[MTD] [NOR] Add qry_mode_on()/qry_omde_off() to deal with odd chips

There are some CFI chips which require non standard procedures to get 
into QRY mode. The possible way to support them would be trying 
different modes till QRY will be read. This patch introduce two new 
functions qry_mode_on qry_mode_off. qry_mode_on tries different commands 
in order switch chip into QRY mode.

So if we have one more "odd" chip - we just could add several lines to 
qry_mode_on. Also using these functions remove unnecessary code 
duplicaton in porbe procedure.

Currently there are two "odd" cases
1. Some old intel chips which require 0xFF before 0x98
2. ST M29DW chip which requires 0x98 to be sent at 0x555 (according to
CFI should be 0x55)

This patch is partialy based on the patch from Uwe
(see "[PATCH 2/4] [RFC][MTD] cfi_probe: remove Intel chip workaround"
thread )

Signed-off-by: Alexey Korolev <akorolev@infradead.org>
Signed-off-by: Alexander Belyakov <abelyako@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 58 insertions, 4 deletions

diff --git a/drivers/mtd/chips/cfi_util.c b/drivers/mtd/chips/cfi_util.c
index 0ee45701801..8d755367052 100644
--- a/drivers/mtd/chips/cfi_util.c
+++ b/drivers/mtd/chips/cfi_util.c
@@ -24,6 +24,62 @@
 #include <linux/mtd/cfi.h>
 #include <linux/mtd/compatmac.h>
 
+int __xipram qry_present(struct map_info *map, __u32 base,
+				struct cfi_private *cfi)
+{
+	int osf = cfi->interleave * cfi->device_type;	/* scale factor */
+	map_word val[3];
+	map_word qry[3];
+
+	qry[0] = cfi_build_cmd('Q', map, cfi);
+	qry[1] = cfi_build_cmd('R', map, cfi);
+	qry[2] = cfi_build_cmd('Y', map, cfi);
+
+	val[0] = map_read(map, base + osf*0x10);
+	val[1] = map_read(map, base + osf*0x11);
+	val[2] = map_read(map, base + osf*0x12);
+
+	if (!map_word_equal(map, qry[0], val[0]))
+		return 0;
+
+	if (!map_word_equal(map, qry[1], val[1]))
+		return 0;
+
+	if (!map_word_equal(map, qry[2], val[2]))
+		return 0;
+
+	return 1; 	/* "QRY" found */
+}
+
+int __xipram qry_mode_on(uint32_t base, struct map_info *map,
+				struct cfi_private *cfi)
+{
+	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);
+	if (qry_present(map, base, cfi))
+		return 1;
+	/* QRY not found probably we deal with some odd CFI chips */
+	/* Some revisions of some old Intel chips? */
+	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);
+	if (qry_present(map, base, cfi))
+		return 1;
+	/* ST M29DW chips */
+	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0x98, 0x555, base, map, cfi, cfi->device_type, NULL);
+	if (qry_present(map, base, cfi))
+		return 1;
+	/* QRY not found */
+	return 0;
+}
+void __xipram qry_mode_off(uint32_t base, struct map_info *map,
+				struct cfi_private *cfi)
+{
+	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL);
+}
+
 struct cfi_extquery *
 __xipram cfi_read_pri(struct map_info *map, __u16 adr, __u16 size, const char* name)
 {
@@ -48,8 +104,7 @@ __xipram cfi_read_pri(struct map_info *map, __u16 adr, __u16 size, const char* n
 #endif
 
 	/* Switch it into Query Mode */
-	cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);
-
+	qry_mode_on(base, map, cfi);
 	/* Read in the Extended Query Table */
 	for (i=0; i<size; i++) {
 		((unsigned char *)extp)[i] =
@@ -57,8 +112,7 @@ __xipram cfi_read_pri(struct map_info *map, __u16 adr, __u16 size, const char* n
 	}
 
 	/* Make sure it returns to read mode */
-	cfi_send_gen_cmd(0xf0, 0, base, map, cfi, cfi->device_type, NULL);
-	cfi_send_gen_cmd(0xff, 0, base, map, cfi, cfi->device_type, NULL);
+	qry_mode_off(base, map, cfi);
 
 #ifdef CONFIG_MTD_XIP
 	(void) map_read(map, base);