sch56xx-common.c revision 0772a640793986d66fd3f89c3cc677bba5d5f94f 
1/***************************************************************************
2 *   Copyright (C) 2010-2011 Hans de Goede <hdegoede@redhat.com>           *
3 *                                                                         *
4 *   This program is free software; you can redistribute it and/or modify  *
5 *   it under the terms of the GNU General Public License as published by  *
6 *   the Free Software Foundation; either version 2 of the License, or     *
7 *   (at your option) any later version.                                   *
8 *                                                                         *
9 *   This program is distributed in the hope that it will be useful,       *
10 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
11 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
12 *   GNU General Public License for more details.                          *
13 *                                                                         *
14 *   You should have received a copy of the GNU General Public License     *
15 *   along with this program; if not, write to the                         *
16 *   Free Software Foundation, Inc.,                                       *
17 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
18 ***************************************************************************/
19
20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22#include <linux/module.h>
23#include <linux/init.h>
24#include <linux/platform_device.h>
25#include <linux/err.h>
26#include <linux/io.h>
27#include <linux/acpi.h>
28#include <linux/delay.h>
29#include "sch56xx-common.h"
30
31#define SIO_SCH56XX_LD_EM	0x0C	/* Embedded uController Logical Dev */
32#define SIO_UNLOCK_KEY		0x55	/* Key to enable Super-I/O */
33#define SIO_LOCK_KEY		0xAA	/* Key to disable Super-I/O */
34
35#define SIO_REG_LDSEL		0x07	/* Logical device select */
36#define SIO_REG_DEVID		0x20	/* Device ID */
37#define SIO_REG_ENABLE		0x30	/* Logical device enable */
38#define SIO_REG_ADDR		0x66	/* Logical device address (2 bytes) */
39
40#define SIO_SCH5627_ID		0xC6	/* Chipset ID */
41#define SIO_SCH5636_ID		0xC7	/* Chipset ID */
42
43#define REGION_LENGTH		9
44
45#define SCH56XX_CMD_READ	0x02
46#define SCH56XX_CMD_WRITE	0x03
47
48static struct platform_device *sch56xx_pdev;
49
50/* Super I/O functions */
51static inline int superio_inb(int base, int reg)
52{
53	outb(reg, base);
54	return inb(base + 1);
55}
56
57static inline int superio_enter(int base)
58{
59	/* Don't step on other drivers' I/O space by accident */
60	if (!request_muxed_region(base, 2, "sch56xx")) {
61		pr_err("I/O address 0x%04x already in use\n", base);
62		return -EBUSY;
63	}
64
65	outb(SIO_UNLOCK_KEY, base);
66
67	return 0;
68}
69
70static inline void superio_select(int base, int ld)
71{
72	outb(SIO_REG_LDSEL, base);
73	outb(ld, base + 1);
74}
75
76static inline void superio_exit(int base)
77{
78	outb(SIO_LOCK_KEY, base);
79	release_region(base, 2);
80}
81
82static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v)
83{
84	u8 val;
85	int i;
86	/*
87	 * According to SMSC for the commands we use the maximum time for
88	 * the EM to respond is 15 ms, but testing shows in practice it
89	 * responds within 15-32 reads, so we first busy poll, and if
90	 * that fails sleep a bit and try again until we are way past
91	 * the 15 ms maximum response time.
92	 */
93	const int max_busy_polls = 64;
94	const int max_lazy_polls = 32;
95
96	/* (Optional) Write-Clear the EC to Host Mailbox Register */
97	val = inb(addr + 1);
98	outb(val, addr + 1);
99
100	/* Set Mailbox Address Pointer to first location in Region 1 */
101	outb(0x00, addr + 2);
102	outb(0x80, addr + 3);
103
104	/* Write Request Packet Header */
105	outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */
106	outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */
107	outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */
108
109	/* Write Value field */
110	if (cmd == SCH56XX_CMD_WRITE)
111		outb(v, addr + 4);
112
113	/* Write Address field */
114	outb(reg & 0xff, addr + 6);
115	outb(reg >> 8, addr + 7);
116
117	/* Execute the Random Access Command */
118	outb(0x01, addr); /* Write 01h to the Host-to-EC register */
119
120	/* EM Interface Polling "Algorithm" */
121	for (i = 0; i < max_busy_polls + max_lazy_polls; i++) {
122		if (i >= max_busy_polls)
123			msleep(1);
124		/* Read Interrupt source Register */
125		val = inb(addr + 8);
126		/* Write Clear the interrupt source bits */
127		if (val)
128			outb(val, addr + 8);
129		/* Command Completed ? */
130		if (val & 0x01)
131			break;
132	}
133	if (i == max_busy_polls + max_lazy_polls) {
134		pr_err("Max retries exceeded reading virtual "
135		       "register 0x%04hx (%d)\n", reg, 1);
136		return -EIO;
137	}
138
139	/*
140	 * According to SMSC we may need to retry this, but sofar I've always
141	 * seen this succeed in 1 try.
142	 */
143	for (i = 0; i < max_busy_polls; i++) {
144		/* Read EC-to-Host Register */
145		val = inb(addr + 1);
146		/* Command Completed ? */
147		if (val == 0x01)
148			break;
149
150		if (i == 0)
151			pr_warn("EC reports: 0x%02x reading virtual register "
152				"0x%04hx\n", (unsigned int)val, reg);
153	}
154	if (i == max_busy_polls) {
155		pr_err("Max retries exceeded reading virtual "
156		       "register 0x%04hx (%d)\n", reg, 2);
157		return -EIO;
158	}
159
160	/*
161	 * According to the SMSC app note we should now do:
162	 *
163	 * Set Mailbox Address Pointer to first location in Region 1 *
164	 * outb(0x00, addr + 2);
165	 * outb(0x80, addr + 3);
166	 *
167	 * But if we do that things don't work, so let's not.
168	 */
169
170	/* Read Value field */
171	if (cmd == SCH56XX_CMD_READ)
172		return inb(addr + 4);
173
174	return 0;
175}
176
177int sch56xx_read_virtual_reg(u16 addr, u16 reg)
178{
179	return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0);
180}
181EXPORT_SYMBOL(sch56xx_read_virtual_reg);
182
183int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val)
184{
185	return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val);
186}
187EXPORT_SYMBOL(sch56xx_write_virtual_reg);
188
189int sch56xx_read_virtual_reg16(u16 addr, u16 reg)
190{
191	int lsb, msb;
192
193	/* Read LSB first, this will cause the matching MSB to be latched */
194	lsb = sch56xx_read_virtual_reg(addr, reg);
195	if (lsb < 0)
196		return lsb;
197
198	msb = sch56xx_read_virtual_reg(addr, reg + 1);
199	if (msb < 0)
200		return msb;
201
202	return lsb | (msb << 8);
203}
204EXPORT_SYMBOL(sch56xx_read_virtual_reg16);
205
206int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg,
207			       int high_nibble)
208{
209	int msb, lsn;
210
211	/* Read MSB first, this will cause the matching LSN to be latched */
212	msb = sch56xx_read_virtual_reg(addr, msb_reg);
213	if (msb < 0)
214		return msb;
215
216	lsn = sch56xx_read_virtual_reg(addr, lsn_reg);
217	if (lsn < 0)
218		return lsn;
219
220	if (high_nibble)
221		return (msb << 4) | (lsn >> 4);
222	else
223		return (msb << 4) | (lsn & 0x0f);
224}
225EXPORT_SYMBOL(sch56xx_read_virtual_reg12);
226
227static int __init sch56xx_find(int sioaddr, unsigned short *address,
228			       const char **name)
229{
230	u8 devid;
231	int err;
232
233	err = superio_enter(sioaddr);
234	if (err)
235		return err;
236
237	devid = superio_inb(sioaddr, SIO_REG_DEVID);
238	switch (devid) {
239	case SIO_SCH5627_ID:
240		*name = "sch5627";
241		break;
242	case SIO_SCH5636_ID:
243		*name = "sch5636";
244		break;
245	default:
246		pr_debug("Unsupported device id: 0x%02x\n",
247			 (unsigned int)devid);
248		err = -ENODEV;
249		goto exit;
250	}
251
252	superio_select(sioaddr, SIO_SCH56XX_LD_EM);
253
254	if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) {
255		pr_warn("Device not activated\n");
256		err = -ENODEV;
257		goto exit;
258	}
259
260	/*
261	 * Warning the order of the low / high byte is the other way around
262	 * as on most other superio devices!!
263	 */
264	*address = superio_inb(sioaddr, SIO_REG_ADDR) |
265		   superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8;
266	if (*address == 0) {
267		pr_warn("Base address not set\n");
268		err = -ENODEV;
269		goto exit;
270	}
271
272exit:
273	superio_exit(sioaddr);
274	return err;
275}
276
277static int __init sch56xx_device_add(unsigned short address, const char *name)
278{
279	struct resource res = {
280		.start	= address,
281		.end	= address + REGION_LENGTH - 1,
282		.flags	= IORESOURCE_IO,
283	};
284	int err;
285
286	sch56xx_pdev = platform_device_alloc(name, address);
287	if (!sch56xx_pdev)
288		return -ENOMEM;
289
290	res.name = sch56xx_pdev->name;
291	err = acpi_check_resource_conflict(&res);
292	if (err)
293		goto exit_device_put;
294
295	err = platform_device_add_resources(sch56xx_pdev, &res, 1);
296	if (err) {
297		pr_err("Device resource addition failed\n");
298		goto exit_device_put;
299	}
300
301	err = platform_device_add(sch56xx_pdev);
302	if (err) {
303		pr_err("Device addition failed\n");
304		goto exit_device_put;
305	}
306
307	return 0;
308
309exit_device_put:
310	platform_device_put(sch56xx_pdev);
311
312	return err;
313}
314
315static int __init sch56xx_init(void)
316{
317	int err;
318	unsigned short address;
319	const char *name;
320
321	err = sch56xx_find(0x4e, &address, &name);
322	if (err)
323		err = sch56xx_find(0x2e, &address, &name);
324	if (err)
325		return err;
326
327	return sch56xx_device_add(address, name);
328}
329
330static void __exit sch56xx_exit(void)
331{
332	platform_device_unregister(sch56xx_pdev);
333}
334
335MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
336MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
337MODULE_LICENSE("GPL");
338
339module_init(sch56xx_init);
340module_exit(sch56xx_exit);
341