mtd: nand: force NAND_CMD_READID onto 8-bit bus

The NAND command helpers tend to automatically shift the column address
for x16 bus devices, since most commands expect a word address, not a
byte address. The Read ID command, however, expects an 8-bit address
(i.e., 0x00, 0x20, or 0x40 should not be translated to 0x00, 0x10, or
0x20).

This fixes the column address for a few drivers which imitate the
nand_base defaults. Note that I don't touch sh_flctl.c, since it already
handles this problem slightly differently (note its comment "READID is
always performed using an 8-bit bus").

I have not tested this patch, as I only have x8 parts up for testing at
this point. Hopefully that can change soon...

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Tested-By: Pekon Gupta <pekon@ti.com>

6 files changed, 26 insertions, 10 deletions

diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index c36e9b84487c..1955389c8fa6 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -1659,8 +1659,8 @@ static void nfc_select_chip(struct mtd_info *mtd, int chip)
                 nfc_writel(host->nfc->hsmc_regs, CTRL, NFC_CTRL_ENABLE);
 }
 
-static int nfc_make_addr(struct mtd_info *mtd, int column, int page_addr,
-                unsigned int *addr1234, unsigned int *cycle0)
+static int nfc_make_addr(struct mtd_info *mtd, int command, int column,
+                int page_addr, unsigned int *addr1234, unsigned int *cycle0)
 {
         struct nand_chip *chip = mtd->priv;
 
@@ -1674,7 +1674,8 @@ static int nfc_make_addr(struct mtd_info *mtd, int column, int page_addr,
         *addr1234 = 0;
 
         if (column != -1) {
-                if (chip->options & NAND_BUSWIDTH_16)
+                if (chip->options & NAND_BUSWIDTH_16 &&
+                                !nand_opcode_8bits(command))
                         column >>= 1;
                 addr_bytes[acycle++] = column & 0xff;
                 if (mtd->writesize > 512)
@@ -1787,8 +1788,8 @@ static void nfc_nand_command(struct mtd_info *mtd, unsigned int command,
         }
 
         if (do_addr)
-                acycle = nfc_make_addr(mtd, column, page_addr, &addr1234,
-                                &cycle0);
+                acycle = nfc_make_addr(mtd, command, column, page_addr,
+                                &addr1234, &cycle0);
 
         nfc_addr_cmd = cmd1 | cmd2 | vcmd2 | acycle | csid | dataen | nfcwr;
         nfc_send_command(host, nfc_addr_cmd, addr1234, cycle0);
diff --git a/drivers/mtd/nand/au1550nd.c b/drivers/mtd/nand/au1550nd.c
index 7d84c4e4bf43..bc5c518828d2 100644
--- a/drivers/mtd/nand/au1550nd.c
+++ b/drivers/mtd/nand/au1550nd.c
@@ -307,7 +307,8 @@ static void au1550_command(struct mtd_info *mtd, unsigned command, int column, i
                 /* Serially input address */
                 if (column != -1) {
                         /* Adjust columns for 16 bit buswidth */
-                        if (this->options & NAND_BUSWIDTH_16)
+                        if (this->options & NAND_BUSWIDTH_16 &&
+                                        !nand_opcode_8bits(command))
                                 column >>= 1;
                         ctx->write_byte(mtd, column);
                 }
diff --git a/drivers/mtd/nand/diskonchip.c b/drivers/mtd/nand/diskonchip.c
index fec31d71b84e..b9b4db607850 100644
--- a/drivers/mtd/nand/diskonchip.c
+++ b/drivers/mtd/nand/diskonchip.c
@@ -698,7 +698,8 @@ static void doc2001plus_command(struct mtd_info *mtd, unsigned command, int colu
                 /* Serially input address */
                 if (column != -1) {
                         /* Adjust columns for 16 bit buswidth */
-                        if (this->options & NAND_BUSWIDTH_16)
+                        if (this->options & NAND_BUSWIDTH_16 &&
+                                        !nand_opcode_8bits(command))
                                 column >>= 1;
                         WriteDOC(column, docptr, Mplus_FlashAddress);
                 }
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index deeaa1cc4a85..6281151e4cb7 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -589,7 +589,8 @@ static void nand_command(struct mtd_info *mtd, unsigned int command,
         /* Serially input address */
         if (column != -1) {
                 /* Adjust columns for 16 bit buswidth */
-                if (chip->options & NAND_BUSWIDTH_16)
+                if (chip->options & NAND_BUSWIDTH_16 &&
+                                !nand_opcode_8bits(command))
                         column >>= 1;
                 chip->cmd_ctrl(mtd, column, ctrl);
                 ctrl &= ~NAND_CTRL_CHANGE;
@@ -680,7 +681,8 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned int command,
                 /* Serially input address */
                 if (column != -1) {
                         /* Adjust columns for 16 bit buswidth */
-                        if (chip->options & NAND_BUSWIDTH_16)
+                        if (chip->options & NAND_BUSWIDTH_16 &&
+                                        !nand_opcode_8bits(command))
                                 column >>= 1;
                         chip->cmd_ctrl(mtd, column, ctrl);
                         ctrl &= ~NAND_CTRL_CHANGE;
diff --git a/drivers/mtd/nand/nuc900_nand.c b/drivers/mtd/nand/nuc900_nand.c
index 90c99ea5184a..331fccbdde61 100644
--- a/drivers/mtd/nand/nuc900_nand.c
+++ b/drivers/mtd/nand/nuc900_nand.c
@@ -151,7 +151,8 @@ static void nuc900_nand_command_lp(struct mtd_info *mtd, unsigned int command,
         if (column != -1 || page_addr != -1) {
 
                 if (column != -1) {
-                        if (chip->options & NAND_BUSWIDTH_16)
+                        if (chip->options & NAND_BUSWIDTH_16 &&
+                                        !nand_opcode_8bits(command))
                                 column >>= 1;
                         write_addr_reg(nand, column);
                         write_addr_reg(nand, column >> 8 | ENDADDR);
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index a719686c9cce..c034dc4224cb 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -832,4 +832,14 @@ static inline bool nand_is_slc(struct nand_chip *chip)
 {
         return chip->bits_per_cell == 1;
 }
+
+/**
+ * Check if the opcode's address should be sent only on the lower 8 bits
+ * @command: opcode to check
+ */
+static inline int nand_opcode_8bits(unsigned int command)
+{
+        return command == NAND_CMD_READID;
+}
+
 #endif /* __LINUX_MTD_NAND_H */