1 files changed, 111 insertions, 0 deletions
diff --git a/drivers/s390/char/sclp_early.c b/drivers/s390/char/sclp_early.c
new file mode 100644
index 000000000000..775112964eef
--- /dev/null
+++ b/drivers/s390/char/sclp_early.c
@@ -0,0 +1,111 @@
+/*
+ * SCLP early driver
+ *
+ * Copyright IBM Corp. 2013
+ */
+
+#define KMSG_COMPONENT "sclp_early"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <asm/sclp.h>
+#include <asm/ipl.h>
+#include "sclp_sdias.h"
+#include "sclp.h"
+
+static __initdata char sccb_early[PAGE_SIZE] __aligned(PAGE_SIZE);
+static unsigned long sclp_hsa_size;
+
+static int __init sclp_cmd_early(sclp_cmdw_t cmd, void *sccb)
+{
+	int rc;
+
+	do {
+		rc = sclp_cmd_sync_early(cmd, sccb);
+	} while (rc == -EBUSY);
+
+	if (rc)
+		return -EIO;
+	if (((struct sccb_header *) sccb)->response_code != 0x0020)
+		return -EIO;
+	return 0;
+}
+
+static void __init sccb_init_eq_size(struct sdias_sccb *sccb)
+{
+	memset(sccb, 0, sizeof(*sccb));
+
+	sccb->hdr.length = sizeof(*sccb);
+	sccb->evbuf.hdr.length = sizeof(struct sdias_evbuf);
+	sccb->evbuf.hdr.type = EVTYP_SDIAS;
+	sccb->evbuf.event_qual = SDIAS_EQ_SIZE;
+	sccb->evbuf.data_id = SDIAS_DI_FCP_DUMP;
+	sccb->evbuf.event_id = 4712;
+	sccb->evbuf.dbs = 1;
+}
+
+static int __init sclp_set_event_mask(unsigned long receive_mask,
+				      unsigned long send_mask)
+{
+	struct init_sccb *sccb = (void *) &sccb_early;
+
+	memset(sccb, 0, sizeof(*sccb));
+	sccb->header.length = sizeof(*sccb);
+	sccb->mask_length = sizeof(sccb_mask_t);
+	sccb->receive_mask = receive_mask;
+	sccb->send_mask = send_mask;
+	return sclp_cmd_early(SCLP_CMDW_WRITE_EVENT_MASK, sccb);
+}
+
+static long __init sclp_hsa_size_init(void)
+{
+	struct sdias_sccb *sccb = (void *) &sccb_early;
+
+	sccb_init_eq_size(sccb);
+	if (sclp_cmd_early(SCLP_CMDW_WRITE_EVENT_DATA, sccb))
+		return -EIO;
+	if (sccb->evbuf.blk_cnt != 0)
+		return (sccb->evbuf.blk_cnt - 1) * PAGE_SIZE;
+	return 0;
+}
+
+static long __init sclp_hsa_copy_wait(void)
+{
+	struct sccb_header *sccb = (void *) &sccb_early;
+
+	memset(sccb, 0, PAGE_SIZE);
+	sccb->length = PAGE_SIZE;
+	if (sclp_cmd_early(SCLP_CMDW_READ_EVENT_DATA, sccb))
+		return -EIO;
+	return (((struct sdias_sccb *) sccb)->evbuf.blk_cnt - 1) * PAGE_SIZE;
+}
+
+unsigned long sclp_get_hsa_size(void)
+{
+	return sclp_hsa_size;
+}
+
+void __init sclp_hsa_size_detect(void)
+{
+	long size;
+
+	/* First try synchronous interface (LPAR) */
+	if (sclp_set_event_mask(0, 0x40000010))
+		return;
+	size = sclp_hsa_size_init();
+	if (size < 0)
+		return;
+	if (size != 0)
+		goto out;
+	/* Then try asynchronous interface (z/VM) */
+	if (sclp_set_event_mask(0x00000010, 0x40000010))
+		return;
+	size = sclp_hsa_size_init();
+	if (size < 0)
+		return;
+	size = sclp_hsa_copy_wait();
+	if (size < 0)
+		return;
+out:
+	sclp_set_event_mask(0, 0);
+	sclp_hsa_size = size;
+}