1/*
2 *  S390 version
3 *    Copyright IBM Corp. 1999, 2007
4 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
5 *               Christian Borntraeger (cborntra@de.ibm.com),
6 */
7
8#define KMSG_COMPONENT "cpcmd"
9#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/spinlock.h>
15#include <linux/stddef.h>
16#include <linux/string.h>
17#include <asm/ebcdic.h>
18#include <asm/cpcmd.h>
19#include <asm/io.h>
20
21static DEFINE_SPINLOCK(cpcmd_lock);
22static char cpcmd_buf[241];
23
24static int diag8_noresponse(int cmdlen)
25{
26	register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
27	register unsigned long reg3 asm ("3") = cmdlen;
28
29	asm volatile(
30		"	sam31\n"
31		"	diag	%1,%0,0x8\n"
32		"	sam64\n"
33		: "+d" (reg3) : "d" (reg2) : "cc");
34	return reg3;
35}
36
37static int diag8_response(int cmdlen, char *response, int *rlen)
38{
39	register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
40	register unsigned long reg3 asm ("3") = (addr_t) response;
41	register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L;
42	register unsigned long reg5 asm ("5") = *rlen;
43
44	asm volatile(
45		"	sam31\n"
46		"	diag	%2,%0,0x8\n"
47		"	sam64\n"
48		"	brc	8,1f\n"
49		"	agr	%1,%4\n"
50		"1:\n"
51		: "+d" (reg4), "+d" (reg5)
52		: "d" (reg2), "d" (reg3), "d" (*rlen) : "cc");
53	*rlen = reg5;
54	return reg4;
55}
56
57/*
58 * __cpcmd has some restrictions over cpcmd
59 *  - the response buffer must reside below 2GB (if any)
60 *  - __cpcmd is unlocked and therefore not SMP-safe
61 */
62int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
63{
64	int cmdlen;
65	int rc;
66	int response_len;
67
68	cmdlen = strlen(cmd);
69	BUG_ON(cmdlen > 240);
70	memcpy(cpcmd_buf, cmd, cmdlen);
71	ASCEBC(cpcmd_buf, cmdlen);
72
73	if (response) {
74		memset(response, 0, rlen);
75		response_len = rlen;
76		rc = diag8_response(cmdlen, response, &rlen);
77		EBCASC(response, response_len);
78        } else {
79		rc = diag8_noresponse(cmdlen);
80        }
81	if (response_code)
82		*response_code = rc;
83	return rlen;
84}
85EXPORT_SYMBOL(__cpcmd);
86
87int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
88{
89	char *lowbuf;
90	int len;
91	unsigned long flags;
92
93	if ((virt_to_phys(response) != (unsigned long) response) ||
94			(((unsigned long)response + rlen) >> 31)) {
95		lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
96		if (!lowbuf) {
97			pr_warning("The cpcmd kernel function failed to "
98				   "allocate a response buffer\n");
99			return -ENOMEM;
100		}
101		spin_lock_irqsave(&cpcmd_lock, flags);
102		len = __cpcmd(cmd, lowbuf, rlen, response_code);
103		spin_unlock_irqrestore(&cpcmd_lock, flags);
104		memcpy(response, lowbuf, rlen);
105		kfree(lowbuf);
106	} else {
107		spin_lock_irqsave(&cpcmd_lock, flags);
108		len = __cpcmd(cmd, response, rlen, response_code);
109		spin_unlock_irqrestore(&cpcmd_lock, flags);
110	}
111	return len;
112}
113EXPORT_SYMBOL(cpcmd);
114