1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * PISMO memory driver - http://www.pismoworld.org/
4 *
5 * For ARM Realview and Versatile platforms
6 */
7#include <linux/init.h>
8#include <linux/module.h>
9#include <linux/i2c.h>
10#include <linux/slab.h>
11#include <linux/platform_device.h>
12#include <linux/spinlock.h>
13#include <linux/mutex.h>
14#include <linux/mtd/physmap.h>
15#include <linux/mtd/plat-ram.h>
16#include <linux/mtd/pismo.h>
17
18#define PISMO_NUM_CS	5
19
20struct pismo_cs_block {
21	u8	type;
22	u8	width;
23	__le16	access;
24	__le32	size;
25	u32	reserved[2];
26	char	device[32];
27} __packed;
28
29struct pismo_eeprom {
30	struct pismo_cs_block cs[PISMO_NUM_CS];
31	char	board[15];
32	u8	sum;
33} __packed;
34
35struct pismo_mem {
36	phys_addr_t base;
37	u32	size;
38	u16	access;
39	u8	width;
40	u8	type;
41};
42
43struct pismo_data {
44	struct i2c_client	*client;
45	void			(*vpp)(void *, int);
46	void			*vpp_data;
47	struct platform_device	*dev[PISMO_NUM_CS];
48};
49
50static void pismo_set_vpp(struct platform_device *pdev, int on)
51{
52	struct i2c_client *client = to_i2c_client(pdev->dev.parent);
53	struct pismo_data *pismo = i2c_get_clientdata(client);
54
55	pismo->vpp(pismo->vpp_data, on);
56}
57
58static unsigned int pismo_width_to_bytes(unsigned int width)
59{
60	width &= 15;
61	if (width > 2)
62		return 0;
63	return 1 << width;
64}
65
66static int pismo_eeprom_read(struct i2c_client *client, void *buf, u8 addr,
67			     size_t size)
68{
69	int ret;
70	struct i2c_msg msg[] = {
71		{
72			.addr = client->addr,
73			.len = sizeof(addr),
74			.buf = &addr,
75		}, {
76			.addr = client->addr,
77			.flags = I2C_M_RD,
78			.len = size,
79			.buf = buf,
80		},
81	};
82
83	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
84
85	return ret == ARRAY_SIZE(msg) ? size : -EIO;
86}
87
88static int pismo_add_device(struct pismo_data *pismo, int i,
89			    struct pismo_mem *region, const char *name,
90			    void *pdata, size_t psize)
91{
92	struct platform_device *dev;
93	struct resource res = { };
94	phys_addr_t base = region->base;
95	int ret;
96
97	if (base == ~0)
98		return -ENXIO;
99
100	res.start = base;
101	res.end = base + region->size - 1;
102	res.flags = IORESOURCE_MEM;
103
104	dev = platform_device_alloc(name, i);
105	if (!dev)
106		return -ENOMEM;
107	dev->dev.parent = &pismo->client->dev;
108
109	do {
110		ret = platform_device_add_resources(dev, &res, 1);
111		if (ret)
112			break;
113
114		ret = platform_device_add_data(dev, pdata, psize);
115		if (ret)
116			break;
117
118		ret = platform_device_add(dev);
119		if (ret)
120			break;
121
122		pismo->dev[i] = dev;
123		return 0;
124	} while (0);
125
126	platform_device_put(dev);
127	return ret;
128}
129
130static int pismo_add_nor(struct pismo_data *pismo, int i,
131			 struct pismo_mem *region)
132{
133	struct physmap_flash_data data = {
134		.width = region->width,
135	};
136
137	if (pismo->vpp)
138		data.set_vpp = pismo_set_vpp;
139
140	return pismo_add_device(pismo, i, region, "physmap-flash",
141		&data, sizeof(data));
142}
143
144static int pismo_add_sram(struct pismo_data *pismo, int i,
145			  struct pismo_mem *region)
146{
147	struct platdata_mtd_ram data = {
148		.bankwidth = region->width,
149	};
150
151	return pismo_add_device(pismo, i, region, "mtd-ram",
152		&data, sizeof(data));
153}
154
155static void pismo_add_one(struct pismo_data *pismo, int i,
156			  const struct pismo_cs_block *cs, phys_addr_t base)
157{
158	struct device *dev = &pismo->client->dev;
159	struct pismo_mem region;
160
161	region.base = base;
162	region.type = cs->type;
163	region.width = pismo_width_to_bytes(cs->width);
164	region.access = le16_to_cpu(cs->access);
165	region.size = le32_to_cpu(cs->size);
166
167	if (region.width == 0) {
168		dev_err(dev, "cs%u: bad width: %02x, ignoring\n", i, cs->width);
169		return;
170	}
171
172	/*
173	 * FIXME: may need to the platforms memory controller here, but at
174	 * the moment we assume that it has already been correctly setup.
175	 * The memory controller can also tell us the base address as well.
176	 */
177
178	dev_info(dev, "cs%u: %.32s: type %02x access %u00ps size %uK\n",
179		i, cs->device, region.type, region.access, region.size / 1024);
180
181	switch (region.type) {
182	case 0:
183		break;
184	case 1:
185		/* static DOC */
186		break;
187	case 2:
188		/* static NOR */
189		pismo_add_nor(pismo, i, &region);
190		break;
191	case 3:
192		/* static RAM */
193		pismo_add_sram(pismo, i, &region);
194		break;
195	}
196}
197
198static void pismo_remove(struct i2c_client *client)
199{
200	struct pismo_data *pismo = i2c_get_clientdata(client);
201	int i;
202
203	for (i = 0; i < ARRAY_SIZE(pismo->dev); i++)
204		platform_device_unregister(pismo->dev[i]);
205
206	kfree(pismo);
207}
208
209static int pismo_probe(struct i2c_client *client)
210{
211	struct pismo_pdata *pdata = client->dev.platform_data;
212	struct pismo_eeprom eeprom;
213	struct pismo_data *pismo;
214	int ret, i;
215
216	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
217		dev_err(&client->dev, "functionality mismatch\n");
218		return -EIO;
219	}
220
221	pismo = kzalloc(sizeof(*pismo), GFP_KERNEL);
222	if (!pismo)
223		return -ENOMEM;
224
225	pismo->client = client;
226	if (pdata) {
227		pismo->vpp = pdata->set_vpp;
228		pismo->vpp_data = pdata->vpp_data;
229	}
230	i2c_set_clientdata(client, pismo);
231
232	ret = pismo_eeprom_read(client, &eeprom, 0, sizeof(eeprom));
233	if (ret < 0) {
234		dev_err(&client->dev, "error reading EEPROM: %d\n", ret);
235		goto exit_free;
236	}
237
238	dev_info(&client->dev, "%.15s board found\n", eeprom.board);
239
240	for (i = 0; i < ARRAY_SIZE(eeprom.cs); i++)
241		if (eeprom.cs[i].type != 0xff)
242			pismo_add_one(pismo, i, &eeprom.cs[i],
243				      pdata->cs_addrs[i]);
244
245	return 0;
246
247 exit_free:
248	kfree(pismo);
249	return ret;
250}
251
252static const struct i2c_device_id pismo_id[] = {
253	{ "pismo" },
254	{ },
255};
256MODULE_DEVICE_TABLE(i2c, pismo_id);
257
258static struct i2c_driver pismo_driver = {
259	.driver	= {
260		.name	= "pismo",
261	},
262	.probe		= pismo_probe,
263	.remove		= pismo_remove,
264	.id_table	= pismo_id,
265};
266
267static int __init pismo_init(void)
268{
269	BUILD_BUG_ON(sizeof(struct pismo_cs_block) != 48);
270	BUILD_BUG_ON(sizeof(struct pismo_eeprom) != 256);
271
272	return i2c_add_driver(&pismo_driver);
273}
274module_init(pismo_init);
275
276static void __exit pismo_exit(void)
277{
278	i2c_del_driver(&pismo_driver);
279}
280module_exit(pismo_exit);
281
282MODULE_AUTHOR("Russell King <linux@arm.linux.org.uk>");
283MODULE_DESCRIPTION("PISMO memory driver");
284MODULE_LICENSE("GPL");
285