[PATCH 1/2] powerpc/powernv: new function to access OPAL msglog

[Andrew Donnellan <andrew.donnellan@au1.ibm.com>]

Currently, the OPAL msglog/console buffer is exposed as a sysfs file, with
the sysfs read handler responsible for retrieving the log from the OPAL
buffer. We'd like to be able to use it in xmon as well.

Refactor the OPAL msglog code to create a new function, opal_msglog_copy(),
that copies to an arbitrary buffer.

Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
---
 arch/powerpc/include/asm/opal.h              |  2 ++
 arch/powerpc/platforms/powernv/opal-msglog.c | 15 +++++++++++----
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 07a99e6..3f6cb85 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -273,6 +273,8 @@ void opal_free_sg_list(struct opal_sg_list *sg);
 
 extern int opal_error_code(int rc);
 
+ssize_t opal_msglog_copy(char *to, loff_t pos, size_t count);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_POWERPC_OPAL_H */
diff --git a/arch/powerpc/platforms/powernv/opal-msglog.c b/arch/powerpc/platforms/powernv/opal-msglog.c
index 44ed78a..a06191c 100644
--- a/arch/powerpc/platforms/powernv/opal-msglog.c
+++ b/arch/powerpc/platforms/powernv/opal-msglog.c
@@ -31,11 +31,11 @@ struct memcons {
 	__be32 in_cons;
 };
 
-static ssize_t opal_msglog_read(struct file *file, struct kobject *kobj,
-				struct bin_attribute *bin_attr, char *to,
-				loff_t pos, size_t count)
+static struct bin_attribute opal_msglog_attr;
+
+ssize_t opal_msglog_copy(char *to, loff_t pos, size_t count)
 {
-	struct memcons *mc = bin_attr->private;
+	struct memcons *mc = opal_msglog_attr.private;
 	const char *conbuf;
 	ssize_t ret;
 	size_t first_read = 0;
@@ -91,6 +91,13 @@ out:
 	return ret;
 }
 
+static ssize_t opal_msglog_read(struct file *file, struct kobject *kobj,
+				struct bin_attribute *bin_attr, char *to,
+				loff_t pos, size_t count)
+{
+	return opal_msglog_copy(to, pos, count);
+}
+
 static struct bin_attribute opal_msglog_attr = {
 	.attr = {.name = "msglog", .mode = 0444},
 	.read = opal_msglog_read
-- 
Andrew Donnellan              Software Engineer, OzLabs
andrew.donnellan@au1.ibm.com  Australia Development Lab, Canberra
+61 2 6201 8874 (work)        IBM Australia Limited