The LX2160A esdhc controllers are setup by the driver to be DMA coherent, but without marking them as such in DT, Linux thinks they are not. This can lead to random sporadic DMA errors, even to the extent of preventing boot, such as: mmc0: ADMA error mmc0: sdhci: ============ SDHCI REGISTER DUMP =========== mmc0: sdhci: Sys addr: 0x00000000 | Version: 0x00002202 mmc0: sdhci: Blk size: 0x00000008 | Blk cnt: 0x00000001 mmc0: sdhci: Argument: 0x00000000 | Trn mode: 0x00000013 mmc0: sdhci: Present: 0x01f50008 | Host ctl: 0x00000038 mmc0: sdhci: Power: 0x00000003 | Blk gap: 0x00000000 mmc0: sdhci: Wake-up: 0x00000000 | Clock: 0x000040d8 mmc0: sdhci: Timeout: 0x00000003 | Int stat: 0x00000001 mmc0: sdhci: Int enab: 0x037f108f | Sig enab: 0x037f108b mmc0: sdhci: ACmd stat: 0x00000000 | Slot int: 0x00002202 mmc0: sdhci: Caps: 0x35fa0000 | Caps_1: 0x0000af00 mmc0: sdhci: Cmd: 0x0000333a | Max curr: 0x00000000 mmc0: sdhci: Resp[0]: 0x00000920 | Resp[1]: 0x001d8a33 mmc0: sdhci: Resp[2]: 0x325b5900 | Resp[3]: 0x3f400e00 mmc0: sdhci: Host ctl2: 0x00000000 mmc0: sdhci: ADMA Err: 0x00000009 | ADMA Ptr: 0x000000236d43820c mmc0: sdhci: ============================================ mmc0: error -5 whilst initialising SD card These are caused by the device's descriptor fetch hitting speculatively loaded CPU cache lines that the CPU does not see through the normal, non-cacheable DMA coherent mapping that it uses for non-coherent devices. DT and the device must agree wrt whether the device is DMA coherent or not. Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx> --- arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi b/arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi index 36b153e3da47..508af23edef0 100644 --- a/arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi +++ b/arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi @@ -593,6 +593,7 @@ reg = <0x0 0x2140000 0x0 0x10000>; interrupts = <0 28 0x4>; /* Level high type */ clocks = <&clockgen 4 1>; + dma-coherent; voltage-ranges = <1800 1800 3300 3300>; sdhci,auto-cmd12; little-endian; @@ -605,6 +606,7 @@ reg = <0x0 0x2150000 0x0 0x10000>; interrupts = <0 63 0x4>; /* Level high type */ clocks = <&clockgen 4 1>; + dma-coherent; voltage-ranges = <1800 1800 3300 3300>; sdhci,auto-cmd12; broken-cd; -- 2.7.4
