From 5a3a0664b63feba8aff288a5691a9f873e4ea6eb Mon Sep 17 00:00:00 2001
From: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Date: Thu, 27 Apr 2017 11:55:26 +1000
Subject: mboxd: Implement timeout return value in GET_MBOX_INFO

The previous patch added a new return field in GET_MBOX_INFO called
"suggested timeout" to be used to provide a suggested maximum timeout
value to the host.

Add this to the return arguments of GET_MBOX_INFO.

Note that the host is free to ignore the value and the daemon can
leave this blank if it doesn't want to provide a timeout.

We hard code a milliseconds per megabyte value which was determined
to be approximately 8000 based on testing and is close to linear
as the access size changes. Testing was conducted on an Aspeed ast2500
on a Witherspoon with the dev-4.7 OpenBMC branch.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Change-Id: If24e41ebb1d9f03c2bdcca84819f9430fd3eeff6
---
 mboxd_msg.c     | 15 +++++++++++++++
 mboxd_msg.h     |  9 +++++++--
 mboxd_windows.c | 24 ++++++++++++++++++++++++
 mboxd_windows.h |  1 +
 4 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/mboxd_msg.c b/mboxd_msg.c
index d02e0bf..0cc1cd2 100644
--- a/mboxd_msg.c
+++ b/mboxd_msg.c
@@ -146,6 +146,20 @@ static int mbox_handle_reset(struct mbox_context *context,
 	return point_to_flash(context);
 }
 
+/*
+ * get_suggested_timeout() - get the suggested timeout value in seconds
+ * @context:	The mbox context pointer
+ *
+ * Return:	Suggested timeout in seconds
+ */
+static uint16_t get_suggested_timeout(struct mbox_context *context)
+{
+	struct window_context *window = find_largest_window(context);
+	uint32_t max_size_mb = window ? (window->size >> 20) : 0;
+
+	return align_up(max_size_mb * FLASH_ACCESS_MS_PER_MB, 1000) / 1000;
+}
+
 /*
  * Command: GET_MBOX_INFO
  * Get the API version, default window size and block size
@@ -229,6 +243,7 @@ static int mbox_handle_mbox_info(struct mbox_context *context,
 	}
 	if (context->version >= API_VERSION_2) {
 		resp->args[5] = context->block_size_shift;
+		put_u16(&resp->args[6], get_suggested_timeout(context));
 	}
 
 	return 0;
diff --git a/mboxd_msg.h b/mboxd_msg.h
index 44a2f91..7d81d7a 100644
--- a/mboxd_msg.h
+++ b/mboxd_msg.h
@@ -18,8 +18,13 @@
 #ifndef MBOXD_MSG_H
 #define MBOXD_MSG_H
 
-#define NO_BMC_EVENT	false
-#define SET_BMC_EVENT	true
+#include "common.h"
+
+/* Estimate as to how long (milliseconds) it takes to access a MB from flash */
+#define FLASH_ACCESS_MS_PER_MB		8000
+
+#define NO_BMC_EVENT			false
+#define SET_BMC_EVENT			true
 
 struct mbox_msg {
 	uint8_t command;
diff --git a/mboxd_windows.c b/mboxd_windows.c
index c64d19b..f02b0d7 100644
--- a/mboxd_windows.c
+++ b/mboxd_windows.c
@@ -478,6 +478,30 @@ struct window_context *find_oldest_window(struct mbox_context *context)
 	return oldest;
 }
 
+/*
+ * find_largest_window() - Find the largest window in the window cache
+ * @context:	The mbox context pointer
+ *
+ * Return:	The largest window
+ */
+struct window_context *find_largest_window(struct mbox_context *context)
+{
+	struct window_context *largest = NULL, *cur;
+	uint32_t max_size = 0;
+	int i;
+
+	for (i = 0; i < context->windows.num; i++) {
+		cur = &context->windows.window[i];
+
+		if (cur->size > max_size) {
+			max_size = cur->size;
+			largest = cur;
+		}
+	}
+
+	return largest;
+}
+
 /*
  * search_windows() - Search the window cache for a window containing offset
  * @context:	The mbox context pointer
diff --git a/mboxd_windows.h b/mboxd_windows.h
index 3625521..925697c 100644
--- a/mboxd_windows.h
+++ b/mboxd_windows.h
@@ -40,6 +40,7 @@ void close_current_window(struct mbox_context *context, bool set_bmc_event,
 void reset_window(struct mbox_context *context, struct window_context *window);
 void reset_all_windows(struct mbox_context *context, bool set_bmc_event);
 struct window_context *find_oldest_window(struct mbox_context *context);
+struct window_context *find_largest_window(struct mbox_context *context);
 struct window_context *search_windows(struct mbox_context *context,
 				      uint32_t offset, bool exact);
 int create_map_window(struct mbox_context *context,
-- 
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