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>
diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index 12b311e..f21e857 100644
--- a/drivers/spi/spi-xilinx.c
+++ b/drivers/spi/spi-xilinx.c
@@ -173,8 +173,11 @@
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 @@
~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 @@
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) {