powerpc/boot: Add OPAL console to epapr wrappers

This patch adds an OPAL console backend to the powerpc boot wrapper so
that decompression failures inside the wrapper can be reported to the
user. This is important since it typically indicates data corruption in
the firmware and other nasty things.

Currently this only works when building a little endian kernel. When
compiling a 64 bit BE kernel the wrapper is always build 32 bit to be
compatible with some 32 bit firmwares. BE support will be added at a
later date. Another limitation of this is that only the "raw" type of
OPAL console is supported, however machines that provide a hvsi console
also provide a raw console so this is not an issue in practice.

Actually-written-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
[mpe: Move #ifdef __powerpc64__ to avoid warnings on 32-bit]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/boot/Makefile

@@ -70,7 +70,7 @@ $(addprefix $(obj)/,$(zlib) cuboot-c2k.o gunzip_util.o main.o): \
 libfdt       := fdt.c fdt_ro.c fdt_wip.c fdt_sw.c fdt_rw.c fdt_strerror.c
 libfdtheader := fdt.h libfdt.h libfdt_internal.h
 
-$(addprefix $(obj)/,$(libfdt) libfdt-wrapper.o simpleboot.o epapr.o): \
+$(addprefix $(obj)/,$(libfdt) libfdt-wrapper.o simpleboot.o epapr.o opal.o): \
 	$(addprefix $(obj)/,$(libfdtheader))
 
 src-wlib-y := string.S crt0.S crtsavres.S stdio.c main.c \
@@ -78,7 +78,7 @@ src-wlib-y := string.S crt0.S crtsavres.S stdio.c main.c \
 		ns16550.c serial.c simple_alloc.c div64.S util.S \
 		gunzip_util.c elf_util.c $(zlib) devtree.c stdlib.c \
 		oflib.c ofconsole.c cuboot.c mpsc.c cpm-serial.c \
-		uartlite.c mpc52xx-psc.c
+		uartlite.c mpc52xx-psc.c opal.c opal-calls.S
 src-wlib-$(CONFIG_40x) += 4xx.c planetcore.c
 src-wlib-$(CONFIG_44x) += 4xx.c ebony.c bamboo.c
 src-wlib-$(CONFIG_8xx) += mpc8xx.c planetcore.c fsl-soc.c

arch/powerpc/boot/opal-calls.S

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2016 IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include "ppc_asm.h"
+#include "../include/asm/opal-api.h"
+
+	.text
+
+#define OPAL_CALL(name, token)				\
+	.globl name;					\
+name:							\
+	li	r0, token;				\
+	b	opal_call;
+
+opal_call:
+	mflr	r11
+	std	r11,16(r1)
+	mfcr	r12
+	stw	r12,8(r1)
+	mr	r13,r2
+
+	/* Set opal return address */
+	ld	r11,opal_return@got(r2)
+	mtlr	r11
+	mfmsr	r12
+
+	/* switch to BE when we enter OPAL */
+	li	r11,MSR_LE
+	andc	r12,r12,r11
+	mtspr	SPRN_HSRR1,r12
+
+	/* load the opal call entry point and base */
+	ld	r11,opal@got(r2)
+	ld	r12,8(r11)
+	ld	r2,0(r11)
+	mtspr	SPRN_HSRR0,r12
+	hrfid
+
+opal_return:
+	FIXUP_ENDIAN
+	mr	r2,r13;
+	lwz	r11,8(r1);
+	ld	r12,16(r1)
+	mtcr	r11;
+	mtlr	r12
+	blr
+
+OPAL_CALL(opal_console_write,			OPAL_CONSOLE_WRITE);
+OPAL_CALL(opal_console_read,			OPAL_CONSOLE_READ);
+OPAL_CALL(opal_console_write_buffer_space,	OPAL_CONSOLE_WRITE_BUFFER_SPACE);
+OPAL_CALL(opal_poll_events,			OPAL_POLL_EVENTS);
+OPAL_CALL(opal_console_flush,			OPAL_CONSOLE_FLUSH);

arch/powerpc/boot/opal.c

@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2016 IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include "ops.h"
+#include "stdio.h"
+#include "io.h"
+#include <libfdt.h>
+#include "../include/asm/opal-api.h"
+
+#ifdef __powerpc64__
+
+/* Global OPAL struct used by opal-call.S */
+struct opal {
+	u64 base;
+	u64 entry;
+} opal;
+
+static u32 opal_con_id;
+
+int64_t opal_console_write(int64_t term_number, u64 *length, const u8 *buffer);
+int64_t opal_console_read(int64_t term_number, uint64_t *length, u8 *buffer);
+int64_t opal_console_write_buffer_space(uint64_t term_number, uint64_t *length);
+int64_t opal_console_flush(uint64_t term_number);
+int64_t opal_poll_events(uint64_t *outstanding_event_mask);
+
+static int opal_con_open(void)
+{
+	return 0;
+}
+
+static void opal_con_putc(unsigned char c)
+{
+	int64_t rc;
+	uint64_t olen, len;
+
+	do {
+		rc = opal_console_write_buffer_space(opal_con_id, &olen);
+		len = be64_to_cpu(olen);
+		if (rc)
+			return;
+		opal_poll_events(NULL);
+	} while (len < 1);
+
+
+	olen = cpu_to_be64(1);
+	opal_console_write(opal_con_id, &olen, &c);
+}
+
+static void opal_con_close(void)
+{
+	opal_console_flush(opal_con_id);
+}
+
+static void opal_init(void)
+{
+	void *opal_node;
+
+	opal_node = finddevice("/ibm,opal");
+	if (!opal_node)
+		return;
+	if (getprop(opal_node, "opal-base-address", &opal.base, sizeof(u64)) < 0)
+		return;
+	opal.base = be64_to_cpu(opal.base);
+	if (getprop(opal_node, "opal-entry-address", &opal.entry, sizeof(u64)) < 0)
+		return;
+	opal.entry = be64_to_cpu(opal.entry);
+}
+
+int opal_console_init(void *devp, struct serial_console_data *scdp)
+{
+	opal_init();
+
+	if (devp) {
+		int n = getprop(devp, "reg", &opal_con_id, sizeof(u32));
+		if (n != sizeof(u32))
+			return -1;
+		opal_con_id = be32_to_cpu(opal_con_id);
+	} else
+		opal_con_id = 0;
+
+	scdp->open = opal_con_open;
+	scdp->putc = opal_con_putc;
+	scdp->close = opal_con_close;
+
+	return 0;
+}
+#else
+int opal_console_init(void *devp, struct serial_console_data *scdp)
+{
+	return -1;
+}
+#endif /* __powerpc64__ */

arch/powerpc/boot/ops.h

@@ -89,6 +89,7 @@ int mpsc_console_init(void *devp, struct serial_console_data *scdp);
 int cpm_console_init(void *devp, struct serial_console_data *scdp);
 int mpc5200_psc_console_init(void *devp, struct serial_console_data *scdp);
 int uartlite_console_init(void *devp, struct serial_console_data *scdp);
+int opal_console_init(void *devp, struct serial_console_data *scdp);
 void *simple_alloc_init(char *base, unsigned long heap_size,
 			unsigned long granularity, unsigned long max_allocs);
 extern void flush_cache(void *, unsigned long);

arch/powerpc/boot/ppc_asm.h

@@ -61,6 +61,10 @@
 
 #define SPRN_TBRL	268
 #define SPRN_TBRU	269
+#define SPRN_HSRR0	0x13A	/* Hypervisor Save/Restore 0 */
+#define SPRN_HSRR1	0x13B	/* Hypervisor Save/Restore 1 */
+
+#define MSR_LE		0x0000000000000001
 
 #define FIXUP_ENDIAN						   \
 	tdi   0, 0, 0x48; /* Reverse endian of b . + 8		*/ \

arch/powerpc/boot/serial.c

@@ -132,6 +132,8 @@ int serial_console_init(void)
 	else if (dt_is_compatible(devp, "xlnx,opb-uartlite-1.00.b") ||
 		 dt_is_compatible(devp, "xlnx,xps-uartlite-1.00.a"))
 		rc = uartlite_console_init(devp, &serial_cd);
+	else if (dt_is_compatible(devp, "ibm,opal-console-raw"))
+		rc = opal_console_init(devp, &serial_cd);
 
 	/* Add other serial console driver calls here */
 

arch/powerpc/boot/types.h

@@ -12,6 +12,16 @@ typedef short			s16;
 typedef int			s32;
 typedef long long		s64;
 
+/* required for opal-api.h */
+typedef u8  uint8_t;
+typedef u16 uint16_t;
+typedef u32 uint32_t;
+typedef u64 uint64_t;
+typedef s8  int8_t;
+typedef s16 int16_t;
+typedef s32 int32_t;
+typedef s64 int64_t;
+
 #define min(x,y) ({ \
 	typeof(x) _x = (x);	\
 	typeof(y) _y = (y);	\