msm8909+android5.1.1 由BLSP3改为BLSP1后SPI读写速度慢问题解决
发现SPI的读写速度慢了不少，msm8909-cb03.dtsi文件相关内容如下：
spi_0: spi@78b5000 { /* BLSP1 QUP1 */ compatible ="qcom,spi-qup-v2"; #address-cells = <1>; #size-cells = <0>; reg-names ="spi_physical", "spi_bam_physical"; reg = <0x78b5000 0x600>, <0x7884000 0x23000>; interrupt-names ="spi_irq", "spi_bam_irq"; interrupts = <0 95 0>,<0 238 0>; spi-max-frequency =<19200000>; pinctrl-names ="spi_default", "spi_sleep"; pinctrl-0 =<&spi0_default &spi0_cs0_active>; pinctrl-1 = <&spi0_sleep&spi0_cs0_sleep>; clocks = <&clock_gccclk_gcc_blsp1_ahb_clk>, <&clock_gccclk_gcc_blsp1_qup1_spi_apps_clk>; clock-names ="iface_clk", "core_clk"; qcom,infinite-mode = <0>; qcom,use-bam; qcom,use-pinctrl; qcom,ver-reg-exists; qcom,bam-consumer-pipe-index =<8>; qcom,bam-producer-pipe-index =<9>; qcom,master-id = <86>; };改成下面的pipe就OK了，之前也改过这里，但高通给的文档是错的。
qcom,bam-consumer-pipe-index =<4>;//<8>;qcom,bam-producer-pipe-index =<5>;//<9>;