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