sparc64: Get rid of indirect p1275 PROM call buffer.

This is based upon a report by Meelis Roos showing that it's possible
that we'll try to fetch a property that is 32K in size with some
devices.  With the current fixed 3K buffer we use for moving data in
and out of the firmware during PROM calls, that simply won't work.

In fact, it will scramble random kernel data during bootup.

The reasoning behind the temporary buffer is entirely historical.  It
used to be the case that we had problems referencing dynamic kernel
memory (including the stack) early in the boot process before we
explicitly told the firwmare to switch us over to the kernel trap
table.

So what we did was always give the firmware buffers that were locked
into the main kernel image.

But we no longer have problems like that, so get rid of all of this
indirect bounce buffering.

Besides fixing Meelis's bug, this also makes the kernel data about 3K
smaller.

It was also discovered during these conversions that the
implementation of prom_retain() was completely wrong, so that was
fixed here as well.  Currently that interface is not in use.

Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 37 insertions, 11 deletions

diff --git a/arch/sparc/prom/console_64.c b/arch/sparc/prom/console_64.c
index f55d58a..10322dc 100644
--- a/arch/sparc/prom/console_64.c
+++ b/arch/sparc/prom/console_64.c
@@ -21,14 +21,22 @@ extern int prom_stdin, prom_stdout;
 inline int
 prom_nbgetchar(void)
 {
+	unsigned long args[7];
 	char inc;
 
-	if (p1275_cmd("read", P1275_ARG(1,P1275_ARG_OUT_BUF)|
-			      P1275_INOUT(3,1),
-			      prom_stdin, &inc, P1275_SIZE(1)) == 1)
+	args[0] = (unsigned long) "read";
+	args[1] = 3;
+	args[2] = 1;
+	args[3] = (unsigned int) prom_stdin;
+	args[4] = (unsigned long) &inc;
+	args[5] = 1;
+	args[6] = (unsigned long) -1;
+
+	p1275_cmd_direct(args);
+
+	if (args[6] == 1)
 		return inc;
-	else
-		return -1;
+	return -1;
 }
 
 /* Non blocking put character to console device, returns -1 if
@@ -37,12 +45,22 @@ prom_nbgetchar(void)
 inline int
 prom_nbputchar(char c)
 {
+	unsigned long args[7];
 	char outc;
 	
 	outc = c;
-	if (p1275_cmd("write", P1275_ARG(1,P1275_ARG_IN_BUF)|
-			       P1275_INOUT(3,1),
-			       prom_stdout, &outc, P1275_SIZE(1)) == 1)
+
+	args[0] = (unsigned long) "write";
+	args[1] = 3;
+	args[2] = 1;
+	args[3] = (unsigned int) prom_stdout;
+	args[4] = (unsigned long) &outc;
+	args[5] = 1;
+	args[6] = (unsigned long) -1;
+
+	p1275_cmd_direct(args);
+
+	if (args[6] == 1)
 		return 0;
 	else
 		return -1;
@@ -67,7 +85,15 @@ prom_putchar(char c)
 void
 prom_puts(const char *s, int len)
 {
-	p1275_cmd("write", P1275_ARG(1,P1275_ARG_IN_BUF)|
-			   P1275_INOUT(3,1),
-			   prom_stdout, s, P1275_SIZE(len));
+	unsigned long args[7];
+
+	args[0] = (unsigned long) "write";
+	args[1] = 3;
+	args[2] = 1;
+	args[3] = (unsigned int) prom_stdout;
+	args[4] = (unsigned long) s;
+	args[5] = len;
+	args[6] = (unsigned long) -1;
+
+	p1275_cmd_direct(args);
 }