[patch] HVSI early boot console

[Hollis Blanchard <hollisb@us.ibm.com>]

Hi Linus, this patch adds support for the udbg early console interfaces
when using an HVSI console. Please apply.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>

-- 
Hollis Blanchard
IBM Linux Technology Center

===== arch/ppc64/kernel/pSeries_lpar.c 1.41 vs edited =====
--- 1.41/arch/ppc64/kernel/pSeries_lpar.c	Tue Sep 21 23:40:30 2004
+++ edited/arch/ppc64/kernel/pSeries_lpar.c	Thu Oct  7 10:52:23 2004
@@ -59,6 +59,74 @@
 
 int vtermno;	/* virtual terminal# for udbg  */
 
+#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
+static void udbg_hvsi_putc(unsigned char c)
+{
+	/* packet's seqno isn't used anyways */
+	uint8_t packet[] __ALIGNED__ = { 0xff, 5, 0, 0, c };
+	int rc;
+
+	if (c == '\n')
+		udbg_hvsi_putc('\r');
+
+	do {
+		rc = plpar_put_term_char(vtermno, sizeof(packet), packet);
+	} while (rc == H_Busy);
+}
+
+static long hvsi_udbg_buf_len;
+static uint8_t hvsi_udbg_buf[256];
+
+static int udbg_hvsi_getc_poll(void)
+{
+	unsigned char ch;
+	int rc, i;
+
+	if (hvsi_udbg_buf_len == 0) {
+		rc = plpar_get_term_char(vtermno, &hvsi_udbg_buf_len, hvsi_udbg_buf);
+		if (rc != H_Success || hvsi_udbg_buf[0] != 0xff) {
+			/* bad read or non-data packet */
+			hvsi_udbg_buf_len = 0;
+		} else {
+			/* remove the packet header */
+			for (i = 4; i < hvsi_udbg_buf_len; i++)
+				hvsi_udbg_buf[i-4] = hvsi_udbg_buf[i];
+			hvsi_udbg_buf_len -= 4;
+		}
+	}
+
+	if (hvsi_udbg_buf_len <= 0 || hvsi_udbg_buf_len > 256) {
+		/* no data ready */
+		hvsi_udbg_buf_len = 0;
+		return -1;
+	}
+
+	ch = hvsi_udbg_buf[0];
+	/* shift remaining data down */
+	for (i = 1; i < hvsi_udbg_buf_len; i++) {
+		hvsi_udbg_buf[i-1] = hvsi_udbg_buf[i];
+	}
+	hvsi_udbg_buf_len--;
+
+	return ch;
+}
+
+static unsigned char udbg_hvsi_getc(void)
+{
+	int ch;
+	for (;;) {
+		ch = udbg_hvsi_getc_poll();
+		if (ch == -1) {
+			/* This shouldn't be needed...but... */
+			volatile unsigned long delay;
+			for (delay=0; delay < 2000000; delay++)
+				;
+		} else {
+			return ch;
+		}
+	}
+}
+
 static void udbg_putcLP(unsigned char c)
 {
 	char buf[16];
@@ -167,11 +235,15 @@
 				ppc_md.udbg_getc_poll = udbg_getc_pollLP;
 				found = 1;
 			}
-		} else {
-			/* XXX implement udbg_putcLP_vtty for hvterm-protocol1 case */
-			printk(KERN_WARNING "%s doesn't speak hvterm1; "
-					"can't print udbg messages\n",
-			       stdout_node->full_name);
+		} else if (device_is_compatible(stdout_node, "hvterm-protocol")) {
+			termno = (u32 *)get_property(stdout_node, "reg", NULL);
+			if (termno) {
+				vtermno = termno[0];
+				ppc_md.udbg_putc = udbg_hvsi_putc;
+				ppc_md.udbg_getc = udbg_hvsi_getc;
+				ppc_md.udbg_getc_poll = udbg_hvsi_getc_poll;
+				found = 1;
+			}
 		}
 	} else if (strncmp(name, "serial", 6)) {
 		/* XXX fix ISA serial console */