From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: Execute spi transfers inside FIQ (NMI) or panic Date: Tue, 25 Feb 2020 15:53:54 +0000 Message-ID: <20200225155354.GF4633@sirena.org.uk> References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="z+pzSjdB7cqptWpS" Cc: linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Herbrechtsmeier Dr.-Ing. , Stefan" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: --z+pzSjdB7cqptWpS Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Feb 25, 2020 at 02:27:27PM +0100, Herbrechtsmeier Dr.-Ing. , Stefan wrote: > would it be acceptable to add an additional function to the struct > spi_controller which handle a transfer inside a NMI context or a panic? The > new function will transfer data via register polling without any lock. That would need to happen as part of a wider change that made it possible to use such an interface safely and did so, off the top of my head it's not immediately obvious how one would do that. You'd need to get the hardware into a sensible state and then do whatever needs doing with some cooperation from the client driver in all this which is a bit of an ask. It's not a trivial bit of work, but I do see the use case and it's absolutely valid. --z+pzSjdB7cqptWpS Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl5VQxEACgkQJNaLcl1U h9BInAf/QelYi6vedS0fjXl7PL92uXstsOeFOuEGEl/vYzP803jTtV9R0y9+kmoX eeKw19ZFzYETL46DA/qGVExWzl4QX2Gx/fE47+v6Fg0G+Cp9hvWztHmXzP+hGAWF fPYSkkHON5jwV7vk0kw0WsPJs5dhtghRVWtHv2IY2VoA6582rPJzJ/y1ZLcMrFDv JDQJ1hF/vDDZ5SLp5/9VLhVOypzC67KeVYqA/FLlM842afPApvG6K++dPHEosRzg L+BzEPP7xSBh3zTNbJghvwSwiHFYFvNTadJ85pFcBLi+nsPebkpmPhzuH3UBkOfp H4TNpg+SjABi7ZtHh2MBiBnO2kGj0w== =Er1+ -----END PGP SIGNATURE----- --z+pzSjdB7cqptWpS--