Pad jump tags to 4 bytes inside the system module

That way all the users of jump tags don't need to know about the
padding requirements.

BUG=chrome-os-partner:23851
BRANCH=none
TEST=enable CONFIG_CMD_JUMPTAGS, then 'jumptags'.  Output should be
     something like this:

     20007fbc: 0x5550 UP.1  2
     20007fc4: 0x4b42 KB.2  3
     20007fcc: 0x4c50 LP.1 12
     20007fdc: 0x4d54 MT.1  8

     All the addresses in the first column should be word-aligned.  The
     sizes in the last column don't need to be a multiple of 4.

Change-Id: I91f9c29701a007ef8a56b5b7e0ea09930dfbea31
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/175591
Reviewed-by: Bill Richardson <wfrichar@chromium.org>

8 files changed, 44 insertions, 15 deletions

diff --git a/common/fan.c b/common/fan.c
index b080253944..9d9c0f68fc 100644
--- a/common/fan.c
+++ b/common/fan.c
@@ -339,7 +339,6 @@ BUILD_ASSERT(CONFIG_FANS <= EC_FAN_SPEED_ENTRIES);
 struct pwm_fan_state {
 	uint16_t fan_rpm;
 	uint8_t fan_en;
-	char pad; /* Pad to multiple of 4 bytes. */
 };
 
 static void pwm_fan_init(void)
diff --git a/common/keyboard_8042.c b/common/keyboard_8042.c
index 566864e958..c3791e0068 100644
--- a/common/keyboard_8042.c
+++ b/common/keyboard_8042.c
@@ -148,7 +148,6 @@ struct kb_state {
 	uint8_t codeset;
 	uint8_t ctlram;
 	uint8_t keystroke_enabled;
-	uint8_t pad;	/* Pad to 4 bytes for system_add_jump_tag(). */
 };
 
 /* The standard Chrome OS keyboard matrix table. */
diff --git a/common/pwm_kblight.c b/common/pwm_kblight.c
index 41448ce7e8..5f84dd66af 100644
--- a/common/pwm_kblight.c
+++ b/common/pwm_kblight.c
@@ -21,7 +21,6 @@
 struct pwm_kbd_state {
 	uint8_t kblight_en;
 	uint8_t kblight_percent;
-	uint8_t pad0, pad1; /* Pad to multiple of 4 bytes. */
 };
 
 /*****************************************************************************/
diff --git a/common/system.c b/common/system.c
index db91d1a6b6..b09d804891 100644
--- a/common/system.c
+++ b/common/system.c
@@ -27,10 +27,16 @@
 #define CPUTS(outstr) cputs(CC_SYSTEM, outstr)
 #define CPRINTF(format, args...) cprintf(CC_SYSTEM, format, ## args)
 
+/* Round up to a multiple of 4 */
+#define ROUNDUP4(x) (((x) + 3) & ~3)
+
+/* Data for an individual jump tag */
 struct jump_tag {
-	uint16_t tag;
-	uint8_t data_size;
-	uint8_t data_version;
+	uint16_t tag;		/* Tag ID */
+	uint8_t data_size;	/* Size of data which follows */
+	uint8_t data_version;	/* Data version */
+
+	/* Followed by data_size bytes of data */
 };
 
 /*
@@ -171,9 +177,9 @@ int system_add_jump_tag(uint16_t tag, int version, int size, const void *data)
 		return EC_ERROR_UNKNOWN;
 
 	/* Make room for the new tag */
-	if (size > 255 || (size & 3))
+	if (size > 255)
 		return EC_ERROR_INVAL;
-	jdata->jump_tag_total += size + sizeof(struct jump_tag);
+	jdata->jump_tag_total += ROUNDUP4(size) + sizeof(struct jump_tag);
 
 	t = (struct jump_tag *)system_usable_ram_end();
 	t->tag = tag;
@@ -197,7 +203,7 @@ const uint8_t *system_get_jump_tag(uint16_t tag, int *version, int *size)
 	while (used < jdata->jump_tag_total) {
 		/* Check the next tag */
 		t = (const struct jump_tag *)(system_usable_ram_end() + used);
-		used += sizeof(struct jump_tag) + t->data_size;
+		used += sizeof(struct jump_tag) + ROUNDUP4(t->data_size);
 		if (t->tag != tag)
 			continue;
 
@@ -814,6 +820,35 @@ DECLARE_CONSOLE_COMMAND(sleepmask, command_sleepmask,
 			NULL);
 #endif
 
+#ifdef CONFIG_CMD_JUMPTAGS
+static int command_jumptags(int argc, char **argv)
+{
+	const struct jump_tag *t;
+	int used = 0;
+
+	/* Jump tags valid only after a sysjump */
+	if (!jdata)
+		return EC_SUCCESS;
+
+	while (used < jdata->jump_tag_total) {
+		/* Check the next tag */
+		t = (const struct jump_tag *)(system_usable_ram_end() + used);
+		used += sizeof(struct jump_tag) + ROUNDUP4(t->data_size);
+
+		ccprintf("%08x: 0x%04x %c%c.%d %3d\n",
+			 (uintptr_t)t,
+			 t->tag, t->tag >> 8, (uint8_t)t->tag,
+			 t->data_version, t->data_size);
+	}
+
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(jumptags, command_jumptags,
+			NULL,
+			"List jump tags",
+			NULL);
+#endif /* CONFIG_CMD_JUMPTAGS */
+
 /*****************************************************************************/
 /* Host commands */
 
diff --git a/common/usb_port_power_dumb.c b/common/usb_port_power_dumb.c
index 62ac0732f6..8c4081dd6d 100644
--- a/common/usb_port_power_dumb.c
+++ b/common/usb_port_power_dumb.c
@@ -26,7 +26,6 @@ BUILD_ASSERT(USB_PORT_COUNT == 2);
 
 static struct usb_state {
 	uint8_t en[USB_PORT_COUNT];
-	uint8_t pad[2]; /* Pad to 4 bytes for system_add_jump_tag(). */
 } state;
 
 static void usb_port_set_enabled(int port_id, int en)
diff --git a/common/usb_port_power_smart.c b/common/usb_port_power_smart.c
index def565239a..6a60e8a04f 100644
--- a/common/usb_port_power_smart.c
+++ b/common/usb_port_power_smart.c
@@ -26,8 +26,6 @@
 /* The previous USB port state before sys jump */
 struct usb_state {
 	uint8_t port_mode[USB_CHARGE_PORT_COUNT];
-	/* Pad to 4 bytes for system_add_jump_tag(). */
-	uint8_t pad[4 - USB_CHARGE_PORT_COUNT];
 };
 
 static uint8_t charge_mode[USB_CHARGE_PORT_COUNT];
diff --git a/include/config.h b/include/config.h
index 32bb725e11..97262e78d2 100644
--- a/include/config.h
+++ b/include/config.h
@@ -208,6 +208,7 @@
 #undef CONFIG_CMD_ECTEMP
 #undef CONFIG_CMD_GSV
 #undef CONFIG_CMD_ILIM
+#undef CONFIG_CMD_JUMPTAGS
 #undef CONFIG_CMD_PLL
 #undef CONFIG_CMD_PMU
 #undef CONFIG_CMD_POWERLED
diff --git a/include/system.h b/include/system.h
index cf936d64bf..b4c68bd3ce 100644
--- a/include/system.h
+++ b/include/system.h
@@ -109,8 +109,7 @@ int system_jumped_to_this_image(void);
  * This may ONLY be called from within a HOOK_SYSJUMP handler.
  *
  * @param tag		Data type
- * @param size          Size of data; must be a multiple of 4 bytes, and less
- *			than 255 bytes.
+ * @param size          Size of data; must be less than 255 bytes.
  * @param version       Data version, so that tag data can evolve as firmware
  *			is updated.
  * @param data		Pointer to data to save
@@ -128,7 +127,7 @@ int system_add_jump_tag(uint16_t tag, int version, int size, const void *data);
  * @param version	Set to data version if successful
  * @param size		Set to data size if successful
  * @return		A pointer to the data, or NULL if no matching tag is
- *			found.
+ *			found.  This pointer will be 32-bit aligned.
  */
 const uint8_t *system_get_jump_tag(uint16_t tag, int *version, int *size);