2 files changed, 86 insertions, 29 deletions

diff --git a/drivers/s390/char/sclp.h b/drivers/s390/char/sclp.h
index dbb99d1b6f57..cb5888f79007 100644
--- a/drivers/s390/char/sclp.h
+++ b/drivers/s390/char/sclp.h
@@ -72,6 +72,13 @@ typedef unsigned int sclp_cmdw_t;
 
 typedef u32 sccb_mask_t;	/* ATTENTION: assumes 32bit mask !!! */
 
+struct sccb_header {
+	u16	length;
+	u8	function_code;
+	u8	control_mask[3];
+	u16	response_code;
+} __attribute__((packed));
+
 struct gds_subvector {
 	u8	length;
 	u8	key;
diff --git a/drivers/s390/char/sclp_info.c b/drivers/s390/char/sclp_info.c
index 7bcbe643b087..7d21dbb12fcd 100644
--- a/drivers/s390/char/sclp_info.c
+++ b/drivers/s390/char/sclp_info.c
@@ -11,47 +11,97 @@
 #include <asm/sclp.h>
 #include "sclp.h"
 
-struct sclp_readinfo_sccb s390_readinfo_sccb;
+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;
 
 void __init sclp_readinfo_early(void)
 {
-	sclp_cmdw_t command;
-	struct sccb_header *sccb;
 	int ret;
+	int i;
+	struct sclp_readinfo_sccb *sccb;
+	sclp_cmdw_t commands[] = {SCLP_CMDW_READ_SCP_INFO_FORCED,
+				  SCLP_CMDW_READ_SCP_INFO};
 
-	__ctl_set_bit(0, 9); /* enable service signal subclass mask */
-
-	sccb = &s390_readinfo_sccb.header;
-	command = SCLP_CMDW_READ_SCP_INFO_FORCED;
-	while (1) {
-		u16 response;
-
-		memset(&s390_readinfo_sccb, 0, sizeof(s390_readinfo_sccb));
-		sccb->length = sizeof(s390_readinfo_sccb);
-		sccb->control_mask[2] = 0x80;
-
-		ret = sclp_service_call(command, &s390_readinfo_sccb);
-
-		if (ret == -EIO)
-			goto out;
-		if (ret == -EBUSY)
-			continue;
+	/* 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);
+}
 
-		response = sccb->response_code;
+unsigned long long __init sclp_memory_detect(void)
+{
+	unsigned long long memsize;
+	struct sclp_readinfo_sccb *sccb;
 
-		if (response == 0x10)
-			break;
+	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;
+}
 
-		if (response != 0x1f0 || command == SCLP_CMDW_READ_SCP_INFO)
-			break;
+/*
+ * 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;
 
-		command = SCLP_CMDW_READ_SCP_INFO;
-	}
-out:
-	__ctl_clear_bit(0, 9); /* disable service signal subclass mask */
+	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);
 }