[PATCH v4 05/37] mtd: st_spi_fsm: Supply a method to read from the FSM's FIFO

[Lee Jones]

When invoked the driver will attempt to read any available data from
the FSM's data register. Any data collected from this FIFO would have
originated from the flash chip.

Signed-off-by: Lee Jones <lee.jones at linaro.org>
---
 drivers/mtd/devices/st_spi_fsm.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/mtd/devices/st_spi_fsm.c b/drivers/mtd/devices/st_spi_fsm.c
index c7daeca..0eba759 100644
--- a/drivers/mtd/devices/st_spi_fsm.c
+++ b/drivers/mtd/devices/st_spi_fsm.c
@@ -274,6 +274,32 @@ static void stfsm_wait_seq(struct stfsm *fsm)
 		dev_err(fsm->dev, "timeout on sequence completion\n");
 }
 
+static void stfsm_read_fifo(struct stfsm *fsm, uint32_t *buf,
+			    const uint32_t size)
+{
+	uint32_t remaining = size >> 2;
+	uint32_t avail;
+	uint32_t words;
+
+	dev_dbg(fsm->dev, "Reading %d bytes from FIFO\n", size);
+
+	BUG_ON((((uint32_t)buf) & 0x3) || (size & 0x3));
+
+	while (remaining) {
+		for (;;) {
+			avail = stfsm_fifo_available(fsm);
+			if (avail)
+				break;
+			udelay(1);
+		}
+		words = min(avail, remaining);
+		remaining -= words;
+
+		readsl(fsm->base + SPI_FAST_SEQ_DATA_REG, buf, words);
+		buf += words;
+	}
+}
+
 static int stfsm_set_mode(struct stfsm *fsm, uint32_t mode)
 {
 	int ret, timeout = 10;
-- 
1.8.3.2