Hi Krzystof, On 5/4/15 12:30 AM, Krzysztof Kozlowski wrote: > 2015-05-04 13:28 GMT+09:00 <dinguyen@xxxxxxxxxxxxxxxxxxxxx>: >> From: Dinh Nguyen <dinguyen@xxxxxxxxxxxxxxxxxxxxx> >> >> Turn on the clock to the PL330 DMA if there is a clock node provided. > > Why? There is no explanation in the patch for this important question - why? > > Amba bus already does this and provide a wrapper function. > Additionally that would mess up with runtime PM and clock > enable/disable. I don't see the clock for the DMA getting turned on at all, which is why after the kernel has booted, the filesystem tries to open up a serial port using DMA and the system hangs. The failure is seen here: http://arm-soc.lixom.net/bootlogs/next/next-20150504/socfpga-arm-multi_v7_defconfig.html This only happens with the multi_v7_defconfig, because the PL330 DMA is getting built into the kernel, while the socfpga_defconfig does not enable the PL330. The DTS for the socfpga platform looks like this: pdma: pdma@ffe01000 { compatible = "arm,pl330", "arm,primecell"; reg = <0xffe01000 0x1000>; interrupts = <0 104 4>, <0 105 4>, ... #dma-cells = <1>; #dma-channels = <8>; #dma-requests = <32>; clocks = <&l4_main_clk>; clock-names = "apb_pclk"; }; Perhaps I have the wrong designation for clock-names and the amba bus is not able to pick up the correct clock? Dinh -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
