Hi all, this series implements UHS-I signaling for the Tegra SDHCI host, which mainly means putting a proper tuning sequence in place.
I've tested this on Jetson TK1 and got the following speed results, where mmcblk0 is the on-board eMMC and mmcblk1 is a micro SDXC card: Without series applied: hdparm -t /dev/mmcblk0 Timing buffered disk reads: 110 MB in 3.05 seconds = 36.02 MB/sec hdparm -t /dev/mmcblk1 Timing buffered disk reads: 56 MB in 3.01 seconds = 18.63 MB/sec With series applied: hdparm -t /dev/mmcblk0 Timing buffered disk reads: 236 MB in 3.00 seconds = 78.58 MB/sec hdparm -t /dev/mmcblk1 Timing buffered disk reads: 102 MB in 3.04 seconds = 33.51 MB/sec Tegra 30 does support UHS-I speeds too, but currently has problems when lowering the card voltage, which is needed in order to switch to UHS-I signaling. I have some more patches to fix this, but they need a bit more cleanup, with them applied the gains on Tegra30 are similar to the results above. For now the gains are limited to Tegra124+, with no regressions on Tegra30 and Tegra20. V2 fixes some minor style problems and is rebased on top of mmc/next. This means it enables the same tuning logic on Tegra210 also. I don't have a way to test this myself, so any testing on Tegra210 much appreciated. Regards, Lucas Lucas Stach (5): mmc: tegra: implement module external clock change mmc: tegra: disable SPI_MODE_CLKEN mmc: tegra: implement UHS tuning mmc: tegra: enable UHS-I modes mmc: tegra: use correct accessor for misc ctrl register drivers/mmc/host/sdhci-tegra.c | 166 ++++++++++++++++++++++++++++++++++------- 1 file changed, 138 insertions(+), 28 deletions(-) -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
