[U-Boot] [PATCH v6 00/15] Add Support for eMMC in Am65x-evm

[Andreas Dannenberg]

On Tue, Jun 04, 2019 at 09:32:21PM +0530, Lokesh Vutla wrote:
> 
> 
> On 04/06/19 6:46 PM, Faiz Abbas wrote:
> > Add Support for eMMC in TI's AM65x-evm. The series starts
> > by syncing the sdhci0 node from the kernel. Then it adds APIs and
> > changes to the driver required for handling the driver's integrated
> > phy. The current maximum supported speed is DDR52. Higher speeds and
> > tuning support will be added in a subsequent series.
> > 
> > Changes in v6:
> > 1. Squashed one more dependency for clk_200mhz from Andreas's patches[1]
> >    into patch 1. Patches now build without any help from the other series.
> > 
> > 2. Improved line wrapping in patch 8.
> 
> Thanks for the quick update. For the entire series:
> 
> Tested-by: Lokesh Vutla <lokeshvutla at ti.com>

Seems like the test coverage was limited.

While eMMC (sdhci0) works when booting from SD card (sdhci1) the eMMC
probe fails when booting from eMMC itself defeating the main purpose of
a series adding eMMC support.

"sdhci at 4f80000 - probe failed: -22"

I did some debugging and tracked this down to a missing drive strength
setting on the R5 DTS file:


$ git diff
diff --git a/arch/arm/dts/k3-am654-r5-base-board.dts b/arch/arm/dts/k3-am654-r5-base-board.dts
index 2f178c8b07..b10df50ef9 100644
--- a/arch/arm/dts/k3-am654-r5-base-board.dts
+++ b/arch/arm/dts/k3-am654-r5-base-board.dts
@@ -186,6 +186,7 @@
        clock-names = "clk_xin";
        clocks = <&clk_200mhz>;
        /delete-property/ power-domains;
+       ti,driver-strength-ohm = <50>;
 };
 
 &sdhci1 {


Can we please have this added.


With this change added and SYSFW loader series applied I can boot all
the way to U-Boot prompt on AM654x EVM from eMMC.

Also SYSFW loader series no longer applies on top of this; will re-post
a rebased/refactored version to be used on top of this series.


--
Andreas Dannenberg
Texas Instruments Inc