1 files changed, 223 insertions, 0 deletions
diff --git a/drivers/char/powernv-op-panel.c b/drivers/char/powernv-op-panel.c
new file mode 100644
index 000000000000..a45dabcc8e10
--- /dev/null
+++ b/drivers/char/powernv-op-panel.c
@@ -0,0 +1,223 @@
+/*
+ * OPAL Operator Panel Display Driver
+ *
+ * Copyright 2016, Suraj Jitindar Singh, IBM Corporation.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/miscdevice.h>
+
+#include <asm/opal.h>
+
+/*
+ * This driver creates a character device (/dev/op_panel) which exposes the
+ * operator panel (character LCD display) on IBM Power Systems machines
+ * with FSPs.
+ * A character buffer written to the device will be displayed on the
+ * operator panel.
+ */
+
+static DEFINE_MUTEX(oppanel_mutex);
+
+static u32		num_lines, oppanel_size;
+static oppanel_line_t	*oppanel_lines;
+static char		*oppanel_data;
+
+static loff_t oppanel_llseek(struct file *filp, loff_t offset, int whence)
+{
+	return fixed_size_llseek(filp, offset, whence, oppanel_size);
+}
+
+static ssize_t oppanel_read(struct file *filp, char __user *userbuf, size_t len,
+			    loff_t *f_pos)
+{
+	return simple_read_from_buffer(userbuf, len, f_pos, oppanel_data,
+			oppanel_size);
+}
+
+static int __op_panel_update_display(void)
+{
+	struct opal_msg msg;
+	int rc, token;
+
+	token = opal_async_get_token_interruptible();
+	if (token < 0) {
+		if (token != -ERESTARTSYS)
+			pr_debug("Couldn't get OPAL async token [token=%d]\n",
+				token);
+		return token;
+	}
+
+	rc = opal_write_oppanel_async(token, oppanel_lines, num_lines);
+	switch (rc) {
+	case OPAL_ASYNC_COMPLETION:
+		rc = opal_async_wait_response(token, &msg);
+		if (rc) {
+			pr_debug("Failed to wait for async response [rc=%d]\n",
+				rc);
+			break;
+		}
+		rc = opal_get_async_rc(msg);
+		if (rc != OPAL_SUCCESS) {
+			pr_debug("OPAL async call returned failed [rc=%d]\n",
+				rc);
+			break;
+		}
+	case OPAL_SUCCESS:
+		break;
+	default:
+		pr_debug("OPAL write op-panel call failed [rc=%d]\n", rc);
+	}
+
+	opal_async_release_token(token);
+	return rc;
+}
+
+static ssize_t oppanel_write(struct file *filp, const char __user *userbuf,
+			     size_t len, loff_t *f_pos)
+{
+	loff_t f_pos_prev = *f_pos;
+	ssize_t ret;
+	int rc;
+
+	if (!*f_pos)
+		memset(oppanel_data, ' ', oppanel_size);
+	else if (*f_pos >= oppanel_size)
+		return -EFBIG;
+
+	ret = simple_write_to_buffer(oppanel_data, oppanel_size, f_pos, userbuf,
+			len);
+	if (ret > 0) {
+		rc = __op_panel_update_display();
+		if (rc != OPAL_SUCCESS) {
+			pr_err_ratelimited("OPAL call failed to write to op panel display [rc=%d]\n",
+				rc);
+			*f_pos = f_pos_prev;
+			return -EIO;
+		}
+	}
+	return ret;
+}
+
+static int oppanel_open(struct inode *inode, struct file *filp)
+{
+	if (!mutex_trylock(&oppanel_mutex)) {
+		pr_debug("Device Busy\n");
+		return -EBUSY;
+	}
+	return 0;
+}
+
+static int oppanel_release(struct inode *inode, struct file *filp)
+{
+	mutex_unlock(&oppanel_mutex);
+	return 0;
+}
+
+static const struct file_operations oppanel_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= oppanel_llseek,
+	.read		= oppanel_read,
+	.write		= oppanel_write,
+	.open		= oppanel_open,
+	.release	= oppanel_release
+};
+
+static struct miscdevice oppanel_dev = {
+	.minor		= MISC_DYNAMIC_MINOR,
+	.name		= "op_panel",
+	.fops		= &oppanel_fops
+};
+
+static int oppanel_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	u32 line_len;
+	int rc, i;
+
+	rc = of_property_read_u32(np, "#length", &line_len);
+	if (rc) {
+		pr_err_ratelimited("Operator panel length property not found\n");
+		return rc;
+	}
+	rc = of_property_read_u32(np, "#lines", &num_lines);
+	if (rc) {
+		pr_err_ratelimited("Operator panel lines property not found\n");
+		return rc;
+	}
+	oppanel_size = line_len * num_lines;
+
+	pr_devel("Operator panel of size %u found with %u lines of length %u\n",
+			oppanel_size, num_lines, line_len);
+
+	oppanel_data = kcalloc(oppanel_size, sizeof(*oppanel_data), GFP_KERNEL);
+	if (!oppanel_data)
+		return -ENOMEM;
+
+	oppanel_lines = kcalloc(num_lines, sizeof(oppanel_line_t), GFP_KERNEL);
+	if (!oppanel_lines) {
+		rc = -ENOMEM;
+		goto free_oppanel_data;
+	}
+
+	memset(oppanel_data, ' ', oppanel_size);
+	for (i = 0; i < num_lines; i++) {
+		oppanel_lines[i].line_len = cpu_to_be64(line_len);
+		oppanel_lines[i].line = cpu_to_be64(__pa(&oppanel_data[i *
+						line_len]));
+	}
+
+	rc = misc_register(&oppanel_dev);
+	if (rc) {
+		pr_err_ratelimited("Failed to register as misc device\n");
+		goto free_oppanel;
+	}
+
+	return 0;
+
+free_oppanel:
+	kfree(oppanel_lines);
+free_oppanel_data:
+	kfree(oppanel_data);
+	return rc;
+}
+
+static int oppanel_remove(struct platform_device *pdev)
+{
+	misc_deregister(&oppanel_dev);
+	kfree(oppanel_lines);
+	kfree(oppanel_data);
+	return 0;
+}
+
+static const struct of_device_id oppanel_match[] = {
+	{ .compatible = "ibm,opal-oppanel" },
+	{ },
+};
+
+static struct platform_driver oppanel_driver = {
+	.driver	= {
+		.name		= "powernv-op-panel",
+		.of_match_table	= oppanel_match,
+	},
+	.probe	= oppanel_probe,
+	.remove	= oppanel_remove,
+};
+
+module_platform_driver(oppanel_driver);
+
+MODULE_DEVICE_TABLE(of, oppanel_match);
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("PowerNV Operator Panel LCD Display Driver");
+MODULE_AUTHOR("Suraj Jitindar Singh <sjitindarsingh@gmail.com>");