[PATCH v4 03/12] fpga: dfl: afu: add AFU state related sysfs interfaces

From: Wu Hao
Date: Sun Aug 04 2019 - 06:38:10 EST

This patch introduces more sysfs interfaces for Accelerated
Function Unit (AFU). These interfaces allow users to read
current AFU Power State (APx), read / clear AFU Power (APx)
events which are sticky to identify transient APx state,
and manage AFU's LTR (latency tolerance reporting).

Signed-off-by: Ananda Ravuri <ananda.ravuri@xxxxxxxxx>
Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx>
Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
Acked-by: Alan Tull <atull@xxxxxxxxxx>
Signed-off-by: Moritz Fischer <mdf@xxxxxxxxxx>
---
v2: rebased, and remove DRV/MODULE_VERSION modifications
v3: update kernel version and date in sysfs doc
v4: improve description in sysfs doc avoid misunderstanding.
switch to kstrtobool in sysfs entry store function.
---
Documentation/ABI/testing/sysfs-platform-dfl-port | 32 +++++
drivers/fpga/dfl-afu-main.c | 137 ++++++++++++++++++++++
drivers/fpga/dfl.h | 11 ++
3 files changed, 180 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-platform-dfl-port b/Documentation/ABI/testing/sysfs-platform-dfl-port
index 6a92dda..1ab3e6f 100644
--- a/Documentation/ABI/testing/sysfs-platform-dfl-port
+++ b/Documentation/ABI/testing/sysfs-platform-dfl-port
@@ -14,3 +14,35 @@ Description: Read-only. User can program different PR bitstreams to FPGA
Accelerator Function Unit (AFU) for different functions. It
returns uuid which could be used to identify which PR bitstream
is programmed in this AFU.
+
+What: /sys/bus/platform/devices/dfl-port.0/power_state
+Date: August 2019
+KernelVersion: 5.4
+Contact: Wu Hao <hao.wu@xxxxxxxxx>
+Description: Read-only. It reports the APx (AFU Power) state, different APx
+ means different throttling level. When reading this file, it
+ returns "0" - Normal / "1" - AP1 / "2" - AP2 / "6" - AP6.
+
+What: /sys/bus/platform/devices/dfl-port.0/ap1_event
+Date: August 2019
+KernelVersion: 5.4
+Contact: Wu Hao <hao.wu@xxxxxxxxx>
+Description: Read-write. Read this file for AP1 (AFU Power State 1) event.
+ It's used to indicate transient AP1 state. Write 1 to this
+ file to clear AP1 event.
+
+What: /sys/bus/platform/devices/dfl-port.0/ap2_event
+Date: August 2019
+KernelVersion: 5.4
+Contact: Wu Hao <hao.wu@xxxxxxxxx>
+Description: Read-write. Read this file for AP2 (AFU Power State 2) event.
+ It's used to indicate transient AP2 state. Write 1 to this
+ file to clear AP2 event.
+
+What: /sys/bus/platform/devices/dfl-port.0/ltr
+Date: August 2019
+KernelVersion: 5.4
+Contact: Wu Hao <hao.wu@xxxxxxxxx>
+Description: Read-write. Read or set AFU latency tolerance reporting value.
+ Set ltr to 1 if the AFU can tolerate latency >= 40us or set it
+ to 0 if it is latency sensitive.
diff --git a/drivers/fpga/dfl-afu-main.c b/drivers/fpga/dfl-afu-main.c
index 68b4d08..12175bb 100644
--- a/drivers/fpga/dfl-afu-main.c
+++ b/drivers/fpga/dfl-afu-main.c
@@ -141,8 +141,145 @@ static int port_get_id(struct platform_device *pdev)
}
static DEVICE_ATTR_RO(id);

+static ssize_t
+ltr_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+ void __iomem *base;
+ u64 v;
+
+ base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_HEADER);
+
+ mutex_lock(&pdata->lock);
+ v = readq(base + PORT_HDR_CTRL);
+ mutex_unlock(&pdata->lock);
+
+ return sprintf(buf, "%x\n", (u8)FIELD_GET(PORT_CTRL_LATENCY, v));
+}
+
+static ssize_t
+ltr_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+ void __iomem *base;
+ bool ltr;
+ u64 v;
+
+ if (kstrtobool(buf, &ltr))
+ return -EINVAL;
+
+ base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_HEADER);
+
+ mutex_lock(&pdata->lock);
+ v = readq(base + PORT_HDR_CTRL);
+ v &= ~PORT_CTRL_LATENCY;
+ v |= FIELD_PREP(PORT_CTRL_LATENCY, ltr ? 1 : 0);
+ writeq(v, base + PORT_HDR_CTRL);
+ mutex_unlock(&pdata->lock);
+
+ return count;
+}
+static DEVICE_ATTR_RW(ltr);
+
+static ssize_t
+ap1_event_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+ void __iomem *base;
+ u64 v;
+
+ base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_HEADER);
+
+ mutex_lock(&pdata->lock);
+ v = readq(base + PORT_HDR_STS);
+ mutex_unlock(&pdata->lock);
+
+ return sprintf(buf, "%x\n", (u8)FIELD_GET(PORT_STS_AP1_EVT, v));
+}
+
+static ssize_t
+ap1_event_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+ void __iomem *base;
+ bool clear;
+
+ if (kstrtobool(buf, &clear) || !clear)
+ return -EINVAL;
+
+ base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_HEADER);
+
+ mutex_lock(&pdata->lock);
+ writeq(PORT_STS_AP1_EVT, base + PORT_HDR_STS);
+ mutex_unlock(&pdata->lock);
+
+ return count;
+}
+static DEVICE_ATTR_RW(ap1_event);
+
+static ssize_t
+ap2_event_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+ void __iomem *base;
+ u64 v;
+
+ base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_HEADER);
+
+ mutex_lock(&pdata->lock);
+ v = readq(base + PORT_HDR_STS);
+ mutex_unlock(&pdata->lock);
+
+ return sprintf(buf, "%x\n", (u8)FIELD_GET(PORT_STS_AP2_EVT, v));
+}
+
+static ssize_t
+ap2_event_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+ void __iomem *base;
+ bool clear;
+
+ if (kstrtobool(buf, &clear) || !clear)
+ return -EINVAL;
+
+ base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_HEADER);
+
+ mutex_lock(&pdata->lock);
+ writeq(PORT_STS_AP2_EVT, base + PORT_HDR_STS);
+ mutex_unlock(&pdata->lock);
+
+ return count;
+}
+static DEVICE_ATTR_RW(ap2_event);
+
+static ssize_t
+power_state_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+ void __iomem *base;
+ u64 v;
+
+ base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_HEADER);
+
+ mutex_lock(&pdata->lock);
+ v = readq(base + PORT_HDR_STS);
+ mutex_unlock(&pdata->lock);
+
+ return sprintf(buf, "0x%x\n", (u8)FIELD_GET(PORT_STS_PWR_STATE, v));
+}
+static DEVICE_ATTR_RO(power_state);
+
static struct attribute *port_hdr_attrs[] = {
&dev_attr_id.attr,
+ &dev_attr_ltr.attr,
+ &dev_attr_ap1_event.attr,
+ &dev_attr_ap2_event.attr,
+ &dev_attr_power_state.attr,
NULL,
};
ATTRIBUTE_GROUPS(port_hdr);
diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
index b3f2f53..6625d73 100644
--- a/drivers/fpga/dfl.h
+++ b/drivers/fpga/dfl.h
@@ -119,6 +119,7 @@
#define PORT_HDR_NEXT_AFU NEXT_AFU
#define PORT_HDR_CAP 0x30
#define PORT_HDR_CTRL 0x38
+#define PORT_HDR_STS 0x40

/* Port Capability Register Bitfield */
#define PORT_CAP_PORT_NUM GENMASK_ULL(1, 0) /* ID of this port */
@@ -130,6 +131,16 @@
/* Latency tolerance reporting. '1' >= 40us, '0' < 40us.*/
#define PORT_CTRL_LATENCY BIT_ULL(2)
#define PORT_CTRL_SFTRST_ACK BIT_ULL(4) /* HW ack for reset */
+
+/* Port Status Register Bitfield */
+#define PORT_STS_AP2_EVT BIT_ULL(13) /* AP2 event detected */
+#define PORT_STS_AP1_EVT BIT_ULL(12) /* AP1 event detected */
+#define PORT_STS_PWR_STATE GENMASK_ULL(11, 8) /* AFU power states */
+#define PORT_STS_PWR_STATE_NORM 0
+#define PORT_STS_PWR_STATE_AP1 1 /* 50% throttling */
+#define PORT_STS_PWR_STATE_AP2 2 /* 90% throttling */
+#define PORT_STS_PWR_STATE_AP6 6 /* 100% throttling */
+
/**
* struct dfl_fpga_port_ops - port ops
*
--
1.8.3.1