Messages in this thread | | | Date | Tue, 25 Oct 2022 09:09:06 +0300 | From | Mika Westerberg <> | Subject | Re: [PATCH 0/2] intel-spi: Split hardware and software sequencing |
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Hi,
On Thu, Oct 20, 2022 at 01:45:06PM -0300, Mauro Lima wrote: > Right now the only driver for Intel's spi has a DANGEROUS tag for > a bug in the past on certain Lenovo platforms. It was cleared out > that the bug was caused for the spi software sequencing mechanism > and if we only use the driver with the hardware sequencing > capabilities will be much safer[1]. > > This changes will remove all the software sequencing bits from > the driver and left only the hardware sequencing functionality. > If the software sequencing capabilities are needed, the old driver > can be build using the DANGEROUS option from the menu. > > [1] https://lkml.org/lkml/2021/11/11/468 > > Mauro Lima (2): > spi: intel-spi: Move software sequencing logic outside the core > spi: intel-spi: build the driver with hardware sequencing by default
I'be been thinking about this and I believe we can do something simpler instead.
All the modern "Core" CPUs expose this as PCI device and that only supports hardware sequencer which should be safe so I think we can do something like this:
1. Make spi-intel-pci.c to set the type to INTEL_SPI_CNL for all the controllers it supports (and double check that this is the case for all these controllers).
As a side effect the ispi->sregs will be set to NULL so the core driver does not even try to use the software seguencer.
2. Update Kconfig of SPI_INTEL_PCI to remove "DANGEROUS" and mention in the help text that this only supports the hardware sequencer and only the modern core hardware.
3. Update Kconfig of SPI_INTEL_PLATFORM help text to mention that most of these are using software sequencer, leave "DANGEROUS" there.
Does this make sense? Let me know what you think. I can do this myself as well (might take some while though since busy with other things usual).
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