On 1 March 2018 at 10:57, Ludovic BARRE <ludovic.barre@xxxxxx> wrote:
Hi Ulf
On 03/01/2018 10:06 AM, Ulf Hansson wrote:
Hi Ludovic,
On 28 February 2018 at 16:47, Ludovic Barre <ludovic.Barre@xxxxxx> wrote:
From: Ludovic Barre <ludovic.barre@xxxxxx>
This patch serie adds support of stm32 SDMMC controller.
stm32h7 is the first SoC to use stm32 SDMMC controller
(previous SoC had pl180 controller).
I am a not convinced this isn't a new improved variant of the pl180.
According to register layout and the code you submitted in patch2,
there are great similarities to pl180 and the mmci driver.
In fact, ST designers which created stm32-sdmmc hardware block from scratch
are the same which have done the modifications on pl180 variant (stm32
legacy f4, f7).
So some registers or bits name seem identical (or strongly inspirited) but
the engine and features are different.
Well, in that case, I assume the driver would also need work
differently, but when looking at the code in patch2 this doesn't seem
to be the case.
You could find the datasheet of STM32H7x3 on:
http://www.st.com/content/ccc/resource/technical/document/reference_manual/group0/c9/a3/76/fa/55/46/45/fa/DM00314099/files/DM00314099.pdf/jcr:content/translations/en.DM00314099.pdf
Chapters: 55 Secure digital input/output MultiMediaCard interface
(SDMMC)
Thanks for sharing this. However this confirms my view, it looks
exactly as a new improved mmci variant. :-)
This hardware block has own roadmap and some features are already in the
pipe for next SoC.
That's fine. I don't have a problem extending the mmci driver, even
several times, as to cope with new revisions.
For code design: like I also worked on pl180 in the past :-)
my code is inspirited of this driver.
Right, that may explain things a bit.
However, besides a re-name of the registers, I really think that the
code execution, dealing with IRQs etc, is very similar to the mmci
driver. Isn't it?
So, I think it's at least worth to give it a go with the mmci driver
first, to see if we can get it to work.
I guess you understand why I am pushing!? This is about maintenance -
and I really want to avoid having a yet another driver to maintain,
unless we can extend an existing one.
[...]
Kind regards
Uffe