From 886f1db7edbfc9ef4c9727b4f564c1e7e35d6565 Mon Sep 17 00:00:00 2001
From: consts <grudnevkv@gmail.com>
Date: Fri, 2 Mar 2018 07:03:37 +0000
Subject: [PATCH] Workaround for MX25 chips

https://notabug.org/libreboot/libreboot/issues/193
---
 cli_classic.c | 5 +++++
 programmer.h  | 1 +
 spi.c         | 9 +++++++++
 3 files changed, 15 insertions(+)

diff --git a/cli_classic.c b/cli_classic.c
index 31f7394..c60168c 100644
--- a/cli_classic.c
+++ b/cli_classic.c
@@ -62,6 +62,7 @@ static void cli_classic_usage(const char *name)
 	       " -o | --output <logfile>            log output to <logfile>\n"
 	       "      --flash-contents <ref-file>   assume flash contents to be <ref-file>\n"
 	       " -L | --list-supported              print supported devices\n"
+	       " -m | --workaround-mx               keep flash busy before sending command\n"
 #if CONFIG_PRINT_WIKI == 1
 	       " -z | --list-supported-wiki         print supported devices in wiki syntax\n"
 #endif
@@ -136,6 +137,7 @@ int main(int argc, char *argv[])
 		{"help",		0, NULL, 'h'},
 		{"version",		0, NULL, 'R'},
 		{"output",		1, NULL, 'o'},
+		{"workaround-mx", 	0, NULL, 'm'},
 		{NULL,			0, NULL, 0},
 	};
 
@@ -347,6 +349,9 @@ int main(int argc, char *argv[])
 			}
 #endif /* STANDALONE */
 			break;
+		case 'm': /* --workaround-mx */
+			workaround_mx = 1;
+			break;
 		default:
 			cli_classic_abort_usage();
 			break;
diff --git a/programmer.h b/programmer.h
index 139f4fa..f54e690 100644
--- a/programmer.h
+++ b/programmer.h
@@ -664,6 +664,7 @@ enum ich_chipset {
 	CHIPSET_100_SERIES_SUNRISE_POINT, /* also 6th/7th gen Core i/o (LP) variants */
 	CHIPSET_C620_SERIES_LEWISBURG,
 };
+extern int workaround_mx; /* workaround for MX25* chips, makes flash operations more reliable, less failures */
 
 /* ichspi.c */
 #if CONFIG_INTERNAL == 1
diff --git a/spi.c b/spi.c
index 56f1fdf..4e61d88 100644
--- a/spi.c
+++ b/spi.c
@@ -30,10 +30,19 @@
 #include "programmer.h"
 #include "spi.h"
 
+int workaround_mx; /* Make operations with MX25* chips more reliable */
+
 int spi_send_command(struct flashctx *flash, unsigned int writecnt,
 		     unsigned int readcnt, const unsigned char *writearr,
 		     unsigned char *readarr)
 {
+	if (workaround_mx) {
+		const unsigned char cmd[JEDEC_READ_OUTSIZE] = {JEDEC_READ, 0, 0, 0};
+		unsigned char buf[256];
+		/* keep flash busy for some time, keep CS warm before sending actual command */
+		flash->mst->spi.command(flash, sizeof(cmd), sizeof(buf), cmd, buf);
+	}
+	/* actual command */
 	return flash->mst->spi.command(flash, writecnt, readcnt, writearr,
 				       readarr);
 }
-- 
1.9.1