Re: [U-Boot] [PATCH] mmc: support hs400 enhanced strobe mode

Hi Peng,

On Mon, Apr 15, 2019 at 10:33 PM Peng Fan peng.fan@nxp.com wrote:

eMMC 5.1+ supports HS400 Enhances Strobe mode without the need for tuning procedure. The flow is as following:

• set HS_TIMIMG (Highspeed)
• Host change freq to <= 52Mhz
• set the bus width to Enhanced strobe and DDR8Bit(CMD6), EXT_CSD[183] = 0x86 instead of 0x80
• set HS_TIMING to 0x3 (HS400)
• Host change freq to <= 200Mhz
• Host select HS400 enhanced strobe complete

Signed-off-by: Peng Fan peng.fan@nxp.com

This is actually a resend of https://patchwork.ozlabs.org/patch/1018188/ which got no response. Rebased on master.

drivers/mmc/Kconfig | 12 ++++++++ drivers/mmc/mmc-uclass.c | 15 +++++++++ drivers/mmc/mmc.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++- include/mmc.h | 15 +++++++++ 4 files changed, 120 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig index 04a4e7716f..3ef7580a43 100644 --- a/drivers/mmc/Kconfig +++ b/drivers/mmc/Kconfig @@ -111,6 +111,18 @@ config SPL_MMC_UHS_SUPPORT cards. The IO voltage must be switchable from 3.3v to 1.8v. The bus frequency can go up to 208MHz (SDR104)

+config MMC_HS400_ES_SUPPORT

•   bool "enable HS400 Enhanced Strobe support"
  

•   help
  

•     The HS400 Enhanced Strobe mode is support by some eMMC. The bus frequency is up to
  

•     200MHz. This mode does not tune the IO.
  

Is there any board that can select this option?

Otherwise it will be just dead code.

Thanks