RE: [PATCH 5/6] soc: aspeed: Add eSPI driver
From: ChiaWei Wang
Date: Wed Jan 06 2021 - 21:37:48 EST
Hi Rob,
> -----Original Message-----
> From: Rob Herring <robh@xxxxxxxxxx>
> Sent: Wednesday, January 6, 2021 11:32 PM
> To: ChiaWei Wang <chiawei_wang@xxxxxxxxxxxxxx>
> Subject: Re: [PATCH 5/6] soc: aspeed: Add eSPI driver
>
> On Wed, Jan 06, 2021 at 01:59:38PM +0800, Chia-Wei, Wang wrote:
> > The Aspeed eSPI controller is slave device to communicate with the
> > master through the Enhanced Serial Peripheral Interface (eSPI).
> > All of the four eSPI channels, namely peripheral, virtual wire,
> > out-of-band, and flash are supported.
> >
> > Signed-off-by: Chia-Wei, Wang <chiawei_wang@xxxxxxxxxxxxxx>
> > ---
> > drivers/soc/aspeed/Kconfig | 49 ++
> > drivers/soc/aspeed/Makefile | 5 +
> > drivers/soc/aspeed/aspeed-espi-ctrl.c | 197 ++++++
> > drivers/soc/aspeed/aspeed-espi-flash.c | 490 ++++++++++++++
> > drivers/soc/aspeed/aspeed-espi-oob.c | 706
> ++++++++++++++++++++
> > drivers/soc/aspeed/aspeed-espi-peripheral.c | 613 +++++++++++++++++
> > drivers/soc/aspeed/aspeed-espi-vw.c | 211 ++++++
> > include/uapi/linux/aspeed-espi.h | 160 +++++
> > 8 files changed, 2431 insertions(+)
> > create mode 100644 drivers/soc/aspeed/aspeed-espi-ctrl.c
> > create mode 100644 drivers/soc/aspeed/aspeed-espi-flash.c
> > create mode 100644 drivers/soc/aspeed/aspeed-espi-oob.c
> > create mode 100644 drivers/soc/aspeed/aspeed-espi-peripheral.c
> > create mode 100644 drivers/soc/aspeed/aspeed-espi-vw.c
>
> drivers/spi/ is the correct location for a SPI controller.
>
> > create mode 100644 include/uapi/linux/aspeed-espi.h
>
> This userspace interface is not going to be accepted upstream.
>
> I'd suggest you look at similar SPI flash capable SPI controller drivers upstream
> and model your driver after them. This looks like it needs major reworking.
>
eSPI resues the timing and electrical specification of SPI but runs completely different protocol.
Only the flash channel is related to SPI and the other 3 channels are for EC/BMC/SIO.
Therefore, an eSPI driver might not fit into the SPI model.
Chiawei