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
