s390/sclp: make early sclp code readable

This patch

 - unifies the old sclp early code and the sclp early printk code, so
   they can use common functions

 - makes sure all sclp early functions and variables have the same
   "sclp_early" prefix

 - converts the sclp early printk code into readable code by using
   existing data structures instead of hard coded magic arrays

 - splits the early sclp code into two files: sclp_early.c and
   sclp_early_core.c. The core file contains everything that is
   required by the kernel decompressor and may not call functions not
   contained within the core file. Otherwise the result would be a
   link error.

 - changes interrupt handling to be completely synchronous. The old
   early sclp code had a small window which allowed to receive several
   interrupts instead of exactly the single expected interrupt. This
   did hide a subtle potential bug, which is fixed with this large
   rework.

 - contains a couple of small cleanups.

Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/boot/compressed/misc.c

@@ -66,7 +66,7 @@ static unsigned long free_mem_end_ptr;
 
 static int puts(const char *s)
 {
-	_sclp_print_early(s);
+	sclp_early_printk(s);
 	return 0;
 }
 

arch/s390/include/asm/sclp.h

@@ -101,7 +101,12 @@ struct zpci_report_error_header {
 	u8 data[0];	/* Subsequent Data passed verbatim to SCLP ET 24 */
 } __packed;
 
-int _sclp_get_core_info_early(struct sclp_core_info *info);
+int sclp_early_get_core_info(struct sclp_core_info *info);
+void sclp_early_get_ipl_info(struct sclp_ipl_info *info);
+void sclp_early_detect(void);
+void sclp_early_printk(const char *s);
+void __sclp_early_printk(const char *s, unsigned int len);
+
 int _sclp_get_core_info(struct sclp_core_info *info);
 int sclp_core_configure(u8 core);
 int sclp_core_deconfigure(u8 core);
@@ -110,21 +115,17 @@ int sclp_sdias_copy(void *dest, int blk_num, int nr_blks);
 int sclp_chp_configure(struct chp_id chpid);
 int sclp_chp_deconfigure(struct chp_id chpid);
 int sclp_chp_read_info(struct sclp_chp_info *info);
-void sclp_get_ipl_info(struct sclp_ipl_info *info);
 int sclp_pci_configure(u32 fid);
 int sclp_pci_deconfigure(u32 fid);
 int sclp_pci_report(struct zpci_report_error_header *report, u32 fh, u32 fid);
 int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count);
 int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count);
-void sclp_early_detect(void);
-void _sclp_print_early(const char *);
-void __sclp_print_early(const char *s, unsigned int len);
 void sclp_ocf_cpc_name_copy(char *dst);
 
 static inline int sclp_get_core_info(struct sclp_core_info *info, int early)
 {
 	if (early)
-		return _sclp_get_core_info_early(info);
+		return sclp_early_get_core_info(info);
 	return _sclp_get_core_info(info);
 }
 

arch/s390/kernel/als.c

@@ -41,7 +41,7 @@ static void __init print_machine_type(void)
 	get_cpu_id(&id);
 	u16_to_hex(type_str, id.machine);
 	strcat(mach_str, type_str);
-	_sclp_print_early(mach_str);
+	sclp_early_printk(mach_str);
 }
 
 static void __init u16_to_decimal(char *str, u16 val)
@@ -79,21 +79,21 @@ static void __init print_missing_facilities(void)
 			 * z/VM adds a four character prefix.
 			 */
 			if (strlen(als_str) > 70) {
-				_sclp_print_early(als_str);
+				sclp_early_printk(als_str);
 				*als_str = '\0';
 			}
 			u16_to_decimal(val_str, i * BITS_PER_LONG + j);
 			strcat(als_str, val_str);
 			first = 0;
 		}
 	}
-	_sclp_print_early(als_str);
-	_sclp_print_early("See Principles of Operations for facility bits");
+	sclp_early_printk(als_str);
+	sclp_early_printk("See Principles of Operations for facility bits");
 }
 
 static void __init facility_mismatch(void)
 {
-	_sclp_print_early("The Linux kernel requires more recent processor hardware");
+	sclp_early_printk("The Linux kernel requires more recent processor hardware");
 	print_machine_type();
 	print_missing_facilities();
 	disabled_wait(0x8badcccc);

arch/s390/kernel/early_printk.c

@@ -9,7 +9,7 @@
 
 static void sclp_early_write(struct console *con, const char *s, unsigned int len)
 {
-	__sclp_print_early(s, len);
+	__sclp_early_printk(s, len);
 }
 
 static struct console sclp_early_console = {

arch/s390/kernel/ipl.c

@@ -1864,7 +1864,7 @@ static int __init s390_ipl_init(void)
 {
 	char str[8] = {0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40};
 
-	sclp_get_ipl_info(&sclp_ipl_info);
+	sclp_early_get_ipl_info(&sclp_ipl_info);
 	/*
 	 * Fix loadparm: There are systems where the (SCSI) LOADPARM
 	 * returned by read SCP info is invalid (contains EBCDIC blanks)

arch/s390/kernel/swsusp.S

@@ -196,7 +196,7 @@ pgm_check_entry:
 	larl	%r15,init_thread_union
 	ahi	%r15,1<<(PAGE_SHIFT+THREAD_SIZE_ORDER)
 	larl	%r2,.Lpanic_string
-	larl	%r3,_sclp_print_early
+	larl	%r3,sclp_early_printk
 	lghi	%r1,0
 	sam31
 	sigp	%r1,%r0,SIGP_SET_ARCHITECTURE

drivers/s390/char/sclp.c

@@ -140,31 +140,6 @@ static void __sclp_make_read_req(void);
 static int sclp_init_mask(int calculate);
 static int sclp_init(void);
 
-/* Perform service call. Return 0 on success, non-zero otherwise. */
-int
-sclp_service_call(sclp_cmdw_t command, void *sccb)
-{
-	int cc = 4; /* Initialize for program check handling */
-
-	asm volatile(
-		"0:	.insn	rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
-		"1:	ipm	%0\n"
-		"	srl	%0,28\n"
-		"2:\n"
-		EX_TABLE(0b, 2b)
-		EX_TABLE(1b, 2b)
-		: "+&d" (cc) : "d" (command), "a" (__pa(sccb))
-		: "cc", "memory");
-	if (cc == 4)
-		return -EINVAL;
-	if (cc == 3)
-		return -EIO;
-	if (cc == 2)
-		return -EBUSY;
-	return 0;
-}
-
-
 static void
 __sclp_queue_read_req(void)
 {

drivers/s390/char/sclp.h

@@ -204,7 +204,6 @@ void sclp_unregister(struct sclp_register *reg);
 int sclp_remove_processed(struct sccb_header *sccb);
 int sclp_deactivate(void);
 int sclp_reactivate(void);
-int sclp_service_call(sclp_cmdw_t command, void *sccb);
 int sclp_sync_request(sclp_cmdw_t command, void *sccb);
 int sclp_sync_request_timeout(sclp_cmdw_t command, void *sccb, int timeout);
 
@@ -222,8 +221,41 @@ extern int sclp_console_pages;
 extern int sclp_console_drop;
 extern unsigned long sclp_console_full;
 
+extern char sclp_early_sccb[PAGE_SIZE];
+
+void sclp_early_wait_irq(void);
+int sclp_early_cmd_sync(sclp_cmdw_t cmd, void *sccb);
+int sclp_early_cmd(sclp_cmdw_t cmd, void *sccb);
+unsigned int sclp_early_con_check_linemode(struct init_sccb *sccb);
+int sclp_early_set_event_mask(struct init_sccb *sccb,
+			      unsigned long receive_mask,
+			      unsigned long send_mask);
+
 /* useful inlines */
 
+/* Perform service call. Return 0 on success, non-zero otherwise. */
+static inline int sclp_service_call(sclp_cmdw_t command, void *sccb)
+{
+	int cc = 4; /* Initialize for program check handling */
+
+	asm volatile(
+		"0:	.insn	rre,0xb2200000,%1,%2\n"	 /* servc %1,%2 */
+		"1:	ipm	%0\n"
+		"	srl	%0,28\n"
+		"2:\n"
+		EX_TABLE(0b, 2b)
+		EX_TABLE(1b, 2b)
+		: "+&d" (cc) : "d" (command), "a" ((unsigned long)sccb)
+		: "cc", "memory");
+	if (cc == 4)
+		return -EINVAL;
+	if (cc == 3)
+		return -EIO;
+	if (cc == 2)
+		return -EBUSY;
+	return 0;
+}
+
 /* VM uses EBCDIC 037, LPAR+native(SE+HMC) use EBCDIC 500 */
 /* translate single character from ASCII to EBCDIC */
 static inline unsigned char