From 25047d86c478beb58fd7c9a3539b03ea9426edb6 Mon Sep 17 00:00:00 2001
From: consts <grudnevkv@gmail.com>
Date: Fri, 2 Mar 2018 07:03:37 +0000
Subject: [PATCH 1/1] Workaround for MX25 chips

TEST: In-system programming a ThinkPad X200 using a clip and
pico-serprog works now. It just doesn't without this hack.

Chip: MX25L6405D

Tested-by: Riku Viitanen <riku.viitanen@protonmail.com>
Change-Id: I43a306b67862b59c1dcd02729e189f3bf73f481b
---
 cli_classic.c        | 5 +++++
 include/programmer.h | 1 +
 spi.c                | 9 +++++++++
 3 files changed, 15 insertions(+)

diff --git a/cli_classic.c b/cli_classic.c
index ab5f8b1..2825033 100644
--- a/cli_classic.c
+++ b/cli_classic.c
@@ -67,6 +67,7 @@ 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
@@ -262,6 +263,7 @@ int main(int argc, char *argv[])
 		{"version",		0, NULL, 'R'},
 		{"output",		1, NULL, 'o'},
 		{"progress",		0, NULL, OPTION_PROGRESS},
+		{"workaround-mx", 	0, NULL, 'm'},
 		{NULL,			0, NULL, 0},
 	};
 
@@ -478,6 +480,9 @@ int main(int argc, char *argv[])
 				cli_classic_abort_usage("No log filename specified.\n");
 			}
 			break;
+		case 'm': /* --workaround-mx */
+			workaround_mx = 1;
+			break;
 		case OPTION_PROGRESS:
 			show_progress = true;
 			break;
diff --git a/include/programmer.h b/include/programmer.h
index edef52b..722e599 100644
--- a/include/programmer.h
+++ b/include/programmer.h
@@ -356,6 +356,7 @@ enum ich_chipset {
 	CHIPSET_GEMINI_LAKE,
 	CHIPSET_ELKHART_LAKE,
 };
+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 ac51d87..be62588 100644
--- a/spi.c
+++ b/spi.c
@@ -26,10 +26,19 @@
 #include "programmer.h"
 #include "spi.h"
 
+int workaround_mx; /* Make operations with MX25* chips more reliable */
+
 int spi_send_command(const 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);
 }
-- 
2.39.2

