On Tue, 23 Apr 2019 at 11:02, Jerome Brunet <jbrunet@xxxxxxxxxxxx> wrote: > > The purpose of this series is too improve reliability of the amlogic mmc > driver on new (g12a) and old ones (axg, gxl, gxbb, etc...) > > * The 3 first patches are just harmless clean ups. Applied these first three, postponing the the rest until Martin are happy with all of them. Thanks! Kind regards Uffe > * Patch 4 makes sure HS400 can't be enabled, we still have not been able > to crack this modes. > * Patch 5 removes some clock glitches when switching to DDR modes > * Patch 6 and 7 changes the tuning method from Rx phase to signal > resampling. It could have been done in a single patch but the unified > diff was extremely ugly. The change has been split in two patches to > ease review. > > The last tuning update that went through was meant to improve the axg > support. Since then, it was reported to break some other boards, like the > s912 vim2. > > Also with the current tuning method, it was impossible to find phase > settings which would work on all the SoCs, including the new ones. > > After redoing all the tests from scratch, it appeared that Rx phase made > (strangely) almost no difference, especially on g12a and axg. However, it > showed that it is important to have a phase shift between the Core and Tx > clock, 180 works best. > > I discussed the test results with Amlogic. They suggested to use 180/0 or > 0/180 for the Core and Tx phase. For tuning, they suggested to use > signal resampling. > > So far, so good ... here the platform and modes tested: > > NanoPi-K2 (S905): SD UHS SDR50/DDR50, SDIO HS > Odroid-C2 (S905): SD UHS SDR50/DDR50, eMMC DDR52/HS200 (16GB module) > Khadas Vim (S905X): SD HS, SDIO HS, eMMC HS200 > Libretech CC (S905X): SD HS, eMMC HS200 > Khadas Vim2 (S912): SD HS, SDIO HS, eMMC HS200 > S400 (A113D): SDIO UHS SDR104, eMMC DDR52/HS200 > U200 (S905D2): SD HS, eMMC DDR52/HS200 > SEI510 (S905X2): SD HS, eMMC DDR52/HS200 > > Changes since v1 [0]: > * Add missing writel in patch 5 (error when switching width) > * Change patch 3 commit description > > [0]: https://lkml.kernel.org/r/20190417204355.469-1-jbrunet@xxxxxxxxxxxx > > Jerome Brunet (7): > mmc: meson-gx: remove open coded read with timeout > mmc: meson-gx: ack only raised irq > mmc: meson-gx: correct irq flag > mmc: meson-gx: disable HS400 > mmc: meson-gx: avoid clock glitch when switching to DDR modes > mmc: meson-gx: remove Rx phase tuning > mmc: meson-gx: add signal resampling tuning > > drivers/mmc/host/meson-gx-mmc.c | 419 +++++++++----------------------- > 1 file changed, 114 insertions(+), 305 deletions(-) > > -- > 2.20.1 >
