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spi/xilinx: Support cores with no interrupt 

The core can run in polling mode. In fact, the performance of the core
is similar (or even better), due to the fact most of the spi
transactions are just a couple of bytes and there is one irq per
transactions.

When an mtd device is connected via spi, reading 8MB of data produces
more than 80K interrupts (with irq disabling, context swith....)

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Ricardo Ribalda Delgado 2015-01-28 13:23:44 +01:00 committed by Mark Brown
parent 5b74d7a3b8
commit 5fe11cc09c
1 changed files with 19 additions and 14 deletions
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33
drivers/spi/spi-xilinx.c
View File

@ -173,8 +173,11 @@ static void xspi_init_hw(struct xilinx_spi *xspi)
xspi->write_fn(XSPI_INTR_TX_EMPTY,
regs_base + XIPIF_V123B_IIER_OFFSET);
/* Enable the global IPIF interrupt */
xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
regs_base + XIPIF_V123B_DGIER_OFFSET);
if (xspi->irq >= 0)
xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
regs_base + XIPIF_V123B_DGIER_OFFSET);
else
xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
/* Deselect the slave on the SPI bus */
xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET);
/* Disable the transmitter, enable Manual Slave Select Assertion,
@ -264,7 +267,12 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
~XSPI_CR_TRANS_INHIBIT;
xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
wait_for_completion(&xspi->done);
if (xspi->irq >= 0)
wait_for_completion(&xspi->done);
else
while (!(xspi->read_fn(xspi->regs + XSPI_SR_OFFSET) &
XSPI_SR_TX_EMPTY_MASK))
;
/* A transmit has just completed. Process received data and
* check for more data to transmit. Always inhibit the
@ -419,20 +427,17 @@ static int xilinx_spi_probe(struct platform_device *pdev)
xspi->buffer_size = xilinx_spi_find_buffer_size(xspi);
/* SPI controller initializations */
xspi_init_hw(xspi);
xspi->irq = platform_get_irq(pdev, 0);
if (xspi->irq < 0) {
ret = xspi->irq;
goto put_master;
if (xspi->irq >= 0) {
/* Register for SPI Interrupt */
ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0,
dev_name(&pdev->dev), xspi);
if (ret)
goto put_master;
}
/* Register for SPI Interrupt */
ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0,
dev_name(&pdev->dev), xspi);
if (ret)
goto put_master;
/* SPI controller initializations */
xspi_init_hw(xspi);
ret = spi_bitbang_start(&xspi->bitbang);
if (ret) {