1 // SPDX-License-Identifier: GPL-2.0+
2 #include <linux/init.h>
3 #include <linux/module.h>
4 #include <linux/types.h>
6 #include <linux/export.h>
7 #include <linux/slab.h>
8 #include <linux/platform_device.h>
10 #include <linux/rwsem.h>
11 #include "kpc_dma_driver.h"
13 MODULE_LICENSE("GPL");
14 MODULE_AUTHOR("Matt.Sickler@daktronics.com");
16 #define KPC_DMA_CHAR_MAJOR UNNAMED_MAJOR
17 #define KPC_DMA_NUM_MINORS BIT(MINORBITS)
18 static DEFINE_MUTEX(kpc_dma_mtx);
19 static int assigned_major_num;
20 static LIST_HEAD(kpc_dma_list);
22 /********** kpc_dma_list list management **********/
23 struct kpc_dma_device *kpc_dma_lookup_device(int minor)
25 struct kpc_dma_device *c;
27 mutex_lock(&kpc_dma_mtx);
28 list_for_each_entry(c, &kpc_dma_list, list) {
29 if (c->pldev->id == minor)
32 c = NULL; // not-found case
34 mutex_unlock(&kpc_dma_mtx);
38 static void kpc_dma_add_device(struct kpc_dma_device *ldev)
40 mutex_lock(&kpc_dma_mtx);
41 list_add(&ldev->list, &kpc_dma_list);
42 mutex_unlock(&kpc_dma_mtx);
45 static void kpc_dma_del_device(struct kpc_dma_device *ldev)
47 mutex_lock(&kpc_dma_mtx);
48 list_del(&ldev->list);
49 mutex_unlock(&kpc_dma_mtx);
52 /********** SysFS Attributes **********/
53 static ssize_t show_engine_regs(struct device *dev, struct device_attribute *attr, char *buf)
55 struct kpc_dma_device *ldev;
56 struct platform_device *pldev = to_platform_device(dev);
60 ldev = platform_get_drvdata(pldev);
64 return scnprintf(buf, PAGE_SIZE,
65 "EngineControlStatus = 0x%08x\n"
66 "RegNextDescPtr = 0x%08x\n"
67 "RegSWDescPtr = 0x%08x\n"
68 "RegCompletedDescPtr = 0x%08x\n"
69 "desc_pool_first = %p\n"
70 "desc_pool_last = %p\n"
72 "desc_completed = %p\n",
73 readl(ldev->eng_regs + 1),
74 readl(ldev->eng_regs + 2),
75 readl(ldev->eng_regs + 3),
76 readl(ldev->eng_regs + 4),
77 ldev->desc_pool_first,
83 static DEVICE_ATTR(engine_regs, 0444, show_engine_regs, NULL);
85 static const struct attribute *ndd_attr_list[] = {
86 &dev_attr_engine_regs.attr,
90 static struct class *kpc_dma_class;
92 /********** Platform Driver Functions **********/
94 int kpc_dma_probe(struct platform_device *pldev)
96 struct resource *r = NULL;
100 struct kpc_dma_device *ldev = kzalloc(sizeof(*ldev), GFP_KERNEL);
103 dev_err(&pldev->dev, "%s: unable to kzalloc space for kpc_dma_device\n", __func__);
108 INIT_LIST_HEAD(&ldev->list);
111 platform_set_drvdata(pldev, ldev);
112 atomic_set(&ldev->open_count, 1);
114 mutex_init(&ldev->sem);
117 // Get Engine regs resource
118 r = platform_get_resource(pldev, IORESOURCE_MEM, 0);
120 dev_err(&ldev->pldev->dev, "%s: didn't get the engine regs resource!\n", __func__);
124 ldev->eng_regs = ioremap(r->start, resource_size(r));
125 if (!ldev->eng_regs) {
126 dev_err(&ldev->pldev->dev, "%s: failed to ioremap engine regs!\n", __func__);
131 r = platform_get_resource(pldev, IORESOURCE_IRQ, 0);
133 dev_err(&ldev->pldev->dev, "%s: didn't get the IRQ resource!\n", __func__);
137 ldev->irq = r->start;
139 // Setup miscdev struct
140 dev = MKDEV(assigned_major_num, pldev->id);
141 ldev->kpc_dma_dev = device_create(kpc_dma_class, &pldev->dev, dev, ldev, "kpc_dma%d", pldev->id);
142 if (IS_ERR(ldev->kpc_dma_dev)) {
143 rv = PTR_ERR(ldev->kpc_dma_dev);
144 dev_err(&ldev->pldev->dev, "%s: device_create failed: %d\n", __func__, rv);
148 // Setup the DMA engine
149 rv = setup_dma_engine(ldev, 30);
151 dev_err(&ldev->pldev->dev, "%s: failed to setup_dma_engine: %d\n", __func__, rv);
155 // Setup the sysfs files
156 rv = sysfs_create_files(&(ldev->pldev->dev.kobj), ndd_attr_list);
158 dev_err(&ldev->pldev->dev, "%s: Failed to add sysfs files: %d\n", __func__, rv);
159 goto err_destroy_eng;
162 kpc_dma_add_device(ldev);
167 destroy_dma_engine(ldev);
169 device_destroy(kpc_dma_class, dev);
177 int kpc_dma_remove(struct platform_device *pldev)
179 struct kpc_dma_device *ldev = platform_get_drvdata(pldev);
185 sysfs_remove_files(&(ldev->pldev->dev.kobj), ndd_attr_list);
186 destroy_dma_engine(ldev);
187 kpc_dma_del_device(ldev);
188 device_destroy(kpc_dma_class, MKDEV(assigned_major_num, ldev->pldev->id));
194 /********** Driver Functions **********/
195 static struct platform_driver kpc_dma_plat_driver_i = {
196 .probe = kpc_dma_probe,
197 .remove = kpc_dma_remove,
199 .name = KP_DRIVER_NAME_DMA_CONTROLLER,
204 int __init kpc_dma_driver_init(void)
208 err = __register_chrdev(KPC_DMA_CHAR_MAJOR, 0, KPC_DMA_NUM_MINORS, "kpc_dma", &kpc_dma_fops);
210 pr_err("Can't allocate a major number (%d) for kpc_dma (err = %d)\n", KPC_DMA_CHAR_MAJOR, err);
211 goto fail_chrdev_register;
213 assigned_major_num = err;
215 kpc_dma_class = class_create(THIS_MODULE, "kpc_dma");
216 err = PTR_ERR(kpc_dma_class);
217 if (IS_ERR(kpc_dma_class)) {
218 pr_err("Can't create class kpc_dma (err = %d)\n", err);
219 goto fail_class_create;
222 err = platform_driver_register(&kpc_dma_plat_driver_i);
224 pr_err("Can't register platform driver for kpc_dma (err = %d)\n", err);
225 goto fail_platdriver_register;
230 fail_platdriver_register:
231 class_destroy(kpc_dma_class);
233 __unregister_chrdev(KPC_DMA_CHAR_MAJOR, 0, KPC_DMA_NUM_MINORS, "kpc_dma");
234 fail_chrdev_register:
237 module_init(kpc_dma_driver_init);
240 void __exit kpc_dma_driver_exit(void)
242 platform_driver_unregister(&kpc_dma_plat_driver_i);
243 class_destroy(kpc_dma_class);
244 __unregister_chrdev(KPC_DMA_CHAR_MAJOR, 0, KPC_DMA_NUM_MINORS, "kpc_dma");
246 module_exit(kpc_dma_driver_exit);