This patch adds support for power management private feature under
FPGA Management Engine (FME). This private feature driver registers
a hwmon for power (power1_input), thresholds information, e.g.
(power1_max / crit / max_alarm / crit_alarm) and also read-only sysfs
interfaces for other power management information. For configuration,
user could write threshold values via above power1_max / crit sysfs
interface under hwmon too.

Signed-off-by: Luwei Kang <luwei.k...@intel.com>
Signed-off-by: Xu Yilun <yilun...@intel.com>
Signed-off-by: Wu Hao <hao...@intel.com>
Acked-by: Guenter Roeck <li...@roeck-us.net>
Reviewed-by: Moritz Fischer <m...@kernel.org>
---
v2: create a dfl_fme_power hwmon to expose power sysfs interfaces.
    move all sysfs interfaces under hwmon
        consumed          --> hwmon power1_input
        threshold1        --> hwmon power1_cap
        threshold2        --> hwmon power1_crit
        threshold1_status --> hwmon power1_cap_status
        threshold2_status --> hwmon power1_crit_status
        xeon_limit        --> hwmon power1_xeon_limit
        fpga_limit        --> hwmon power1_fpga_limit
        ltr               --> hwmon power1_ltr
v3: rename some hwmon sysfs interfaces to follow hwmon ABI.
        power1_cap         --> power1_max
        power1_cap_status  --> power1_max_alarm
        power1_crit_status --> power1_crit_alarm
    update sysfs doc for above sysfs interface changes.
    replace scnprintf with sprintf in sysfs interface.
v4: use HWMON_CHANNEL_INFO.
    update date in sysfs doc.
v5: clamp threshold inputs in power_hwmon_write function.
    update sysfs doc as threshold inputs are clamped now.
    add more descriptions to ltr sysfs interface.
v6: rebase and clean up (remove empty uinit function).
    update date in sysfs doc.
---
 Documentation/ABI/testing/sysfs-platform-dfl-fme |  70 ++++++++
 drivers/fpga/dfl-fme-main.c                      | 207 +++++++++++++++++++++++
 2 files changed, 277 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-platform-dfl-fme 
b/Documentation/ABI/testing/sysfs-platform-dfl-fme
index c84b3c1..9ea4697 100644
--- a/Documentation/ABI/testing/sysfs-platform-dfl-fme
+++ b/Documentation/ABI/testing/sysfs-platform-dfl-fme
@@ -114,6 +114,7 @@ Contact:    Wu Hao <hao...@intel.com>
 Description:   Read-Only. Read this file to get the name of hwmon device, it
                supports values:
                    'dfl_fme_thermal' - thermal hwmon device name
+                   'dfl_fme_power'   - power hwmon device name
 
 What:          /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/temp1_input
 Date:          September 2019
@@ -170,3 +171,72 @@ Description:       Read-Only. Read this file to get the 
policy of hardware threshold1
                (see 'temp1_max'). It only supports two values (policies):
                    0 - AP2 state (90% throttling)
                    1 - AP1 state (50% throttling)
+
+What:          /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/power1_input
+Date:          September 2019
+KernelVersion: 5.4
+Contact:       Wu Hao <hao...@intel.com>
+Description:   Read-Only. It returns current FPGA power consumption in uW.
+
+What:          /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/power1_max
+Date:          September 2019
+KernelVersion: 5.4
+Date:          June 2019
+KernelVersion: 5.3
+Contact:       Wu Hao <hao...@intel.com>
+Description:   Read-Write. Read this file to get current hardware power
+               threshold1 in uW. If power consumption rises at or above
+               this threshold, hardware starts 50% throttling.
+               Write this file to set current hardware power threshold1 in uW.
+               As hardware only accepts values in Watts, so input value will
+               be round down per Watts (< 1 watts part will be discarded) and
+               clamped within the range from 0 to 127 Watts. Write fails with
+               -EINVAL if input parsing fails.
+
+What:          /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/power1_crit
+Date:          September 2019
+KernelVersion: 5.4
+Contact:       Wu Hao <hao...@intel.com>
+Description:   Read-Write. Read this file to get current hardware power
+               threshold2 in uW. If power consumption rises at or above
+               this threshold, hardware starts 90% throttling.
+               Write this file to set current hardware power threshold2 in uW.
+               As hardware only accepts values in Watts, so input value will
+               be round down per Watts (< 1 watts part will be discarded) and
+               clamped within the range from 0 to 127 Watts. Write fails with
+               -EINVAL if input parsing fails.
+
+What:          
/sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/power1_max_alarm
+Date:          September 2019
+KernelVersion: 5.4
+Contact:       Wu Hao <hao...@intel.com>
+Description:   Read-only. It returns 1 if power consumption is currently at or
+               above hardware threshold1 (see 'power1_max'), otherwise 0.
+
+What:          
/sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/power1_crit_alarm
+Date:          September 2019
+KernelVersion: 5.4
+Contact:       Wu Hao <hao...@intel.com>
+Description:   Read-only. It returns 1 if power consumption is currently at or
+               above hardware threshold2 (see 'power1_crit'), otherwise 0.
+
+What:          
/sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/power1_xeon_limit
+Date:          September 2019
+KernelVersion: 5.4
+Contact:       Wu Hao <hao...@intel.com>
+Description:   Read-Only. It returns power limit for XEON in uW.
+
+What:          
/sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/power1_fpga_limit
+Date:          September 2019
+KernelVersion: 5.4
+Contact:       Wu Hao <hao...@intel.com>
+Description:   Read-Only. It returns power limit for FPGA in uW.
+
+What:          /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/power1_ltr
+Date:          September 2019
+KernelVersion: 5.4
+Contact:       Wu Hao <hao...@intel.com>
+Description:   Read-only. Read this file to get current Latency Tolerance
+               Reporting (ltr) value. It returns 1 if all Accelerated
+               Function Units (AFUs) can tolerate latency >= 40us for memory
+               access or 0 if any AFU is latency sensitive (< 40us).
diff --git a/drivers/fpga/dfl-fme-main.c b/drivers/fpga/dfl-fme-main.c
index 752d71c..7c930e6 100644
--- a/drivers/fpga/dfl-fme-main.c
+++ b/drivers/fpga/dfl-fme-main.c
@@ -355,6 +355,209 @@ static int fme_thermal_mgmt_init(struct platform_device 
*pdev,
        .init = fme_thermal_mgmt_init,
 };
 
+#define FME_PWR_STATUS         0x8
+#define FME_LATENCY_TOLERANCE  BIT_ULL(18)
+#define PWR_CONSUMED           GENMASK_ULL(17, 0)
+
+#define FME_PWR_THRESHOLD      0x10
+#define PWR_THRESHOLD1         GENMASK_ULL(6, 0)       /* in Watts */
+#define PWR_THRESHOLD2         GENMASK_ULL(14, 8)      /* in Watts */
+#define PWR_THRESHOLD_MAX      0x7f                    /* in Watts */
+#define PWR_THRESHOLD1_STATUS  BIT_ULL(16)
+#define PWR_THRESHOLD2_STATUS  BIT_ULL(17)
+
+#define FME_PWR_XEON_LIMIT     0x18
+#define XEON_PWR_LIMIT         GENMASK_ULL(14, 0)      /* in 0.1 Watts */
+#define XEON_PWR_EN            BIT_ULL(15)
+#define FME_PWR_FPGA_LIMIT     0x20
+#define FPGA_PWR_LIMIT         GENMASK_ULL(14, 0)      /* in 0.1 Watts */
+#define FPGA_PWR_EN            BIT_ULL(15)
+
+static int power_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+                           u32 attr, int channel, long *val)
+{
+       struct dfl_feature *feature = dev_get_drvdata(dev);
+       u64 v;
+
+       switch (attr) {
+       case hwmon_power_input:
+               v = readq(feature->ioaddr + FME_PWR_STATUS);
+               *val = (long)(FIELD_GET(PWR_CONSUMED, v) * 1000000);
+               break;
+       case hwmon_power_max:
+               v = readq(feature->ioaddr + FME_PWR_THRESHOLD);
+               *val = (long)(FIELD_GET(PWR_THRESHOLD1, v) * 1000000);
+               break;
+       case hwmon_power_crit:
+               v = readq(feature->ioaddr + FME_PWR_THRESHOLD);
+               *val = (long)(FIELD_GET(PWR_THRESHOLD2, v) * 1000000);
+               break;
+       case hwmon_power_max_alarm:
+               v = readq(feature->ioaddr + FME_PWR_THRESHOLD);
+               *val = (long)FIELD_GET(PWR_THRESHOLD1_STATUS, v);
+               break;
+       case hwmon_power_crit_alarm:
+               v = readq(feature->ioaddr + FME_PWR_THRESHOLD);
+               *val = (long)FIELD_GET(PWR_THRESHOLD2_STATUS, v);
+               break;
+       default:
+               return -EOPNOTSUPP;
+       }
+
+       return 0;
+}
+
+static int power_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
+                            u32 attr, int channel, long val)
+{
+       struct dfl_feature_platform_data *pdata = dev_get_platdata(dev->parent);
+       struct dfl_feature *feature = dev_get_drvdata(dev);
+       int ret = 0;
+       u64 v;
+
+       val = clamp_val(val / 1000000, 0, PWR_THRESHOLD_MAX);
+
+       mutex_lock(&pdata->lock);
+
+       switch (attr) {
+       case hwmon_power_max:
+               v = readq(feature->ioaddr + FME_PWR_THRESHOLD);
+               v &= ~PWR_THRESHOLD1;
+               v |= FIELD_PREP(PWR_THRESHOLD1, val);
+               writeq(v, feature->ioaddr + FME_PWR_THRESHOLD);
+               break;
+       case hwmon_power_crit:
+               v = readq(feature->ioaddr + FME_PWR_THRESHOLD);
+               v &= ~PWR_THRESHOLD2;
+               v |= FIELD_PREP(PWR_THRESHOLD2, val);
+               writeq(v, feature->ioaddr + FME_PWR_THRESHOLD);
+               break;
+       default:
+               ret = -EOPNOTSUPP;
+               break;
+       }
+
+       mutex_unlock(&pdata->lock);
+
+       return ret;
+}
+
+static umode_t power_hwmon_attrs_visible(const void *drvdata,
+                                        enum hwmon_sensor_types type,
+                                        u32 attr, int channel)
+{
+       switch (attr) {
+       case hwmon_power_input:
+       case hwmon_power_max_alarm:
+       case hwmon_power_crit_alarm:
+               return 0444;
+       case hwmon_power_max:
+       case hwmon_power_crit:
+               return 0644;
+       }
+
+       return 0;
+}
+
+static const struct hwmon_ops power_hwmon_ops = {
+       .is_visible = power_hwmon_attrs_visible,
+       .read = power_hwmon_read,
+       .write = power_hwmon_write,
+};
+
+static const struct hwmon_channel_info *power_hwmon_info[] = {
+       HWMON_CHANNEL_INFO(power, HWMON_P_INPUT |
+                                 HWMON_P_MAX   | HWMON_P_MAX_ALARM |
+                                 HWMON_P_CRIT  | HWMON_P_CRIT_ALARM),
+       NULL
+};
+
+static const struct hwmon_chip_info power_hwmon_chip_info = {
+       .ops = &power_hwmon_ops,
+       .info = power_hwmon_info,
+};
+
+static ssize_t power1_xeon_limit_show(struct device *dev,
+                                     struct device_attribute *attr, char *buf)
+{
+       struct dfl_feature *feature = dev_get_drvdata(dev);
+       u16 xeon_limit = 0;
+       u64 v;
+
+       v = readq(feature->ioaddr + FME_PWR_XEON_LIMIT);
+
+       if (FIELD_GET(XEON_PWR_EN, v))
+               xeon_limit = FIELD_GET(XEON_PWR_LIMIT, v);
+
+       return sprintf(buf, "%u\n", xeon_limit * 100000);
+}
+
+static ssize_t power1_fpga_limit_show(struct device *dev,
+                                     struct device_attribute *attr, char *buf)
+{
+       struct dfl_feature *feature = dev_get_drvdata(dev);
+       u16 fpga_limit = 0;
+       u64 v;
+
+       v = readq(feature->ioaddr + FME_PWR_FPGA_LIMIT);
+
+       if (FIELD_GET(FPGA_PWR_EN, v))
+               fpga_limit = FIELD_GET(FPGA_PWR_LIMIT, v);
+
+       return sprintf(buf, "%u\n", fpga_limit * 100000);
+}
+
+static ssize_t power1_ltr_show(struct device *dev,
+                              struct device_attribute *attr, char *buf)
+{
+       struct dfl_feature *feature = dev_get_drvdata(dev);
+       u64 v;
+
+       v = readq(feature->ioaddr + FME_PWR_STATUS);
+
+       return sprintf(buf, "%u\n",
+                      (unsigned int)FIELD_GET(FME_LATENCY_TOLERANCE, v));
+}
+
+static DEVICE_ATTR_RO(power1_xeon_limit);
+static DEVICE_ATTR_RO(power1_fpga_limit);
+static DEVICE_ATTR_RO(power1_ltr);
+
+static struct attribute *power_extra_attrs[] = {
+       &dev_attr_power1_xeon_limit.attr,
+       &dev_attr_power1_fpga_limit.attr,
+       &dev_attr_power1_ltr.attr,
+       NULL
+};
+
+ATTRIBUTE_GROUPS(power_extra);
+
+static int fme_power_mgmt_init(struct platform_device *pdev,
+                              struct dfl_feature *feature)
+{
+       struct device *hwmon;
+
+       hwmon = devm_hwmon_device_register_with_info(&pdev->dev,
+                                                    "dfl_fme_power", feature,
+                                                    &power_hwmon_chip_info,
+                                                    power_extra_groups);
+       if (IS_ERR(hwmon)) {
+               dev_err(&pdev->dev, "Fail to register power hwmon\n");
+               return PTR_ERR(hwmon);
+       }
+
+       return 0;
+}
+
+static const struct dfl_feature_id fme_power_mgmt_id_table[] = {
+       {.id = FME_FEATURE_ID_POWER_MGMT,},
+       {0,}
+};
+
+static const struct dfl_feature_ops fme_power_mgmt_ops = {
+       .init = fme_power_mgmt_init,
+};
+
 static struct dfl_feature_driver fme_feature_drvs[] = {
        {
                .id_table = fme_hdr_id_table,
@@ -373,6 +576,10 @@ static int fme_thermal_mgmt_init(struct platform_device 
*pdev,
                .ops = &fme_thermal_mgmt_ops,
        },
        {
+               .id_table = fme_power_mgmt_id_table,
+               .ops = &fme_power_mgmt_ops,
+       },
+       {
                .ops = NULL,
        },
 };
-- 
1.8.3.1

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