fpga: mgr: add status for fpga-manager

This patch adds status sysfs interface for fpga manager, it's a
read only interface which allows user to get fpga manager status,
including full/partial reconfiguration error and other status
information. It adds a status callback to fpga_manager_ops too,
allows each fpga_manager driver to define its own method to
collect latest status from hardware.

The following sysfs file is created:
* /sys/class/fpga_manager/<fpga>/status
  Return status of fpga manager, including reconfiguration errors.

Signed-off-by: Wu Hao <hao.wu@intel.com>
Acked-by: Alan Tull <atull@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-class-fpga-manager

@@ -35,3 +35,27 @@ Description:	Read fpga manager state as a string.
 		* write complete	= Doing post programming steps
 		* write complete error	= Error while doing post programming
 		* operating		= FPGA is programmed and operating
+
+What:		/sys/class/fpga_manager/<fpga>/status
+Date:		June 2018
+KernelVersion:	4.19
+Contact:	Wu Hao <hao.wu@intel.com>
+Description:	Read fpga manager status as a string.
+		If FPGA programming operation fails, it could be caused by crc
+		error or incompatible bitstream image. The intent of this
+		interface is to provide more detailed information for FPGA
+		programming errors to userspace. This is a list of strings for
+		the supported status.
+
+		* reconfig operation error 	- invalid operations detected by
+						  reconfiguration hardware.
+						  e.g. start reconfiguration
+						  with errors not cleared
+		* reconfig CRC error		- CRC error detected by
+						  reconfiguration hardware.
+		* reconfig incompatible image	- reconfiguration image is
+						  incompatible with hardware
+		* reconfig IP protocol error	- protocol errors detected by
+						  reconfiguration hardware
+		* reconfig fifo overflow error	- FIFO overflow detected by
+						  reconfiguration hardware

drivers/fpga/fpga-mgr.c

@@ -406,12 +406,40 @@ static ssize_t state_show(struct device *dev,
 	return sprintf(buf, "%s\n", state_str[mgr->state]);
 }
 
+static ssize_t status_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct fpga_manager *mgr = to_fpga_manager(dev);
+	u64 status;
+	int len = 0;
+
+	if (!mgr->mops->status)
+		return -ENOENT;
+
+	status = mgr->mops->status(mgr);
+
+	if (status & FPGA_MGR_STATUS_OPERATION_ERR)
+		len += sprintf(buf + len, "reconfig operation error\n");
+	if (status & FPGA_MGR_STATUS_CRC_ERR)
+		len += sprintf(buf + len, "reconfig CRC error\n");
+	if (status & FPGA_MGR_STATUS_INCOMPATIBLE_IMAGE_ERR)
+		len += sprintf(buf + len, "reconfig incompatible image\n");
+	if (status & FPGA_MGR_STATUS_IP_PROTOCOL_ERR)
+		len += sprintf(buf + len, "reconfig IP protocol error\n");
+	if (status & FPGA_MGR_STATUS_FIFO_OVERFLOW_ERR)
+		len += sprintf(buf + len, "reconfig fifo overflow error\n");
+
+	return len;
+}
+
 static DEVICE_ATTR_RO(name);
 static DEVICE_ATTR_RO(state);
+static DEVICE_ATTR_RO(status);
 
 static struct attribute *fpga_mgr_attrs[] = {
 	&dev_attr_name.attr,
 	&dev_attr_state.attr,
+	&dev_attr_status.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(fpga_mgr);

include/linux/fpga/fpga-mgr.h

@@ -101,6 +101,7 @@ struct fpga_image_info {
  * struct fpga_manager_ops - ops for low level fpga manager drivers
  * @initial_header_size: Maximum number of bytes that should be passed into write_init
  * @state: returns an enum value of the FPGA's state
+ * @status: returns status of the FPGA, including reconfiguration error code
  * @write_init: prepare the FPGA to receive confuration data
  * @write: write count bytes of configuration data to the FPGA
  * @write_sg: write the scatter list of configuration data to the FPGA
@@ -115,6 +116,7 @@ struct fpga_image_info {
 struct fpga_manager_ops {
 	size_t initial_header_size;
 	enum fpga_mgr_states (*state)(struct fpga_manager *mgr);
+	u64 (*status)(struct fpga_manager *mgr);
 	int (*write_init)(struct fpga_manager *mgr,
 			  struct fpga_image_info *info,
 			  const char *buf, size_t count);
@@ -126,6 +128,13 @@ struct fpga_manager_ops {
 	const struct attribute_group **groups;
 };
 
+/* FPGA manager status: Partial/Full Reconfiguration errors */
+#define FPGA_MGR_STATUS_OPERATION_ERR		BIT(0)
+#define FPGA_MGR_STATUS_CRC_ERR			BIT(1)
+#define FPGA_MGR_STATUS_INCOMPATIBLE_IMAGE_ERR	BIT(2)
+#define FPGA_MGR_STATUS_IP_PROTOCOL_ERR		BIT(3)
+#define FPGA_MGR_STATUS_FIFO_OVERFLOW_ERR	BIT(4)
+
 /**
  * struct fpga_manager - fpga manager structure
  * @name: name of low level fpga manager