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Commit 5fe11cc0 authored by Ricardo Ribalda Delgado's avatar Ricardo Ribalda Delgado Committed by Mark Brown
Browse files

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: default avatarRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 5b74d7a3

drivers/spi/spi-xilinx.c

+19 −14
Original line number Diff line number Diff line
@@ -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 */

	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);



		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;

	}



	/* SPI controller initializations */

	xspi_init_hw(xspi);



	ret = spi_bitbang_start(&xspi->bitbang);

	if (ret) {