1/*
2 *  arch/s390/kernel/cpcmd.c
3 *
4 *  S390 version
5 *    Copyright (C) 1999,2005 IBM Deutschland Entwicklung GmbH, IBM Corporation
6 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
7 *               Christian Borntraeger (cborntra@de.ibm.com),
8 */
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/slab.h>
13#include <linux/spinlock.h>
14#include <linux/stddef.h>
15#include <linux/string.h>
16#include <asm/ebcdic.h>
17#include <asm/cpcmd.h>
18#include <asm/system.h>
19#include <asm/io.h>
20
21static DEFINE_SPINLOCK(cpcmd_lock);
22static char cpcmd_buf[241];
23
24/*
25 * __cpcmd has some restrictions over cpcmd
26 *  - the response buffer must reside below 2GB (if any)
27 *  - __cpcmd is unlocked and therefore not SMP-safe
28 */
29int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
30{
31	unsigned cmdlen;
32	int return_code, return_len;
33
34	cmdlen = strlen(cmd);
35	BUG_ON(cmdlen > 240);
36	memcpy(cpcmd_buf, cmd, cmdlen);
37	ASCEBC(cpcmd_buf, cmdlen);
38
39	if (response != NULL && rlen > 0) {
40		register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
41		register unsigned long reg3 asm ("3") = (addr_t) response;
42		register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L;
43		register unsigned long reg5 asm ("5") = rlen;
44
45		memset(response, 0, rlen);
46		asm volatile(
47#ifndef CONFIG_64BIT
48			"	diag	%2,%0,0x8\n"
49			"	brc	8,1f\n"
50			"	ar	%1,%4\n"
51#else /* CONFIG_64BIT */
52			"	sam31\n"
53			"	diag	%2,%0,0x8\n"
54			"	sam64\n"
55			"	brc	8,1f\n"
56			"	agr	%1,%4\n"
57#endif /* CONFIG_64BIT */
58			"1:\n"
59			: "+d" (reg4), "+d" (reg5)
60			: "d" (reg2), "d" (reg3), "d" (rlen) : "cc");
61		return_code = (int) reg4;
62		return_len = (int) reg5;
63                EBCASC(response, rlen);
64        } else {
65		register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
66		register unsigned long reg3 asm ("3") = cmdlen;
67		return_len = 0;
68		asm volatile(
69#ifndef CONFIG_64BIT
70			"	diag	%1,%0,0x8\n"
71#else /* CONFIG_64BIT */
72			"	sam31\n"
73			"	diag	%1,%0,0x8\n"
74			"	sam64\n"
75#endif /* CONFIG_64BIT */
76			: "+d" (reg3) : "d" (reg2) : "cc");
77		return_code = (int) reg3;
78        }
79	if (response_code != NULL)
80		*response_code = return_code;
81	return return_len;
82}
83
84EXPORT_SYMBOL(__cpcmd);
85
86int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
87{
88	char *lowbuf;
89	int len;
90	unsigned long flags;
91
92	if ((virt_to_phys(response) != (unsigned long) response) ||
93			(((unsigned long)response + rlen) >> 31)) {
94		lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
95		if (!lowbuf) {
96			printk(KERN_WARNING
97				"cpcmd: could not allocate response buffer\n");
98			return -ENOMEM;
99		}
100		spin_lock_irqsave(&cpcmd_lock, flags);
101		len = __cpcmd(cmd, lowbuf, rlen, response_code);
102		spin_unlock_irqrestore(&cpcmd_lock, flags);
103		memcpy(response, lowbuf, rlen);
104		kfree(lowbuf);
105	} else {
106		spin_lock_irqsave(&cpcmd_lock, flags);
107		len = __cpcmd(cmd, response, rlen, response_code);
108		spin_unlock_irqrestore(&cpcmd_lock, flags);
109	}
110	return len;
111}
112
113EXPORT_SYMBOL(cpcmd);
114