Hi Shawn,

On 03/07/2016 06:35 PM, Shawn Lin wrote:

Hi Jaehoon,

On 2016/3/7 8:53, Jaehoon Chung wrote:

quoted

Hi Goudong,

On 03/06/2016 05:47 PM, Guodong Xu wrote:

quoted

Add resets property to synopsys-dw-mshc bindings. It is intended to
represent the hardware reset signal present internally in some host
controller IC designs.

See Documentation/devicetree/bindings/reset/reset.txt for details.

Signed-off-by: Guodong Xu <redacted>
Acked-by: Rob Herring <robh@kernel.org>
---
  Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt | 4 ++++
  1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt
index 8636f5a..4e00e85 100644
--- a/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt
+++ b/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt

@@ -39,6 +39,10 @@ Required Properties:

  Optional properties:

+* resets: phandle + reset specifier pair, intended to represent hardware
+  reset signal present internally in some host controller IC designs.
+  See Documentation/devicetree/bindings/reset/reset.txt for details.

Is this reset property for common dwmmc IP controller?

I think so. By discussion with my ASIC team, it's provided by synopsys.
From dw_mmc databook version 270a, section 3.2.5, FBE Scenarios:

An FBE occurs due to an AHB error response on the AHB bus. This is a
system error, so the software driver should not perform any further
programming to the DWC_mobile_storage. The only recovery mechanism
from such scenarios is to do one of the following:
■ Issue a hard reset by asserting the reset_n signal
■ Do a program controller reset by writing to the CTRL[0] register

the reset_n signal can be used to reset all the internal logic block
with dwmmc and reset the register value to default stat.

Note: reset_n is a internal signal, which is diff from rst_n for mmc hw
reset. (refer to databook section 5.2 Signal Descriptions, table 5-1)

Thanks for this information. :)

quoted

Best Regards,
Jaehoon Chung

quoted

+
  * clocks: from common clock binding: handle to biu and ciu clocks for the
    bus interface unit clock and the card interface unit clock.