From mboxrd@z Thu Jan 1 00:00:00 1970 From: hkallweit1@gmail.com (Heiner Kallweit) Date: Thu, 16 Feb 2017 18:49:17 +0100 Subject: [PATCH 02/18] mmc: meson-gx: remove code for unsupported CMD23 In-Reply-To: References: <420b75a9-b8c2-b3d7-ae60-3ed8a5a18ead@gmail.com> <642a46aa-416c-32a3-f9ef-3feafca72636@gmail.com> <468688a8-8a25-ae07-8027-00779d7ceb07@gmail.com> Message-ID: <887e63e9-43cf-13eb-4190-4a8ee0b68032@gmail.com> To: linus-amlogic@lists.infradead.org List-Id: linus-amlogic.lists.infradead.org Am 16.02.2017 um 09:14 schrieb Ulf Hansson: > On 16 February 2017 at 08:03, Heiner Kallweit wrote: >> Am 15.02.2017 um 17:54 schrieb Kevin Hilman: >>> Heiner Kallweit writes: >>> >>>> CMD23 isn't supported on meson-gx and therefore the "set block count" >>>> command isn't used. So remove this dead code. >>> >>> I'm admittedly a bit unfamiliar with the MMC spec and wrote this driver >>> mostly by looking at the vendor driver, so forgive the silly >>> questions... >>> >>> Why isn't CMD23 supported, and should we support instead of deleting >>> this support? >>> >> As far as I understand this needs to be supported by the host controller. >> And setting the respective host flag to enable CMD23 mode lead to a >> non-working driver when testing on my system. > > CMD23 can be supported by the host *driver*, you don't need HW-support > to implement this. > Thanks for the explanation. I think I got confused by this comment in core/block.c: "If CMD23 is supported by card and host, [..]" I interpreted this as "host controller needs to support this feature". > You may for example be inspired by the mmci.c driver to understand how > to implement this. Looks for "mrq->sbc". > > [...] > > Kind regards > Uffe >