spi_s3c24xx: add FIQ pseudo-DMA support

Add pseudo-DMA by FIQ to the S3C24XX SPI driver.  This allows the driver
to get DMA-like performance where there are either no free DMA channels or
when doing transfers that required both TX and RX data paths.

Since this patch requires the addition of an assembly file to hold the FIQ
code, we rename the module (instead of adding a rename of the .c file to
this patch).  We expect most users are loading this via udev and thus
there should be no change to the userland configuration.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Simtec Linux Team <linux@simtec.co.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index d7c1741c4c5b..6fa595e0c989 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -219,6 +219,17 @@ config SPI_S3C24XX
         help
           SPI driver for Samsung S3C24XX series ARM SoCs
 
+config SPI_S3C24XX_FIQ
+        bool "S3C24XX driver with FIQ pseudo-DMA"
+        depends on SPI_S3C24XX
+        select FIQ
+        help
+          Enable FIQ support for the S3C24XX SPI driver to provide pseudo
+          DMA by using the fast-interrupt request framework, This allows
+          the driver to get DMA-like performance when there are either
+          no free DMA channels, or when doing transfers that required both
+          TX and RX data paths.
+
 config SPI_S3C24XX_GPIO
         tristate "Samsung S3C24XX series SPI by GPIO"
         depends on ARCH_S3C2410 && EXPERIMENTAL