--- /dev/null
+/*
+ * 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>");
projects / linux-platform-drivers-x86.git / commitdiff