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authorRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>2015-01-28 15:23:44 +0300
committerMark Brown <broonie@kernel.org>2015-01-28 22:42:42 +0300
commit5fe11cc09ce81b000b1deadcdec3813fcb423c8c (patch)
tree030a436c3e6e28e80579c629aa398fc0655605e8 /drivers/spi/spi-xilinx.c
parent5b74d7a3b888fd3db6dce77eb11b3d55b64f6833 (diff)
downloadlinux-5fe11cc09ce81b000b1deadcdec3813fcb423c8c.tar.xz
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>
Diffstat (limited to 'drivers/spi/spi-xilinx.c')
-rw-r--r--drivers/spi/spi-xilinx.c33
1 files changed, 19 insertions, 14 deletions
diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index 12b311ed9bfa..f21e857d54b1 100644
--- a/drivers/spi/spi-xilinx.c
+++ b/drivers/spi/spi-xilinx.c
@@ -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) {