diff options
| author | Mugunthan V N <mugunthanvnm@ti.com> | 2015-02-18 00:33:51 +0530 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2015-02-21 18:29:09 +0900 |
| commit | 006110476478c69c399d0cd25888eefab0e69267 (patch) | |
| tree | 629e830087284cec4134234dff0fe67f0a2062a4 /drivers/spi | |
| parent | 66886337bf2a523aef76cff84c846335db5f85f9 (diff) | |
| download | linux-006110476478c69c399d0cd25888eefab0e69267.tar.bz2 | |
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: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-ti-qspi.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c index 884a716e50cb..5c0616870358 100644 --- a/drivers/spi/spi-ti-qspi.c +++ b/drivers/spi/spi-ti-qspi.c @@ -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)) { |