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 int
143axon_ram_direct_access(struct block_device *device, sector_t sector,
144		       void **kaddr, unsigned long *pfn)
145{
146	struct axon_ram_bank *bank = device->bd_disk->private_data;
147	loff_t offset;
148
149	offset = sector;
150	if (device->bd_part != NULL)
151		offset += device->bd_part->start_sect;
152	offset <<= AXON_RAM_SECTOR_SHIFT;
153	if (offset >= bank->size) {
154		dev_err(&bank->device->dev, "Access outside of address space\n");
155		return -ERANGE;
156	}
157
158	*kaddr = (void *)(bank->ph_addr + offset);
159	*pfn = virt_to_phys(kaddr) >> PAGE_SHIFT;
160
161	return 0;
162}
163
164static const struct block_device_operations axon_ram_devops = {
165	.owner		= THIS_MODULE,
166	.direct_access	= axon_ram_direct_access
167};
168
169/**
170 * axon_ram_probe - probe() method for platform driver
171 * @device: see platform_driver method
172 */
173static int axon_ram_probe(struct platform_device *device)
174{
175	static int axon_ram_bank_id = -1;
176	struct axon_ram_bank *bank;
177	struct resource resource;
178	int rc = 0;
179
180	axon_ram_bank_id++;
181
182	dev_info(&device->dev, "Found memory controller on %s\n",
183			device->dev.of_node->full_name);
184
185	bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
186	if (bank == NULL) {
187		dev_err(&device->dev, "Out of memory\n");
188		rc = -ENOMEM;
189		goto failed;
190	}
191
192	device->dev.platform_data = bank;
193
194	bank->device = device;
195
196	if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
197		dev_err(&device->dev, "Cannot access device tree\n");
198		rc = -EFAULT;
199		goto failed;
200	}
201
202	bank->size = resource_size(&resource);
203
204	if (bank->size == 0) {
205		dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
206				AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
207		rc = -ENODEV;
208		goto failed;
209	}
210
211	dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
212			AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
213
214	bank->ph_addr = resource.start;
215	bank->io_addr = (unsigned long) ioremap_prot(
216			bank->ph_addr, bank->size, _PAGE_NO_CACHE);
217	if (bank->io_addr == 0) {
218		dev_err(&device->dev, "ioremap() failed\n");
219		rc = -EFAULT;
220		goto failed;
221	}
222
223	bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
224	if (bank->disk == NULL) {
225		dev_err(&device->dev, "Cannot register disk\n");
226		rc = -EFAULT;
227		goto failed;
228	}
229
230	bank->disk->major = azfs_major;
231	bank->disk->first_minor = azfs_minor;
232	bank->disk->fops = &axon_ram_devops;
233	bank->disk->private_data = bank;
234	bank->disk->driverfs_dev = &device->dev;
235
236	sprintf(bank->disk->disk_name, "%s%d",
237			AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
238
239	bank->disk->queue = blk_alloc_queue(GFP_KERNEL);
240	if (bank->disk->queue == NULL) {
241		dev_err(&device->dev, "Cannot register disk queue\n");
242		rc = -EFAULT;
243		goto failed;
244	}
245
246	set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
247	blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
248	blk_queue_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
249	add_disk(bank->disk);
250
251	bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
252	if (bank->irq_id == NO_IRQ) {
253		dev_err(&device->dev, "Cannot access ECC interrupt ID\n");
254		rc = -EFAULT;
255		goto failed;
256	}
257
258	rc = request_irq(bank->irq_id, axon_ram_irq_handler,
259			AXON_RAM_IRQ_FLAGS, bank->disk->disk_name, device);
260	if (rc != 0) {
261		dev_err(&device->dev, "Cannot register ECC interrupt handler\n");
262		bank->irq_id = NO_IRQ;
263		rc = -EFAULT;
264		goto failed;
265	}
266
267	rc = device_create_file(&device->dev, &dev_attr_ecc);
268	if (rc != 0) {
269		dev_err(&device->dev, "Cannot create sysfs file\n");
270		rc = -EFAULT;
271		goto failed;
272	}
273
274	azfs_minor += bank->disk->minors;
275
276	return 0;
277
278failed:
279	if (bank != NULL) {
280		if (bank->irq_id != NO_IRQ)
281			free_irq(bank->irq_id, device);
282		if (bank->disk != NULL) {
283			if (bank->disk->major > 0)
284				unregister_blkdev(bank->disk->major,
285						bank->disk->disk_name);
286			del_gendisk(bank->disk);
287		}
288		device->dev.platform_data = NULL;
289		if (bank->io_addr != 0)
290			iounmap((void __iomem *) bank->io_addr);
291		kfree(bank);
292	}
293
294	return rc;
295}
296
297/**
298 * axon_ram_remove - remove() method for platform driver
299 * @device: see of_platform_driver method
300 */
301static int
302axon_ram_remove(struct platform_device *device)
303{
304	struct axon_ram_bank *bank = device->dev.platform_data;
305
306	BUG_ON(!bank || !bank->disk);
307
308	device_remove_file(&device->dev, &dev_attr_ecc);
309	free_irq(bank->irq_id, device);
310	del_gendisk(bank->disk);
311	iounmap((void __iomem *) bank->io_addr);
312	kfree(bank);
313
314	return 0;
315}
316
317static const struct of_device_id axon_ram_device_id[] = {
318	{
319		.type	= "dma-memory"
320	},
321	{}
322};
323
324static struct platform_driver axon_ram_driver = {
325	.probe		= axon_ram_probe,
326	.remove		= axon_ram_remove,
327	.driver = {
328		.name = AXON_RAM_MODULE_NAME,
329		.owner = THIS_MODULE,
330		.of_match_table = axon_ram_device_id,
331	},
332};
333
334/**
335 * axon_ram_init
336 */
337static int __init
338axon_ram_init(void)
339{
340	azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
341	if (azfs_major < 0) {
342		printk(KERN_ERR "%s cannot become block device major number\n",
343				AXON_RAM_MODULE_NAME);
344		return -EFAULT;
345	}
346	azfs_minor = 0;
347
348	return platform_driver_register(&axon_ram_driver);
349}
350
351/**
352 * axon_ram_exit
353 */
354static void __exit
355axon_ram_exit(void)
356{
357	platform_driver_unregister(&axon_ram_driver);
358	unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
359}
360
361module_init(axon_ram_init);
362module_exit(axon_ram_exit);
363
364MODULE_LICENSE("GPL");
365MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
366MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");
367