[PATCH v4 07/37] mtd: st_spi_fsm: Add support for JEDEC ID extraction

Lee Jones lee.jones at linaro.org
Wed Jan 8 08:46:50 EST 2014


Once we start supporting devices it will be handy go detect them
dynamically. This will be done using the chip's unique JEDEC ID. This
patch allows us to extract a device's JEDEC ID using the a predefined
FSM register write sequence.

Signed-off-by: Lee Jones <lee.jones at linaro.org>
---
 drivers/mtd/devices/st_spi_fsm.c | 55 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/drivers/mtd/devices/st_spi_fsm.c b/drivers/mtd/devices/st_spi_fsm.c
index bb0f20a..8a10f16 100644
--- a/drivers/mtd/devices/st_spi_fsm.c
+++ b/drivers/mtd/devices/st_spi_fsm.c
@@ -255,6 +255,22 @@ struct stfsm_seq {
 	uint32_t seq_cfg;
 } __packed __aligned(4);
 
+static struct stfsm_seq stfsm_seq_read_jedec = {
+	.data_size = TRANSFER_SIZE(8),
+	.seq_opc[0] = (SEQ_OPC_PADS_1 |
+		       SEQ_OPC_CYCLES(8) |
+		       SEQ_OPC_OPCODE(FLASH_CMD_RDID)),
+	.seq = {
+		STFSM_INST_CMD1,
+		STFSM_INST_DATA_READ,
+		STFSM_INST_STOP,
+	},
+	.seq_cfg = (SEQ_CFG_PADS_1 |
+		    SEQ_CFG_READNOTWRITE |
+		    SEQ_CFG_CSDEASSERT |
+		    SEQ_CFG_STARTSEQ),
+};
+
 static inline int stfsm_is_idle(struct stfsm *fsm)
 {
 	return readl(fsm->base + SPI_FAST_SEQ_STA) & 0x10;
@@ -338,6 +354,42 @@ static void stfsm_read_fifo(struct stfsm *fsm, uint32_t *buf,
 	}
 }
 
+static void stfsm_read_jedec(struct stfsm *fsm, uint8_t *const jedec)
+{
+	const struct stfsm_seq *seq = &stfsm_seq_read_jedec;
+	uint32_t tmp[2];
+
+	stfsm_load_seq(fsm, seq);
+
+	stfsm_read_fifo(fsm, tmp, 8);
+
+	memcpy(jedec, tmp, 5);
+
+	stfsm_wait_seq(fsm);
+}
+
+static struct flash_info *stfsm_jedec_probe(struct stfsm *fsm)
+{
+	u16                     ext_jedec;
+	u32			jedec;
+	u8			id[5];
+
+	stfsm_read_jedec(fsm, id);
+
+	jedec     = id[0] << 16 | id[1] << 8 | id[2];
+	/*
+	 * JEDEC also defines an optional "extended device information"
+	 * string for after vendor-specific data, after the three bytes
+	 * we use here. Supporting some chips might require using it.
+	 */
+	ext_jedec = id[3] << 8  | id[4];
+
+	dev_dbg(fsm->dev, "JEDEC =  0x%08x [%02x %02x %02x %02x %02x]\n",
+		jedec, id[0], id[1], id[2], id[3], id[4]);
+
+	return NULL;
+}
+
 static int stfsm_set_mode(struct stfsm *fsm, uint32_t mode)
 {
 	int ret, timeout = 10;
@@ -474,6 +526,9 @@ static int stfsm_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	/* Detect SPI FLASH device */
+	stfsm_jedec_probe(fsm);
+
 	platform_set_drvdata(pdev, fsm);
 
 	fsm->mtd.dev.parent	= &pdev->dev;
-- 
1.8.3.2




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