[U-Boot] [PATCH v3 12/20] mtd: spi: spi-nor-core: Add back U-Boot specific features

[Vignesh R <vigneshr@ti.com>]

For legacy reasons, we will have to keep around U-Boot specific
SPI_FLASH_BAR and SPI_TX_BYTE. Add them back to the new framework

Signed-off-by: Vignesh R <vigneshr@ti.com>
---
 drivers/mtd/spi/spi-nor-core.c | 162 ++++++++++++++++++++++++++++++++-
 include/linux/mtd/spi-nor.h    |   9 ++
 2 files changed, 168 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index 97ec8e8e7a19..c3f6929db506 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -291,6 +291,7 @@ static struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd)
 	return mtd->priv;
 }
 
+#ifndef CONFIG_SPI_FLASH_BAR
 static u8 spi_nor_convert_opcode(u8 opcode, const u8 table[][2], size_t size)
 {
 	size_t i;
@@ -365,6 +366,7 @@ static void spi_nor_set_4byte_opcodes(struct spi_nor *nor,
 	nor->program_opcode = spi_nor_convert_3to4_program(nor->program_opcode);
 	nor->erase_opcode = spi_nor_convert_3to4_erase(nor->erase_opcode);
 }
+#endif /* !CONFIG_SPI_FLASH_BAR */
 
 /* Enable/disable 4-byte addressing mode. */
 static int set_4byte(struct spi_nor *nor, const struct flash_info *info,
@@ -499,6 +501,79 @@ static int spi_nor_wait_till_ready(struct spi_nor *nor)
 						    DEFAULT_READY_WAIT_JIFFIES);
 }
 
+#ifdef CONFIG_SPI_FLASH_BAR
+/*
+ * This "clean_bar" is necessary in a situation when one was accessing
+ * spi flash memory > 16 MiB by using Bank Address Register's BA24 bit.
+ *
+ * After it the BA24 bit shall be cleared to allow access to correct
+ * memory region after SW reset (by calling "reset" command).
+ *
+ * Otherwise, the BA24 bit may be left set and then after reset, the
+ * ROM would read/write/erase SPL from 16 MiB * bank_sel address.
+ */
+static int clean_bar(struct spi_nor *nor)
+{
+	u8 cmd, bank_sel = 0;
+
+	if (nor->bank_curr == 0)
+		return 0;
+	cmd = nor->bank_write_cmd;
+	nor->bank_curr = 0;
+	write_enable(nor);
+
+	return nor->write_reg(nor, cmd, &bank_sel, 1);
+}
+
+static int write_bar(struct spi_nor *nor, u32 offset)
+{
+	u8 cmd, bank_sel;
+	int ret;
+
+	bank_sel = offset / SZ_16M;
+	if (bank_sel == nor->bank_curr)
+		goto bar_end;
+
+	cmd = nor->bank_write_cmd;
+	write_enable(nor);
+	ret = nor->write_reg(nor, cmd, &bank_sel, 1);
+	if (ret < 0) {
+		debug("SF: fail to write bank register\n");
+		return ret;
+	}
+
+bar_end:
+	nor->bank_curr = bank_sel;
+	return nor->bank_curr;
+}
+
+static int read_bar(struct spi_nor *nor, const struct flash_info *info)
+{
+	u8 curr_bank = 0;
+	int ret;
+
+	switch (JEDEC_MFR(info)) {
+	case SNOR_MFR_SPANSION:
+		nor->bank_read_cmd = SPINOR_OP_BRRD;
+		nor->bank_write_cmd = SPINOR_OP_BRWR;
+		break;
+	default:
+		nor->bank_read_cmd = SPINOR_OP_RDEAR;
+		nor->bank_write_cmd = SPINOR_OP_WREAR;
+	}
+
+	ret = nor->read_reg(nor, nor->bank_read_cmd,
+				    &curr_bank, 1);
+	if (ret) {
+		debug("SF: fail to read bank addr register\n");
+		return ret;
+	}
+	nor->bank_curr = curr_bank;
+
+	return 0;
+}
+#endif
+
 /*
  * Initiate the erasure of a single sector
  */
@@ -543,6 +618,11 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
 	len = instr->len;
 
 	while (len) {
+#ifdef CONFIG_SPI_FLASH_BAR
+		ret = write_bar(nor, addr);
+		if (ret < 0)
+			return ret;
+#endif
 		write_enable(nor);
 
 		ret = spi_nor_erase_sector(nor, addr);
@@ -557,9 +637,12 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
 			goto erase_err;
 	}
 
+erase_err:
+#ifdef CONFIG_SPI_FLASH_BAR
+	ret = clean_bar(nor);
+#endif
 	write_disable(nor);
 
-erase_err:
 	return ret;
 }
 
@@ -1144,8 +1227,23 @@ static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
 
 	while (len) {
 		loff_t addr = from;
+		size_t read_len = len;
 
-		ret = nor->read(nor, addr, len, buf);
+#ifdef CONFIG_SPI_FLASH_BAR
+		u32 remain_len;
+
+		ret = write_bar(nor, addr);
+		if (ret < 0)
+			return log_ret(ret);
+		remain_len = (SZ_16M * (nor->bank_curr + 1)) - addr;
+
+		if (len < remain_len)
+			read_len = len;
+		else
+			read_len = remain_len;
+#endif
+
+		ret = nor->read(nor, addr, read_len, buf);
 		if (ret == 0) {
 			/* We shouldn't see 0-length reads */
 			ret = -EIO;
@@ -1162,18 +1260,49 @@ static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
 	ret = 0;
 
 read_err:
+#ifdef CONFIG_SPI_FLASH_BAR
+	ret = clean_bar(nor);
+#endif
 	return ret;
 }
 
 #ifdef CONFIG_SPI_FLASH_SST
+static int sst_write_byteprogram(struct spi_nor *nor, loff_t to, size_t len,
+				 size_t *retlen, const u_char *buf)
+{
+	size_t actual;
+	int ret = 0;
+
+	for (actual = 0; actual < len; actual++) {
+		nor->program_opcode = SPINOR_OP_BP;
+
+		write_enable(nor);
+		/* write one byte. */
+		ret = nor->write(nor, to, 1, buf + actual);
+		if (ret < 0)
+			goto sst_write_err;
+		ret = spi_nor_wait_till_ready(nor);
+		if (ret)
+			goto sst_write_err;
+		to++;
+	}
+
+sst_write_err:
+	write_disable(nor);
+	return ret;
+}
+
 static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,
 		     size_t *retlen, const u_char *buf)
 {
 	struct spi_nor *nor = mtd_to_spi_nor(mtd);
+	struct spi_slave *spi = nor->spi;
 	size_t actual;
 	int ret;
 
 	dev_dbg(nor->dev, "to 0x%08x, len %zd\n", (u32)to, len);
+	if (spi->mode & SPI_TX_BYTE)
+		return sst_write_byteprogram(nor, to, len, retlen, buf);
 
 	write_enable(nor);
 
@@ -1271,6 +1400,11 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
 		page_remain = min_t(size_t,
 				    nor->page_size - page_offset, len - i);
 
+#ifdef CONFIG_SPI_FLASH_BAR
+		ret = write_bar(nor, addr);
+		if (ret < 0)
+			return ret;
+#endif
 		write_enable(nor);
 		ret = nor->write(nor, addr, page_remain, buf + i);
 		if (ret < 0)
@@ -1289,6 +1423,9 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
 	}
 
 write_err:
+#ifdef CONFIG_SPI_FLASH_BAR
+	ret = clean_bar(nor);
+#endif
 	return ret;
 }
 
@@ -2532,12 +2669,20 @@ int spi_nor_scan(struct spi_nor *nor)
 		/* already configured from SFDP */
 	} else if (info->addr_width) {
 		nor->addr_width = info->addr_width;
-	} else if (mtd->size > 0x1000000) {
+	} else if (mtd->size > SZ_16M) {
+#ifndef CONFIG_SPI_FLASH_BAR
 		/* enable 4-byte addressing if the device exceeds 16MiB */
 		nor->addr_width = 4;
 		if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
 		    info->flags & SPI_NOR_4B_OPCODES)
 			spi_nor_set_4byte_opcodes(nor, info);
+#else
+	/* Configure the BAR - discover bank cmds and read current bank */
+	nor->addr_width = 3;
+	ret = read_bar(nor, info);
+	if (ret < 0)
+		return ret;
+#endif
 	} else {
 		nor->addr_width = 3;
 	}
@@ -2571,6 +2716,17 @@ int spi_nor_scan(struct spi_nor *nor)
 }
 EXPORT_SYMBOL_GPL(spi_nor_scan);
 
+/* U-Boot specific functions, need to extend MTD to support these */
+int spi_flash_cmd_get_sw_write_prot(struct spi_nor *nor)
+{
+	int sr = read_sr(nor);
+
+	if (sr < 0)
+		return sr;
+
+	return (sr >> 2) & 7;
+}
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Huang Shijie <shijie8@gmail.com>");
 MODULE_AUTHOR("Mike Lavender");
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 507458a76076..88e80af57941 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -105,6 +105,7 @@
 
 /* Used for Spansion flashes only. */
 #define SPINOR_OP_BRWR		0x17	/* Bank register write */
+#define SPINOR_OP_BRRD		0x16	/* Bank register read */
 #define SPINOR_OP_CLSR		0x30	/* Clear status register 1 */
 
 /* Used for Micron flashes only. */
@@ -256,6 +257,9 @@ struct flash_info;
  * @read_opcode:	the read opcode
  * @read_dummy:		the dummy needed by the read operation
  * @program_opcode:	the program opcode
+ * @bank_read_cmd:	Bank read cmd
+ * @bank_write_cmd:	Bank write cmd
+ * @bank_curr:		Current flash bank
  * @sst_write_second:	used by the SST write operation
  * @flags:		flag options for the current SPI-NOR (SNOR_F_*)
  * @read_proto:		the SPI protocol for read operations
@@ -291,6 +295,11 @@ struct spi_nor {
 	u8			read_opcode;
 	u8			read_dummy;
 	u8			program_opcode;
+#ifdef CONFIG_SPI_FLASH_BAR
+	u8			bank_read_cmd;
+	u8			bank_write_cmd;
+	u8			bank_curr;
+#endif
 	enum spi_nor_protocol	read_proto;
 	enum spi_nor_protocol	write_proto;
 	enum spi_nor_protocol	reg_proto;
-- 
2.20.1