1/*
2 * (C) Copyright IBM Deutschland Entwicklung GmbH 2006
3 *
4 * Author: Maxim Shchetynin <maxim@de.ibm.com>
5 *
6 * Axon DDR2 device driver.
7 * It registers one block device per Axon's DDR2 memory bank found on a system.
8 * Block devices are called axonram?, their major and minor numbers are
9 * available in /proc/devices, /proc/partitions or in /sys/block/axonram?/dev.
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2, or (at your option)
14 * any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 */
25
26#include <linux/bio.h>
27#include <linux/blkdev.h>
28#include <linux/device.h>
29#include <linux/errno.h>
30#include <linux/fs.h>
31#include <linux/genhd.h>
32#include <linux/interrupt.h>
33#include <linux/io.h>
34#include <linux/ioport.h>
35#include <linux/irq.h>
36#include <linux/irqreturn.h>
37#include <linux/kernel.h>
38#include <linux/mm.h>
39#include <linux/mod_devicetable.h>
40#include <linux/module.h>
41#include <linux/slab.h>
42#include <linux/string.h>
43#include <linux/types.h>
44#include <linux/of_device.h>
45#include <linux/of_platform.h>
46
47#include <asm/page.h>
48#include <asm/prom.h>
49
50#define AXON_RAM_MODULE_NAME		"axonram"
51#define AXON_RAM_DEVICE_NAME		"axonram"
52#define AXON_RAM_MINORS_PER_DISK	16
53#define AXON_RAM_BLOCK_SHIFT		PAGE_SHIFT
54#define AXON_RAM_BLOCK_SIZE		1 << AXON_RAM_BLOCK_SHIFT
55#define AXON_RAM_SECTOR_SHIFT		9
56#define AXON_RAM_SECTOR_SIZE		1 << AXON_RAM_SECTOR_SHIFT
57#define AXON_RAM_IRQ_FLAGS		IRQF_SHARED | IRQF_TRIGGER_RISING
58
59static int azfs_major, azfs_minor;
60
61struct axon_ram_bank {
62	struct platform_device	*device;
63	struct gendisk		*disk;
64	unsigned int		irq_id;
65	unsigned long		ph_addr;
66	unsigned long		io_addr;
67	unsigned long		size;
68	unsigned long		ecc_counter;
69};
70
71static ssize_t
72axon_ram_sysfs_ecc(struct device *dev, struct device_attribute *attr, char *buf)
73{
74	struct platform_device *device = to_platform_device(dev);
75	struct axon_ram_bank *bank = device->dev.platform_data;
76
77	BUG_ON(!bank);
78
79	return sprintf(buf, "%ld\n", bank->ecc_counter);
80}
81
82static DEVICE_ATTR(ecc, S_IRUGO, axon_ram_sysfs_ecc, NULL);
83
84/**
85 * axon_ram_irq_handler - interrupt handler for Axon RAM ECC
86 * @irq: interrupt ID
87 * @dev: pointer to of_device
88 */
89static irqreturn_t
90axon_ram_irq_handler(int irq, void *dev)
91{
92	struct platform_device *device = dev;
93	struct axon_ram_bank *bank = device->dev.platform_data;
94
95	BUG_ON(!bank);
96
97	dev_err(&device->dev, "Correctable memory error occurred\n");
98	bank->ecc_counter++;
99	return IRQ_HANDLED;
100}
101
102/**
103 * axon_ram_make_request - make_request() method for block device
104 * @queue, @bio: see blk_queue_make_request()
105 */
106static void
107axon_ram_make_request(struct request_queue *queue, struct bio *bio)
108{
109	struct axon_ram_bank *bank = bio->bi_bdev->bd_disk->private_data;
110	unsigned long phys_mem, phys_end;
111	void *user_mem;
112	struct bio_vec vec;
113	unsigned int transfered;
114	struct bvec_iter iter;
115
116	phys_mem = bank->io_addr + (bio->bi_iter.bi_sector <<
117				    AXON_RAM_SECTOR_SHIFT);
118	phys_end = bank->io_addr + bank->size;
119	transfered = 0;
120	bio_for_each_segment(vec, bio, iter) {
121		if (unlikely(phys_mem + vec.bv_len > phys_end)) {
122			bio_io_error(bio);
123			return;
124		}
125
126		user_mem = page_address(vec.bv_page) + vec.bv_offset;
127		if (bio_data_dir(bio) == READ)
128			memcpy(user_mem, (void *) phys_mem, vec.bv_len);
129		else
130			memcpy((void *) phys_mem, user_mem, vec.bv_len);
131
132		phys_mem += vec.bv_len;
133		transfered += vec.bv_len;
134	}
135	bio_endio(bio, 0);
136}
137
138/**
139 * axon_ram_direct_access - direct_access() method for block device
140 * @device, @sector, @data: see block_device_operations method
141 */
142static long
143axon_ram_direct_access(struct block_device *device, sector_t sector,
144		       void **kaddr, unsigned long *pfn, long size)
145{
146	struct axon_ram_bank *bank = device->bd_disk->private_data;
147	loff_t offset = (loff_t)sector << AXON_RAM_SECTOR_SHIFT;
148
149	*kaddr = (void *)(bank->ph_addr + offset);
150	*pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
151
152	return bank->size - offset;
153}
154
155static const struct block_device_operations axon_ram_devops = {
156	.owner		= THIS_MODULE,
157	.direct_access	= axon_ram_direct_access
158};
159
160/**
161 * axon_ram_probe - probe() method for platform driver
162 * @device: see platform_driver method
163 */
164static int axon_ram_probe(struct platform_device *device)
165{
166	static int axon_ram_bank_id = -1;
167	struct axon_ram_bank *bank;
168	struct resource resource;
169	int rc = 0;
170
171	axon_ram_bank_id++;
172
173	dev_info(&device->dev, "Found memory controller on %s\n",
174			device->dev.of_node->full_name);
175
176	bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
177	if (bank == NULL) {
178		dev_err(&device->dev, "Out of memory\n");
179		rc = -ENOMEM;
180		goto failed;
181	}
182
183	device->dev.platform_data = bank;
184
185	bank->device = device;
186
187	if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
188		dev_err(&device->dev, "Cannot access device tree\n");
189		rc = -EFAULT;
190		goto failed;
191	}
192
193	bank->size = resource_size(&resource);
194
195	if (bank->size == 0) {
196		dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
197				AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
198		rc = -ENODEV;
199		goto failed;
200	}
201
202	dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
203			AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
204
205	bank->ph_addr = resource.start;
206	bank->io_addr = (unsigned long) ioremap_prot(
207			bank->ph_addr, bank->size, _PAGE_NO_CACHE);
208	if (bank->io_addr == 0) {
209		dev_err(&device->dev, "ioremap() failed\n");
210		rc = -EFAULT;
211		goto failed;
212	}
213
214	bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
215	if (bank->disk == NULL) {
216		dev_err(&device->dev, "Cannot register disk\n");
217		rc = -EFAULT;
218		goto failed;
219	}
220
221	bank->disk->major = azfs_major;
222	bank->disk->first_minor = azfs_minor;
223	bank->disk->fops = &axon_ram_devops;
224	bank->disk->private_data = bank;
225	bank->disk->driverfs_dev = &device->dev;
226
227	sprintf(bank->disk->disk_name, "%s%d",
228			AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
229
230	bank->disk->queue = blk_alloc_queue(GFP_KERNEL);
231	if (bank->disk->queue == NULL) {
232		dev_err(&device->dev, "Cannot register disk queue\n");
233		rc = -EFAULT;
234		goto failed;
235	}
236
237	set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
238	blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
239	blk_queue_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
240	add_disk(bank->disk);
241
242	bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
243	if (bank->irq_id == NO_IRQ) {
244		dev_err(&device->dev, "Cannot access ECC interrupt ID\n");
245		rc = -EFAULT;
246		goto failed;
247	}
248
249	rc = request_irq(bank->irq_id, axon_ram_irq_handler,
250			AXON_RAM_IRQ_FLAGS, bank->disk->disk_name, device);
251	if (rc != 0) {
252		dev_err(&device->dev, "Cannot register ECC interrupt handler\n");
253		bank->irq_id = NO_IRQ;
254		rc = -EFAULT;
255		goto failed;
256	}
257
258	rc = device_create_file(&device->dev, &dev_attr_ecc);
259	if (rc != 0) {
260		dev_err(&device->dev, "Cannot create sysfs file\n");
261		rc = -EFAULT;
262		goto failed;
263	}
264
265	azfs_minor += bank->disk->minors;
266
267	return 0;
268
269failed:
270	if (bank != NULL) {
271		if (bank->irq_id != NO_IRQ)
272			free_irq(bank->irq_id, device);
273		if (bank->disk != NULL) {
274			if (bank->disk->major > 0)
275				unregister_blkdev(bank->disk->major,
276						bank->disk->disk_name);
277			del_gendisk(bank->disk);
278		}
279		device->dev.platform_data = NULL;
280		if (bank->io_addr != 0)
281			iounmap((void __iomem *) bank->io_addr);
282		kfree(bank);
283	}
284
285	return rc;
286}
287
288/**
289 * axon_ram_remove - remove() method for platform driver
290 * @device: see of_platform_driver method
291 */
292static int
293axon_ram_remove(struct platform_device *device)
294{
295	struct axon_ram_bank *bank = device->dev.platform_data;
296
297	BUG_ON(!bank || !bank->disk);
298
299	device_remove_file(&device->dev, &dev_attr_ecc);
300	free_irq(bank->irq_id, device);
301	del_gendisk(bank->disk);
302	iounmap((void __iomem *) bank->io_addr);
303	kfree(bank);
304
305	return 0;
306}
307
308static const struct of_device_id axon_ram_device_id[] = {
309	{
310		.type	= "dma-memory"
311	},
312	{}
313};
314
315static struct platform_driver axon_ram_driver = {
316	.probe		= axon_ram_probe,
317	.remove		= axon_ram_remove,
318	.driver = {
319		.name = AXON_RAM_MODULE_NAME,
320		.of_match_table = axon_ram_device_id,
321	},
322};
323
324/**
325 * axon_ram_init
326 */
327static int __init
328axon_ram_init(void)
329{
330	azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
331	if (azfs_major < 0) {
332		printk(KERN_ERR "%s cannot become block device major number\n",
333				AXON_RAM_MODULE_NAME);
334		return -EFAULT;
335	}
336	azfs_minor = 0;
337
338	return platform_driver_register(&axon_ram_driver);
339}
340
341/**
342 * axon_ram_exit
343 */
344static void __exit
345axon_ram_exit(void)
346{
347	platform_driver_unregister(&axon_ram_driver);
348	unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
349}
350
351module_init(axon_ram_init);
352module_exit(axon_ram_exit);
353
354MODULE_LICENSE("GPL");
355MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
356MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");
357