linux/drivers/s390/char/sclp_info.c
Heiko Carstens 83119ad4a1 [S390] sclp: Test facility list before executing a service call.
Check if a command is available before executing. Saves some
superfluous service calls that won't succeed anyway.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-07-10 11:24:43 +02:00

116 lines
2.8 KiB
C

/*
* drivers/s390/char/sclp_info.c
*
* Copyright IBM Corp. 2007
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
*/
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <asm/sclp.h>
#include "sclp.h"
struct sclp_readinfo_sccb {
struct sccb_header header; /* 0-7 */
u16 rnmax; /* 8-9 */
u8 rnsize; /* 10 */
u8 _reserved0[24 - 11]; /* 11-23 */
u8 loadparm[8]; /* 24-31 */
u8 _reserved1[48 - 32]; /* 32-47 */
u64 facilities; /* 48-55 */
u8 _reserved2[91 - 56]; /* 56-90 */
u8 flags; /* 91 */
u8 _reserved3[100 - 92]; /* 92-99 */
u32 rnsize2; /* 100-103 */
u64 rnmax2; /* 104-111 */
u8 _reserved4[4096 - 112]; /* 112-4095 */
} __attribute__((packed, aligned(4096)));
static struct sclp_readinfo_sccb __initdata early_readinfo_sccb;
static int __initdata early_readinfo_sccb_valid;
u64 sclp_facilities;
void __init sclp_readinfo_early(void)
{
int ret;
int i;
struct sclp_readinfo_sccb *sccb;
sclp_cmdw_t commands[] = {SCLP_CMDW_READ_SCP_INFO_FORCED,
SCLP_CMDW_READ_SCP_INFO};
/* Enable service signal subclass mask. */
__ctl_set_bit(0, 9);
sccb = &early_readinfo_sccb;
for (i = 0; i < ARRAY_SIZE(commands); i++) {
do {
memset(sccb, 0, sizeof(*sccb));
sccb->header.length = sizeof(*sccb);
sccb->header.control_mask[2] = 0x80;
ret = sclp_service_call(commands[i], sccb);
} while (ret == -EBUSY);
if (ret)
break;
__load_psw_mask(PSW_BASE_BITS | PSW_MASK_EXT |
PSW_MASK_WAIT | PSW_DEFAULT_KEY);
local_irq_disable();
/*
* Contents of the sccb might have changed
* therefore a barrier is needed.
*/
barrier();
if (sccb->header.response_code == 0x10) {
early_readinfo_sccb_valid = 1;
break;
}
if (sccb->header.response_code != 0x1f0)
break;
}
/* Disable service signal subclass mask again. */
__ctl_clear_bit(0, 9);
}
void __init sclp_facilities_detect(void)
{
if (!early_readinfo_sccb_valid)
return;
sclp_facilities = early_readinfo_sccb.facilities;
}
unsigned long long __init sclp_memory_detect(void)
{
unsigned long long memsize;
struct sclp_readinfo_sccb *sccb;
if (!early_readinfo_sccb_valid)
return 0;
sccb = &early_readinfo_sccb;
if (sccb->rnsize)
memsize = sccb->rnsize << 20;
else
memsize = sccb->rnsize2 << 20;
if (sccb->rnmax)
memsize *= sccb->rnmax;
else
memsize *= sccb->rnmax2;
return memsize;
}
/*
* This function will be called after sclp_memory_detect(), which gets called
* early from early.c code. Therefore the sccb should have valid contents.
*/
void __init sclp_get_ipl_info(struct sclp_ipl_info *info)
{
struct sclp_readinfo_sccb *sccb;
if (!early_readinfo_sccb_valid)
return;
sccb = &early_readinfo_sccb;
info->is_valid = 1;
if (sccb->flags & 0x2)
info->has_dump = 1;
memcpy(&info->loadparm, &sccb->loadparm, LOADPARM_LEN);
}