[PATCH 23/23] mtd: st_spi_fsm: Supply the N25Qxxx specific read configurations

[Lee Jones]

The N25Qxxx Serial Flash devices required different sequence
configurations depending on whether they're running in 24bit (3Byte)
or 32bit (4Byte) mode. We provide those here.

Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
---
 drivers/mtd/devices/st_spi_fsm.c | 43 ++++++++++++++++++++++++++++++++++++++++
 drivers/mtd/devices/st_spi_fsm.h | 10 ++++++++++
 2 files changed, 53 insertions(+)

diff --git a/drivers/mtd/devices/st_spi_fsm.c b/drivers/mtd/devices/st_spi_fsm.c
index 2b7df68..c906739 100644
--- a/drivers/mtd/devices/st_spi_fsm.c
+++ b/drivers/mtd/devices/st_spi_fsm.c
@@ -57,6 +57,49 @@ static struct seq_rw_config default_write_configs[] = {
 	{0x00,			 0,			 0, 0, 0, 0x00, 0, 0},
 };
 
+/*
+ * [N25Qxxx] Configuration
+ */
+#define N25Q_VCR_DUMMY_CYCLES(x)	(((x) & 0xf) << 4)
+#define N25Q_VCR_XIP_DISABLED		((uint8_t)0x1 << 3)
+#define N25Q_VCR_WRAP_CONT		0x3
+
+/* N25Q 3-byte Address READ configurations
+ *	- 'FAST' variants configured for 8 dummy cycles.
+ *
+ * Note, the number of dummy cycles used for 'FAST' READ operations is
+ * configurable and would normally be tuned according to the READ command and
+ * operating frequency.  However, this applies universally to all 'FAST' READ
+ * commands, including those used by the SPIBoot controller, and remains in
+ * force until the device is power-cycled.  Since the SPIBoot controller is
+ * hard-wired to use 8 dummy cycles, we must configure the device to also use 8
+ * cycles.
+ */
+static struct seq_rw_config n25q_read3_configs[] = {
+	{FLASH_FLAG_READ_1_4_4, FLASH_CMD_READ_1_4_4,	0, 4, 4, 0x00, 0, 8},
+	{FLASH_FLAG_READ_1_1_4, FLASH_CMD_READ_1_1_4,	0, 1, 4, 0x00, 0, 8},
+	{FLASH_FLAG_READ_1_2_2, FLASH_CMD_READ_1_2_2,	0, 2, 2, 0x00, 0, 8},
+	{FLASH_FLAG_READ_1_1_2, FLASH_CMD_READ_1_1_2,	0, 1, 2, 0x00, 0, 8},
+	{FLASH_FLAG_READ_FAST,	FLASH_CMD_READ_FAST,	0, 1, 1, 0x00, 0, 8},
+	{FLASH_FLAG_READ_WRITE, FLASH_CMD_READ,	        0, 1, 1, 0x00, 0, 0},
+	{0x00,			0,			0, 0, 0, 0x00, 0, 0},
+};
+
+/* N25Q 4-byte Address READ configurations
+ *	- use special 4-byte address READ commands (reduces overheads, and
+ *        reduces risk of hitting watchdog reset issues).
+ *	- 'FAST' variants configured for 8 dummy cycles (see note above.)
+ */
+static struct seq_rw_config n25q_read4_configs[] = {
+	{FLASH_FLAG_READ_1_4_4, FLASH_CMD_READ4_1_4_4,	0, 4, 4, 0x00, 0, 8},
+	{FLASH_FLAG_READ_1_1_4, FLASH_CMD_READ4_1_1_4,	0, 1, 4, 0x00, 0, 8},
+	{FLASH_FLAG_READ_1_2_2, FLASH_CMD_READ4_1_2_2,	0, 2, 2, 0x00, 0, 8},
+	{FLASH_FLAG_READ_1_1_2, FLASH_CMD_READ4_1_1_2,	0, 1, 2, 0x00, 0, 8},
+	{FLASH_FLAG_READ_FAST,	FLASH_CMD_READ4_FAST,	0, 1, 1, 0x00, 0, 8},
+	{FLASH_FLAG_READ_WRITE, FLASH_CMD_READ4,	0, 1, 1, 0x00, 0, 0},
+	{0x00,			0,			0, 0, 0, 0x00, 0, 0},
+};
+
 static struct stfsm_seq stfsm_seq_read_jedec = {
 	.data_size = TRANSFER_SIZE(8),
 	.seq_opc[0] = (SEQ_OPC_PADS_1 |
diff --git a/drivers/mtd/devices/st_spi_fsm.h b/drivers/mtd/devices/st_spi_fsm.h
index 8eb9e20..163c09f 100644
--- a/drivers/mtd/devices/st_spi_fsm.h
+++ b/drivers/mtd/devices/st_spi_fsm.h
@@ -229,6 +229,15 @@
 #define FLASH_CMD_READ4_1_1_4	0x6c
 #define FLASH_CMD_READ4_1_4_4	0xec
 
+/*
+ * Flags to tweak operation of default read/write/erase routines
+ */
+#define CFG_READ_TOGGLE_32BIT_ADDR	0x00000001
+#define CFG_WRITE_TOGGLE_32BIT_ADDR	0x00000002
+#define CFG_WRITE_EX_32BIT_ADDR_DELAY	0x00000004
+#define CFG_ERASESEC_TOGGLE_32BIT_ADDR	0x00000008
+#define CFG_S25FL_CHECK_ERROR_FLAGS	0x00000010
+
 struct stfsm {
 	struct device		*dev;
 	void __iomem		*base;
@@ -237,6 +246,7 @@ struct stfsm {
 	struct mutex		lock;
 	struct flash_info 	*info;
 
+	uint32_t		configuration;
 	uint32_t		fifo_dir_delay;
 	bool			booted_from_spi;
 	bool			reset_signal;
-- 
1.8.1.2

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