Hi, On 01/09/2015 01:21 PM, Jaehoon Chung wrote: > On 01/09/2015 08:23 AM, Sjoerd Simons wrote: >> On Thu, 2015-01-08 at 14:44 +0900, Joonyoung Shim wrote: >>> Some exynos boards require special handling of SD4_nRESET_OUT line for >>> eMMC memory to perform complete reboot e.g. Odroid X2/U3/XU3 boards. >>> >>> This will support eMMC reset using DT from reset_misc of samsung common >>> board file and each board files can support eMMC reset on non DT case. >>> >>> Signed-off-by: Joonyoung Shim <jy0922.s...@samsung.com> >> >>> diff --git a/doc/device-tree-bindings/exynos/emmc-reset.txt >>> b/doc/device-tree-bindings/exynos/emmc-reset.txt >>> new file mode 100644 >>> index 0000000..e48e508 >>> --- /dev/null >>> +++ b/doc/device-tree-bindings/exynos/emmc-reset.txt >>> @@ -0,0 +1,15 @@ >>> +* Samsung eMMC reset >>> + >>> +Some exynos boards require special handling of SD4_nRESET_OUT line for eMMC >>> +memory to perform complete reboot. >> >> Nitpick, on XU3 the line you apparently need to twiddle is >> SD0_nRESET_OUT. >>
Then, i think it's better to omit "SD4_". >> Is this type of usage of this pin specific to the Odroid Exynos boards >> or potentially on more boards? (Sorry for the simple questions, but my >> exynos documentation just says the line exists not what its intended >> usage is). > > In case of Exynos4, eMMC can be used with sdhci controller or dw-mmc > controller. > So Pin name should be used to SD0 or SD4. > > But Exynos5 is only supported the dw-mmc controller. > (So eMMC is used pin-name as "SD0".) > I can find only "SD_4_nRESET_OUT" from exynos4412 user manual and only "SD_0__nRESET_OUT" from exynos5422 user manual. > Best Regards, > Jaehoon Chung >> >> Fwiw, I did a quick check in the linux code and it doesn't seem to be >> using those pins for currently for any boards. However my X2 does >> successfully reset/reboot in u-boot and linux, so it seems optional >> there. The XU3 does fail to reset itself, so it seems required for that >> board. >> I checked upstream u-boot and hardkernel u-boot and i found codes to reset eMMC using gpio. upstream u-boot: reset_misc() of board/samsung/odroid/odroid.c hardkernel u-boot: reset_cpu() of arch/arm/cpu/armv7/exynos/reset.c Thanks. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot