[PATCH v4 2/2] fpga: zynqmp-fpga: Adds status interface

[Nava kishore Manne <nava.kishore.manne@xxxxxxx>]

Adds status interface for zynqmp-fpga, It's a read only interface
which allows the user to get the Programmable Logic(PL) configuration
status.

Usage:
To read the Programmable Logic(PL) configuration status
        cat /sys/class/fpga_manager/<fpga>/device/status

Signed-off-by: Nava kishore Manne <nava.kishore.manne@xxxxxxx>
---
Changes for v2:
              - Updated status messages handling logic as suggested by Xu Yilun.

Changes for v3:
              - Updated status interface handling logic (Restrict the status
                interface to the device-specific instead of handled by the core)
                as suggested by Xu Yilun.

Changes for v4:
              - Limit the error strings to one word for each as suggested by
                Xu Yilun

 drivers/fpga/zynqmp-fpga.c | 87 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)

diff --git a/drivers/fpga/zynqmp-fpga.c b/drivers/fpga/zynqmp-fpga.c
index c60f20949c47..81d3e18527ee 100644
--- a/drivers/fpga/zynqmp-fpga.c
+++ b/drivers/fpga/zynqmp-fpga.c
@@ -15,6 +15,37 @@
 /* Constant Definitions */
 #define IXR_FPGA_DONE_MASK	BIT(3)
 
+/* Error Register */
+#define IXR_FPGA_ERR_CRC_ERR		BIT(0)
+#define IXR_FPGA_ERR_SECURITY_ERR	BIT(16)
+
+/* Signal Status Register */
+#define IXR_FPGA_END_OF_STARTUP		BIT(4)
+#define IXR_FPGA_GST_CFG_B		BIT(5)
+#define IXR_FPGA_INIT_B_INTERNAL	BIT(11)
+#define IXR_FPGA_DONE_INTERNAL_SIGNAL	BIT(13)
+
+/* FPGA error status. */
+enum {
+	ZYNQMP_FPGA_STATUS_CRC_ERR,
+	ZYNQMP_FPGA_STATUS_SECURITY_ERR,
+	ZYNQMP_FPGA_STATUS_DEVICE_INIT_ERR,
+	ZYNQMP_FPGA_STATUS_SIGNAL_ERR,
+	ZYNQMP_FPGA_STATUS_HIGH_Z_STATE_ERR,
+	ZYNQMP_FPGA_STATUS_EOS_ERR,
+	ZYNQMP_FPGA_MGR_STATUS_FIRMWARE_REQ_ERR,
+};
+
+static const char * const zynqmp_fpga_error_statuses[] = {
+	[ZYNQMP_FPGA_STATUS_CRC_ERR] = "CRC-Error",
+	[ZYNQMP_FPGA_STATUS_SECURITY_ERR] = "Security-Error",
+	[ZYNQMP_FPGA_STATUS_DEVICE_INIT_ERR] = "Initialization-Error",
+	[ZYNQMP_FPGA_STATUS_SIGNAL_ERR] = "Internal-Signal-Error",
+	[ZYNQMP_FPGA_STATUS_HIGH_Z_STATE_ERR] = "I/Os-High-Z-state",
+	[ZYNQMP_FPGA_STATUS_EOS_ERR] = "Sequence-Error",
+	[ZYNQMP_FPGA_MGR_STATUS_FIRMWARE_REQ_ERR] = "Firmware-Error",
+};
+
 /**
  * struct zynqmp_fpga_priv - Private data structure
  * @dev:	Device data structure
@@ -77,6 +108,54 @@ static enum fpga_mgr_states zynqmp_fpga_ops_state(struct fpga_manager *mgr)
 	return FPGA_MGR_STATE_UNKNOWN;
 }
 
+static ssize_t status_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	unsigned long status = 0;
+	ssize_t len = 0;
+	u32 reg_val;
+	int ret;
+	u8 i;
+
+	ret = zynqmp_pm_fpga_get_config_status(&reg_val);
+	if (!ret) {
+		if (reg_val & IXR_FPGA_ERR_CRC_ERR)
+			status |= ZYNQMP_FPGA_STATUS_CRC_ERR;
+		if (reg_val & IXR_FPGA_ERR_SECURITY_ERR)
+			status |= ZYNQMP_FPGA_STATUS_SECURITY_ERR;
+		if (!(reg_val & IXR_FPGA_INIT_B_INTERNAL))
+			status |= ZYNQMP_FPGA_STATUS_DEVICE_INIT_ERR;
+		if (!(reg_val & IXR_FPGA_DONE_INTERNAL_SIGNAL))
+			status |= ZYNQMP_FPGA_STATUS_SIGNAL_ERR;
+		if (!(reg_val & IXR_FPGA_GST_CFG_B))
+			status |= ZYNQMP_FPGA_STATUS_HIGH_Z_STATE_ERR;
+		if (!(reg_val & IXR_FPGA_END_OF_STARTUP))
+			status |= ZYNQMP_FPGA_STATUS_EOS_ERR;
+	} else {
+		status = ZYNQMP_FPGA_MGR_STATUS_FIRMWARE_REQ_ERR;
+	}
+
+	for_each_set_bit(i, &status, ARRAY_SIZE(zynqmp_fpga_error_statuses))
+		len += sysfs_emit_at(buf, len, "%s ",
+				     zynqmp_fpga_error_statuses[i]);
+
+	if (len)
+		buf[len - 1] = '\n';
+
+	return len;
+}
+
+static DEVICE_ATTR_RO(status);
+
+static struct attribute *zynqmp_fpga_device_attrs[] = {
+	&dev_attr_status.attr,
+	NULL,
+};
+
+static const struct attribute_group zynqmp_fpga_attr_group = {
+	.attrs = zynqmp_fpga_device_attrs,
+};
+
 static const struct fpga_manager_ops zynqmp_fpga_ops = {
 	.state = zynqmp_fpga_ops_state,
 	.write_init = zynqmp_fpga_ops_write_init,
@@ -88,6 +167,7 @@ static int zynqmp_fpga_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct zynqmp_fpga_priv *priv;
 	struct fpga_manager *mgr;
+	int ret;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -95,6 +175,13 @@ static int zynqmp_fpga_probe(struct platform_device *pdev)
 
 	priv->dev = dev;
 
+	/* Add the device attributes */
+	ret = sysfs_create_group(&dev->kobj, &zynqmp_fpga_attr_group);
+	if (ret) {
+		dev_err(dev, "Error creating sysfs files\n");
+		return ret;
+	}
+
 	mgr = devm_fpga_mgr_register(dev, "Xilinx ZynqMP FPGA Manager",
 				     &zynqmp_fpga_ops, priv);
 	return PTR_ERR_OR_ZERO(mgr);
-- 
2.25.1