[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, 8 insertions, 1 deletions

diff --git a/include/linux/mtd/cfi.h b/include/linux/mtd/cfi.h
index d6fb115..3058917 100644
--- a/include/linux/mtd/cfi.h
+++ b/include/linux/mtd/cfi.h
@@ -12,6 +12,7 @@
 #include <linux/mtd/flashchip.h>
 #include <linux/mtd/map.h>
 #include <linux/mtd/cfi_endian.h>
+#include <linux/mtd/xip.h>
 
 #ifdef CONFIG_MTD_CFI_I1
 #define cfi_interleave(cfi) 1
@@ -430,7 +431,6 @@ static inline uint32_t cfi_send_gen_cmd(u_char cmd, uint32_t cmd_addr, uint32_t
 {
 	map_word val;
 	uint32_t addr = base + cfi_build_cmd_addr(cmd_addr, cfi_interleave(cfi), type);
-
 	val = cfi_build_cmd(cmd, map, cfi);
 
 	if (prev_val)
@@ -483,6 +483,13 @@ static inline void cfi_udelay(int us)
 	}
 }
 
+int __xipram qry_present(struct map_info *map, __u32 base,
+				struct cfi_private *cfi);
+int __xipram qry_mode_on(uint32_t base, struct map_info *map,
+				struct cfi_private *cfi);
+void __xipram qry_mode_off(uint32_t base, struct map_info *map,
+				struct cfi_private *cfi);
+
 struct cfi_extquery *cfi_read_pri(struct map_info *map, uint16_t adr, uint16_t size,
 			     const char* name);
 struct cfi_fixup {