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Commit 00611047 authored by Mugunthan V N's avatar Mugunthan V N Committed by Mark Brown
Browse files

drivers: spi: ti-qspi: wait for busy bit clear before data write/read 



Data corruption is seen while reading/writing large data from/to qspi
device because the data register is over written or read before data
is ready which is denoted by busy bit in status register. SO adding
a busy bit check before writing/reading data to/from qspi device.

Signed-off-by: default avatarMugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 66886337

drivers/spi/spi-ti-qspi.c

+22 −0
Original line number Diff line number Diff line
@@ -101,6 +101,7 @@ struct ti_qspi { 
#define QSPI_FLEN(n)			((n - 1) << 0)



/* STATUS REGISTER */

#define BUSY				0x01

#define WC				0x02



/* INTERRUPT REGISTER */
@@ -199,6 +200,21 @@ static void ti_qspi_restore_ctx(struct ti_qspi *qspi) 
	ti_qspi_write(qspi, ctx_reg->clkctrl, QSPI_SPI_CLOCK_CNTRL_REG);

}



static inline u32 qspi_is_busy(struct ti_qspi *qspi)

{

	u32 stat;

	unsigned long timeout = jiffies + QSPI_COMPLETION_TIMEOUT;



	stat = ti_qspi_read(qspi, QSPI_SPI_STATUS_REG);

	while ((stat & BUSY) && time_after(timeout, jiffies)) {

		cpu_relax();

		stat = ti_qspi_read(qspi, QSPI_SPI_STATUS_REG);

	}



	WARN(stat & BUSY, "qspi busy\n");

	return stat & BUSY;

}



static int qspi_write_msg(struct ti_qspi *qspi, struct spi_transfer *t)

{

	int wlen, count;
@@ -211,6 +227,9 @@ static int qspi_write_msg(struct ti_qspi *qspi, struct spi_transfer *t) 
	wlen = t->bits_per_word >> 3;	/* in bytes */



	while (count) {

		if (qspi_is_busy(qspi))

			return -EBUSY;



		switch (wlen) {

		case 1:

			dev_dbg(qspi->dev, "tx cmd %08x dc %08x data %02x\n",
@@ -266,6 +285,9 @@ static int qspi_read_msg(struct ti_qspi *qspi, struct spi_transfer *t) 


	while (count) {

		dev_dbg(qspi->dev, "rx cmd %08x dc %08x\n", cmd, qspi->dc);

		if (qspi_is_busy(qspi))

			return -EBUSY;



		ti_qspi_write(qspi, cmd, QSPI_SPI_CMD_REG);

		if (!wait_for_completion_timeout(&qspi->transfer_complete,

						 QSPI_COMPLETION_TIMEOUT)) {