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spi: spi-zynqmp-gqspi: transmit dummy circles by using the controller's internal functionality 

There is a data corruption issue that occurs in the reading operation
(cmd:0x6c) when transmitting common data as dummy circles.

The gqspi controller has the functionality to send dummy clock circles.
When writing data with the fields [receive, transmit, data_xfer] = [0,0,1]
to the Generic FIFO, and configuring the correct SPI mode, the controller
will transmit dummy circles.

So let's switch to hardware dummy cycles transfer to fix this issue.

Fixes: 1c26372e5a ("spi: spi-zynqmp-gqspi: Update driver to use spi-mem framework")
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Reviewed-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@xilinx.com>
Link: https://lore.kernel.org/r/20210408040223.23134-4-quanyang.wang@windriver.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Quanyang Wang 2021-04-08 12:02:22 +08:00 committed by Mark Brown
parent a0f65be6e8
commit 8ad07d79bd
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 18 additions and 22 deletions
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40
drivers/spi/spi-zynqmp-gqspi.c
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@ -521,7 +521,7 @@ static void zynqmp_qspi_filltxfifo(struct zynqmp_qspi *xqspi, int size)
{
u32 count = 0, intermediate;
while ((xqspi->bytes_to_transfer > 0) && (count < size)) {
while ((xqspi->bytes_to_transfer > 0) && (count < size) && (xqspi->txbuf)) {
memcpy(&intermediate, xqspi->txbuf, 4);
zynqmp_gqspi_write(xqspi, GQSPI_TXD_OFST, intermediate);
@ -580,7 +580,7 @@ static void zynqmp_qspi_fillgenfifo(struct zynqmp_qspi *xqspi, u8 nbits,
genfifoentry |= GQSPI_GENFIFO_DATA_XFER;
genfifoentry |= GQSPI_GENFIFO_TX;
transfer_len = xqspi->bytes_to_transfer;
} else {
} else if (xqspi->rxbuf) {
genfifoentry &= ~GQSPI_GENFIFO_TX;
genfifoentry |= GQSPI_GENFIFO_DATA_XFER;
genfifoentry |= GQSPI_GENFIFO_RX;
@ -588,6 +588,11 @@ static void zynqmp_qspi_fillgenfifo(struct zynqmp_qspi *xqspi, u8 nbits,
transfer_len = xqspi->dma_rx_bytes;
else
transfer_len = xqspi->bytes_to_receive;
} else {
/* Sending dummy circles here */
genfifoentry &= ~(GQSPI_GENFIFO_TX | GQSPI_GENFIFO_RX);
genfifoentry |= GQSPI_GENFIFO_DATA_XFER;
transfer_len = xqspi->bytes_to_transfer;
}
genfifoentry |= zynqmp_qspi_selectspimode(xqspi, nbits);
xqspi->genfifoentry = genfifoentry;
@ -1011,32 +1016,23 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
}
if (op->dummy.nbytes) {
tmpbuf = kzalloc(op->dummy.nbytes, GFP_KERNEL | GFP_DMA);
if (!tmpbuf)
return -ENOMEM;
memset(tmpbuf, 0xff, op->dummy.nbytes);
reinit_completion(&xqspi->data_completion);
xqspi->txbuf = tmpbuf;
xqspi->txbuf = NULL;
xqspi->rxbuf = NULL;
xqspi->bytes_to_transfer = op->dummy.nbytes;
/*
* xqspi->bytes_to_transfer here represents the dummy circles
* which need to be sent.
*/
xqspi->bytes_to_transfer = op->dummy.nbytes * 8 / op->dummy.buswidth;
xqspi->bytes_to_receive = 0;
zynqmp_qspi_write_op(xqspi, op->dummy.buswidth,
/*
* Using op->data.buswidth instead of op->dummy.buswidth here because
* we need to use it to configure the correct SPI mode.
*/
zynqmp_qspi_write_op(xqspi, op->data.buswidth,
genfifoentry);
zynqmp_gqspi_write(xqspi, GQSPI_CONFIG_OFST,
zynqmp_gqspi_read(xqspi, GQSPI_CONFIG_OFST) |
GQSPI_CFG_START_GEN_FIFO_MASK);
zynqmp_gqspi_write(xqspi, GQSPI_IER_OFST,
GQSPI_IER_TXEMPTY_MASK |
GQSPI_IER_GENFIFOEMPTY_MASK |
GQSPI_IER_TXNOT_FULL_MASK);
if (!wait_for_completion_interruptible_timeout
(&xqspi->data_completion, msecs_to_jiffies(1000))) {
err = -ETIMEDOUT;
kfree(tmpbuf);
goto return_err;
}
kfree(tmpbuf);
}
if (op->data.nbytes) {