statistics are currently copied from npcm7xx. > > > + * Perhaps a more universal set of statistics can be used. > > > + * > > > + * The stats are currently modeled as pointers to members in the bus drivers. > > > + * A null pointer indicates the counter is not supported by the bus driver. > > > + */ > > > +struct i2c_adapter_stats { > > > + struct kobject *kobj; > > > + > > > + u64 transfers; > > > + u64 bus_errors; > > > + u64 nacks; > > > + u64 recovery_successes; > > > + u64 recovery_failures; > > > + u64 timeouts; > > > +}; > > > + > > > /* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */ > > > #define I2C_AQ_COMB BIT(0) > > > /* first combined message must be write */ > > > @@ -735,12 +755,18 @@ struct i2c_adapter { > > > > > > struct i2c_bus_recovery_info *bus_recovery_info; > > > const struct i2c_adapter_quirks *quirks; > > > + struct i2c_adapter_stats *stats; > > > > > > struct irq_domain *host_notify_domain; > > > struct regulator *bus_regulator; > > > }; > > > #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev) > > > > > > +int i2c_adapter_create_stats_directory(struct i2c_adapter *adapter); > > > + > > > +void i2c_adapter_stats_register_counter(struct i2c_adapter *adapter, > > > + const char *counter_name, void *data_source); > > > + > > > static inline void *i2c_get_adapdata(const struct i2c_adapter *adap) > > > { > > > return dev_get_drvdata(&adap->dev); > > > -- > > > 2.35.1.1094.g7c7d902a7c-goog > > > > > > > > > -- > > Regards, > > Avi -- Regards, Avi
