s390/sclp: introduce sclp_early_get_hsa_size

Introduce sclp_early_get_hsa_size function to be used during early
memory detection. This function allows to find a memory limit imposed
during zfcpdump.

Reviewed-by: Heiko Carstens <[e-mail]>
Reviewed-by: Martin Schwidefsky <[e-mail]>
Signed-off-by: Vasily Gorbik <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/asm/sclp.h

···
 void __sclp_early_printk(const char *s, unsigned int len, unsigned int force);
 
 int sclp_early_get_memsize(unsigned long *mem);
+int sclp_early_get_hsa_size(unsigned long *hsa_size);
 int _sclp_get_core_info(struct sclp_core_info *info);
 int sclp_core_configure(u8 core);
 int sclp_core_deconfigure(u8 core);

drivers/s390/char/sclp_early_core.c

···
 	return 0;
 }
 
+int __init sclp_early_get_hsa_size(unsigned long *hsa_size)
+{
+	if (!sclp_info_sccb_valid)
+		return -EIO;
+
+	*hsa_size = 0;
+	if (sclp_info_sccb.hsa_size)
+		*hsa_size = (sclp_info_sccb.hsa_size - 1) * PAGE_SIZE;
+	return 0;
+}
+
 #define SCLP_STORAGE_INFO_FACILITY     0x0000400000000000UL
 
 void __weak __init add_mem_detect_block(u64 start, u64 end) {}