[coreboot-gerrit] Change in em100[master]: Limit USB errors in trace / terminal mode

[Stefan Reinauer (Code Review)]

Stefan Reinauer has submitted this change. ( https://review.coreboot.org/c/em100/+/47841 )

Change subject: Limit USB errors in trace / terminal mode
......................................................................

Limit USB errors in trace / terminal mode

If the device gets into a bad state (or, say, gets disconnected),
bail out after 10 errors instead of continuing ad infinitum.

Signed-off-by: Stefan Reinauer 
Change-Id: I1474386c69d267dba3bccaa740213753c06fee0c
Reviewed-on: https://review.coreboot.org/c/em100/+/47841
Reviewed-by: Angel Pons 
Tested-by: build bot (Jenkins) 
---
M em100.c
1 file changed, 15 insertions(+), 6 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Angel Pons: Looks good to me, approved

diff --git a/em100.c b/em100.c
index f7bbb2d..350b8db 100644
--- a/em100.c
+++ b/em100.c
@@ -25,6 +25,8 @@

#include "em100.h"

+#define MAX_USB_ERRORS 10
+
 TFILE *configs;
 char *database_version;
 int debug = 0;
@@ -1190,6 +1192,8 @@
    }

if (trace || terminal) {
+		int usb_errors = 0;
+
    	if ((holdpin == NULL) && (!set_hold_pin_state(em100, 3))) {
    		printf("Error: Failed to set EM100 to input\n");
    		return 1;
@@ -1212,13 +1216,18 @@

printf(". Press CTL-C to exit.\n\n");

-		while (!do_exit_flag) {
-			if (trace)
-				read_spi_trace(em100, terminal,
-						address_offset);
-			else
-				read_spi_terminal(em100, 0);
+		while (!do_exit_flag && usb_errors < MAX_USB_ERRORS) {
+			if (trace) {
+				if (!read_spi_trace(em100, terminal,
+						address_offset))
+					usb_errors++;
+			} else {
+				if (!read_spi_terminal(em100, 0))
+					usb_errors++;
+			}
    	}
+		if (usb_errors >= MAX_USB_ERRORS)
+			printf("Error: Bailed out with too many USB errors.\n");

if (!do_start && !do_stop)
    		set_state(em100, 0);