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authorRajeshwari Shinde <rajeshwari.s@samsung.com>2013-10-08 16:20:06 +0530
committerJagannadha Sutradharudu Teki <jaganna@xilinx.com>2013-10-08 18:18:12 +0530
commitc4a796329d00ce46de6b5afeb1fdabec82830677 (patch)
tree01b2274734a04752e2d0fc139de7f3a726721e4b /arch
parent120af1572a3647bb87eff2f62dd8f8a919ee71f0 (diff)
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spi: exynos: Support word transfers
Since SPI register access is so expensive, it is worth transferring data a word at a time if we can. This complicates the driver unfortunately. Use the byte-swapping feature to avoid having to convert to/from big endian in software. This change increases speed from about 2MB/s to about 4.5MB/s. Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Rajeshwari S Shinde <rajeshwari.s@samsung.com> Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/include/asm/arch-exynos/spi.h11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/arm/include/asm/arch-exynos/spi.h b/arch/arm/include/asm/arch-exynos/spi.h
index fb23aa6..147c1a7 100644
--- a/arch/arm/include/asm/arch-exynos/spi.h
+++ b/arch/arm/include/asm/arch-exynos/spi.h
@@ -22,7 +22,7 @@ struct exynos_spi {
unsigned int rx_data; /* 0x1c */
unsigned int pkt_cnt; /* 0x20 */
unsigned char reserved2[4];
- unsigned char reserved3[4];
+ unsigned int swap_cfg; /* 0x28 */
unsigned int fb_clk; /* 0x2c */
unsigned char padding[0xffd0];
};
@@ -62,5 +62,14 @@ struct exynos_spi {
/* Packet Count */
#define SPI_PACKET_CNT_EN (1 << 16)
+/* Swap config */
+#define SPI_TX_SWAP_EN (1 << 0)
+#define SPI_TX_BYTE_SWAP (1 << 2)
+#define SPI_TX_HWORD_SWAP (1 << 3)
+#define SPI_TX_BYTE_SWAP (1 << 2)
+#define SPI_RX_SWAP_EN (1 << 4)
+#define SPI_RX_BYTE_SWAP (1 << 6)
+#define SPI_RX_HWORD_SWAP (1 << 7)
+
#endif /* __ASSEMBLY__ */
#endif