[RK3288][Android6.0] 调试笔记 --- 开机提示mmc rescan错误

Platform: RK3288

OS: Android 6.0

Kernel: 3.10.92

遇到一块板子无法开机报mmc rescan相关的错误(这种情况基本上是硬件问题)：

[ 5.323725] Workqueue: kmmcd mmc_rescan[ 5.323745] [<c0013fc4>] (unwind_backtrace+0x0/0xe0) from [<c0011864>] (show_stack+0x10/0x14)[ 5.323758] [<c0011864>] (show_stack+0x10/0x14) from [<c0694ce0>] (dw_mci_set_ios+0xa4/0x264)[ 5.323770] [<c0694ce0>] (dw_mci_set_ios+0xa4/0x264) from [<c0681d90>] (mmc_set_chip_select+0x18/0x1c)[ 5.323782] [<c0681d90>] (mmc_set_chip_select+0x18/0x1c) from [<c0686188>] (mmc_go_idle+0x94/0xc4)[ 5.323792] [<c0686188>] (mmc_go_idle+0x94/0xc4) from [<c06823e4>] (mmc_rescan_try_freq+0x54/0xd0)[ 5.323802] [<c06823e4>] (mmc_rescan_try_freq+0x54/0xd0) from [<c0682cac>] (mmc_rescan+0x204/0x298)[ 5.323815] [<c0682cac>] (mmc_rescan+0x204/0x298) from [<c005b3cc>] (process_one_work+0x29c/0x458)[ 5.323826] [<c005b3cc>] (process_one_work+0x29c/0x458) from [<c005b71c>] (worker_thread+0x194/0x2d4)[ 5.323837] [<c005b71c>] (worker_thread+0x194/0x2d4) from [<c0060cf8>] (kthread+0xa0/0xac)[ 5.323850] [<c0060cf8>] (kthread+0xa0/0xac) from [<c000dba0>] (ret_from_fork+0x14/0x34)[ 5.323859] dwmmc_rockchip ff0c0000.rksdmmc: dw_mci_set_ios: wait for unbusy timeout.. STATUS = 0x206 [mmc1]

由于SD和eMMC共用驱动，一开始验证把SD拔掉后还是报错，以为是eMMC问题，后来从logff0c0000.rksdmmc这个地址确实是SD问题。

rk3288.dts:

sdmmc: rksdmmc@ff0c0000 {compatible = "rockchip,rk_mmc", "rockchip,rk32xx-sdmmc";reg = <0xff0c0000 0x4000>;interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>;#address-cells = <1>;#size-cells = <0>;pinctrl-names = "default", "idle";pinctrl-0 = <&sdmmc0_clk &sdmmc0_cmd &sdmmc0_dectn&sdmmc0_bus4>;pinctrl-1 = <&sdmmc0_gpio>;cd-gpios = <&gpio6 GPIO_C6 GPIO_ACTIVE_HIGH>;/*CD GPIO*/clocks = <&clk_sdmmc>, <&clk_gates8 3>;clock-names = "clk_mmc", "hclk_mmc";num-slots = <1>;fifo-depth = <0x100>;bus-width = <4>;tune_regsbase = <0x200>;resets = <&reset RK3288_SOFT_RST_MMC0>;reset-names = "mmc_ahb_reset";};

disable掉这块功能后就能正常开机了。

最终确认是硬件问题。